Geomech. Geophys. Geo-energ. Geo-resour. DOI 10.1007/s40948-016-0046-y
ORIGINAL ARTICLE
Geo-disaster prediction with double-block mechanics based on Newton force measurement M. C. He . Z. G. Tao . W. L. Gong
Received: 11 November 2016 / Accepted: 30 November 2016 Ó Springer International Publishing Switzerland 2016
Abstract The prediction of earthquakes remains challenging. An unconventional idea that earthquakes can be predicted is proposed, based on the mechanics of the double block system (DBS). The central point of the mechanics of DBS lies in the measurement of the forces acting on the surface separating the two blocks, the relation of which should obey Newton’s laws (referred to as Newton’s forces). A Newton’s force monitoring system (NFMS), consisting of in situ measurement, remote sensing and indoor monitoring, has been developed. The key instrument of the NFMS is the constant-resistance and large-deformation (CRLD) bolt incorporated with a negative Poisson’s ratio (NPR) structure, referred to as CRLD bolt or NPR bolt, because of its unconventional performance that makes measurement of the Newton’s forces possible in seismically-active faults. The basic analytical and experimental work on formulating the DBS M. C. He Z. G. Tao W. L. Gong (&) China University of Mining and Technology, Beijing, China e-mail:
[email protected];
[email protected] Z. G. Tao e-mail:
[email protected] W. L. Gong e-mail:
[email protected] M. C. He Z. G. Tao W. L. Gong State Key Laboratory for Geomechanics and Deep Underground Engineering, Beijing, China
and NPR cable is outlined. The methods and techniques of the NFMS are presented. The validity of the mechanics of DBS and the applicability of the NRMS were verified by indoor experiments on Wenchuan and Longmen mountain active faults. Among many successful applications of NFMS to forecasting landslides, one field case in Nanfen open pit iron mines is presented; four field cases of the application of NFMS in registering the activities of the seismically active faults are also presented. Keywords Double block mechanics Active fault Landslide Disaster prediction Newton force measurement
1 Introduction Earthquakes and landslides are two major geological disasters causing huge casualties and economic losses each year in China. In 2015, a total of 5616 landslides occurred, totalling 68.3% of the overall geo-disasters recorded within the country (Communique on Land and Resources of China 2016). An earthquake is a natural disaster caused by vibration in the process of the rapid release of energy during motion of the earth’s crust. According to statistics many landslides and over 90% of earthquakes occur as a result of the motion of active faults, such as the 2008 Wenchuan earthquake (Ms 8.0) due to the movement of the Longmenshan fault.
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Various techniques have been developed for geodisaster monitoring and forecasting. These approaches, which map changes of the earth’s surface and groundwater level, include telemetry, GPS, total station, theodolite, borehole inclinometer, and manpower observation (Xu et al. 2007; Kamai 1998; Zan et al. 2002; Reeve et al. 2000; Ohbayashi et al. 2008; Puglisi et al. 2005). Currently, geo-mechanics engineers rely heavily on these conventional displacement-mappingbased techniques for landslide monitoring and forecasting. Major limitations of ground surface displacement monitoring techniques derive from the inconsistency between the displacement in ground surface and that in the sliding surface of the sliding mass. Surface displacement is only a necessary condition, which cannot guarantee the occurrence of a landslide within the expected time duration. Debate on whether or not geo-disasters like earthquakes can be predicted has long existed in the geomechanics community. The main-stream opinion is that earthquakes cannot be predicted, which is the title of an article by Geller et al. (1997) published in Science magazine. The counterpart is earthquakes can be predicted. Those holding this unconventional idea are few and their voice has seldom been heard over a long period in the geo-mechanics community. This article outlines the ideas, proposed by Manchao He, and related findings on how to predict two geodisasters using the unconventional in-plane Newton force measurement technique (He 2009; He et al. 2009, 2011, 2014) and mechanics of the double block system (DBS). The present studies were conducted at the State Key Laboratory for Geo-mechanics and Deep Underground Engineering (SKL-GDUE), China University of Mining and Technology, Beijing (CUMTB).
2 Mechanics of double block system 2.1 Physical model of the double block system Figure 1 shows the physical model of the DBS, composed of an active fault and two blocks which were originally a geological body cut by the fault. The mechanics of the DBS are represented by the forces acting on the surfaces separating the two blocks, the relation of which should obey the relevant Newton’s laws (referred to as Newton’s forces).
