university of newcastle upon tyne

OF NEWCASTLE UPON TYNE

UNIVERSITY DEPARTMENT

ENGINEERING

OF CIVIL

I

SEDIMENT

TRANSPORT IN

SEWERS

by AMINUDDIN

GHANI

AB.

LIBRARY

NEWCASTLE UNIVERSITY ---------------------------093 51137 3 ---------------------------ýhe5 is LS tS2.

Thesis

submitted

Degree

of

in

Doctor

fulfilment of

of

Philosophy November

the in

1993

requirements Civil

for

Engineering.

the

ABSTRACT

Sewers have been designed of self-cleansing on the concept where deposition. to move continuously sediments are expected without deposition Due to the intermittent nature of the flow, of solids in sewers flows low especially at could occur still such as during flow. flow the receding or dry weather in sewers The study therefore movement will of sediment need to (no-deposition) both loose (some deposition) cover and rigid boundary The present the available conditions. study extended (clean data in rigid boundary to include the conditions pipes) A complimentary of roughness and pipe effects surface size. deposits (pipes deposited study on the effect of sediment with beds) was also carried out. load Extensive transport experiments on bed of non-cohesive deposition in pipe sediments without were carried out channels 154mm, 305mm and 450mm dia. of flow covering wide of -ranges (0.15 depths (0.46 < ya/D < 0.80), sediments < dso (mm) < 8.3) and different bed roughness (0.0 three values < ko (mm) < 1.34). data Supplementary loose beds were on transport over collected in a 450mm dia. bed thicknesses channel with various up to 23% diameter. of pipe New

transport based equations involved in on all variables the derived. Extensive were process from uses of data other relevant The combination were studies made. data of the present and other for both loose boundary rigid in pipes and conditions produced be applicable equations which could over wide range of conditions in sewers. A complimentary bed study on the rigid rectangular channels was also carried out.

Using derived the newly equations, appraisals concept of constant velocity criterion were inadequacy show the the design of present diameters, larger 300mm. than

of the made. practice

traditional The results for pipe

The comparisons derived the made between newly for equations boundaries rigid in pipes and loose that suggest be sewers can designed inverts for diameters with clean up to 1.0m while sewers larger diameters with be designed should for allowing an "optimum" depth deposits. Design of sediment based on the charts derived newly equations were devised.

i

ACKNOWLEDGEMENTS

I

like

also

thank

to Also,

criticism.

Many thanks for

for

the

I wish P. M

Brown

thanks

of to

to

Mr.

R.

help

Payne

to

Special

acknowledgements fellowship the

Newcastle

I

to

at

during

the

course

for also

,

study to

Mr.

their

Willoughby

its

using

R. W. P May, advice

to

wish

and

express

who

University

made

my parents,

and moral this

this

Wal 1 ingford

many

were

always

Malaysia

Sains for

possible

me to

come

for to

research.

Salbiah, of

R.

due to

that

to

my wife,

I.

are

encouragement

acknowledge

Mr.

I

P. Dawber

laboratory.

the

this

conduct

am deep lyA gratitude

providing

and

HRL.

(HRL)

thanks

Escarameia

at

and Mr.

of

my grateful

University

Newcastle.

Ltd.

part

Roorkee

of

Newcastle.

at

Research

M.

Raju

Jefferson

A.

undertaking

my stay

me

J.

made

were

Chalmers to

visits

constructive

study

Ranga of

laboratory

the

Mrs.

willing

providing

Mr.

extend

and

during

supervision

their

Hydraulics

to

opportunity

facility. Mrs.

in

indebted

I am also

K. G.

his

this

to

Perrusquia

during

assistance

for

Novak

Professor G.

time

period.

contributions

due to

also

are

their

P.

Dr.

and

Sweden

Technology,

Professor

with

India

University,

study

valuable

discussions

through

the

of

his

of

provision

generous

and

duration

the

throughout

of

supervisor

my

encouragement,

guidance,

I

to

grateful

very

am

his

for

Nalluri

C.

Dr.

for study.

11

brothers

support. her

patience

and

Finally, and

sisters I sincerely understanding

for

TABLE OF CONTENTS Page ABSTRACT ii

ACKNOWLEDGEMENT TABLE

iii

OF CONTENTS

vii

LIST

OF FIGURES

LIST

OF TABLES

LIST

OF PLATES

LIST

OF MAIN SYMBOLS

1.

INTRODUCTION

1

1.1

Background

1

1.2

Scope

1.3

Outline

2.

3.

xv xviii

xix

Present

of

of

The

NATU RE OF SEDIMENTS

2.1

Background

2.2

Characteristics

Thesis

3

IN

6

SEWERS

6

Earlier

2.2.2

Recent

2.3

Classification

2.4

Modes

2.5

Hydraulic

2.6

Current

8

3.2

Incipient

Sediments Transport

Roughness

Design

Background

7

Studies

Sewer

3.1

Sediments

7

of

OF RELEVANT

of

studies

Sediment

of

Quantity

and

2.2.1

REVIEW

3

Study

Criteria

and

Sewers

14 15 16 18

LITERATURE

22

22 Motion

23

iii

3.3

Sediment 3.3.1

Transport Studies

3.3.2

Transport in Pipes Transport

3.3.3 3.4

4.

Transport

Introduction

4.2

Experimental

Deposited

in

Test

Work

Bed

Studies

Channels

Non-Circular

4.2.2 4.2.3

Flow

Characteristics Supply and

Work

at

Discharge

450mm Pipe Techniques

Sediment Sediment

Characteristics Supply and

Transport Transport

Deposition without Loose Beds over

Resistance

Clean

Pipes

5.1.2

Pipes

with

Discharge

Uniform Flow Experimental

ANALYSES

5.1.1

(HRL)

HR Wallingford

Establishment of Sediment Transport 4.3.5.1 4.3.5.2

PRELIMINARY

Sediment Sediment

Test Pipe Measurement The Sediments

4.3.3.1 4.3.3.2 4.3.4 4.3.5

Pipe Pipe

Artificial Roughening of the 305mm Pipe Establishment Flow of Uniform Sediment Transport Experimental Procedure

Experimental 4.3.1 4.3.2 4.3.3

154mm 305mm

Techniques Measurement The Sediments 4.2.3.1 4.2.3.2

4.2.4 4.2.5 4.2.6

(UNUT)

Newcastle

at

Pipes

4.2.1.1 4.2.1.2

5.1

over

Deposition

of

APPARATUS AND PROCEDURE

4.1

4.2.1

5.

Limit

Summary

EXPERIMENTAL

4.3

the at in Pipes

Deposited iv

Beds

Procedure

5.2

5.3

Sediment 5.3.1 5.3.2 5.3.3 5.3.4 5.3.5 5.3.6 5.3.7

6.

ANALYSES 6.1

Experimental Roughness

Clear-Water Pipe Wall

Clean 6.1.1 6.1.2 6.1.3

OF

Experimental

Transport Effect Effect Effect Effect Effect Effect Friction

of of of of of of

Results

Background Appraisal Bed Load

of Existing for Models Introduction

6.1.3.2 6.1.3.3

Proposed Sediment Transport Equations Application (1991) Equation of Ackers to Clean Pipes Application (1991) of El-Zaemey Equations to Clean Pipe Bed and Rigid Rectangular Channels

with

6.2.1

Background

6.2.2 6.2.3

Appraisal Bed Load

6.3.2.1 6.3.2.2 6.3.3

Proposed

Design

of

Clean Pipes

Equations Pipes with

Sediment

Deposited

Transport

Beds

Equations

Design

Sewer

General Assessment

Channels

Beds

of Existing for Models

for

Implication 6.3.1 6.3.2

Introduction Clean Pipes Rigid Bed Rectangular

Deposited

6.2.3.1

6.3

Equations Clean Pipes

6.1.3.1

6.1.3.4.1 6.1.3.4.2 6.1.3.4.3

Pipes

DATA

Pipes

6.1.3.4

6.2

Results

Sediment Concentration Flow Depth Sediment Size Roughness Wall Pipe Size Deposit Sediment Sediment Factor with

TRANSPORT

SEDIMENT

-

the

Constant

Pipes Deposited with

Charts

264

Velocity

Loose

Criterion

Beds

264 264 264 268 271

V

7.

CONCLUSIONS AND RECOMMENDATIONS

275

7.1

275

Conclusions 7.1.1 7.1.2 7.1.3

7.2

(Rigid Clean Pipes Pipes Deposited with Design Implications

Recommendations

for

Further

Boundary) Beds (Loose

Research

REFERENCES BIBLIOGRAPHY APPENDICES A. B. C.

Clear Water Data Experimental Transport Sediment Experimental Data Cross-Sectional Geometry of Pipes

Vi

Boundary)

275 278 280

281

LIST

OF FIGURES Page

Figures

2.1

2.2

2.3

2.4

Detailed (After

view of gradual 1992) Verbanck

Effect (After

operation of cleaning 1992) Verbanck

(After 2.5

2.6

trend

Long-term

invert 1992)

on the sediment (After Verbanck

Build-up of trunk sewer

Laplace

Longitudinal

of

profile

(After

Laplace

Typical (After

particle Ashley et

on

deposited 12

13

present

to

Nalluri

present

design

practice

due

to

Ackers

3.2

Incipient Eqn. 3.4

motion (After

Durand's pipe-full

(1953) flow

Bed-load pipe-full

function transport (After flow Craven

3.7

3.8

3.9

3.10

3.11

d iagram

(After

Graf

Functional relationship boundary rigid channels Excess alluvial

functional

channels

(After

28

31 with

beds:

deposited

31

flow

part-full

clean

pipes

at

of 1982)

deposition

for

in

clean

part-full

for suspended (After Arora

for

relationship

Paul-Sakhuja

vii

1990)

circular 1975

36

part-full 38

load et al

rigid

in

transport 1984)

for total-load transport mobility model (After Ackers 1973) channels - White

Bed-load

for

deposition

bed-load in transport (After Novak - Nalluri

limit at Macke

model (After

of

channels

34

for Shear criterion stress flowing channels part-full load pipes

21

34 for

function 1956)

limit

for pipes 1953)

for

21

25

boundary rigid 1975)

criterion a t the (After 1984) Graf

Bed-load transport (After flow Laursen

(1984)

1984)

for criterion Novak - Nal luri

function Bed-load transport (After 1953) Ambrose pipes

Suspended flows in

(1985)

due

Shields

3.6

13 practice

3.1.

3.5

inverts

sewer

design

Appraisal

3.4

in

found sizes al 1992)

2.8

3.3

depth

sediment

Appraisal

of

deposition

sediment

12

2.7

of

10

1992)

al

et

10

1992)

al

et

main

build-up

sediment

volume

of

Brussels

of

in

43 wide 45

boundary 55

3.12

Loveless'

3.13

Effect (After

3.14

3.15

3.16

(1991)

deposits of sediment 1953) Ambrose 3.60

Verification of EQn. (After Nalluri-Kithsiri

Plots

non-circular Test

4.2

Sediment

4.3

Test (After

for

of (p -$

4.1

on

arrangement

capacity

(1990)

data 64

for

other 1992)

load

rectangular

in

154mm -

D=

circular 1968)

Graf-Acaroglu

Newcastle:

channel 64

transport

(After

at

transporting

Kithsiri's

with 1992)

total

channels

flow

56

3.60 of Eqn. Nalluri-Kithsiri

Verification (After data

52

channels

experimental

and

71

305mm

77

sizes Research

Hydraulics

at

arrangement May

66

Ltd:

450mm

D=

85

1993)

4.4

Sediment

sensor

4.5

Sediment

discharge

5.1a

Cross-sectional

geometry

for

clean

pipe

5.1b

Cross-sectional

geometry

for

pipes

with

5.2a

Clear-water

friction

factor

in

a smooth

154mm dia.

pipe

104

5.2b

Clear-water

friction

factor

in

a smooth

305mm dia.

pipe

104

5.2c

Clear-water

friction

factor

in

a smooth

450mm dia.

pipe

105

5.3a

Clear-water (Roughness

friction 1)

factor

in

a rough

Clear-water (Roughness

friction 2)

factor

5.3b

5.4

(After

May

calibration

Validity of the (D = 4R) data

89

1993)

91

curve

99 deposited

beds

305mm dia.

99

pipe 105

in

305mm dia.

a rough

pipe 106

Colebrook-White's

Eqn.

5.6

for

present 106

5.5a

Effect

of

flow

depth

5.5b

Effect

of

flow

depth

5.5c

Effect

of

flow

depth

5.5d

Effect

of

flow

depth

5.6a

Effect

of

particle

size:

flow

depths

up

5.6b

Effect

of

particle

size:

flow

depths

more

-

dso = 0.46mm

111

-

d50 = 1.0mm

111

-

d50 = 2.0mm

112

-

dso = 5.7mm

112

viii

to

half-full

than

half-full

113

113

5.7a

5.7b

5.8a

5.8b

roughness of wall half-full) depths to up

Effect (Flow

dso 1.0mm roughness = of wall half-full) depths more than

Effect (Flow

roughness of wall depths up to half-full)

Effect

(Flow 5.9a 5.9b

5.10a

5.10b

roughness

depths

Effect

-

d50 = 2.0mm

117

depths

Effect (Flow

d50 4.2mm = of wall roughness depths more than half-full)

Effect (Flow

of wall roughness depths up to half-full)

Effect (Flow

d50 5.7mm = of wall roughness half-full) depths more than

5.12a

Definitions

of

pipe

half-full)

of

mean

Definitions features

of mean (Continuous

sediment dunes)

5.14

Increase (Smooth

deposits

in friction pipes)

factor

in

(Rough

119

bed

bedform

and

thickness

bedform

and

122 122 at

limit

of-deposition 124

friction

factor

limit

at

of

deposition

124

pipes)

Friction

5.17

Effect'of Froude number deposited beds with

on

5.18

Effect

Froude

number

on

the

5.19

Effect of Froude bed sediment

number

on

flow

factor

of

6.1a

Predicted

6.1b

Discrepancy dimensionless

Predicted

thickness

bed

5.16

6.2a

119

121

sediment

Increase

d50 = 5.7mm

sediment

dunes)

of

118

121

(Separated

Effect

118

size

features

5.13

117

d50 = 2.0mm

(Flow

to

116

dso 4.2mm = -

roughness up

116

half-full)

more than

of wall

Effect

5.15

wall

of

5.11

5.12b

d50 = 1.0mm

Effect (Flow

C,

at

using

and

limit

the

of

flow

overall

deposition

126 in

resistance

pipe 126

bed

friction

factor due

resistance

128

to 128

Laursen's

for ratio particle

Cv using

beyond

Eqn.

Laursen's size

Novak-Nalluri's ix

3.11

Eqn.

134 3.11

as

a function

of 134

Eqn.

3.15

136

6.2b

Discrepancy function of

6.3a

Predicted

6.3b


for ratio particle

Predicted

6.4b

Discrepancy dimensionless, Predicted

6.5b


6.6a

Predicted

6.6b

Discrepancy

Mayerle's

C,, using

6.4a

6.5a

for Novak-Nalluri's ratio dimensionless particle

for ratio particle C. using

for ratio particle

for

ratio

Eqn.

Macke's

Eqn.

velocity

criterion

-

Eqn.

6.9

Friction

factor

with

sediment

(Combined

data)

6.10

Transport

capacity

criterion

6.11

Transport

capacity

criterion

6.12

Excess velocity criterion (Combined Eqn. 3.35 data)

3.17

as

function

a

of

(All

(Combined

6.13

model

-

data)

present

data)

150 156

6.16

Eqn.

158

of critical data present

6.15

Excess velocity criterion (Combined Eqn. 6.28 data)

-

Excess velocity criterion (Combined 6.29 Eqn. data)

-

particle

ratio flow

160

-

Eqn.

6.22

(Combined

data)

163

6.26b

with

Novak-Nalluri'

s 167

incipient

criteria

for

data)

for

Incipient

ratio

(Combined

incipient

6.14

motion

6.19

for velocity - Eqn. 6.28

critical data

-

-

Eqn.

Eqn.

-

Interpolation of from the combined

Discrepancy proportional

of 142

6.2

Limiting

6.17b

a function

as

142

6.8

dimensionless

of

size

particle

-

Discrepancy

a function

as

3.17

Eqn

6.17a

3.35

141

criterion

6.16

137 139

3.19

velocity

6.13b

of

141

Limiting

Interpolation from entire

a function -

3.19

6.7

6.13a

as

139

Eqn.

Macke's

C,, using

dimensionless

May's size

3.34

Eqn.

Eqn.

May's

137

3.35

Eqn.

Mayerle's size

136

3.34 Eqn.

Mayerle's

C. using

as a

size

Eqn.

Mayerle's size

3.15

Eqn.

velocity Eqn. 6.29 for

169 motion 169

clean

Eqn.

motion

170

pipes

6.31b

with

author's 174

Eqn.

6.33b

with

author's 175

Eqn.

6.13

as

a function

size

for Eqn. depth

of179

6.13

as a function

of 179

X

6.17c

Discrepancy ratio volumetric observed

for

6.17d

Discrepancy ratio velocity observed

for

6.18

Predicted 305mm dia.

6.19

6.20

6.21

6.22

6.23

6.24 6.25

6.26

6.27

6.28

6.29

6.30a

6.30b

Eqn. 6.13 as a function concentration sediment

of

a function

of

6.13

Eqn.

as

for

3.29 Eqn. Ackers' C,, using (W, data = 10dso) pipe

180

180 smooth

author's

184

Ratio of computed particle

measured by Ackers' for size

to critical total mobility Eqn. 3.30 as a function 305mm dia. smooth author's

mobility of dimensionless data pipe

185

Ratio of computed particle

measured by Ackers' for size

to critical total mobility Eqn. 3.30 as a function 305mm dia. smooth author's

mobility of dimensionless data pipe

185

Comparison boundaries

of

incipient

motion

criteria

for

loose

and

187

total Ratio of measured by Novak-Nalluri's computed dimensionless particle dia. pipe data

to critical mobility mobility Eqn. 3.5 as a function of for 305mm size author's smooth

total Ratio of measured by Novak-Nalluri's computed dimensionless particle dia. pipe data

to critical mobility mobility Eqn. 3.5 as a function of for 305mm size author's smooth

Verification data with 'Verification data with

188

188

Ackers'

of modified W. = 1050

Ackers' of modified W. = 1050 or 0.12D

Verification (1988) data

of

modified

Ackers'


of

modified

Ackers'


of

Limiting equation

equation

for

equation

for

equation

for

equation

for

all

present

all

present

191 193

Mayerle 194

May et

al 195

Ackers'

modified

for

equation

Loveless 195

velocity (Combined

due

criterion data)

to

modified

Ackers' 197

of

for ratio dimensionless

Ackers' modified particle size


for ratio proportional

modified flow

Discrepancy function

rigid

xi

Ackers' depth

equation-as

a 201

equation

as a

201

6.30c

6.30d

6.31

6.32

6.33a

6.33b

6.33c

6.33d 6.34 6.35 6.36

6.37

6.38

6.39

6.40

6.41

6.42

ratio

function

limiting

of

Validity of (b = 0.5D)

Eqn.

Validity Loveless'

a

as

equation

202

concentration

for modified ratio limiting velocity 6.37

for

Ackers'

Mayerle's

for of Eqn. 6.37 data clean pipe

clean

202

data

pipe

May et present, (b = 0.5D)

a

as

equation

208 and

al

208

Discrepancy (Eqn. 6.38)

b=0.5D for E1-Zaemey's Eqn. 6.37 with ratio size particle of dimensionless as a function


for Eqn. El-Zaemey's ratio of proportional as a function


b=0.5D for E1-Zaemey's Eqn. 6.37 with ratio size of dimensionless particle as a function


for Eqn. E1-Zaemey's ratio of proportional as a function

Validity (b data

3.57

of Eqn. = 0.5D)

for

Modification Mayerle's

of rough

E1-Zaemey's bed rigid


of smooth

E1-Zaemey's bed rigid


of rough

El-Zaemey's bed rigid Eqn. =

Validity channels'

for of Eqn. 6.37 (D = 1.35b) data

Validity

of

Eqn.

Discrepancy or

Eqn.

6.37

Eqn. (D

ratio

6.40 6.40

6.37 Eqn. rectanular 6.37 Eqn. rectanular

= for

ratio

for

for application (D channels

=

for application (D = channels

Mayerle's

to 1.5b)

219

to 1.5b)

219

rectangular

smooth

221

Mayerle's

rough

rectangular 221

rectangular

smooth

other

223

for

rough

other

rectangular

1.35b)

223

of

dimensionless

E1-Zaemey's

a function

of xii

6.37

Eqn.

El-Zaemey's

as a function as

al's

218

for

Discrepancy

May et

and

212

for to Eqn. 6.37 application (D = 2.0b) channels rectanular

Application of Eqn. 6.37 (D = 1.35b) data channel

(D

data

b=0.5D with depth flow

212

218

for

data

211

for to application (D = 2.0b) channels

Eqn. 6.37 rectanular

6.37 1.35b)

of

6.37

b=0.5D with depth flow

211

214

of E1-Zaemey's bed smooth rigid

Application channel

6.37

Mayerle

present,


or 6.43b

Ackers'

modified


channels' 6.43a

for

Discrepancy

Eqn.

aspect

6.37

ratio

with

D=1.35b

particle with

size

227

D=1.35b 227

6.43c

6.43d

6.44

Discrepancy 6.40 or Eqn.

ratio as

a

Eqn. for E1-Zaemey's limiting function of

6.37 with D=1.35b concentration

228

a

for Eqn. E1-Zaemey's limiting function of

6.37 with velocity

228

Discrepancy 6.40 or Eqn.

ratio as

Validity. rectangular

for 3.57 Eqn. data channel

of

Predicted

6.45b

Discrepancy

function

for

ratio

of

230

6.46b

for Ackers's Discrepancy ratio depth sediment of proportional

6.47a

6.47b

for Discrepancy ratio from effective computed sediment proportional Predicted

6.48b


6.49a

for ratio sediment

C,. using

Predicted

6.50b

a function

as

237 3.29

with

Cv

observed

239 C,, of

with observed as a function

239 240

3.46

Eqn.

May's depth

Eqn.

3.46

as

function

a

of 240

Discrepancy

for

ratio

3.55

Eqn.

bed

with

242

as

C. using factor

Predicted friction

a function

Perrusquia's

3.55

Eqn.

with

242 overall

243

plot

for

all

present

6.52

4-$

plot

for

the

combined

6.53

Bed-load (Combined

for

pipes

ratio

proportional

243

.-$

Discrepancy concentration

of

utilising

for 3.55, Perrusquia's Eqn. utilising factor as a function of proportional

Discrepancy ratio friction overall depth sediment

model data)

3.55,

Eqn.

Perrusquia's

6.51

6.54a

3.29

Eqn.

Perrusquia's

factor, bed friction depth sediment 6.50a

237

factor

friction 6.49b

May's

C,, using

6.48a

235

Eqn. 3.29 discharge,

Ackers' flow bed

a

3.29

Eqn. C,, using Ackers' discharge from effective

Predicted computed

as

depth

Eqn.

Ackers's

Predicted

3.64

Eqn.

sediment

6.46a

235

3.64

Eqn.

Graf-Acaroglu's

proportional

C. using

Kithsiri's

and

Graf-Acaroglu's

C. using

6.45a

Mayerle

D=1.35b

data

246

data

with

246

deposited

beds

-

Eqn.

6.44 249

for

Eqn.

6.44

as

a function

of

sediment 252

xiii

6.54b

6.54c


for ratio sediment

Discrepancy

ratio

bed

sediment

for

to

width


for ratio particle

6.54e

Discrepancy

ratio

6.55

Bed-load models (Combined data)

6.54d

6.56a

6.56b

6.56c

Eqn. 6.44 depth

for

Eqn.

6.44

flow

depth

for

ratio


for ratio sediment for to

Discrepancy ratio bed width sediment

Eqn. 6.46 depth

6.56e

Discrepancy

ratio

6.57

friction factor Composite data) beds (combined

6.59 6.60

6.62b

6.62c

6.63

6.64

function

a

as

of

beds

a function

velocity

- Eqn. of

254

6.56 256

sediment

for

as

a function

of 259

Eqn. 6.46 size

as

Eqn.

as a function

6.46 model

a function

of 260 of 260

for

pipes

of with

velocity

261

deposited 263

ko = O. Omm)

267

Q-S-D plot - dso = 1.0mm (CV = 50ppm, yo/D = 0.5,

ko = 0.6mm)

267

y1/D

= 0.01)

270

= 0.5,

yg/D

= 0.1)

270

Optimum sediment (Cv = 50ppm, Y/D

depth: = 0.25)

d30 = 1.0mm

Optimum sediment (C = S0ppm, Y/D

depth: = 0.50)

dso = 1. Omm

Optimum sediment (Cv = 50ppm, Y/D

depth: = 0.75)

dso = 1.0mm

Q-S-D

plot

= Soppm,

Q-S-D (C

6.62a

253

dso Q-S-D plot 1.0mm = (CV = 50ppm, y, /D = 0.5,

(C 6.61

of

6.46 as a function depth ratio

Eqn. flow

for ratio particle

6.58

as a function

259


6.56d

of

253

deposited

6.46

Eqn.

function

a

ratio

as

with

pipes

Discrepancy concentration

as

6.44

Eqn.

of 252

Eqn. 6.44 size

for

function

as 'a

plot

= S0ppm,

-

Y/D -

Design charts (Cv = S0ppm,

Design

charts

(Cv = 50ppm,

d30 =

1.0mm

= 0.5,

d50 = 1.0mm Y/D

272

272

273

for clean pipes dso = 1.0mm, ko = 0.6mm)

for

pipes

d30 = 1. Omm)

with

Xlv

deposited

274

beds 274

OF TABLES

LIST

Page

Table

2.1

Sediment

characteristics

Pipe-full

2.3

Additional'roughness. (after Henderson

2.5 3.1

for

k-values

2.2

2.4

in

Constant

due

Shields'

sewers

(after

joint

to

criteria criteria

curve

(after

Van Rijn

3.2

3.3

Values

3.4

Suggested in circular

for values channels'

3.5

Values

transport

coefficient

Experimental

4.1

Sediment

4.2

Average'values

works

= 305mm)

clear-water

ranges

for

transport

5.3

Flow

resistance

beds .

(D = 450mm,

pipe 6.5

108

data deposited

with

pipes

-

for

parameters

82 102

127 in

transport

sediment

clean 130

ranges ratio

-

All (Fr.

different

-

All 133

present )

equations

for

Eqn.

data 6.2

(Clean

pipes)

All

present

-

data

Transport relationships

pipe

dso = 0.72mm)

(C) for Discrepancy ratio (Clean data pipes) present

Discrepancy

roughened data

characteristics:

Characteristic channels pipe

6.4

58

bed

68

an artificially

ranges

Experimental

Parameter

a loose

for

3.46)

channels

for

5.2

6.3

Eqn.

76

ko for

of

Experimental

6.2

circular

3.41

Eqn.

54

(May's

over

47

characteristics

5.1

6.1

in

for

3.29

Loveless'

of

q

pipes

3.20)

41 Eqn.

application

in

24 S"_(Egn.

Ackers'

parameter,

transport

3.6

(D

for

19

1984)

transport Values parameter, of May's in transport pipes clean sediment

sediment

17

1987)

CIRIA

17

19

stress

of

1984)

Henderson

eccentricity

(see

shear

of

9

1987)

CIRIA

1984)

velocity

Constant

pipe

sewers

(see

147 clean

150 equations for

based on modified data present entire

xv

functional 152

6.6

Ranges

6.7

Discrepancy

(Clean 6.8

6.9

6.11

6.12

6.13

6.14

6.15

6.17

6.18

ratio

ratio

(Cv)

Discrepancy ratio (Clean pipes)

(Cv)

6.19

Eqn.

for

-

Combined

-

Combined

-

Combined

data 158 data 160

163 3.5

Eqn.

166 for

(Cv)

6.26b

Eqn.

using

Excess motion's

velocity Eqn.

equations 6.29

using

data

Combined

-

167

interpolated

incipient 171

(Cv)

ratio

data

Novak-Nalluri's

using

equations 6.28

Discrepancy

6.22

Eqn.

velocity Eqn.

interpolated

incipient 172

for

6.31b

Eqn.

-

Combined

-

Combined

data 174

pipes)

(Cv)


Selection of the best (Combined clean pipes Discrepancy

(Fr,

ratio

parameters

6.20

Verification pipe clean

6.24

for

Excess motion's

of

Verification

-

measured of data of

for

model data)

for

)

Eqn.

for

Combined

width

of

6.13

in

of data

modified

functions

of

pipes)

178

(W1)

183

spread

equation

for

present 191

Ackers'

Verification pipe clean

as

(Clean

data

sediment

(W. = 1Odso or

Discrepancy Combined

175 transport

sediment

Ackers' modified (W. = 10d30) modified

data

176

data

of effective equation

6.33b

Eqn.

pipe

Values Ackers'

6.16

Eqn.

criterion motion


Values

6.23

data

Combined

-

pipes)

Excess velocity for incipient

clean

6.13

Eqn.

156

Discrepancy

6.19

6.22

for

(I. ) for

relevant

6.21

)

(Fr,

154

pipes)

pipes)

(Clean

6.16

parameters

(Clean

data

combined

Discrepancy ratio (Clean pipes) (Clean

6.10

of

for

equation

for

present

0.12D)

Ackers'

193

equation

for

other, 194

(We) to

width

be

used

in

the

modified 196

(Fr. ) for ratio (Clean data pipes)

xvi

modified

Ackers'

equation

197

6.25

6.26

6.27

6.28

(Fr, ) for Discrepancy ratio (Clean data Combined pipes) (Fr, Discrepancy ratio functions of relevant (Clean pipes) Discrepancy

ratio

(Clean

pipes)

6.29

Ranges

of

6.30

Discrepancy (Rigid bed

6.31

6.34

6.35 6.36

6.39

6.40

bed

rigid

) for Eqn. channels)

(Frs) -

for

rectangular

6.40

-

(Rigid

data

Combined

as 210

214 channels

parameter beds)

222 of

bed

226

for

the

Discrepancy

ratio

(Fr,

Eqn.

parameters

-

beds)

(Fr,

ratio

(Pipes

deposited

)

for

Combined ) for

Eqn.

6.44

(Pipes

6.44

data

Combined

-

All 234 with

data 249

functions

as

(Pipes

6.46

of

with

(Fr, -

Combined

-

beds)

data

256

) for 6.46 as functions Eqn. data (Pipes Combined with

of 258

(A. ) for Eqn. ratio deposited beds)

used for criterion

data

-

230

251

Discrepancy

Discrepancy (Pipes with

equations beds)

-

247

Eqn.

Discrepancy ratio relevant parametres deposited beds)

Eqn. 3.57 channels)

combined

(Fr1, ) for ratio deposited beds)

with

217

data

functions

as

207

data

Combined -

6.40

Eqn.

Discrepancy (Pipes with

Equations velocity

6.38

Eqn.

- Combined

(C) for different Discrepancy ratio (Pipes data deposited with present Range of deposited

200

channels)

deposited

6.38

6.39

Eqn.

(Is) for E1-Zaemey's Discrepancy ratio (Rigid bed rectangular data Combined

relevant

6.37

for

for

parameters

rectangular

6.33

(1Q)

(Fr. ratio rectangular ratio

E1-Zaemey's

as

equation data

) for E1-Zaemey's Eqn. 6.38 data Combined parameters -

parameters

Discrepancy relevant

6.32

) for Ackers' modified Combined parameters -

(Fr, Discrepancy ratio functions of relevant (Clean pipes)

the

appraisals

6.48

-

Combined

data 263

of

the

constant 265

xvii

LIST

OF PLATES Page

Plate 4.1

General

view

of

test

pipe:

D=

154mm

72

4.2

General

view

of

test

pipe:

D=

305mm

73

4.3

Sediment

4.4a

Roughness Pipe wall roughness: (sand d50 = 0.5mm) size

1

Pipe wall Roughness roughness: (sand d30 = 1.0mm) size

2

4.4b

4.5

General

4.6

Sediment

supply

view

of

channel

79

system

test

pipe:

D=

81

81 450mm

86 93

return

xviii

Cross-sectional

A As

of

the

of

the

area

Cross-sectional

area

b

cemented

B

Water

C

Concentration,

Cp

Drag

coefficient

CL

Lift

force

C,

Volumetric

d

Particle

SYMBOLS

OF MAIN

LIST

flow sediment

bed width,

sediment

bed channel

rectangular

width

width

surface

in

constant

Ackers'

equation

coefficient concentration

sediment size diameter

d50

median

D

Internal

diameter

Dh

Hydraulic

depth

Dgr

Dimensionless

Fgr

Mobility

Fr

Flow

Fra

Modified

FS

May's

g

Gravitational

Ggr

General

Ga

Bed load

transport

limit

deposition

particles

of

pipe

of (=

number

d5ß (g(S$-1)/y2

(=

in

Ackers'

(=

(BV2 /gA )0'S )

for

parameter

)1/3)

equation

V/ (gd50

(=

number

mobility

channel

number

parameter

Froude

a mixture

A/B)

particle

Froude

in

(S8-1) with

pipes

)1/2 ) deposited

beds

constant

transport

of

in

parameter (N/s);

Ackers'

May's

equation

mobility

parameter

sediment

transport

at

height

H

Dunes'

J

Ackers'

parameter

k

Linear

roughness

ko

Clear-water

ka

Overall

ksb

Bed

representing

height sand

equivalent sand

equivalent

equivalent

sand

roughness

roughness

roughness Xi x

with

of

with

rigid sediment

sediment

bed

K

Ackers'

L

Dunes'

m

Empirical

n

Manning

roughness

Ackers'

equation

parameter

incipient

representing

motion

length in

parameter

na

Clear-water

ns

Overall

Manning

P

Wetted

parameter

q

Unit

flow

Q

Flow

discharge

Qq

Absolute

Manning

Overall

Rb

Bed

Re

Flow

s

Standard

So

Bed

SC

Slope

Ss

Specific

T

Temperature

u

Particle

coefficient

with

(= Q/B)

discharge

discharge

(N. m1,5 /

hydraulic

of

flow

the

of

S2.5 ) (=

radius

A/P)

radius

Reynolds

(=

number

4VR/y)

deviation

slope (=

parameter gravity

So/ (SS

of

1) )

-

(=

sediment

ps/p

)

velocity

Shear

velocity

V

Mean velocity

of

flow

VV

Mean

of

flow

Wb

Sediment

We

Effective

WS

Width

of

sediment

ya

Depth

of

uniform

YS

Thickness

velocity bed

in

width

for

incipient

motion

pipes

width

of

spread

flow

sediment

bed.

XX

in

clean

in

parameter

coefficient

roughness

hydraulic

R

empirical

roughness

rate

equation

coefficient,

sediment

QSz Transport

Ackers'

pipes

rigid

bed

sediment

(=

depth

flow

Y

Overall

C

Friction

angle

ß

Velocity

distribution

Ys

Specific

weight

Ic

Clear

Is

Overall

"sb

Bed

1g

Grain

roughness

11

May's

transport

8

May's

related

6b

Bed mobility

V

Kinematic

P

Density

of

water

Ps

Density

of

sediment

To

Mean

Tb

Bed

between

factor with

sediment

(Pipes

parameter

(= (=p

fluid

pgRS) g%S )

(=

parameter intensity

or

May's

transport

parameter

velocity

deposited

factor

of

viscosity

stress

with

= (11fib)

number

stress

sediment

with

Shear

Settling

sediment

factor

transition

shear

and

sediment

of

factor

friction

channel

coefficient

friction

Transport

the

friction

water

shear

yo + ys )

flow

of

CvVR/ (gd3 (S$ 1) )112) parameter (Clean

particle

xxi

(_ pipes)

(Se

1)d/SR))

beds)

1

CHAPTER

INTRODUCTION

Background

1.1

The

in

studies

'Several

in

sediments

Besides

and

guide

practice

designed

velocity any

al

1991,

limiting

in

several the

supply

sediment,

and

studies

single

sediment the is

that

the

aim

point

out

1990,

is

most

of

resulting

1

blockage, design

of

of

(Mayerle the small to

enough

single sewers prevent

deposition

size

et

highlight

studies

and

important

equations

free

sewers

while for

not

the

either

works

that

have

sewers

the

sediment

Another

might

criterion,

These

sewers.

sewers

review

results it

size.