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From a geo-mechanics point of view, for the investigation of landslides, the two blocks are two loaded bodies in relative motion along the sliding surface controlled by the forces on the surface, the relation of which should obey the relevant Newton’s laws (referred to as Newton’s forces); while, for earthquakes, the two blocks are a hanging wall and a footwall hanging wall respectively, intersected by the faulting surface; the motion of the two hanging walls is controlled by the Newton’s forces. Therefore, earthquakes and landslides are of the the same type and their mechanisms can be understood by investigating the mechanics of the DBS. The necessary and sufficient condition for the initiation of a geo-disaster can be formulated using the Newton’s forces on the fault surface. For example, if a slope contains a sliding surface, the DBS can be sketched in Fig. 2. The weight of the sliding mass, G, acting above the sliding surface, the shearing force, T1 and resistant force T2, can be written as: T1 ¼ G sin a
and
T2 ¼ G cos a
ð1Þ
The necessary and sufficient condition can be stated as: if T1 T2 ; the slope will be stable, and if T1 [ T2 ; the slope will be unstable:
ð2Þ
If T1, and T2, are known, the stress redistribution can be evaluated, and a landslide can be predicted in advance. 2.2 Mathematical model of DBS In order to establish a sliding force monitoring and landslide forecasting system incorporating the necessary and sufficient condition for slope stability, the following problems are encountered: (1) how to monitor the sliding force; (2) the formulation of the mathematical model of the necessary and sufficient condition; (3) the development of a large deformation rock cable with an elongation of more than 1 m, and (4) how to integrate these techniques and remote sensing into one system. He (2009) proposed embedding an artificially measurable system into the natural mechanics system, i.e. making the artificial and natural systems a new system to make the sliding force measurable. The approach to the proposal is schematically
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Fig. 1 Physical model of DBS: a generic concept of the DBS containing a normal fault; b DBS containing a reverse fault; c DBS containing a strick-slip fault, and d DBS containing a composite fault
Fig. 2 Physical model of a natural slope
illustrated in Fig. 3. As the figure shows, the shearing forces along the sliding surface include the natural sliding force T1 = Gsina (also see Fig. 2) and man-made shear force is the projection of the tensioned anchorage force (also known as perturbed force) P along the surface. In this way, the natural sliding force, T1, and resistance force, T2, are linked to the measurable force P. A rock anchor/cable with a negative Poisson’s ratio (NPR) structure can be used for measuring the perturbed force P, as explained in the following section. Figure 3 indicates that the slope contains a continuous sliding plane and is reinforced by a rock anchor/cable with the fixed part below the sliding
surface. The X axis of a Cartesian coordinate system is placed overlapping the sliding surface and the Y axis perpendicular to the sliding surface. The frictional resistant force (or resistance) can be written as: F/ ¼ ðPn þ Gn Þ tan / þ cA
ð3Þ
where F/ is the frictional resistance; Pn is the normal component decomposed from the tensioned force (or pull load) along the rebar (anchor) or strand rope (cable) generated by the deformation of the sliding blocks; Gn is the normal component of the weight of the sliding block, G; / is the internal friction angle of the rock mass; c is the cohesion of the sliding surface, and A is the area of the sliding plane.
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Geomech. Geophys. Geo-energ. Geo-resour. Fig. 3 Schematic showing the coupling of the manmade sliding force measuring system and DBS realized as a natural rock slope system
Assuming that the slope is in the limited equilibrium state, the forces parallel to the sliding surface follow the equilibrium equation in the X direction: Pt þ F/ Gt ¼ 0
ð4Þ
where Pt is the tangential component of the tensioned force of the anchor/cable; and Gt is the tangential component (sliding force) of G. Substituting Eq. (3) into Eq. (4), the sliding force is given by: G t ¼ k1 P þ k2
ð5Þ
where k1 ¼ cosða þ hÞ þ sinða þ hÞ tan /
ð6Þ
and k2 ¼ G cos a tan / þ cA
ð7Þ
where a is the dip of the sliding surface; h is the anchorage angle that the rock anchor/cable makes with respect to the horizontal; and P is the pull force/tensioned force of the rock anchor/cable which can be monitored readily using current measurement techniques. Equations (5)–(7) are the mathematical models of the necessary and sufficient condition for the stability of both natural and excavated slopes.
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3 Rock anchor/cable with NPR structure 3.1 Structural characterization of NPR anchor/cable A rock anchor/cable with a NPR structure can exhibit extraordinarily large elongation at very high working resistance to the external load, and also have an ideal elastic–plastic behaviour. He (2009, 2011) proposed the original idea of the NPR structure at an engineering rock mass scale and developed the NPR anchor/cable (i.e. anchor/cable with NPR structure). The NPR anchor/cable can be collectively known as NPR bolt, also known in different articles as a constant-resistance-large-deformation (CRLD) bolt (He 2009), and an H bolt (He et al. 2004). The NPR structure of the H bolt (also CRLD bolt) is schematically shown in Fig. 4. The resistance force P of the H bolt is given by (He et al. 2014), P ¼ 2pfIs Ic
ð8Þ
where f is the static frictional coefficient for the interface between the cone body and sleeve; Is is the elastic constant of the sleeve and a function of the elastic modulus E, Poisson’s ratio l, and geometrical factors a, b and a of the sleeve only; and Ic is the geometrical constant of the cone body and a function of the geometrical factors of the cone only (see Fig. 4). Is and Ic are given by (He et al. 2014):
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Nomenclature α: Cone angle; h: Height of the cone; a: Inner radius of the sleeve; b: Outer radius of the sleeve; p: Pressure acting on the sleeve at radius an exerted by the cone; p (z): Pressure acting on the sleeve at distance z for the cross cut plane A-A exerted by the sleeve; u: Radial displacement; v: velocity of elongation of the bolt shank
δ (z): Radial displacement of the cut plane at a
p (z)
distance z for the cur plane A-A; p and p(z): Reacting forces acting on the cone corresponding to p and p (z); P: External load/resistance force; m: Mass of the cone;
h
p (z) y
p (z)cosα
α
F (z)
p(z)sinα
δ (z)
α
(a) b
T=P
z
a O
v
z
h dz α
Bolt shank
Cone Sleeve
ds
Fig. 4 NPR structure embedded He et al. (2014)
Is ¼
Ic ¼
Eðb2 a2 Þ tan a þ b 2 lð b 2 a 2 Þ
a½ a2
ah2 h3 cos a þ sin a 2 3
ð9Þ
ð10Þ
3.2 Unconventional behaviour of NPR anchor/cable Static pull-out tests were carried out to evaluate the load-elongation behaviour and the strength of the H bolt. The testing machine has the capacity to generate a maximum pull load of 2000 kN and accommodates the maximum deformation of 5 m. Here we present 16 results for the NPR cable developed by He et al. (2011a), which is suited to the measurement of the Newton’s forces in the DBS. The static loading was conducted in a displacement-controlled manner with loading rates ranging from 5 to 100 mm/min. The 16 NPR cable samples consist of three models, i.e. the HMS-I with 7 samples, HMS-II with 4 samples and HMS-III with 5 samples. Figure 5 shows the 16
curves of the constant resistance (CR) versus displacement for the 16 NPR cable samples of three kinds. The figure shows that all 16 curves fluctuate around their mean values exhibiting a quasi-ideal elasto-plastic behaviour; the maximum elongation is as much as 2.2 m and the maximum average resistance is 800 kN. 4 Newton’s force monitoring system 4.1 In-situ measurement In earthquakes and large-scale landslides, displacement of the two hanging walls in the DBS is usually of an order of meters. For example, in the 2008 Wenchuan earthquake, the displacement was as much as 5–6 m. In this case, only the NPR cable (He et al. 2011a) with unconventional behaviour (see Fig. 5) is adequate for measuring the Newton’s forces on the faulting planes in the DBS. The Newton’s force monitoring system (NFMS) consists of in situ measurement, remote sensing and indoor monitoring sub-systems, which are explained
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Fig. 5 Plots of the working resistance versus displacement for 16 NPR cable samples of three specifications from the static pull-out tests
separately in the following sections. The main instrument for in situ measurement is the NPR cable that measures the Newton’s forces acting on the fault surface with the following methods (refer to Fig. 6): 1.
2. 3.
Drilling a borehole at the monitoring site; keep drilling for 6–10 m after arriving at the fault surface, ensuring the rock at the end of the borehole is stable; Installing the NPR cable and anchoring the fixed end with a free end larger than 2 m; Mounting a high-precision fore-measuring sensor on the free end of the cable; the sensor has the capacity to communicate with the Beidou satellite-based remote sensing system;
4.