A

recent

concentration,

the

to

presence

in

keeping

of

influencing

sewer

the

critical

500mm),

factors

important

Verbanck

example,

that

conservative

larger

1991,

few.

a

shows

1978)

than

smaller

pollution

sediment

However,

Ackers

deposition

sediment

a

with

gives

criterion

(diameters

these

stress

1982,

May

1987)

on

of

subject

of

relate

for

name

deposition.

sediment

of

to

mainly shear

or

of

problems

(CIRIA,

the

concentrations.

presence

flooding

al

to

pollutant

other

and

et

attempted

the

several

surcharging,

as

to

sewers

pollution,

produce

been

have

been fear

the

to (Ashley

studies

1990)

al

et

has

sewers

due

years

recent

watercourses. Larson

sediments

of

movement

in

such

density

finding

obtained

of from

give.

larger

significantly

the

to

those

sewer

tested.

originally (mostly

pipes

small

to

extrapolated

sizes

This

result

) used

150mm dia.

in

experiments.

(1984)

Henderson

in

roughness the

that

drew

but

the

and

ageing

due

roughness

their

transporting

et

hydraulic

roughness

the

importance

The

(1978) would steeper However, the

where lead

to

sewers

while

used

sewers.

in

Laplace

stationary this

of he

finding

suggested slopes

as

produced

limited transporting

data

al

sediment

milder

slopes

et

was that

by

the

the

Recent

works

1992)

conceptually

sediment

2

occur

of

sewers -

on the

(Ashley

depth large

pipes.

studies

raised

"limited

sewers

deposits.

to

(for

permanently-

found

also

deposits

hinders of

of

in

loss

a

smooth

conducting

for

to

in

studies

in

presence

required

available capacity

a

increase

earlier

conducted

the

reported

1992,

Verbanck

mostly

lead

the

sliming,

The

might

However,

were

in

sediments

possible

factors

show by

only

sections,

deposits.

sewer

studies

not

the

of

of

His

influenced

sediment

these

(1964)

al

for

to

1988)

deposited

1992,

of

capacities.

Mayerle

Ackers

is

jointing

the

also

importance

the

performance.

sewer

roughness

presence

sewer

example,

the

hydraulic

sewer

to

attention to

relation

materials

sewer

of

than

due

been

have

might

when

predictions

widely-differing

free

et

al

that

it

is

in

sewers.

by Ackers deposits" instead criterion.

the

quantitative

studies

with

stationary

sediment

of

1.2

Scope

The present

the

that

influencing

the

to

gain

in

the

sewer

transporting

The of Ltd.,

texture size,

sewer sewer

c)

sediment

by

of

sewers

or

wall

the

of

the

in

All flow

smooth

research

and were

sediment

transport

sediment

transport the

supplementing factors

the

on

1990).

load

improved

achieved

factor

lack

influencing

of the

namely,

roughness,

and

deposits

were

experiments University

the

is

aims

on

provide

studies

capacity

a) b)

to

and This

in

data

understanding

sewers

relationships.

The

is

uniform

bed

as

it

another

part-full

transported

boundaries.

improved

an

process

loose

and

rigid

under

storm

though

even

(Alvarez

capacity

conducted

separate

be

would

transporting

stormwater,

for used

were

itself

sediments

carrying

mainly

sediments

sewer

with

conditions

sewers

applicable

cohesion

were

experiments

rough

are

non-cohesive

acknowledged

for

intended

were

results

Only

sewers.

Study

studies

hence

and

Present

of

of

carried

out

Newcastle

the

at

Hydraulic

Tyne

upon

and

Laboratories

Hydraulic

Research

Wallingford.

1.3

Outline

This

thesis

of

The

consists

Following

the

Sediments

in

Thesis

of

introductory, Sewers"

gives

seven

chapters

chapter, a review

3

and Chapter

on the

three 2 on

behaviour

appendices. "Nature

the of

sediments

of

in

incorporating

sewers

sewers

and

the design

current

3 entitled

Chapter

experimental

and

studies

4 covers

Chapter describes the

the

the

for

sediment

the

It

the

highlighting

details

of

of

and in

adopted

the

test

pipes, It

characteristics.

also

flow

uniform

and

experiments.

Analyses"

factors

sewers

Procedures"

procedures

transport

load

data

the

presents

bed

the

in

boundaries.

and

establishment

presents

the

loose

and

sediment

"Preliminary also

the

real

presents

transport

Apparatus

with and

Literature"

and

apparatus

for

roughness. of

experimental

5 on the

rigid

in

works

practice.

on sediment

"Experimental

the

method

procedures

Chapter

both

techniques,

measurement gives

for

in

Relevant

of

field

of

used

works

investigation,

present

results

criteria

"Review

the

a summary of relevant

recent

results

influencing

on pipe the

with

the

aim

self-cleansing

velocity.

6 consists

Chapter where

analyses

each

the

established

transport analyses. performance

analysis

transport

established

Design the

examples newly

in

loose starts

the

using

the

with

later

are derived

then help

of

Data"

sediment

transport

are

described.

comparisons

among

the

data.

present

considered multiple

presented

transport

4

the

with

are

Transport

boundaries

relationships

relationships

models

of

and

Sediment

of

obtained

rigid

the

functional

"Analyses

data

the

both

boundary,

For

Several

of for

experiments

the

of

to

equations

and

new

regression compare

the

with

the

equations

established

and

also

to

assess

the

current

design

practice.

7 entitled

Finally

Chapter

Further

Research"

present

study

works

in

light

summarises

and suggests of

the

present

"Conclusions the

and Recommendations

conclusions

several study.

from

obtained

recommendations

for

for the

further

2

CHAPTER

NATURE

2.1

OF

SEDIMENTS

IN

SEWERS

Background

Due

to

in

variation in

some extent hence

sewers transport

flows

sewerage

The

systems.

involves

a

cycle

deposition

and

have

sediments

of

though

been

always

movement

of

processes not

present

to

sediments

in

namely

erosion,

in

strictly

the

order

mentioned.

(1987)

CIRIA the

conducted

presence

found

of

operation, were

surfacing

materials

be

given

affected

use,

time

and

mainly year

by and

Ashley-Crabtree(1992) studies

(Ashley

spatial

variations

types

but

inputs also

et

to

further

sewers

sources

also

(1992).

Xanthopoulos-Augustin

similar

of

yields

and

(1992) 6

of road

surrounding

ground

discovered

were

to land

type,

sewer

in

works there

origins not

only

inlets.

sewer

results

sources

period.

that

may differ

adjacent

studies

give

indicate

commonly premature

important

location,

reported

most

operations,

ingress

sediment

The

to

related

flooding,

gritting

dry

the

between

winter

preceding

in

problems

UK.

The

geographical

1992)

the

quality.

The

al

on

surcharging,

roadworks,

work.

of

sediment'

as

in

sewers

and water

construction

studies

blockage,

were

sediments

and

in

sediments

problems

overflow

extensive

to

those carried

the

are of

UK.

considerable

sediments

between Other of out

New

where

catchment recent

Ashley samplings

et

al of

types

sediment with

combined

that

the

and

of

there

are

several

for

sewers,

instance

studies

recent

(1987)

CIRIA's

Recent

have

sewers

2.2

with

stationary

Characteristics

CIRIA

(1987)

quantity found

of to

those

gave

samplings

between deposited

in

2.5mm.

the

that

inside In

the

general,

ones

obtained

1992,

Laplace

the

following

and

Quantity

sediment

from

Details (See

section

et

al

concentrations

deposits.

sediment

these

of

Section

2.2.2).

Sediments

of

comprehensive

in

eleven

and

review sewerage

locations

where

the

invert

generally

storm

sewers

The

sediment

CIRIA

of

in

cities

9.0mm.

in

the

sewers

(1982)

May and

reported

concentration

7

systems the

is

the was

which

were were to

herein.

reported

the

studied

and

relating

1987)

with

source

samplings

(1987)

UK (CIRIA

well-graded

the

on

the

findings

the

made

are

in

the

on

of

at

0.1

the

Verbanck

quantify

present

be dependent

sediments

1992,

al to

a

sediments

samplings

found

partition. to

results

main

Studies

A summary

made.

about

in

given

Earlier

the

et

attempted

2.2.1

The

(Ashley

also

are

studies

similar

the

deposition

flow

from

show

studies.

studies

1992)

downstream

produce

for

sections

results

(1992)

Bachoc

areas

that

and

runoff.

street

vulnerable

The

site-specific

were

was the

catchment

systems.

sewerage

separate sizes

solids

different

at

concentrations

sediment

source

in

and

range the

average found

that

showed

(=dso)

sediments d30 size to

be

of

2oppm

by volume 1.83m

dia.

in

with

gravel

in the

0.34mm

conducted

samplings

sediments

in

of

range

the

particles

et

Mittelstadt

found 7 to

varied

from

These

studies the

the

110

sewers of

by

a mean

2.1)

mainly

of

depths sand

sewers

(1983)

Shultz and

obtained

(1984)

studied

average

specific sediments.

volumetric

of

that coarse

sediment the

where 50

about

the

values

ppm.

sediments low

with

and

sediments

coarse

researchers

Table

are

Broecker

compiled

of

of

Germany

implying

2.45

about

size

the

depths

combined

and

reported

and

ppm with

inverts

2.0mm.

to

previous

(see

in

cities

(1979)

suggest

sewer

0.06

mean

(1983)

Macke

several

al

concentrations

in

found

of

combined

from

and

in

in

deposition gravity

the

12mm.

sediments

the

average up

to

of

2.94mm.

and

300mm made

0.54mm

40mm in

the

the

gave

samples

Slovakia

about

measured

and

25mm to

between

of

(1964)

sewers

of

size

deposit

of

al

combined

obtained

Bratislava,

between

et

range

median

(1984)

Urcikan in

sewer.

deposit

depth

average Ackers

deposits

sediment of

the

with

present volumetric

concentration.

2.2.2

,

Recent

Studies

Following

CIRIA

occurence

of

polluting

and

deposits.

(1987)

sediment

studies, deposits

operational

Herein

only

several have

aspect the

new investigations

been

going

resulting

results

8

relating

on to from

on the

quantify

these to

the

sediment

operational

aspects,

linked

maintain

the

to

the

designed

2.1

TABLE AUTHOR

cleaning

hydraulic

operation

capacity,

0.10

of

the

be

discussed.

IN

VOLUMETRIC CONCENTRATION (ppm)

9.00

2.50

MACKE (1983)

0.06

URCIKAN (1984)

0.34

20

-

2.00

-

2.94 2.45

BROECKER (1984) MITTELSDADT (1979)

7-

(1992)

Verbanck June

1986

in

4.0m

dia.

and

5.4km

Fig.

2.1

of

development

of

deposit Fig. time.

The

the

also Analysis

effects shown

further of

in

shown

2.2)

observed

in

Fig.

was

2.1

the

2.3

generally

illustrates

level

a stable taken

along 9

the

volume trunk.

be

without

a

bed

load

on

the

'mean

very of

a

gradual

period

invert

of

indicates

to

operations

the

of

The

cleaning were

The

main

deposits. during

the

the the

of

of

(Verbanck

time

of

Fig.

deposits

of

samples

in

length

total

sewer

length

time

with

sediment

(Fig.

total

since

0.0004.

of

reproducible

the

trunk

slope

the

on

110

profiles

combined

average

evolution

events

stationary

as

an

very

stationary

operations

level 2.3

be

for

of

main

profile

calculated

development

process.

with

to

shows

study

closer

cleaning

long

found

deposits,

the A

been

accumulation

(Belgium)

accumulation

has

1990).

sediment

obtained

a Brussels

longitudinal sewer

to

sewers

SEWERS

SPECIFIC GRAVITY

PARTICLE SIZE (mm)

MAY (1982)

,. r

will

SEDIMENT CHARACTERISTICS (See CIRIA 1987)

(1987)

CIRIA

costly

limited.

deposits of

the

over sewer

1200 Storm of 14 Sept. loge (. xtnn. ly violent)

23/081

1000

00/01 /87 To

I

24/00 00/09 OT/04 E3 Q

QQ

O CL

800

O0 13

QQQ

Cleaning out

Q 10/02/88

Q

26/10/88

w 0 U. 0 W

600

1 ,,/86 ea Cl

0

14-16

nn

6apt.

1

rain 1988

0 20/00/88

Anti

ývv

Dec-88

Jun-86 TIME (months)

FIG. 2.1 Build-up of sediment on the invert of Brussels main trunk sewer (After Verbanck 1992)

40

c 0 0 12

Co

E U

ob S. 01

0

CL 0

v 0 m > Jm

to

1.7

1.8

1.9 2 2.1 Kilometres

2.2 f2.3

2.4

1 2 3 4

11-Jun-86 03-Jul-86 11-Sep-86 16-Oct-86

5 6

n9-nH--RA 09-Jan-87

Input 2

e.

4:

,ý`

FIG. 2.2 Detailed view of gradual sediment build-up (After Verbanck 1992)

ýý

ý.

ý,ý

10

that

showed

the

(=dso)

from

ranging

July

Since

sediments

1988

deposits

in

(France)

for

a

wide)

with

indicates

the

which

profiles of

time.

with

invert between load

process

load

et

was

3.0mm,

al

(1992)

sediment

of

deposits level. gave

a size

concentrations

(Ashley-Crabtree

for

trend

of

particle

of

sediments

in

the

size

of

the

bed

that of

some

formation

sediments

concluded

stationary

transported

as

of

),

0.1

found shows

show of

the

to

0.5

to

vary

sediments

11

an interceptor The

175m

and

measurements

yet

Samplings

in

1986.

since

The

not

1992)

level

the

of

the

formation

mm dia.

0.00069.

were

the

an equilibrium

deposition

(UK)

(1500

range

1.80m

succession

the

sediment

Dundee

do

and

asymptotic

average al

made

25ppm.

studied

circular

equilibrium

et

were

shows

manner of

an

Laplace

be

to

at

slope

average

gave

concentration

found

approximately

the

sampling

responsible

was

sewer

combined

load

and

which

Corresponding

Ashley

invert

sewer,

0.3mm

beds. bed

the

of

a

of

Marseille

high

reaching

represents

the

on

The

of

in

2.4

Fig.

deposits

the

formation

the

(2.75m

studied.

2.5

Based

sands

observations

sewer

an indication

gives

well-graded

sewer

The

0.001.

of

of Fig.

deposits.

the

trunk

years.

period

possibility

of

followed

egg-shape

slope

the

over

two

the

an average

(1992)

combined

of of

up

made

mm.

al

man-entry

a 460m section

level

et

a period

deposits

0.5

to

Laplace

along

of

0.2

were

a

of

tendency sediments

mm. up

The to

found

long

with

an

the

level

of

to

reach

an

on

the

volumetric 20ppm. in

is

sewer

sewer bed

Fig. sewers

2.6 from

25

. "'0

20 4

E U

"l.

15

oa

Ctboa o° q3 o

0 m V

10

C

a

13

0

o

0

0

0 6

rain event leading to scouring rain event leading to deposition "

I,

Jun-86 FIG. 2.3 deposition

1988

1987

Effect (After

measurement during cleaning

1989

of cleaning operation 1992) Verbanck

1990

Jun-91

on sediment

120 110 100 90 BO 70 0 60 50 40 w

30 20 10 0

C

10 NUMBER

20 OF

MONTHS-AFTER

COMPLETE

30 DREDGING

FIG. 2.4 Long-term trend of volume deposited (After Laplace et al 1992)

12

5.0 Intake

5.!

S. 2 W

S. 0

4.8

4.6

4.4 100

0

[m]

ABSCISSE

Longitudinal FIG. 2.5 (After Laplace et al

profile 1992)

400

300

200

of

sediment

depth

DUNDEE INTERCEPTOR DUNDEE

BED-LOAD

(DWF INTERCEPTOR)

SEDIMENT

100 90 80 -ý

70

rt

60 (d

U Si d

50 40

30

20 10 0

10

100

1000

10000

micron

FIG. 2.6. Typical partical (After Ashley et al 1992)

13

sizes found in sewer inverts

recent

(Ashley

studies

Ristenpart

range

al

1992).

from

recent

et

The results of

sediment

be concluded

equilibrium

level

Classification

Based

on studies

which

showed into

insight

location

presence

the

nature

a

of

it

time

the

al,

on the

agreement of

is

et

sewers.

It

to

an

possible

reach

Sewers

and

(1988)

Crabtree

deposits

sediment

combined

sewer based

category sewerage

Laplace

deposits.

(1987),

of

five-fold

within

over

invert

the

Sediments

by CIRIA

the

a

suggested

in

sediment

of

1992,

Verbanck

show a general

found that

of

1992,

al

studies

sizes

can also

2.3

et

system,

to

gain

sites a greater

deposits.

sediment on

and

revisited

visual

He

appearance,

physical

and

chemical

analysis:

Classes

:-ACD-

coarse Class mineral mobile organic

E-

deposits

B-

Among

these,

invert mentioned of

the

of

Class

sewers. in

Section

granular material A deposits concreted cements fine grained - usually wall slimes

found

A represents This 2.2

is

in

in

suggesting

classification.

t

14

greases

and A

overlying

tanks

typical general

by

sediments agreement

the

universal

with

found the

in

the

results

applicability

Following

their

attempted

to

cumulative

contributing

distinguishable results

Dundee

are

sewers

Modes

the

and

2)

or

continuous

transport

mode)

of

sediments

is

possible at

organic

the

A)

while

and

size.

The

deposits

are

In

the

trunk

interceptor

the

(Class

particles

on the

and

the

also

sediments

1)

in

transport

sediments

mode)

or

physical level

of

move

time.

15

will

roll

and/

and chemical turbulence. both

as

sewers with

deposits,

sediment

The

depending

same

C).

sediments :

loose

over

the

of

categories

dunes.

if

size

G).

Transport

(suspended-load

suspension

load

two

sewer

(Class

finer

or

sediment

collector

(Class

movement

into

and

head of networks flows from

relative

relative

coarser

with

Sediment

of

the

material

are

slope

gradient

increasing

of

the

that

organic

deposited

general

classified

load

by

show

deposits

the

sewers,

In

are

migrating

mainly

2.4

categories

(1992)

al

disposals

to

collectors interceptors flat large,

-

et

diameter,

on

local at small, convey - steeper,

principally

at

Ashley

area:

catchment

Interceptors

these

general

based

sewers

Collectors Trunks

:-

(UK),

Dundee

at

classify

Classes

In

work

clean

invert dunes

separated

either or

be

could

move

in

(bed-

saltate characteristics Total-load

suspended

load

mode and

bed

Based on the

classifications

(1955)

al

May et

likely

are

(1989)

runoff

(1992)

move

in

on

sediment

Sewer

in

sewers

the

He

sand

Colebrook-White

0.4mm

than

that

finer

fraction

larger

0.125

mm will

than

larger

than

of storm

0.4mm

will

move

of for

can

be

concluded

of

transport

mode

for

that for

sediments

non-cohesive

load.

Roughness

out

studies

obtain

al

hydraulic

a realistic his

combined et

on

of

previous

data

with

to

come

up

1964)

roughness,

appraisal

own

k-values,

in

roughness

with

existing work

suggested from

calculated

the

equation.

2.2 gives

condition

it

UK to

Ackers

of

equivalent

account

and Spells

coarser

suggested

sediments

carried

capacity.

(mainly

'k

(1955)

a classification

sediments

the

mm,

(1984)

Henderson

Table

that

be bed

will

Hydraulic

sewer

load.

sizes

0.4

than

particles

used

bed

while

sediments

proposed they

found

al

load.

where as

et

load.

larger

2.5"

move

suspension

bed

Based

will

(1992)

Verbanck

as

particles

0.6mm

than

bed

as

Xanthopoulos-Augustine water

that

suggest

be moving

to

by Newitt

k-values

pipefull sewers.

any

These

misalignment

for

k-values the

of

16

pipe

sewers

should sections

be and

for

the given

modified the

suggested

to

PIPE-FULL k-VALUES FOR PIPE SEWERS TABLE 2.2 (AFTER HENDERSON, 1984)

SUGGESTED k, VALUE (mm)

TYPICALCONDITION Virtually as new condition. Light coating of slime (55

k, DUE TO JOINT ECCENTRICITY (mm)

0.15 0.30 0.60 1.5 3.0 6.0 15.0

17

(Henderson

values

1984) and

slime

material, would

it

2.2

From Table alignment, the

pipefull

k-values

The

Water

Authorities

for

use:

0.6mm

2.6

Current

Sewers

storm

is

deposits

(1987) design

shear

criteria

are

be expected

0.3

1989)

1.5mm

to

be

3.0

to

mm.

in

its

k-values

the

for

good

deposits,

suggested

combined

to

sewers.

the

self-cleansing. to

expected intermittent

during

continuously of

flows

receding

conditions,

it

picked-up

by

high

flush

the

available

is

All

move nature

these

thoroughly

reviewed in

criteria

self-cleansing or

WAA,

with

dry

or

expected hence

flows,

the

weather that

hindering

the any

deposition.

long-term

and

sewers sediment

no

and

designed sewers

be

would

k-values

Criteria

Under

conditions.

for

(WAA) (

pipe

deposits.

between

range

sewers

Due to

to

the

Adoption

water

entering

deposition

CIRIA

for

deposition.

without

and

Association

generally

sediments

invert

in

are

Design

are

that

Besides

different

sediment

concluded of

sliming

Sewers

publication,

be

2.3.

Table joints,

of with

sewers

can

minimum

in

given

misalignment

for

be obtained

are

the

criterion Tables

stress. given

in

CIRIA

UK and

is based 2.4

elsewhere.

either and

(1987).

18

codes

2.5

In

of

practice

general.

the

on minimum mean velocity reproduce

some

of

the

2.4

TABLE

REFERENCE SOURCE AMERICAN

CONSTANT VELOCITY (See CIRIA 1987)

COUNTRY

SEWER TYPE

MINIMUM VELOCITY

USA

FOUL

0.6

SOCIETY OF CIVIL ENGINEERS (1970) BRITISH

PIPE CONDITIONS FULL/HALF-

FULL

UK

STANDARD (1987) ESCRITT

CRITERIA

STORM

0.9

STORM

0.75

FULL

COMBINED

1.0

FULL

0.76

FULL

1.5

FULL

UK

FULL/HALFFULL

(1979) BIELECKI (1982)

GERMANY

TABLE

REFERENCE SOURCE

2.5

CONSTANT SHEAR STRESS (See CIRIA 1987)

COUNTRY

SEWER TYPE

CRITERIA

MINIMUM SHEAR STRESS

PIPE CONDITIONS

(N/m2) MAGUIRE

UK

6.2

FULL/HALF-

RULE YAO (1974)

FULL USA

LYSNE (1969)

NORWAY

ASVISNINGAR

SWEDEN

STORM

3.0

-

4.0

FOUL

1.0

-

2.0

2.0

-

3.0

1.5

(1976)

19

Using

the

Arora

et

transport al

velocity 1985) design

1984)

based

criterion and

Fig.

practice

(D < 500mm)

and

(Novak-Nalluri

relationships on

was 2.8

recent

overdesigns underdesigns

experimental

appraised

(Ackers,

as 1984).

the the

1975,

slope slope

20

shown

Fig.

In

general,

for

small

for

the

works, in

larger

May

the

pipe

minimum (Nalluri,

2.7

pipe

1982,

present diameters

diameters.

C,, = l00ppm d=0.4mm n=0.01 Half-full pipe

1 10

41

ora

t $1 (1984

a,

J

)

Novak_Nalluri (1975)

0

10

'ýof

o0

Vý

h0

b00 00 00 O ý q0ý

10ý

100 FIG. 2.7 Appraisal (1985) Nalluri

100r -m

I

Q ! /s

design

of present

due to

practice

1000

100

10

102

10000

100

c 0 N 7

0 IC

0

Iu CL

In C W V (7

b 111.1

0.5

r

N .

t11t111111......

1

10

FIG. 2.8 Appraisal Ackers (1984)

Discharge

of present

100 for halt-full

design

..

1000 pipe. Its

pfactice

'

0.1 000

due to

21 a

CHAPTER 3

3.1

Background

Majority deal be

LITERATURE

OF RELEVANT

REVIEW

the

of

in

found

(1984),

on

works

textbooks

standard

Garde-Ranga

Van

of

information

(1989)

Rijn

could

(1975),

Vanoni

as

such

(1985),

Raju

deal

transport

sediment

and

motion A good

channels.

alluvial

with

incipient

Graf

Raudkivi

and

(1990).

There of

however

are

rate

supply the

sewers

itself

of the

Secondly,

the

whether sediment

deposits.

also sewers.

of

have

drawbacks The

transportations

sediment are

effectively

sewers

slurries direct

concentrations higher

than

22

clean

in

made

in pipelines application and those

in

from

the 2.1.

Section depending

varies

or

derived while

determined

of

the

much

is

roughness is

is

unlimited

discussed

of in

is

Firstly,

channel

alluvial

in

transport

mentioning.

as

sewers

on transportation

an

Two

sewers.

sediment

worthwhile

in

application

in

system

sewerage

invert

of

sediments

of

effective

the

Studies

and

rate

supply

catchment

are

direct

the

conditions

mechanism

sediments

of

channel the

the

and sewers

channels

alluvial

from

in

to

the

to

models

differences

important

the

several

boundary

loose

limitations

up

of

on loose

(Vanoni to

velocities attainable

1975)

problems in in

slurry sewers.

in

The

the

(1955) both

transport

this

the

studies

UK by

deposits

transport

over

Kleijwegt

1992).

identify

be

those

of

work

was

and

sediment deposition) reported

on

to

following areas

these

with

studied

et new

gain

a

sections which

are

not

1989,

al

of

to

better

studies

of

Perrusquia

1991,

still

remain

understanding

summarize

existing

fully

covered

yet

permanent

the

there

works,

(CIRIA

data

presence

in

mainly

Field

leading

(May

beds

resumed

(1975).

the

inverts,

their

Even

The

problems.

limit

sewers

May

and

revealed

sewers on

in

boundary

rigid

deposited

to

need

further

no

(1972)

used

sediment

areas

on

Novak-Nalluri

from

1987)

However,

(1953)

covering the

Under

1970.

until

subject

Transport

beds.

(at

sewers

USA.

Ambrose

experiments

boundary

rigid

(1953),

Craven

conducted

with

loose

over

(1956),

University,

Iowa

at

in

transport

sediment

researchers

Laursen

of

guidance

Valentine

and

by the

presented

were

on

studies

reported

earliest

the

of works by

and

previous

studies.

3.2

Incipient

Studies in

of

Motion

incipient

Raudkivi"1990)

rate

such

1987). observations

show The as the The

that

there

category

works

by Shields

particle

beginning

Graf

first

second of

or

(e. g.

channels

alluvial

threshold.

motion

1984,

are

two

is

based

possible on

constitutes on

23

the

of

sediments

Lavelle-Mofjeld

and Kramer

definition motion

movement

bed.

definitions

a minimum (see

1987, of

transport

Lavelle-Mofjeld of

the

visual

by

Work

(see

Shields for

standard

defined

Shields

the

interpolation

and

is

'c

where

S. is

the

the

sediment,

threshold

is

shear shear

critical

shear

viscosity

of of

dimensionless

given

in

Table

and

SHIELDS'

D6r 4
O o

o--ý C 4-4

o1 ý. N +J a c. co UG ýn 3 ý4-e 92 Co

F+ cý

CO c

UZ

Co U2 M C.)

a ",

g

N Id "U

Cý

Lz. U

. ýý . _,

ý

-v

.a

0ppO

ýu

th`%VIP ftsý' 0

36

VN

V-1.77

ýß

(d)

C,

ý A;

(3.15)

dl1 (S; 1) s

Macke

(1982)

using

three

smooth

full

part

conducted

and

both

moving model

(192mm,

pipes

used

sands

fitted

it

analysis

for

following

dimensional

the

with

to case

a theoretical regression in

resulting

Region

in

I

Fig.

is

Q.

the

sediment

fall

sediment

densities

transport

for

the

due

to

size

in

of

this

bed

load

transport

load of

to

(3.16)

(Region

II).

I)

37

(1982)

and

Nm"S/s2. S.

However,

relationship II

in

as functions data 1972)

validity and

water

the

sediment

Region

Robinson-Graf

w is

of

a specific

experimental

May

range

obtain

the

the

are

4x10-3

curves

(Region

p. The

(see

individual

N. m1.3/s2'3,

10-6 to

transport

established

transport

p and

respectively. was

1953,

in

rate

and,

By using

Ambrose (1982)

kg/m3

attempt

region.

(eg.

m/s,

studied

not

presence

Macke

suspended load

", Q,

did

case

research 3.8,

in

rates,

the

in

velocity

(1982)

Macke

transport

sediment

the

3.8):

Qý = Q(P. - P)8(1s - 1.64 x 10-4 i

where

0.37mm

and

linear

load

(see

equation

by

data

suspended

of

) flowing

dso) 0.16mm

He derived

experimental

deposition

of

445mm dia.

and (=

of

loads.

and bed

as suspended

and

290mm,

sizes

limit

the

at

experiments

individual re-wrote

as of

Fig. of

from shown Eqn. curves Eqn.

3.8)

sediment previous in

Fig.

3.16

for

for 3.16

bed as:

i : iI

:ý:..

. l: l . ll

Mill

114-1* ti::

i:.

}..

...

iii

7 4..

""i

(P , P) g Cau Q ý=Q . . . )i'Iý. . ' 1_ - .. ý,, nj t : IFl

10

iý!

.: ý""t'

__

.s

I

:Ail!

I",

;.,.

.

:4:...

O.

t.

'..::

ý1

( !i i

Alu .

nW

F l ow con ditio n s with sedimentation

j

'i1,

hill

.;

iý

:

i

1

; i:

ii

t 3_.

II

,,.

j ii

j

tt

'i

'.

I I:.

.. ii''

I

l..

...

t

It

r?

1'ýT: It.

Iii

p

1C

96 .

--1.64 x 10-4 s2

T! I

1( 'ý, i" i

; JI

...;

_yýý

},

i

I. ýt . ý-

* =::

ü f'ü ?

.,: "I i:

:. f

I

l:

i

Iýt.

lii.:

ti

.

t; 1a

tlll

c

'i. '?.`?ic;

}li :::.

-I

l

-tl: oi

iti f Zül

iii

.

I.

ýý.

c

_

y'

ri i ut:L, ': L.

-2

.1

ZL'

ýS " i

'

z: -" . ^ .«

r: -,:

11

fi 1-

_

ýý r-Iý_Q_

-

.1 lY:

Ii., cý":

I;!;

_=

c=

=v_

'

"1

ý.. i

ýi : : -'ate

r_-

..; ý:.

. ---

''...,

ltl mt. .

;-1

:i

_ mß-3

.'.,

.

r.

1-

, =:.".s'

1º .:

0ý

REGION II

L- "!

..

'-

`

pit

t':

}i! i 5'_3 i

t"fl

by Macke (1982)

IT

} lii `ij: ":;;'.ý#, "I .

il 't

_

" CRAVEN(1953) V DURAHD(1953)

' -'

o EINSTEIN at al. (1972) (1961 ) - FOHRBOTER

=-

FOHRBOTER at al. (197S) s FDHRBDTER at al. (1981) (1976) f KtPAIcASS31415

Untersuchungenan IEICHTWEISS-INSTIT. T

o-

" ROBINSON,GRAF (1972

2,

*SAUERMANN(1978)

'i~'"'+i:: t[ 7ý I q:f : " .

10 ae-

.

f::: ýi

legende o Al82OSE(1953)

=`

REGION It

.. tt" 1 "

171 .

ij gj?: i Tý'i, iii " -,

Region studied

-`ý-

tl: "'

ý

T

`r"~

11 " ý1

"1:;.;

"

iii ; -_

---

" Elcene Unu"sutnun-en -_

Abb

7 2 . .

--

Feststolftransportrate von der

a'

QS

Wandscnu b s; annun9

(Auswertung btasnnter

:a'

{

:i " i .

10x6 10-1

a

ßi; 1

.I:ii

:ý+

_

1"

to

AohYnQs ptit

t

Untersuenungen)

ýi:i:

t: .i:

; i. .. t 0

a"

ii

+if,

06

23"ss;.

sjo1

33a

Zaai02

i3i1

1 4149-1

03

FIG.. 3.8 Suspended load model at limit of deposition flow in pipes (After Macke 1982) for part-full

38

V=1.98

it

Again, SI

be noted

should should

units

fall

sediment following

May

is

(1982)

g in

m2/s,

(1982)

developed

0.64mm

forces

", on

7.9mm

to

at

theoretical

model

experimental

acting

the

by

from

the

range

of

(3.17x)

4.7

Eqn.

< Cv (ppm)

the

SB = 2.65.

39

bed

following

3R

for

May

particles the

and

fitted

equation:

(3.18)

velocity

< V(m/s)

is

which

V4 1-V

experimental 0.45

load.

simplified

analysis

motion The

< 2100

sizes

model

He

d ob v2 R g(s-1)D

3.4.

Sediment

sediment

dimensional in

158mm

transport

incipient

critical

as

individual

resulting

Ds

part-full.

deposition.

of

77mm and

using

bed-load

utilising

data

(1975)

Novak-Nalluri's the

the

calculated

transported

and

on

limit

the

Cý=0.0205

Vc is

and

a theoretical

transported

where

that

mm.

deposition

of full

flowing

pipes

d in

and

m/s2

limit

the

studied

ranged

to

be

should

m/s,

suggests

[0.11607 + 0.074405 d] a 10'3

from

it

also

hence

and

ý9v2+ 10-9 d2 g (S, 3v (0.03869 + -0.0248d)]"R -1)

in

-smooth

based:

eº in

dimensional

equation:

v

dia.

(1982)

May

used.

velocity,

ý_

where

be

is

3.17

Eqn.

that

(3.17 )

((So-1) A Cy )u

1003

given data

by

covered < 1.2

and

May

(1989)

al

et

larger

using

pipe

as bed

transported 1982)

were

depth

(yo/D)

flows,

extended

300mm

a load.

to

and

reduce

the

in

scatter

sand

pipes

(May flow

proportional for

data

the

0.72mm

smaller

of

effect

a

part-full

yielding:

y

C, = 0.0211

Analyses

provided

The

covered

the

range

60 (d =2. Omm)

FOR ACKERS'

EQN.

3.29

TRANSITIONAL AND FINE SEDIMENTS 1< Dgr j 60 (d = 0.02 2.00mm) -

n=0.0

n=1.00

Aar = 0.17

Agr = 0.14

m=1.78

m=1.67

C=0.025

log

C=

-

0.56

log

+ 0.23/

Dgr Dgr

+ 6.83/Dgr

+ 2.79109

-3.46

47

Dgr - 0.98(1og

Dgr) 2

(1987)

Mat

Suki

in

smooth

159mm,

8.00mm)

using the

with pipe

sands

whole

k0,

roughnesses,

from

= 249mm),

3.32mm

= 155mm).

Mat

effects

the

single

model

limit

of

Using to

linear

multiple data

experimental

(D = 159mm)

1.61mm

(D

(D = 159mm)

and

8.84mm

(D

high

values bed-load

on

smooth

forces

and

regression

g(Sý 1)d

for

smooth

2.86 c

pipes

the

transport acting

rough

analysis

on

was

fit

the

to

-1A

)) °_ D.

l0 4.80. k.

and,

48

2.01D(d+ký+ °" dk

a

pipes

yielded:

(d+;k)O"22 0

ko to

of

[1o43.13(1+... V

sand

were

based for

applicable

using

equivalent

A theoretical

deposition,

For

equation

these

atttributed

-

roughened

1.3mm ,

resulting

4.73mm

2.65.

of

roughnesses

249mm)

Colebrook-White

misalignments.

particle,

derived.

The

were

1.30mm

=

artificially

uniform

creating

(D = 162mm),

(d50

average

were

pipes

(155mm,

pipes

experiments

size

the

on

deposition

of

rough The

sediment

(D = 162mm and

the

Suki

joint

of at

model

the

155mm).

=

full.

gravity

0.83mm

(D

2.7mm

of

perimeter

diameter

of

and

specific

) and

) flowing

range

conditions,

the

around

a

limit

the

at

253mm dia.

and

249mm dia.

162mm and out

experiments

(164mm

pipes

carried

rough

conducted

(3.32)

-lA

the

pipe

smooth

is

k,,

roughness,

sand

equivalent indeterminate

taken

as

0.3mm

instead

of

in

sand

equivalent 0.0mm.