Pre-tightening the NPR cable with a magnitude approximately equal to 0.4P.
4.2 Remote sensing Figure 7a shows the NPR cable-based slope control and sliding force monitoring model, illustrating the use of the NPR cable for stabilizing the slope and in situ monitoring of the sliding forces by employing the sensor device installed between the face plate and fastening nut indicated at point D2. Modern communication technologies are employed for the force data collection, transformation and emission, as shown in Fig. 7b. Figure 7c depicts the Beidou satellite-based remote sensing system for landslide monitoring. The data from D2 are sensed by the receiver in the Beidou satellite and then transmitted to the indoor monitoring centre. The acquired sliding force data are processed by the computer system, based on the mechanics of DBS represented by the fundamental models in Eqs. (1)–(7) of slope stability, to reveal the entire process of slope failure from stability, limited equilibrium, to the final sliding event. 4.3 Indoor monitoring
Fig. 6 Schematic of the Newton’s forces measurement methods with a NPR cable
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The indoor sub-system, built in the State Key Laboratory for Geo-mechanics and Deep Underground
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Fig. 7 Remote-sensing system for motoring and forecasting landslides: a physical model of pre-stressed HE cable slidingresistant system; b principles of the HE cable in prevention of
the sliding body from sliding, and c Beidou satellite remote sensing system for monitoring sliding force
Engineering (SKL-GDUE) at the China University of Mining and Technology, Beijing (CUMTB), is an artificial intelligence (AI) receiving and analysis system with the ability to receive the in situ data sets transmitted by the satellite system, display them with plots and judge the stability state according to the plots and forewarning criteria, which will be explained in the following section. Figure 8 is a photograph showing the indoor monitoring system at SKL-GDUE. The screens on the wall display the monitoring sites across China (left wall, the largest screen).
5 Application of NFMS for forecasting landslides
Fig. 8 The indoor sliding force monitoring system at SKLGDUE, CUMTB
5.1 Geological background Landslides are major geological disasters and the degree and influence of their hazards are ranked only after earthquakes and volcanic eruptions. China is one of the countries in the world with the most widely distributed landslides and suffering the heaviest damage. The application of the NFMS has been very successful. To date, the NPR anchor/cable has been applied successfully at a total of 245 landslide sites distributed in 12 provinces across China to monitor the Newton’s forces and provide timely forecasting (He et al. 2009, 2015). A practical case of forecasting landslides using NFMS in the Nanfen open-cut iron mine is presented in this section. Nanfen open-cut mine, affiliated to the Benxi Iron & Steel Co., Ltd., is located in Benxi city, Liaoning province in north-east China. It is the largest single open-cut iron mine in Asia and its orebodies occur in the Archean Anshan group containing iron rock sections with monoclinic structure. The foot hanging wall in the mining site belongs to the rocky bedding slope. From 1960 to date, 60 landslides have occurred, forming an old landslide body of around 110,000 square meters, posing a major threat to production.
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The landslide body contains mainly chlorite hornblende schist with a uniaxial compression strength (UCS) of 59.2 MPa in the naturally water-bearing state and a UCS of 22.71 MPa at in the saturated state, and is prone to the loss of strength under the influence of water. At present, the bottom elevation of the mining site is ?160 m and the elevation of the footwall slope is approaching ?694 m, forming a high and steep slope with height different of 534 m and staged angles ranging from 46°–54° (Sun et al. 2011). 5.2 Monitoring points for Newton’s force measurement The distribution of the monitoring points for Newton’s force measurement was arranged according to the structure and scale of the old landslide body in the foot hanging wall at the mine site. In the sliding body (334–662 m bench), 28 monitoring points were installed and two GPS surface displacement monitoring points in the hanging wall, which is stable compared to the foot hanging wall, and one GPRS relay station, one Beidou satellite relay station, and one rainfall monitoring point were installed. These installations were finished in August, 2010 and started to work in October, 2010. Figure 9a shows the distribution of all the Newton’s force monitoring points (blue round dots) and GPS surface displacement monitoring points (green triangles). Figure 9b shows the section of A– A in the Newton’s force monitoring area. 5.3 Monitoring results Figure 10 shows the plots of the monitoring results after 15 months continuous in situ monitoring in 2011, comprising tens of thousands of items of measurement results. The red-coloured line is the Newton’s force against time, the blue-coloured line stands for rainfall against time and the green-coloured line represents the accumulative mining against time. The decisionmaking process for forecasting landslides using the Newton’s force monitoring results is as follows: 1.