Using lead

will

range

an

to

an

volumetric

of

for

1020ppm

to

of

application

3.32

Eqn. The

19.5ppm

was

concentrations

sediment

the

the

velocity.

of

value

for

3.32),

0.0mm

(3.33)

dk°

(Eqn.

of

roughness

-

that

suggested

equation

6.28D(d+k, C,

D 4.80 k°

1

Suki

Mat

pipes.

rough

43.13(1+ k°)

d+k°

(TS. -1)d

for

°°

k

V=3.73

1

0.50

0.5),

and 9'b, is

and his

representing

0.32

< 408

< Y/D

entire

data

(1991)

deposition

in

measured

a. 305mm dia..

with 60

the

mobility

The

experimental

(m/s)

< 0.668,0.2

0.294

""

:" , ýý

1v

ý

,,

ý!NI, ilýjilý, IýIý! 'iili!üli's! ºýiitiýliiijliill-ýliliili 1 11 12 13 14 15 16 17 18

34567891 2 ý, ý4.000 PLATE 4.4a

Pipe

wall

roughness:

Roughness

1 (sand

size

d50 = 0.5mm)

ý Fýý ý,

yy

h.

r

.ýy .

S.

.

ýC Y

i

2

FS 910

34

PLATE 4.4b

Pipe

wall

roughness:

11 12 13 14 15 16 17

Roughness

81

.r1

2 (sand

size

dS0 = 1.0mm)

.6

of

the

White

equivalent

4.2

dso (mm)

each

the

invert

was

obtained

2

1.00

1.34

level

improve

minimum

were

by adjusting

the

flow

at the

and

taken

was

criterion

-

found

flow

to

flow,

is

give

was when less

the

tail

adjusted

necessary.

taken

than

flow

the

The

if

flow

required

and

jack

the

using

The

position

the

be uniform

set

discharge.

levels

Sp]/Sp)

was

recorded.

of

water to

pipe

opened

uniformity

([Se

difference

a fully

maximum

was

the

of

slope

readings

initially

fixed

(mm)

0.53

the

ROUGHENED

VALUE

0.50

test,

For

ko -

ROUGHNESS 1 ROUGHNESS

at

each

absolute or

equal

depths

within

and depth

gate

was

later

on

A set

of

point

gauge.

relative

slope

5%.

to +/-

This

2mm from

mean value.

The effective to

Colebrook-

AVERAGE

SAND SIZE

WALL

CONDITION

the

the

VALUES OF ko FOR AN ARTIFICIALLY (D = 305mm) PIPE

AVERAGE

PIPE

The

from

pipe

equation.

TABLE

to

the

of

roughness

sand

the

water

slope, surface

So, was then slope

obtained

using .

equation:

82

the

by making gradually

a correction varied

flow

(Sp-Sf)

i_ dx

where

Sf is

slope

(Se).

the For

(S=S=Sf).

flow

the

be expressed

the

three

Experimental

After

uniform

flow rate

then

was

)(1

together

and

was

depths

were

flowY

discharge

Sediment

were

transport and

after

point

to

the

effective

by

to

flow

the

depth

readings

83

to

supply

limit

the

to

started

limit

of group

deposition

of

likely,

was to

adjustments

limit

The

the

flow.

the

ensure

to

added

occurred.

deposition

the

were

sediments

at

Necessary

at

Transport

possible

where

no

made

-F=)

sediments

as

move

ensure

rates the

be equal

(4.5)

deposition

dispersed

then

recorded.

the

close

as

as the

to

surface

should

uniform,

Sediment

until

sediments

minutes

several

before

reduced

allowing

for

obtained, rate

defined

deposition

After

was

an increasing

at

water

as:

Procedure

flow

the

slopes

nearly

was

So=Sp-(Sp-S.

4.2.6

is

dy/dx

and

flows,

uniform

Assuming

can

slope

(1-Fi)

gradient

energy

(4.4)

the

uniformity of

deposition were

made.

flow

the tail

of

for

gate

or

the

flow.

were

taken

The width

of

sediment

measured

along

the

4.3

Experimental

Details

of

summarised May

(1993).

4.3.1

Test

This

pipe

Work

the

test

here

are

Pipe

(see of

sections

-

Fig.

spun

450mm and

a total

by

three

up

thin by

plate

allow

pipe

horizontal The flume

and

from

reports

taken

450mm

locations

several

was and

an

pumps

and Plate

of

and

21m.

Flow

(1989)

and

2.52m

long

internal

diameter

of

supplied

to

was over

proportion

et

al

on wooden

position

were

flow

this

of

900mm x

two

a wide

blocks

checked to give

84

90mm slots

along

and

and

invert

adjusted

a maximum slope

the

of

the

levels

as of

pipe

extracted the

in

length

the

the

was

cut

the

rectangular

through

sediments

of bed conditions

be tilted

as

was made up of

recirculated

laid

could

procedure

May

a nominal

recirculated

had

by

4.5)

with

A small

section

experimental

Pipe

4.3

pump which

was

deposition

of

HRL

arrangement

length

observation

pipe

at

concrete

weir.

a slurry

Each

The

to

at

perimeter

wetted

limit

the

was adopted.

value

average

WQ, at

spread,

pipe.

top

to

pipe.

at

the

appropriate. around

0.01.

ýi 0e; U3ýý

ý3

äg

N

111

12

t

¢

C

o

Fc

.

ä

1ý

K&E

4 EO

ýa .

ä

ii Zý CL

a

J 85

ö

O

CD

co 1) 0

cd s.. C7

W EQ

a

86

flow

The to

act

tail

as

the

levels

were to

were

connected

point

gauges.

The

holes

were

tapping

to

A 1.22m

wide

test pumps

the

using

head was

Qw is over

the

given

by:

to

200mm above

made

half-full

at

thin to

used

weir

f low in

with

the

tappings

the

invert

and

above

required

flow

tappings

which digital

electronic

2.50m.

was

total >t;

discharge

the

addition

the

discharge

upstream from

the

of

the

three

relationship:

,+3.521711 0.38927H

-1.5337

(4.6)

1000

rate cm.

the

over The

slurry

electro-current thorough

of

flow

only.

in

weir pump

m3/s

Hp is

and

discharge,

Qp in

Qp = (ECM - 2) x 0.003065

ECM is

The

the

allowing

located

weir,

plate

measure

following

the

where

used

were

allow

pressure

equipped

between

interval

Qý _

where

end

five

using

wells

stilling

rectangular was

pipe,

plates,

uniformity.

measured

be measured

depths

vertical

Techniques

Measurement

The water

flow

two

of

downstream

the

at

gates

for

adjustment

4.3.2

made up

restrictors,

the

meter test

Q,. and Q..

87

pipe,

readings Q (m3/s),

the m3/s,

(4.7

in

volts. was

given

The by

The

digital

counter

made

the

and

varied

was

slope

pipe

by

the

of

to

connected

(4.8)

Sp = 9.964 x 106 FSCR - 0.00314

FSCR is

where

The

the

temperature

upstream

reading.

counter

kinematic

The

a thermometer

using

was, measured

tank.

was

readings

counter

a

from:

calculated

was

slope

a mechanical

Calibration

reading.

jack

viscosity

the

from

obtained

was

in

placed

Eqn.

4.3.

Sediment

was

sediment

the

test

sediment

pipe

Supply

on

sediment

return

the

source

of

outside pipe

(see

detected

with

(=d30)

size

2.62.

and Discharge

in

by the

head

the

hopper

the

and recirculated to

sand

narrowly-graded

introduced

concentration

attached

light

a

gravity

pipe

return

The sediment

the

was

specific

and

4.3.3.2

of

used

sediment

0.72mm

The

Characteristics

Sediment

4.3.3.1

The

Sediments

The

4.3.3

of

was measured of Fig. the

a

im 4.4). signal

88

test

using

long The

the

pipe.

an infra-red

perspex

section

sensor

mounted

which

end

pump through

slurry

the

downstream

the

at

were

modified

sensor of

the

opposite by

the

FIG. 4.4

Sediment

sensor

89

(After

May 1993)

of

amount

sand unit

an amplifier to

passing

the

along

The

pipe.

through

was connected

which

signals

fed

were

to

a voltage-converter

a counter.

Before

the

infra-red

in

weighed

the

a

base

the

catch

slurry

return

the

required

and

a stop

at

pipe

hydraulic

The

calibration could

be

curves,

of

is

shown

the

sediment

Uniform

tests

clear-water roughness

curve in

clear-water

or

into set

more

holes,

resealed

at

taken

at the

and

sediment

Fig.

the

pipe

were

for

to

return

4.5.

Using in

concentration

the

determined.

Establishment

of

then

at

directly

return one

pre-

vertical

sands

readings

were

calibration

1.39m/s

of

sensor

holes

The

from

removed

Ten

started.

it for

sediment

a

and

the

holes

hopper

the

over

readings

the

was

with

carry

introducing

with

tape

was

velocity

appropriate

A series

Then

was stopped.

stopwatch

4.3.4

before

sensor

sizes

The

a funnel

and

carried

various

filled

with

beaker

the

recorded

100s.

of

from

of rates.

mounted

pipe,

The

velocity,

intervals

then

intake.

pipe.

watch

was

test

the

of

the

and

were

supply

beaker

and It

concentrations

holes

of

the

calibrate

calibrations

with

a range

over,

sands

pump were

beaker,

sands.

end

sediment The

allow

taped

downstream to

to

to

was necessary of

range

plastic

of

it

velocities.

pipe

amount

sediment

test

over

the

conditions

pipe

sensor

initially

were

pipe

be used

a 2-litre

using

drilled

the

could

return

sediment out

system

of

the

Flow

were test

carried pipe,

90

and

out also

determine

to to

improve

the the

O

0 0 0

U O .r, Co 9.1 .0 cd U C) Cd

. r. eo q b cý aý c, c. 0 q a) cr

m

ci LO

CD

A LU

CD

(s)

L()

ýf

d'

Cl

Cl

NN

(cui/fix)

0 m

CD U)

CD G)

©0

"-

LIone. puaouoo

91

U)

pyres

mý

V 'd

la)

2 'd Q) c

w

flow were

return

the

upstream

end

a length also

raised

the

upstream

end

as the

flow

by

PVC plates

two

The and

and

slope

were

flow

up

flows

was

at

section

of

12m from

the

limit

of

channel

the

floor

at

flow

depth

were

considered

supported

half-full

of the

required the

of

flow

uniform the

when depth. Eqn.

applying

flume.

the

adjustments

required

by

taken

was

depths

uniform

the

function

of

until

to

was

as to

tested,

made

was with

This

also

The

wall

diameter

plate.

necessary

for

Procedure

Transport

A test

the

channel

pipe

and

that

such

point

Any 4.4

to

pipe was gauge

effect obtain

of the

So.

Experimental

4.3.5.1

to

each

± 2mm of

within

slope,

4.3.5

For

were

pipe.

conducted

and

test

channel

fixed

restrictors

non-uniformity

effective

the

the

were

readings flow

set

test

were

full.

The

obtained.

about

tests

was

the

the

which

the

at

replaced

4.6)

The

the

flow

then

Plate

pipe.

to

the

was

a semicircular

with

to

three-quarter,

discharge

test of

escaping

entrance

clear-water

the

bend

(see

sediments

connected

restricted

The

channel

three-quarter closed

bend

pipe.

inside

from

sands

test

the

bend

a

the

semicircular

to

up

any

avoid

the

of

150mm was

of

via

pipe

However,

pipe.

a 600mm long

with

test

Initially

end.

upstream

the

to

returned

sediment

the

at

conditions

two

the

Limit

2.52m

upstream

deposition

were

Sediment of

long end was made

92

Transport

Deposition

sections chosen. along

the

of

this

The test

pipe

observations section

located of while

W

rJ

.C

vi

a,

ý-, Z

the

length

whole

local

depositions

Once

the

to

added

clear-water

the

hopper

were

each

equilibrium

was to

section

5-10

seconds

interval

reached.

Two

taken

were sets

flow

of

when depths

limit

of

was

taken

to

made

limit

at

the

at

deposition

the

not.

100 was

between

taken

also

at

test

or

readings of

be

Once

deposition

of

were

the

readings.

sensor

the

deposition

constant.

limit

sediment

of

the

readings.

sensor

Transport

4.3.5.2

The

loose

test

pipe

beds up

for

levelled high

consecutive

gradually

sensor

were

the

was at

to

been

the

were

observations

flow

the

up

flow

readings

sensor

had

were

limit

from

the

rate,

obtained,

if

see

of

series

the

rates

continuously

occur.

readings

the

that

ensure

not

sediments

until

transport

supply

when

A

The

monitored

equilibrium

the

4.3)

Fig.

did

sensor

sediment

to

checked

joints

conditions, (see

sediment

always the

at

and

reached.

deposition At

slope

for

been

had

was

pipe

especially

pipe

recorded

the

of

were to

After adjusted

bed

the to

the

raise

to

the

filling

by setting

been water

the

thickness,

required

flatten

has

Beds

by

prepared

each test

discharge

Loose

over

the

whole The

y,,.

flume

the

at

length bed

a steep

of was

slope

the then

and

bedforms.

levelled, levels

94

the to

vertical

preserve

the

plates flat

bed.

were The

flow

discharge

velocity)

was then

adjusted

to

bedforms,

the

required (V=

-

0.7m/s),

flow

sediment

flow

depths

the

readings

were

pumps

pipe

bedforms. upstream bed

width

4.5)

at

and

last

portable

flume

slope

uniform

flow.

for

uniform

It the

(depth

and vertical

plates

Due flow

was

the set

for be

could

criterion

to

that

observed

was

conditions

were

presence

of

± 5mm of

at low

set

and

the

velocity ± 2mm of

at

the

depths.

sensor were

been

vertical

was

left

Due

10cm

in

to

the

/or

point

gauges.

point

gauge.

The

Once

readings. end

sediment

drain

disturbance

over

sensor

was

pump

and all by

sealed the

and

flow

order.

to

ends

intervals

1000s

over

downstream

The

that

thickness

intervals

the

the

taken,

overnight

and downstream and

between

plates.

down

shut

taken

were

readings

recorded

had

the

closing

The

criterion depth.

Five

The

obtain

flow

required

set.

flow

0.5m/s

required

the

at

followed of

the

of

were

the

length

the bed

95

thickness

bed

near

measurement

of

sediment the

pipe, made

by measurements

at

each

of

10m between was

slot

(see

measured

of the the Plate

the

first

using

a

5

CHAPTER 0

ANALYSES

PRELIMINARY

5.1

Flow

Resistance

This

section

provides

theoretical

works

is

to

relevant

(1988),

Featherstone-Nalluri

5.1.1

Clean

flow

The in

of by

flows, hydraulic

for

open

Darcy-Weisbach replacing

radius

frequently

I

is

that

channels

can

be

in

found (1979),

Schlichting (1993).

Chadwick-Morfett

and

channel

known used

flows

diameter,

pipe

Manning's

is

developed

equation,

D,

*

with

usually for four

expressed pipe-full times

the

(4R):

AV2 88R

as

Darcy-Weisbach's

equation

is

the

(5.1)

friction Manning

I R4' Son

n being

works

(1966),

Chow

S_

where

in open

These

and

experimental

Pipes

resistance

terms

as

such

to

resistance

studies.

present

textbooks

standard

flow

regarding

the

introduction

a brief

roughness

factor.

"-96

factor.

Another

equation:

(5.2)

An

approximate

5.1

Eqn.

through

and

5.2

Eqn.

rough

carried

out

flowing

pipes

and

n

extensive

(5.3)

His

experimental

flow

regions:

laminar,

transition

turbulence,

and

turbulence

(further

divided

turbulence). boundary Karman

layer

by

flows

with

expressed

Nikuradse's

developed

and Prandtl

smooth

pipes,

log -2

pipes

Colebrook-White and

developed

Prandtl's

zones

and

-

rough

turbulent

of

experimental

to

results,

equations

von

which

were

2.51

(5.4)

FR.FX)

and

I-

rough

show

laminar

three

theories

and

as:

F)L

for

from into

semi-empirical

1=

for

their

combining

smooth

results

turbulence,

transitional

Later,

in

work

experimental

full.

turbulence,

obtained

RlX

distinctive

smooth

be

could

yielding:

n_

Nikuradse

I

between

relationship

where

k

is

conducted

log -2 3: 1D

the

experimental

a semi-empirical

equations,

for

linear

equation, the

transitional:

given-as:

97

(5.5)

height.

roughness

work

for

commercial

pipes

von

Karman-

verifying zone

of

turbulence

log -2

is

Eqn.

5.6

for

commercial

also

determined to

to

applicable

for

experimentally

open

flows,

channel

the

Reý

whole

the

of

type

each

of

region

application

into

4R

D=

k,

value,

For

pipe.

of

substitution

turbulent

roughness

effective

an

using

pipes

3.7D

+

2.5

5.6

Eqn.

yields:

log -2 VFT

Re = 4VR/v.

where 5.6

5.7

or

direct

It

must

to

be noted

that

iterative

necessitates

solutions

k+2.51 14.8R RoVII

the

(5.7)

Colebrook-White's for

solution (Eqn.

equation

5.6)

was

1.

Eqn. One

proposed

of

the

by Barr

as:

ký; 5 + 148R geý

log -2

after Fig.

5.1a

flow

in

5.1.2

The

D=

substituting shows a clean

Pipes

presence

composite

the

i. e.

a sediment

resistance

open

geometry

without

Deposited

to

application

cross-sectional

pipe

with

of

4R for

(5.8)

of

channel the

open

flows. channel

bed.

sediment

Beds

bed

made up

in of

pipes the

98

pipe

(Fig. wall

5.1b) and

produces the

loose

the bed

D 2 yo

FIG.

5. la

Cross-sectional

geometry

for

clean

D 2

FIG.

pipes

Y=ya+y8

5. lb

Cross-sectional

geometry

99

for

pipes

with

deposited

beds

(1987)

itself.

CIRIA

composite

roughness

linear

based

]ý_

P is

where

the

The

roughness. the

and

Another by

wetted

bed

approach

to (see

Visvalingam

shear

P.

the

of

'w'

(5.9)

and

ks is

and

'sb'

the

composite

refer

to

effective

the

pipe

wall

was

given

respectively.

the

compute May

composite based

1993)

on

resistance perimeter

weighting

of

stress: p*ýtlb

Tý=

where

weighting

perimeter

the

compute

+ P. pý+Pw

perimeter

subscripts

sediment

the

on

to

equation

k:

value,

roughness

an

proposed

is

is

the in

transformed

composite terms

+ pwTw

pt

shear

+ pw

stress.

friction

of

(5.10)

factor

Equation using

5.10

could

be

Darcy-Weisbach

equation:

P, PW), + h11eb w pab+ pw

"

where

1e is

the

friction

composite

(5.11)

factor.

,..ý . ., ýý

Aýt

ý. .

tý.,.

It

100

5.2

for

data

The

calculation in

given is

Appendix

listed

in

A total were

clean

(D

pipes

k0)

0.53mm

The

friction

in

the

factor

126

experiments two

with

Table

without

the

of

(Fig.

5.1a)

are

investigated

conditions

values

The

the of

(D

boundary

in

roughness Section

I.,

305mm

performed

was

corresponding

rough

values

of

from

computed wall

also

the

roughness,

ko,

5.7.

For

Eqn.

no were

and

4.2.4).

Colebrook-White's

Manning's

experiments

154mm,

=

were

4.2,

219

where

pipes

sediment,

5.1.

from

comparison,

preceding

details

The

conducted

clean

(see

Eqn.

obtained

was

A.

the

of

were

= 305mm)

Darcy-Weisbach's

those

geometry

smooth

other

1.34mm

and

Appendix

summary

Roughness

5.1.

out

and

The

Wall

including

cross-sectional

experiments

carried

450mm)

C.

Table

345

of

flow

the

of

in

given

are

Pipe

-

tests

clear-water

all

tests

transport

Results

Experimental

Clear-Water

computed

from

Eqn.

the

range

5.2.

In

general,

the

of

Reynolds

numbers

and

no are

(see

and

5.1a) have

0.009

pipes, higher,,.

-

the

Table

5.1. that

suggest values

0.010

_the.,,,.,

particle.

constant

over

overall

average

The

present

experimental

results

clean

flowing

the

of:, ko and

of

were

The

smooth

no in In

respectively.

mean values

than..

ko and-no

of studied.

in

given

Table

part-full

values

the the

ko (-0.53mm -sizes 101

range case and

.

(dso

pipes of

of

values

O. Omm -

the

1.34mm)

rough arIe

0.50mm ,

ko

of

0.2mm clean

slightly and,.

4.0

TABLE

a)

5.1

FOR CLEAR

WATER

DATA

SMOOTH CLEAN PIPES 305

154

D (mm)

450

V (m/s)

0.244

-

0.931

0.400

-

1.255

0.395

-

yD

0.149

0.756 -

0.206

0.803 -

0.500

0.750 -

k

NO.

0.73x1052.81x103

0.13x1051.49x105

Fr

0.49

So

0.13x10"? 0.51x10"2

0.06x10-2 0.53x10-2

0.02x10"? 0.30x10"2

0.01420.0465

0.03780.0928

0.1110.136

0.32

1.30

-

1.51

-

1.194

1.59x1034.69x105

Re

R (m)

b)

RANGES

EXPERIMENTAL

0.23

0.91

-

(mm)

0.169

-0.010

0.135

no

0.0098

0.0090

0.0103

0.01760.0426

0.01110.0224

0.01470.0204

57

OF DATA

111

51

ROUGH CLEAN PIPES 305 (ROUGHNESS

D (mm)

V (m/s) y ,,/D Re Fr So R (m) "k

0.390

-

(mm)

n ýö NO.

OF DATA

2.78x105

-

0.28

0.0324

0.0188

0.441 0.772

-

0.86x105

0.06x10-2

1)

1.109

0.174

1.22

-

0.56x10"2

-

305 (ROUGHNESS

0.0925

-

0.836

0.200

2.14x105

-

0.38

0.0368

0.756

-

0.62x103

0.10x10-2

1.02

-

0.56x10-2

-

0.0922

0.53

1.34

0.0111

0.0127

-

0.0322

90

0.0272

36

102

2)

0.0458

respectively) The

corresponding It by

calculated

values

resulted

in

ko and

higher

(ko = 0.0mm,

the

plots

pipes

smooth

full

curves

The

the

of

turbulent

5.4

Fig. 5.6-for

Eqn.

were

that

of

the

of

are

sensitive

(k0

ko

as

to

the

may have

pipe

data.

This

k0.

These

average

values

for

smooth

n, = 0.012)

clean

values

= 1.5mm,

0.012

(1987)

in

assessing

are

in

Fig.

5.2

rough

By

applying

pipes. for

5.1)

shown

each

set

Colebrook-White's

data,

of

Eqn.

5.6

for the pipe-

were

also

comparisons.

the

measured

computed

Reynolds

values

pipe-full for

data

fall

tend

be

to

An examination

curves.

numbers

experimental

I.

of

each

boundary

within

the

roughness transitional

zone.

tests

the

applicability

open

channel

flows

5.7.

Good agreements

obtained

equation

show

the

for

Table

using for

ranges that

shows

(see

plots

around

scattered

ko

computed

results

values

suggested

number

5.3

Fig.

of

the

on

shown

the

and Novak-Nalluri

Reynolds

and

values

average

and

practice.

Ao vs.

of

the

rough

and

(1984)

design

present

The

or

no=

by Ackers

used

pipes

0.010)

of

values with

consistent

5.7

part-full

average

0.011

that

Eqn.

the

are

n

noted

White's

1. for

of

no are

be

boundaries.

rough

artificial

Manning's

of

should

Colebrook

measured

the

create

values

respectively.

of

to

used

(Eqn.

confirming 5.7)

for

of in

using

Colebrook-white's

pipes

by

clean

(correlation

the

applicability

the

present

103

substituting

coefficient, of

the

experimental

Eqn. D= r=0.95)

Colebrook-White data.

4R

10-1

0 Egn. 5.6(k,

=0.0mm)

10

154mm (SMOOTH)

00000 D= 10 -0-110'

10'

10°

10'

to'

Re = 4VR/v

factor

friction

FIG. 5.2a Clear-water

in a smooth

154mm

dia.

pipe

10-' 1~ý

.c

Eqn.

5.6 (k,

= O.Omm)

10

00000 D=

305mm

10 a

10'

(SMOOTH)

lU 6

104

log

101,

Re = 4VR/v

FIG. 5.2b Clear-water

friction

factor

104

in a smooth

305mm

dia.

pipe

10"

Eqn. 5.6 (k, = O.Omm) 10

450mm

00000 D= lo-,

lU `

101

(SMOOTH)

to'

io'

in

a smooth

450mm

Eqn.

5.6 (k,

10

Re = 4VR/v FIG. 5.2c

factor

friction

Clear-water

dia.

pipe

10-1

o

.
0.5

01' 01 O

10

100 0

r.

a y;

10

CS I (SMOOTH) 305mm D= doo = 5.70mm (Limit of deposition) 10-11 0.1

1

V (m/s) FIG., 5.5d

Effect

of flow

112

depth

-

deo

5.7mm

10'

o20Q0 d6o = 0.46mm dßa = 2.00mm

Qoggp dao = 5.70mm F'

103 G/ a/

o/ *7/

O0

10`

/

I

a Vº

Of Oz

10

zo

1

D= 305mm (SMOOTH) /D ' 0.5 , (Limit of deposition)

10-1+ 0.1

i V (m/s)

FIG, 5.6a

Effect

10`

of particle

size: flow

depths

up to half-full

QD&= dao = 0.46mm #irir.*i do = 2.00mm ooQoo dao = 5.70mm

10'

10

ad v

dD ö

rr

10

"o

I

305mm (SMOOTH) 0.5 > o/D Limit of deposition)

D=

10-I 0.1

1

V (m/s)

FIG. 5.6b

Effect

of particle

size: flow

113

depths

more, than

half-full

5.3.4

Effect

The

of

effect is

velocity

the

transporting

hydraulic

in

wall

range

in

sizes

transporting

The

of

clean

pipes

was the

sizes

used

the

boundary

than

8.3mm.

sand

used

0.5mm

of

for

the

as

2.0mm

wall

Colebrookused

the

were

second

roughness

8.3mm

to

the

for

the

size,

sediments

1.34mm.

of

sand

by

as given

Similarly

height

of

up

transporting

to

in

There

is

or

decrease

1982,

Loveless be of:

coefficient with

5.7

to

tested,

no

clear with

wall

resulted

Hence

only

were

used

for 1991)

expected friction

increasing

those

that

the

increase

in

transport point to

indicate

sediment

in

out be

felt

between surface

114

that, data

experimental

around

trend the

5.10

the

be scattered

models

can

Figs.

sizes

seem to

Semi-empirical

increases

0.53mm

range

sediment

increase

roughness

height

as shown

range

(May

that

as

the

over

the

materials.

results

pipes.

made

roughness

the

sediment

larger

always

roughness

1.0mm

the

hydraulic

the

are

be recalled

must

the

self-cleansing

(d30 > k0).

1.0mm

of

It

pipes,

the

on

5.10.

to

clean

Therefore

equation.

roughness, in

rough

roughness

the

5.7

Figs.

itself

first

the

roughness

surface

material

height

roughness

White

in in

experiments

Roughness

or

wall

shown

for

For

Wall

of

the

of

for

rough

smooth

clean

velocity wall

will

either

roughness.

boundary

rigid

channels

that

an

increase

in

in

two

ways.

Firstly,

the,

sediment

roughness.

and

Secondly,

the

wall the

the the

wall flow

is

resistance

increased

sediments.

Both

transporting

capacity

suggesting

that

reasonable

to

boundary in

is

may point

The

suggest

presence

of

as

in

seems

the

with secondary

rigid

currents additional

direction.

f low

of

wall

resistance

roughness required

the

increase

in

friction

flows

it

creating

the

the

hence

pipes,

Although

in

designing

in

sediment

velocity

in

sediment

the

clean

1991)

effect to

reduce

the

(see

should

the

be

the

Rather

slope. factor

Section

not

on

other

due

5.3.7)

to

the

should

also

considered.

5.3.5

Fig.

Effect

5.11

of

pipes

works

in

confirming

small

pipe

5.11.

For from

existence

pipes the

regression, dia.

Pipe

shows that

large

data

due

on

needed.

opposite

the

acting

rough

an increase

the

that

consideration such

be

in

velocity

factors

increase

(E1-Zaemey

turbulence,

self-cleansing

is

required,

boundaries

results

for

flow

velocity an

assume

will

effects

the

of

a higher

roughness

rough

sole

these

of

drag

the

reduces

which

which

Size

the (eg.

best-fit has

the

of

parallel

154mm and distinct

interpolated

May 1982,

widest

on

Mayerle

collected data

range

of

lines

were pipe.

depending

115

is higher

from 1988).

the'data

450mm dia.

regions

required

velocity

results

line

comparison, the

limiting

the

is

for

experimental Using in shown

a power the

305mm

in

Fig.

also

plotted

for

the

These

lines

show

the

on pipe

diameter,

hence

D=

305mm

0.5 a oýD Limit of deposition)

10

0 0

ä

Ot*

Oll

10

a 1*

10

doo = 1.0mm k, =0.00mm

00000 k, =0.53mm I$S 0.1

1

v (m/6) FIG. 5.7a

D= 10'

d50 =

Effect of wall roughness (Flow depths up to half-full)

a/D

1.0mm

305mm > 0.5

Limit

of deposition)

10` a oý , 10

0h 0

*

dbo = 1.0mm k, =0.00mm * 00000 k0 0.53mm

1c 0.1

1

V (m/s) FIG. 5.7b. ß Effect of ýwall roughness d50 i. Omm = -(Flow , depths more than half-full) 116

305mm

D=

TjýD s 0.5 Limit of deposition)

10°

o

Qr i

C)

10

a w

t obi

1ö

A

0 10

Iý do0 = 2.0mm *-*.*A* k, =0.00mm 00000 k, =0.53mm 0000° k, =1.34mm

1$S 0.1

1

v (m/s) FIG. 5.8a

Effect (Flow D=

305mm

I o/D>0.5

10'

0

of wall roughness -d=2.0mm depths up to half-full

Limit

of deposition)

10`

of

°

10

2. Omm

d60

°o6eoo

*E*jrjr ko=0.00mm 00000 k, =0.53mm ko=1.34mra

i

1

0.1 v (m/s) FIG. 5.8b

Effect of wall roughness (Flow depths more than 117

d60 2,0mm = half-full)

D=

305mm ? o/D s 0.5 Limit of deposition)

i0'

OA CIA, ä

i0'

a

10 dN4.2mm k, =0.00mm 00000 k, -0.53mm äAAA k, =1.34mm 1$S 0.1

1

v (m/8) FIG. 5.9a

Effect of wall roughness (Flow depths up to half-full) D=

10'

a

d50 = 4.2mm

305mm

a/D>0.5

Limit of deposition)

10ý

ýýý 00

U

ýQ

ap

10

deo = 4.2mm *ý+ i+ k, =0.00mm 00000 k, =0.53mm aAaaa k, =1.34mm 1 0.1

1

V (m/s) FIG. 5.9b

Effect, of 'wall roughness d60 4.2mm = . (Flow depths more than half-full) 118

D=

305mm

0.5 c o/D Limit of deposition)

10 '

o0o

0*/

* öý° * ä

oA#l /o

'* ý,

10 '

a

0

10 d&o = 5.7mm k, =0.00mm

00000 k, =0.53mm oooao k, =1.34mm 1 -0.1

1

V (m/s) FIG. 5.10a

Effect of wall roughness (Flow depths up to half-full) D=

dbo = 5.7mm

305mm

(Limit o/D>0.5 of deposition)

10'

i 10ý

dm

ö

10

dao = 5.7mm '*

ýºi+ ko=0.00mm 00000 ko=0.53mm ko=1.34mm AAA

0.1

1

v (m/s) FIG. 5.10b

Effect of wall roughness (Flow depths more than 119

d60 = 5.7mm half-full)

different

that

suggesting

velocities

are

for

required

pipe

each

size.

5.3.6

Effect

Details

the

of for

5.1b)

(10m

long)

Fig.

5.13

with

a

that

for

a

inverts.

dia.

computed

with

The sediment

in

beds

might

The

author's

10%.

move

as

Fig.

5.12a).

However, trains

beds

sediment

of

for

smaller

separated

et

present are depths dunes

120

mean

yg/D.

al

1989,

present of over

when deposits, the

with of

presence

clean

data ys/D the

clean

the

E1-Zaemey

experimental

is

velocity

those

the

yQ.

implies

This

capacity with

of

capacity

lower

than

flow

All values

depth, a

by

section

5.12).

these

The

obtained

transporting

associated

C.

measured

Fig.

deposits

(May

were

the

be

1991).

than

in

transporting

width

continuous

on

the

bed

that

based

Appendix

the

concentration,

sediment

Loveless

y1,

(see

sediment

increase

in

given

pipe

(Fig.

geometry

along

sediment

sediment

pipes

bed

increase

the

given

are

thickness,

sediment

proportional

for

finite

then

illustrates

larger

required

of 450mm

the

were

beds

sediment

volume

of

parameters

with

mean

the

cross-sectional

deposited

with

the

averaging

of

computation

pipes

of

values

Deposit

Sediment

of

pipes of

a

1991, suggest

is

larger

sediments

inverts

(See

eQ

A

e

10'

$ o

°o

°e

e° ý

°

10`

A

+

A

a

ö 00

o00 o

10

$+ +

o+

SMOOTH PIPES

+

+

(Limit

of deposition)

°e°e°

D = 154mm

22449 D = 305mm +++++ D = 450mm

10-1 0.1

,

-,

1

V (m/s)

FIG. 5.11

10.,

Flow

direction

Effect

of pipe

size

Y0

5.12a Definitions FIG. of (separated features bedform

L

mean sediment dunes)

121

bed

thickness

and

direction

Flow

L'

r

Yo

Definitions 5.12b of FIG. (continuous features bedform

bed

mean sediment dunes)

thickness

* ýrCdr

10'

4

id-

°++

log P4

+

v++ox ° +

10

ocxx x

D450mm

ýx

x

xx 4c 'r` x WX x

x

xxxxxy. /D = 0.00 (Limit of deposition) dunes) oaooo y1/D < 0.01 (Separated dunes) +++++ y, /D = 0.05 Separated /D Continuous dunes = 0.12 y, 4_t**** D=0.22 Continuous dunes ' 10 ', 0.1

se

1

v (m/s)

FIG, 5,13

Effect

122

of sediment

deposits

and

5.3.7

height,

roughness 5.1

and

The

apparent

Both

the

computed

from

tested.

rough

pipes

for

to

of

be the

both

smooth

in

in

rough

larger The

pipes.

of

value

results

create

pipes

the

pipe

factor

for

smooth of

pipes.

clear

also

a

in

clean and

that

5.14

Figs.

friction

the

presence

increase

the

and

than

may

Eqn.

the

concentrations

smaller

sediments

to

shown

indicate

already

rough

due

is

pipes

increase

the

corresponding

Darcy-Weisbach's

factor

sediment

to

for

presence

clean

limiting

due

factor

of

> 1)

appears be

friction

the

and

respectively.

consistently

plots

of

5.7

the

case

However,

could

friction

in

(As/A0

range

sizes

the

were

Eqn.

the

factor

fiction

This

A1,

increase

5.15.

over

sediment,

Colebrook-White's

in

and

with k6,

sediments

Transport

Sediment

with

factor

friction

The

of

Factor

Friction

water

suggest

relatively

that

smoother

boundary.

increase

The is

in

shown

of

friction

Fig.

5.16.

author's

previous

half-full

flows, to

slots due

to

0.7m/s),

the

determining result, quite

passage

low,

It

and

hence

pipes

1990)

gauges

were

measurements of

dunes

of

ýs these

of

the

water

for

several

were

123

from

pipe

However,

velocity

accurately. the

the

at

(V

difficulties

caused

of

the

= 0.22

over

high

surface

omitted

ys/D

levels.

water

level

water

during

that,

where

at

deposits

sediment

mounted

especially

in of

with

be mentioned

Ghani,

point

slope

values

in

should

(Ab.

fluctuations the

the

the direct

obtain the

work

factor

experiments the

plot

> in

As

a

were shown

in

2.00

SMOOTH PIPES

&&A&&D=

154mm

00000 D=

305mm

+++++ D=

450mm

1.50 (xr/x0)

e

---------------------------------

r ------

Q --ö:, o

= 1.30

OCDý

A°

40.0

1.00 ooA 0JL ------------------------

------------------

= 0.85

0.50 10

1

1 oil 11 10

10

10'

10'

C. (PPM)

FIG. 5.14

Increase in friction (Smooth pipes)

factor

at limit

of deposition

2.00 D=

305mm

00000 k, =0.53mm ýooAA k, =1.34mm 1.50

1 20 -------------------------------------------------0 00

0

ao

o

1.00

-------------------

I-=0.93

0.50

1 .11

10

los

10'

C, (ppm)

FIG. 5.15

Increase in friction (Rough pipes)

factor

124

at limit

of deposition

io

Appropriate

5.16.