Before October 1, the slope was stable because the monitored Newton’s force varied little; no marked fracture was observed;
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2.
3.
4.
5.
6.
In October 2, the Newton’s force curve increased significantly with an increment of around 300 kN; a fracture of 1.5–2 m long and 15–40 cm wide was observed on the 334 m bench in the foot hanging wall. In the early morning at 2:14, on October 3, the Newton’s force continued its increasing tendency with an increment of as much as 400 kN; a yellow-colour forewarning signal was sent by the NFMS according to the forecasting criteria to evacuate the personnel and equipment and stop mining; In the afternoon at 14:20 on October 3, the increment of the Newton’s force reached 8000 kN, and an orange-colour near sliding signal was sent; On October 4, the increment of the Newton’s force reached 1000 kN, a red-colour impending forewarning signal was sent; huge amounts of crushed rocks were found along the fracture of the 322–334 bench in the foot hanging wall, forming a loose accumulation of crushed rock blocks; At 19:00 on October 5, concentrated heavy rainfall on the Nanfen open-cut mine occurred, and the Newton’s force dropped abruptly from 1700 to 1400 kN. A red-colour forewarning signal was sent once again and a local landslide occurred on the 322–358 bench in the foot hanging wall with a sliding mass 36 m high and 50 m wide in the South to East direction.
Because of the timely and accurate forewarning messages sent by the NFMS, no casualties or property damage happened as a result of these landslide events in the monitored area in the Nanfen open-cut mine (Fig. 11).
6 Application of NFMS for forecasting earthquakes 6.1 Laboratory modelling In 2008, laboratory physical modelling of the Wenchuan and Longmen mountain faults was conducted at SKL-GDUE, CUMTB. Figure 12a shows the physical model of the Wenchuan and Longmen mountain and Anxin-Guanxian faults located in the
Geomech. Geophys. Geo-energ. Geo-resour. Fig. 9 Distribution of the monitoring points: a photograph showing the monitoring points distribution, and b schematic drawing of the A–A section of the Newton’s force monitoring area
Fig. 10 Monitoring plots including the Newton’s force against time (red colour), rainfall against time (blue) and accumulative mining against time (green)
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Fig. 11 Physical modelling of the mechanics of DBS and Wenchuan and Longmen mountain earthquakes: a physical modelling, and b the monitored Newton’s force curves
Sichuan basin; a laboratory NRMS was installed on the Wenchuan and Longmen mountain faults. Figure 12b shows two plots of the monitored Newton’s forces versus time. It was observed that the Newton’s forces on the two faults dropped abruptly when the model earthquakes in Wenchuan and Longmen mountain occurred. The abrupt drop of the Newton’s force on the active faults has also been found in actual cases of earthquakes. For example, on March 9, 2011 when an earthquake of 9.1 magnitude on the Richter scale occurred in the north-eastern Japan Sea occurred,
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an abrupt drop of the major principal stress was registered by the in situ stress monitoring stations in Pinggu, Beijing; on April 20, 2013 when the Sichuan Mount Lu earthquake of 7.0 magnitude on the Richter scale occurred, a sudden drop of the major principal stress was registered by the Sichuan Baoxing stress monitoring station two days ahead of the event. Sudden drops in the Newton’s forces were also found on November 14, 2001, when the Kunlun Mountains magnitude 8.1 and on April 25, 2015 when the Nepal 8.1 magnitude earthquakes occurred.
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Fig. 12 Sectional views of Newton’s force monitoring points on active faults in different areas: a Zhangjiakou active fault; b Beishan active fault; c Awulale active fault, and d Jinzhou active fault
6.2 Practical case Based on experience in landslide monitoring and forecasting, the NFMS has been applied to monitor the Newton’s force in seismically-active faults. To date, seven monitoring points have been installed in the four earthquake faults. Among them (see Fig. 12), two monitoring points are in the city of Zhangjiakou in Hebei Province, 2 points are in the Beishan active faults in Shaanxi province, two points are in the Awulale earthquake fault in Xinjiang, and one point is in the Jinzhou active fault in Liaoning province. Over ten years of continuous monitoring, hundreds of millions of data items have been obtained on the Newton’s forces of eismic fault activity. The plots of the Newton’s forces in these active faults are shown in Fig. 13. As the figure shows, all the monitored faults are seismically active. However, the effect of the seismicity represented by the Newton’s force is not noticeable, because of the shallow drilling depth (current drilling depth is 70–120 m). Nevertheless, it is expected that the effect will be improved when the drilling depth is deeper. For example, a 4000 m deep
borehole will be drilled for monitoring the Newtons’ force in the near future.