Fig.

have

level

water

measurement

for

5.16

Fig.

Overall, < 1%) the larger

value

(May

made

the

measurement

1993).

The

water

as

explained

is

studies

present

be

of

the

of

level in

for in

increase

shows

Froude

depths

small

of

roughness.

This that

that

is

suggests

definitions shown

> an

with

hence

the

of in

the

Fig.

were height 5.12.

the

around

those

of

with 1%

=

for

an earlier be

would large

the

attractive

very the

of

pipe

clean

May et

of

al

for

a new

studies.

The

pipes.

also

made for-the

and

length

The

corresponding

125

For

values

work

the

roughness

roughness.

5%,

the

corresponding

Froude

a

ye/D

depth

of

a larger

However,

(ye/D

deposits

factor,

friction

pipes.

large

depth

a small

composite

clean

of for

expected Also,

Fig.

the

for

that

shows

that

than

5%).

as

been

the

4.3.2.

Section

to

adjustments

since

method

to

of

present the

individual mean

values

dunes

are

of

the

0.1 ++++ +

KX

XKO

'ýi`'

I

, 0,4.

+++Q

Ck

X

0.01

D = 450 mm (Limit deposition) /D 0.00 of = xxxxxy, dunes) (Separated /D 0.01 < 0000o y. +++++ y, /D

Separated Continuous Continuous

= 0.05 = 0.12 00oao ye/D /D = 0.22 *sý y.

dunes) dunes dunes

111411

0.001 10"'

10'

10

1

jIIIII10`

10'

C, (ppm)

FIG. 5.16

factor

Friction

beyond at and

the limit

of deposition

15.0 12.5

450mm

°D=

10.0

/D 00000 y. +++++ y. /D eo°eo y. /D ***** y. /D

e *°

7.5 5.0

++

54 .

+* eir

2.5

+

0.0

it e

< = = =

dunes) 0.01 (Separated dunes) Separated 0.05 dunes Continuous 0.12 dunes Continuous 0.22

e

+++

ko=0.135mm

---------Qa-----------------------------------

-2.5-5.0

0.0

1.0

0.5

Fr = (BV2 /

FIG. 5.17

1.5 a )o. gA

Effect of Froude number on overall in pipe with deposited beds

126

2.0

flow

resistance

height

length

and

averaging

sediment

the

simplicity, the

compute

values values

corresponding computed show

the

Visvalingam

from

TABLE

of

bed

of

the

AIeb and

of 5.3

5.7.

ksb with

the

Froude

450mm

keb,

were 5.19

and Fr.

number,

CHARACTERISTICS: FLOW RESISTANCE WITH DEPOSITED PIPES BEDS

D=

the

while

5.18

Figs.

to

used

was ABb,

its

to

height,

roughness

depth

each Due

5.11)

factor,

Eqn.

for

the

of

range

5.3.

(Eqn.

friction bed

The dunes

the

Table

method

Colebrook-White's

variation

of

by

obtained

was

dunes.

in

given

test

each

length

and is

deposit

for

individual

the

of height

the

of

mean values of

values

all

dunes

the

of

-

dso = 0.72mm

y3/D

< 1%

5%

12%

22%

Ab

0.0253 0.0349

0.049 0.116

0.038 0.111

0.011 0.108

ksb

0.62 - 37.20

16.60 208.50

6.40 130.00

H (mm)

14 - 22

38 - 69

25 - 83

51 - 74

L (MM)

192 - 367

400 - 633

505 - 940

1090 - 1272

7.20

98.70 -

NOTE:

For bed thickness flow proportional

of 0.22D, the bedform measurements depth (Y/D)'of 0.75 only.

127

were made for

overall

11

nA

+

o+

A

450mm

D= °

°ODOD y. /D /D +++++ y, /D 00000 y, /D **

°

0.01

1.0

0.5

0.0

of Froude

Effect

2.0

1.5

F= = (BV2 /

FIG. 5.18

< = = =

dunes) 0.01 (Separated dunes) 0.05 Separated dunes 0.12 Continuous dunes 0.22 Continuous

a )o. gA

on the bed friction

number

factor

+

100

+ °+e* it

+e $

°F e

10 ý"

o

0

D=

i °

o000o y1/D < 0.01 (Separated +++++ y. /D /D y.

= 0.05 = 0.12

y. /D = 0.22

*+ý 0.10.0

450mm

0.5

Separated Continuous

Continuous

1.0

dunes) dunes) dunes)

dunes)

1.5

Fr = (BV$ / 9A )o.a FIG. 5.19

Effect of Froude number

due to sediment

bed

128

on flow resistance

2.0

6

CHAPTER

6.1

The in

Background

basic

and

steady

(V)

(p)

density

of

concentration

due

acceleration

These

variables

works Sakhuja have

a

number

(Ambrose 1990) great

pipes.

Several

Chapter

3 are

(D)

usually the

1953, have

prediction

identified

examples given

in

channels

(R),

flow

mean

(v)

viscosity

density

bed

of

analysis

(p9) (k0)

of

and pipe,

(So)

slope

and

the

of

these

Table

6.1.

129

ways

to

the

flow

transporting

of

used

obtain

Mayerle these

sediment

Previous

parameters

1988,

parameters

transport as

a

to

extensively

parameters.

1975,

several on

two

was

group

Novak-Nalluri

influence

pipe

roughness

in

applied

dimensionless

of

and (I. ),

dimensional

Firstly,

capacity.

(d),

size

process

(g).

gravity

were

kinematic

sediment

enabling

relationship

obtain

to

('fo),

size

with

clean

radius

water,

sediment,

in

hydraulic

stress

shear of

factor

friction

or

transport

sediment flow

surface

(yo)

depth mean

or

the

govern

free

uniform

flow

the

velocity and

that

variables

include

to

DATA

Pipes

Clean

6.1.1

TRANSPORT

SEDIMENT

OF

ANALYSES

process highlighted

Paulknown in in

The

second

at

the

approach

was

(May

equilibrium

homogeneous

dimensionally being

to

similar

solve

the

forces

1982,

Mat

Suki

those

1987,

by

obtained

on a particle Loveless

equations

are

dimensionless

their

with

acting

These

equations.

semi-empirical

yielding

to

usually

parameters

dimensional

the

1991)

analysis

approach.

TABLE

6.1

PARAMETERS FOR CHARACTERISTIC CHANNELS CLEAN PIPE

TYPE OF

SEDIMENT

DIMENSIONLESS

TRANSPORT

GROUPS

PARAMETERS MOBILITY

V1

ti,

gd5(S,-1)

v V'

TRANSPORT

pg(S.-1)dso

CVR -l)-4 vlg-(-Sa --

SEDIMENT

CONVEYANCE SHAPE

FLOW-

Dgr,

R/dSo,

D2/A,

CBs

RESISTANCE

130

d50/D,

yo/dso,

(ks

-

S8

Dh/yo,

ko) /D

Yo/D

IN

The a

the

values

of

standard

6.1.2

present

5.2)

were

to

3.3.1).

This

(V),

as velocity

involved

hydraulic

performance

in

of

plot

of

observed

A

discrepancy

computed

and

measured

accuracy

of

values.

is

C,

size,

in

analyses was based

model

(adj.

the

of

clean

pipe

r2),

model.

of limit

the

at

other

radius

(R),

several

of

computation

using

(see

channels

applicability

the

(Cv)

The overall

of

the

existing (see

deposition the

of

measured

Table

volumetric

quantities

and

friction

is

presented

such

factor

with

(1a).

sediment

a

and

coefficient

simplicity

transport

concentration

sediment

the

evaluate

sediment

by

Equations

data

experimental

for

equations Section

Existing

of

used

the

preceded

regression

best-fit

the

determination and

were

relationships

multiple

of

selection

(s)

Appraisal

The

by using

adjusted

deviation

transport

existing

final

The

data

experimental

was obtained

equation

extensively. on

present

the

of

comparison

final

the

of

analyses

Dgr,

investigators

equations

plotted

as

experimental presented,

is

values, Here,

a

the

function

introduced

It

data in

1993,

in

Section

should

Loveless

the

appraisal

3.3.1.

131

between

ratio

ratio

dimensionless et

computed

indication

an

discrepancy

by White

relationships. 1982

as

the

of

the

as

used

graphically their

against

defined

ratio,

an approach

(May

equation

concentrations

equation.

transport

alluvial

their

the

each

al

(1975)

be noted 1991) of

have several

of in

the terms

sediment to

assess

that

other

also

used of

the

The

of

categories

were: 3.15,

and

Eqn. be

should

In

pipes

were

effect

of

and of

the

are

the

or

surface

given

in

percentage

variation

of

Eqn.

experimental

50ppm

is and

concentrations

Eqn.

The

second In

(1982)

conjunction

Vc.

velocity, were

transport

Eqn. Novak-

with

equations

sediment

on

analysis.

threshold

the

3.11

in

data

500ppm. using

rough

beds

It

selected

equations

6.2

and

in

terms

of

which

can

Fig.

good

at

of

be found

clean

highlight

results on

average

for

the

Figures

each

the

of 6.1

is

equation

discrepancy

ratio

different

ranges

in

ratios.

6.1(a)

provides

for-the

limiting

3.11

about are

132

within

fit

a reasonable

a mean discrepancy

Overall, Eqn.

to

plotted

performance the

data

The

overall

with

--

present

roughness.

discrepancy

the

rather

and

Table

data

of

the

equations, smooth

statistically

agreement

in

these

of the

of

into

6.2,

Table

Laursen's

all

the

of

wall

presented

the

compute that

grouped

comparisons In

3.19

based

(1975)

Macke's

were:

of

equations

3.35.

and

limit

deposition.

of

comparison

6.6.

to

selected

theoretical

equations

development

the

limit

the

3.5

3.34 from

Eqn.

is

Novak-Nalluri's

derived

(1989)

al's

the

broad

two

the

at

equations

category,

Eqns.

chosen

emphasized

denote

the

is

of

3.11,

(1988)

the

and May et

this

Eqn.

equations

category,

Nalluri's

to

(1956)

Mayerle's of

category

3.17,

In

the

represent

relationships

category

analysis.

Laursen's

comparisons

transport

first

The

dimensional

the

sediment

deposition.

this

for

chosen

equations

ratio

2.37.

of

concentration 55%

of 0.5

The

between

the' and

to

predicted 2

times

the

as

used

(see

values

observed

indication

an

transport

Fig.

similar

results

6.2

TABLE

6.1(a) for

band

This

the

of

of

reliability

(White

relationships

1981).

6.2).

Table

et

of 1975,

al

also

shows

that

Laursen's

both

rough

and

smooth

(predicted)

usually channel

alluvial 1979,

Yang

bed

Brownlie

3.11

Eqn.

produced

data.

DISCREPANCY RATIO (Cv) FOR DIFFERENT ALL PRESENT DATA (CLEAN PIPES)

Equations

is

error

EQUATIONS

(observed)

/

-

No.

of

Mean

min

max

0.91.1 (%)

0.751.25 (%)

0.51.5 (%)

0.52.0 (%)

data

2.37

0.17

33.82

10

23

42

55

256

3.84

0.14

61.20

7

17

31

38

256

3.55

0.01

41.10

5

12

30

35

256

Mayerle (Egn. 3.35)

0.38

0.02

10.41

3

7

21

22

256

May (Eqn. 3.19)

0.18

0.00

1.03

1

2

6

6

256

Macke (Eqn. 3.17)

0.24

0.00

3.04

1

5

14

16

256

Laursen (Eqn.

3.11)

NovakNalluri (Eqn.

3.15)

Mayerle (Eqn.

Fig.

3.34)

indicates

6.1(b)

limiting

at

produce

concentrations equation

itself

higher a

Eqn. for

concentrations

obtained can

that

values

over does

Dgr

3.29 2.0mm)

for

the

above

suggests

that

305mm (SMOOTH) D= (Limit of deposition)

10, I

'o

10

aý

0° a+ CIO

10 `

°

a+

o +* tr ýr o o°'

+ ° +

ö

o

*°

10

0

Ao

Sediment

size 00000 dbo = 0.46mm °°oo° dbo = 0.97mm ýrtrýr,a dso = 2.0mm

". " 1

+++++ dao = 4.2mm aaa°° 00000

10 "'

10`

10' 10' Eqn. 3.29 -

10 C, (ppm)

1

10"=

d6Q = 5.7mm dao = 8.3mm

FIG. 6.18 Predicted C, using Ackers' Eqn. 3.29 for (W8 10deo) dia. 305mm = pipe smooth

the 3.29

form

of

can

be

the

equation

re-written

be

should

K

and

J

respectively). that

it

will

m g-1

condition Fro. of

Figs.

defined

are

as

The

form no

predict

as given 6.19

Dgr and R/d50 for

Eqn.

Ackers'

re-examined.

as:

C, w

where

author's

of

and the

6.20 data

(Eqns.

earlier

the

equation

movement

by K is

(6.34)

of

larger

the

from

6.34) if

the

mobility

plots

author's

184

(Eqn.

sediment

than

show

3.30

total of

Frn/K

smooth

the

as

and

3.31

indicates threshold number, a function

305mm dia.

pipe

4.0-

D = 305mm (SMOOTH) (Limit of deposition)

0 3.0 o 0

0

2.0-

0 o

TRANSPORT 00 00

cA

o0

0 00

°

8

92

1.0

INCIPIENT MOTION

-

.2cc

L .

0

(9

0 NO TRANSPORT 0.0

ht

0

1114

1.,

fill

1111

111

11114114

100

50

oil

fill

1111

160

111

viol

11ij

250

200

Da total to critical Ratio of measured FIG. 6.19 mobility mobility dimensionless Eqn. 3.30 function Ackers' by as of a computed dia. data 305mm smooth particle size for authors 4.0

D= 306mm (SMOOTH) (Limit of deposition) o

3.00

o0

0

0000 2.0

0 cP o e000 (o oV o0®

00 o0

0TRANSPORT

0 0

00

INCIPIENT

1.0-91119

MOTION

0

NO TRANSPORT 0.0

0

50

100,150

200

250

R/dso FIG. 6.20 Ratio of measured total mobility by Ackers' Eqn. 3.30 as a function computed dia. data 305mm particle size in smooth 185

to

critical mobility of dimensionless

could of

in

bedforms

much higher

by the

be explained the

derived.

was originally

upon

channels

alluvial It

dueLthe

resistance

be noted

also

should

3.29

Eqn.

Ackers'

which

presence

that

the

range

10

Eqn.

Novak-Nalluri's ----

R- An

Fnn_

Ar% (Pra'a

3.5

vi v1 PO

10-1 1

10

loll R/d6o

FIG. 6.21 for loose

of

(Ackers

1991).

transport

in

6.23

clean it

suggest

author's

Since

3.5

data

the ýfor

is

3.30

the

the

to

whole

is

6.6)

Table

appropriate for

the

of

define

range

motion

150

within

majority (see

pipes

seems

Eqn.

Nalluri's

Eqn.

of

applicability

R/d50 < 100,

Comparison of incipient boundaries and rigid

of

R/d50

within

data the

K in

terms

Dgr.

Figs.

of

this

modification

smooth

305mm

dia.

pipe

were

30000

4.2mm with

predicted

the

data

determined

The

values

data

shows

the

data.

of

author

the

was

smooth of

for

as

equation.

Fig.

values

Hence,

coefficient

f(d30))

Ackers'

pipes.

observed-Fro

and maximum

the

that

modified

of

for

of

plots

Fro

with

presenting

in

for

analysis

preceding

was

May

parameters

an equation

equation.

correlation

given

values

in

1988,

in

f (dso))

errors

Ackers'

minimum

as the

as well

of

author's

accurate

clean

We (=

(Mayerle

relevant

of

the

of

all

The

form

more in

of

6.6.

the

is

value

given

The average,

majority

that

ranges

Table

proportionate

are

rough

shows

modified

analysis

was

in

process

the

the

minimise using

given

on

studies

other

the

variable

study,

each

1991);

transport

sediment

are

as

from

data

the

done

was

analysis

the

was obtained

>

data

from

TABLE

OF MODIFIED ACKERS' EQUATION VERIFICATION PRESENT CLEAN PIPE DATA (W. = 10dso)

6.20

D (mm)

RATIO

DISCREPANCY

r

FOR

NO.

s

AVERAGE

MIN

MAX

0.92

0.63

1.19

0.95

0.120

39

0.95

0.71

1.15

0.99

0.096

89

0.94

0.75

1.21

0.84

0.119

27

305 (ROUGHNESS 1)

0.97

0.72

1.21

0.97

0.126

71

305

0.90

0.73

1.11

0.96

0.085

30

154

DATA

(SMOOTH)

305 (SMOOTH)

,

450 (SMOOTH)

(ROUGHNESS

2)

' h .d Q>

/5'

.

,'

If

00

.0

of

uni

A

.0

G pip G

n G /

9 /

/o

,"

.' '

**

PIPE CHANNELS D = 154mm SMOOTH

o0 0° oD = 305mm 00000 D =4 50mm

oooao D = 305mm 00000D = 305mm

SMOOTH SMOOTH

ko = 0.3mm ko = 1.34mm)

i 1

10

(S, -1))°'6 - modified Ackers' equation FIG. 6.24. Verification of modified Ackers' equation for all present data with W, = 10dao V/(gds

191

the

author's

this

measurement

better

6.21

1.03.

and

0.5mm

the

This

suggests

and

depends

sediment

with

both

particle

and

on

Ackers'

= d50 for We =

dso = for

10d50

8.74mm.

The

values 0.91

Fig.

with

6.27

and

modified

sizes

of

shows

that

2)

We =

2.56mm

and,

a

of (see

illustrates Frm for Ackers' 0.64mm this

deviation

an of

width

Fr,

predicted

the

using

width

were

d50 =

1.05mm

-1.95mm,

for

dso =5.22mm

4d30 4)

for We =

an of

0.084.

of

the

0.72mm

0.135.

192

results 1)

needed:

with

discrepancy

ratio

data.

application

both

(D = 300mm). ratio

measured

particle Table

of

-

these

of

The

We 3)

comparison

We = dso for

discrepancy

average

The

equation

average

requires and

0.12D

(1989)

al's

data.

Ackers'

6.22)

equation

effective

effective

results

(D = 158mm) gives

and

modified

May et

particle

size.

deviation

the

between

(1988)

Table

standard

of

0.94

Mayerle's

of

application

predicted

a standard

0.50mm,

We yields

of

for

values

d50 =

pipe

Table

of

sizes

the

We =

between

a function

dso > 4.2mm,

measured

equation

different

that

show

the

is

is

1)

used:

varies with

of

there

dso > 4.2mm.

ratio

width

results

that

clear

for

sediments

effective

compares

modified

for

The

We were

of

We = 0.12D

that

for

is

It

discrepancy

average

the

6.26

Fig.

2)

4.2mm,

while

size

of

that

6.25.

definitions

and,

6.19).

Table

see

Fig.

both

when

dso & 4.2mm

shows

in

shown

agreement

10dso for

of

are

analysis

Ws(

of

1.06

6.22 with

TABLE

6.21 VERIFICATION OF MODIFIED ACKERS' EQUATION'FOR PRESENT CLEAN PIPE DATA (W. = 10dso OR 0.12D)

D (mm)

DISCREPANCY

RATIO

r

s

NO. OF

AVERAGE

MIN

MAX

1.00

0.63

1.63

0.87

0.227

39

0.99

0.82

1.18

0.99

0.079

89

450 (SMOOTH)

0.94

0.72

1.21

0.84

0.119

27

305 (ROUGHNESS 1)

1.03

0.84

1.21

0.98

0.086

71

305

0.95

0.83

1.11

0.97

0.065

30

154

DATA

(SMOOTH)

305 (SMOOTH)

(ROUGHNESS

2)

V. = 10dbo : d60s 4.2mm W. = 0.12D : d50> 4.2mm

b

ý'

10 aý m

A(,) O'

0 PC)

/

,'

lh N'

7ý

O'

ol

tý+Q

I, YN Ö

G c,

fi

1ý

i .0

ýf 41

.

PIPE CHANNELS D = 154mm l SMOOTH aa00oD = 305mm SMOOTH 00000 D = 450mm SMOOTH 00000 D = 305mm ko = 0.3mm 00000D = 305mm k. = 1.34mm;

1

1

10

V/(gd60 (S. -1))°'° - modified Ackers' equation FIG. 6.25 Verification Ackers' eation of modified for all present data with W. = 10dba or 0.12T' 193

TABLE

6.22

VERIFICATION OTHER

AUTHORS

OF MODIFIED ACKERS' DATA CLEAN PIPE

RATIO

DISCREPANCY

EQUATION

r

FOR

NO. OF DATA

s

AVERAGE

MIN

MAX

MAYERLE (1988)

0.91

0.67

1.10

0.98

0.084

106

MAY ET AL (1989)

1.06

0.77

1.53

0.94

0.135

51

LOVELESS (1991)

0.96

0.54

1.15

0.95

0.175

46

MAYERLE (1988) DATA (Limit of deposition)

0

10

o' 90o Äö

00

w O

to

Q1

0

.' 1 '.

o6cPQ

AG

. -t

ý'

!d

,'

"'

o N iý' of

Ge

ýe.

yGt

' ox.

Sediment "'

.'

> o.

00000 °0000 ***** Xxxlex 00000 00000

0.50mm 1.05mm 1.95mm 2.56mm 5.22mm 8.74mm

sizes Wý W. W. W, W, w,

= = = = = =

dao) 4d60) 4d60 10dao) 0.12D 0.12D)

1 1

V/(gd0

10

(S,-i))°'5

- modified

FIG. 6.26 Verification of modified for Mayerle (1988) data

194

Ackers' equation Ackers'

equation

MAY ET AL (1989)

(Limit

ý 010. Oll

DATA

of deposition)

/0 0

10 ,.

**N

Sediment

sizes

G

F

ao

,' ,

***** *****

.' ý '

w, = da0 (W. = de0)

0.64mm 0.72mm

10 V/(gd5o

(S. -1))°'5

FIG. 6.27 Verification for May et al (1989)

-

Ackers'

modified

of modified data

Ackers'

LOVELESS (1991) DATA

(Limit

of

equation

equation

-' ''

deposition)

01,

J.

o 10-

/0ý/

.1

.0

01

o

'.

0 'o

.0ý ta'ý

cl

.. Gý

.

If

5

ý-ý GýQ'Q

.

ýý Dr

' .

"a o

.'

' . .'

,

Sediment 00000 0.45mm °0000 1.30mm 130000 O.00mm

sizes W. = d50) i'P. = 5d60) W. = 0.12D)

1 10

V/(gd60 (S.-1))°'6 - modified FIG. 6.28 Verification of modified for Loveless (1991) data 195

Ackers'

equation

Ackers'

equation

6.28

Fig. Ackers'

compares

found

d50 =

for

of (see

yields

on

modified 6.22)

it

four

modified noted

TABLE

6.16 the

of

application

0.5

of

as

given

should

We are in

be

to

with

in

clean

the

on to

particle the

apply It

)s

compute

EFFECTIVE We (m)

in

all

2.0

10d

d 200

available.

the It

extremes.

modified

clean

by

the

96% of ratio.

the

in

applicability such

the of

applicability

87% and

for

the

discrepancy

average

error

for

good

discrepancy

the

of

systematic

transport

when

the

agreement

average

between

applicability

the

for

ratio

94% of

the

where

agreement

1.00

the

within that

Within

the

between

90% and

C

and

over

discrepancy

reasonable

1.12

and

deviations.

(m/s)

V

varies

appears

that

obtained

A fairly of

and

± 0.25

the

0.50

lie

0.99

is

average

between

and

range

between

shows

of

ratio

this

within

1.02

deviations.

of

the

where

1.04

of

deviation.

agreement

good

1000

j

ratio

± 0.25

the

a

and

± 0.25

shown

discrepancy

an

analysis Ackers' that It

used.

(see

must

Ackers'

modified motion

the

criterion Fig.

6.21)

TABLE EQUATION

6.25 FOR MODIFIED ACKERS' DISCREPANCY RATIO (Fro) AS FUNCTIONS OF RELEVANT PARAMETERS - COMBINED DATA (CLEAN

Range of

parameter

Fr, Mean

min

PIPES)

(predicted)

/ Fr

0.901.10

max

(observed) 0.751.25

0.50 1.50

(%) (%) (%)

Dgr

No 0.52.0

of

data

(%)

10-25

1.09

0.67

1.62

40

78

96

100

156

26-50

0.97

0.66

1.39

51

93

100

100

103

51-100

1.00

0.83

1.40

89

98

100

100

56

101150

0.98

0.63

1.63

58

93

99

100

91

151-

1.01

0.86

1.13

79

100

100

100

24

201250

0.94

0.76

1.08

69

100

100

100

29

& 0.5

1.01

0.63

1.62

49

90

99

100

293

> 0.5

1.04

0.66

1.63

67

88

96

100

166

1-10

1.12

0.77

1.61

49

72

96

100

47

11-100

1.02

0.67

1.56

58

90

98

100

155

10150 0

1.00

0.66

1.62

57

92

99

100

186

501-

1.00

0.76

1.63

54

94

98

100

52

10012000

0.99

0.63

1.42

47

79

100

100

19

0.2000.500

0.95

0.63

1.39

47

90

100

100

59

0.5010.600

1.00

0.63

1.61

66

90

99

100

80

0.6010.700

1.02

0.76

1.63

60

92

99

100

99

0.7010.800' -

1.03

0.66

1.56

54

87

98

100

89

0.801900 .

1.04

0.76

1.62

61

90

97

100

62

0.901-

1.01'

0.77

1.54

51

96

99

100

49

1.17

0.78

1.53

33

67

100

100

21

200

y0/D

Pm) (

1000

V(m/s)

1.000 1.0011.500

200

ALL PRESENT DATA °O°O° Smooth pipes +++++ Rough pipes

2.0

a) +

+

ý

°

1.0

aft

Y

*°0 ,V

0.5

k

OTHER DATA *****

Ma erle

(1988

Loveless

(1991)

May et al (1989)

0.00

100

50

0

150

2

200

Dgr for

Discrepancy FIG. 6.30a ratio dimensionless function of a as

Ackers' modified particle size

equation

ALL PRESENT DATA 2.0

0oaao Smooth pipes +++++ Rough pipes OO

A

1.5 CC) #

1.0

Il

°

+ 40 %

10

13

U

19

°

13

i

+

-------

b

w

74

4. LU

+*

* *

RAO O'AUV +

-o---------

°

*oo°

.ý

0.5

aýý

°

*

ti

O

OTHER DATA

***** xxxxx 'ý** 0.0 0.00

Mayerle (1988) May et al (1989) Loveless 1991 0.20

0.40

0.60

0.80

yo/D

FIG, 6.30b

Discrepancy

as a function

ratio

of proportional

for

modified

flow

201

depth

Ackers'

equation

1,

ALL PRESENT DATA acooo Smooth pipes +++++ Rough pipes

2.0

oao 1.5

0130

xo

913 1313 ®a

o

aax

xp

oa4x

+ 1.0

-----------------c

ý x

---------ý

-+a

--------

--ý-o

CD

(1988)

Mayerle

*****

(1989) May xxxxx et al * Loveless (1991)

w

0

------

OTHER DATA

a ý

o

L

V

0.5

0

tý

it

-P

xx

.010 -1

10

1

10'

104

10

C, (ppm)

FIG. 6.30c Discrepancy ratio for modified concentration as a func tion of limiting

Ackers'

equation

ALL PRESENT DATA 2.0

00000 Smooth pipes +++++ Rough pipes o 00

1.5 o

ýr D

oa 113

0 00qo

a 0 °o okkk

ö

°

1.0

IV

öo°

4)

0.5

0

OTHER DATA ***** xxxxx *****

.0 0.0

Mayerle (1988) May et al (1989) Loveless 1991 0.5

1.0

1.5

2.0

V (m/s)

FIG. 6.30d Discrepancy. ratio for modified as a function of limiting velocity

202

Ackers'

equation

(1991) E1-Zaemey 6.1.3.4 Application of Channels Rectangular Bed Rigid and Introduction

6.1.3.4.1

in

As mentioned of

effect the

dry

during

and

can

the

more

likely

(1991)

proposed

transport

sediment

by utilising

a functional

relationship

)d

(b/yo)

to

depth

and

hence the

particular,

been

Paul-Sakhuja in

Eqn.

6.36

touched 1990, is

the

the

relative

by

change

describe

to

with

permanent

as the

dependent

deposits

variable:

1

(6.36)

bed

of

earlier 1991). particle

203

of

to

width

on

to

the

researchers

size

flow

and

In

movement. effective

width

concept

(Ackers

important (dso/D)

parameter

(b)

This

sediments.

Another

depth

width

sediment

be related

movement

Loveless

the

shape

could

on

the

yo

of

channel

bed width for

(W. ) responsible We have

the

remain

cemented.

s,

b,

influence

the

characterize

Cý,

=f

importance

the

emphasized

pipes

(Tb)

stress

S bl

He

in

in

properties

or

shear

pg(

sediment

of

especially

deposits

consolidated

process

bed

the

the

that

flow.

to

networks,

the

on

deposition

the

sewer

longer

The

become

eventually

E1-Zaemey the

flow.

weather

system

sewer

in

the

channels

pipe

resistance

flow,

of

nature

investigated

of

hydraulic

and

spasmodically

occurs

sediments

invert

the

on

capacity

intermittent

the

to

deposits

carrying

(1991)

E1-Zaemey

3.3.2,

Section

permanent

sediment

Due

Pipe

Clean

to

Equations

which

of 1984,

parameter reflects

influence

the

of

diameter

pipe

and

particle

size

on

pipe

with

a range

E1-Zaemey

(1991)

sediment

movement.

on his

Based of

bed

thicknesses

obtained by

an

the

for

application

functional

0.154

of

equation

in

data

experimental

of

multiple Eqn.

of

501ppm.

could

ratio

discrepancy

Eqn.

parameter

the

existence

found

be

for

tendencies

of

of

the

indicates range

data

lie

no

shows 'V

range

of

ratio

varies

that

=

0.94 the

± 0.25

that

0.98

the to to

Even range

generally the

where

1.09.

systematic

is

agreement sizes

to

0.25m/s from

the

particle

within

appears

6.54e

of

from

vary

ratios

presence

be

should

in

6.54c).

could be

can

inability

data.

discrepancy

Similar

overprediction as

the

average

respectively.

3.0

these

respectively.

concentrations

overprediction

(Fig.

the

the

an

ratio

for

for

Wt/yo

< 1% and

yd/D

and

of

and

6.54b

Fig.

plots

discrepancy

of

underprediction

10ppm

C,,
0.8m/s

higher

slightly be

could

the

obtaining

Eqn. 6.44 as a function

for

ratio

2.0

1.5

1.0 V (m/s)

FIG. 6.54e Discrepancy

the

(1992)

aaaaa perrusquia

average to

attributed the

of

slopes

of velocity

water

the

surface

accurately.

Eqn.

Overall,

This

beds. of

for

the

previously function

to

equation

An attempt

flow

highlights

was then presence in (Eqn.

the data

of

6.36)

pipes

with

another

consider beds

in

transport

254

over

of

function

to As

(1991)

cemented

the

q-

beds.

pipes.

E1-Zaemey

deposited

with

deposited

the

over

agreement

applicability

pipes

6.1.3.4, for

in

of

range

sediment

Section

good

conditions

from

made to

fairly

a

provides and

sediments

of

range

form

6.44

beds

account

mentioned proposed in

sewers.

a

the

Utilising

dependent

the

limiting

velocity

variable,

Eqn.

instead 6.36

V.

be emphasized

should

flow

of

effect

in

A multiple

the

regression

to

overall

friction

factor

r2

adj.

Table results

as

0.93

=

values

observed

data

the

on sediment

particle

size

of

The beds

sediment

AB.

parameter

data

combined

on

dso/D.

parameter

presence

to

considered

depth

and

the

is

(see

Table

produced:

with

The

f low

the

using

analysis

W1,/yo

and

by

6.37

shown where

the

gives in

96% of

discrepancy

Fig. the

functions

and

0.34

t2i Fig.

s=0.057. the

discrepancy 6.55

computed

an data

combined

6.55

average are

(6.46)

by Eqn.

terms

of

the

6.46.

Frs.

discrepancy

within

the

compares

values in

ratio

have

-0.31

The

ratio ± 0.25

of range

ratio.

applicability (Table

-01t

(0)

Fr® against

of

Wb

C0.16

8d(Ss-1)

of

as:

(6.4 s)

diameter

pipe

due

V=1.18

1.00

re-written

parameter

characterized

resistance

incorporated

6.34)

is

movement

sediment

of

as

stress

wb, DA

bed width

the

of

influence

The

movement.

is

influence

the

reflect

the

that

shear

Yo

ga, p(s1-1)

It

be

can

f CT,

the

of

of

6.34) of

is C,,

Eqn.

6.46

evaluated y6/D,

over with

Wb/yo,

the

the'discrepancy

Dgr and 255

range

V.

The

of

the

combined

ratio

plotted

measured

values

"TABLE

6.37 DISCREPANCY RATIO (Fr, ) FOR EQN. 6.46 (PIPES WITH DEPOSITED BEDS) COMBINEDDATA

Fr,

Source of data

Mean

(predicted)

0.901.10

max

min

/ Fr

-

(observed) 0.751.25

0.51.5

0.52.0

No. of data

(%) (%) (%) (%) 1.00

0.80

1.21

78

100

100

100

32

Alvarez (1990)

0.94

0.70

1.07

70

93

100

100

30

Perrusquia (1992)

1.06

0.77

1.56

68

97

99

100

79

0.96

0.69

1.30

42

94

100

100

52

1.00

0.69

1.56

62

96

99

100

193

Present

May (1993) Combined

PIPES WITH DEPOSITED BEDS Pd a,

'. , /'

14

'

10

09' l cab

o

*

13 ý1

ýG

,1

' ' ý. 1

00000 Present data Alvarez (1990) 00000 May (1993) 00000 perrus uia (1992

1

10 V/(gdeo(S.

FIG. 6.55

-

1))0.0 -

Eqn.

6.46

Bed load model for pipes with (Combined Eqn. 6.46 data) 256

deposited

beds

of

18 were

Frm.

The

Fig.

6.56a

from

results

0.90

falling

over

the

range

of

to

y, /D

of 1.02

Wb/yo.

transport

Fig. range varies of

6.56d

also

of

particle

Dgr falling

The

1.04

in

the

95%

the

of

within

for

pipes

the

1.05 the

deposited

good

agreement The

± 0.25

range

257

ratio.

good

over from

varies

each

each

range

the 1.00

of

W. /yo

and

Wb/yo

ratio.

of

C,,,

y8/D

in

the

sediment

beds.

obtained

average

95% of

over

for

discrepancy

discrepancy

with

good

discrepancy data

the

very

range

C.

of

reasonably

parameters

tested. with

of

for

each

varies

range

average

ratio

of

these

each

also

is

data

range

of

range

agreement

discrepancy

sizes to

± 0.25

ratio

ratio.

95% of

over

average

reveals

0.91

with

the

shown

process

from

studied.

importance

the

confirms

yg/D

to

correlation

for

is

± 0.25

the

discrepancy data

the

good over

discrepancy

of

6.56.

reasonably

the

of

values

Fig.

and

agreement

that

over

predicted

the

within

The

within

good

of

indicates

with

occurring

The

lying

is

90% of range

that

0.94

6.38

Table

The average

over

range

the

of

agreement

± 0.25

from

6.56c

range

the

with

the

whole

varies

Fig.

1.04

reveals

ratio

in

given

are

within

6.56b

computation

of C, studied.

to

Fig.

the

shows that

range

whole

in

used

of

the

for

the

discrepancy data

discrepancy

for

whole ratio

each ratio.

range

TABLE 6.38 AS FUNCTIONS

Range of parameter

DICREPANCY

RATIO

(Fr,

y/j

Wb/ yo

D gr

V (m/s)

6.46

PARAMETERS OF RELEVANT - COMBINED (PIPES WITH DEPOSITED BEDS)

Mean

Fr,

(predicted)

min

max

/ Fr

0.901.10

(%)

Co (ppm)

) FOR EQN.

DATA.

(observed) 0.75 -

0.501.50

0.52.0

(%)

(%)

1.25 (%)

No of data

1-10

0.91

0.74

1.16

30

90

100

100

10

11-50

1.00

0.69

1.21

67

94

100

100

36

si-100

1.04

0.91

1.30

86

97

100

100

29

101-300

1.02

0.72

1.57

67

97

99

100

101

501-1200

0.90

0.77

1.23

12

100

100

100

17