7 Conclusions The mechanics of DBS formulate concisely the laws of block motion along active faults in geo-disasters such as earthquakes and landslides. The formulation is based on the in situ measurement of the Newton’s forces acting on the faulting surface. A constant-resistance and large-deformation (CRLD) bolt incorporated with a negative Poisson’s ratio (NPR) structure has been developed, which is referred to as a CRLD or NPR bolt because of its unconventional performance that makes measurement of the Newton’s forces possible in active fault. The results of laboratory experiments and field applications show the validity of the mechanics of the DBS and the applicability of the NFMS. These results support the idea that earthquakes can be predicted using these unconventional NPR cable and NFMS techniques.
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Fig. 13 Monitored Newton’s forces in active faults in different areas: a Zhangjiakou active fault; b Beishan active fault; c Awulale active fault, and d Jinzhou active fault Acknowledgements The financial support of the Special Funds for the National Natural Science Foundation of China (Key Project) under Grant No. 51134005, the National Natural Science Foundation of China (51574248) and the National Natural Science Foundation of China for Distinguished Young Scholars (41502323) are gratefully acknowledged.
References Communique on Land and Resources of China (2016) Ministry of Land and Resources of the People’s Republic of China. http://www.mlr.gov.cn/sjpd/gtzygb/ Geller RJ, Jackson DD, Kagan YY et al (1997) Earthquakes cannot be predicted. Science 275(5036):1616–1617 He MC (2009) Real-time remote monitoring and forecasting system for geological disasters of landslides and its engineering application. Chin J Rock Mech Eng 28(6):1081–1090 He MC (2011) Chinese patent. Patented in 2011, No. ZL 2010 1 0196197.2, Certificate No. 852069
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He MC, Tao ZG, Zhang B (2009) Application of remote monitoring technology in landslides in the Luoshan mining area. Min Sci Technol 19(5):609–614 He MC, Tao ZG, Zhang B (2011) Large-deformation cable with constant-resistance and its constant resistance device, Chinese patent, Patent 2011, No. ZL 2011 1 0157137.4, Certificate No. 1157460 He MC, Gong WL, Wang J, Qi P, Tao ZG, Du S, Peng YY (2014) Development of a novel energy-absorbing bolt with extraordinarily large elongation and constant resistance. Int J Rock Mech Min Sci 67:29–42 He MC, Gong WL, Tao ZG, Peng YY, Chen L (2015) Overview of landslide and its control based on sliding force monitoring techniques in China. In: Proceedings of 13th international ISRM congress, Montre`al, Que`bec, Canada, 10–13 May 2015 Kamai T (1998) Monitoring the process of ground failure in repeated landslides and associated stability assessments. Eng Geol 50:71–84 Ohbayashi R, Nakajima Y, Nishikadoet H et al (2008) Monitoring system for landslide disaster by wireless sensing node network. In SICE annual conference 2008 IEEE international, pp 1704–1710
Geomech. Geophys. Geo-energ. Geo-resour. Puglisi G, Bonaccorso A, Mattia M (2005) New integrated geodetic monitoring system at Stromboli volcano (Italy). Eng Geol 79:13–31 Reevea BA, Stickley GF, Noon DA et al (2000) Developments in monitoring mine slope stability using radar interferometry. In: Geoscience and remote sensing symposium, 2000. Proceedings. IGARSS 2000. IEEE International, 2000, vol 5, pp 2325–2327 Sun DX, Tao ZG, Fan LJ et al (2011) Stability assessment and sensitivity analysis of slope at Nanfen open pit iron mine. Metalmine 5:57–60
Xu LK, Li SH, Liu XY et al (2007) Application of real-time telemetry technology to landslide in Tianchi Fengjie of Three Gorges Reservoir Region. Chin J Rock Mech Eng 26(Supp. 2):4477–4483 (in Chinese) Zan L, Latini G, Piscina E et al (2002) Landslides early warning monitoring system. In: Geoscience and remote sensing symposium, 2002. IGARSS 02. 2002 IEEE International, vol 1, pp 188–190
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