Progressive failure in deep-seated rockslides due to seasonal fluctuations in pore pressures and rock mass fatigue

2016 ◽  
pp. 121-136
Author(s):  
E Eberhardt ◽  
G Preisig ◽  
V Gischig
Keyword(s):  
Rock Mass ◽  
Progressive Failure ◽  
Seasonal Fluctuations ◽  
Pore Pressures ◽  
Rock Mass Fatigue

Hydromechanical Rock Mass Fatigue in Deep-Seated Landslides Accompanying Seasonal Variations in Pore Pressures

2016 ◽  
Vol 49 (6) ◽  
pp. 2333-2351 ◽  
Author(s):  
Giona Preisig ◽  
Erik Eberhardt ◽  
Megan Smithyman ◽  
Alexander Preh ◽  
Luca Bonzanigo
Keyword(s):  
Rock Mass ◽  
Seasonal Variations ◽  
Pore Pressures ◽  
Rock Mass Fatigue

Twenty-ninth Canadian Geotechnical Colloquium: The role of advanced numerical methods and geotechnical field measurements in understanding complex deep-seated rock slope failure mechanisms

2008 ◽  
Vol 45 (4) ◽  
pp. 484-510 ◽  
Author(s):  
Erik Eberhardt
Keyword(s):  
Rock Mass ◽  
Numerical Modelling ◽  
Slope Failure ◽  
Rock Slope ◽  
Current Knowledge ◽  
Progressive Failure ◽  
Strength Degradation ◽  
Rock Slope Stability ◽  
Clear Understanding ◽  
Rock Mass Strength

The underlying complexity associated with deep-seated rock slope stability problems usually restricts their treatment to phenomenological studies that are largely descriptive and qualitative. Quantitative assessments, when employed, typically focus on assessing the stability state but ignore factors related to the slope’s temporal evolution including rock mass strength degradation, internal shearing, and progressive failure, all of which are key processes contributing to the final collapse of the slope. Reliance on displacement monitoring for early warning and the difficulty in interpreting the data without a clear understanding of the underlying mechanisms has led to a situation where predictions are highly variable and generally unreliable. This paper reviews current knowledge regarding prefailure mechanisms of massive rock slopes and current practices used to assess the hazard posed. Advanced numerical modelling results are presented that focus on the importance of stress- and strain-controlled rock mass strength degradation leading to failure initiation. Efforts to address issues related to parameter and model uncertainty are discussed in the context of a high alpine research facility, the “Randa In Situ Rockslide Laboratory”, where state-of-the-art instrumentation systems and numerical modelling are being used to better understand the mechanisms controlling prefailure deformations over time and their evolution leading to catastrophic failure.

scholarly journals A Rapid Method of the Rock Mass Surface Reconstruction for Surface Deformation Detection at Close Range

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5371
Author(s):  
Qijun Hu ◽  
Chunlin Ma ◽  
Yu Bai ◽  
Leping He ◽  
Jie Tan ◽  
...  
Keyword(s):  
Rock Mass ◽  
Surface Reconstruction ◽  
Feature Detection ◽  
Surface Deformation ◽  
Progressive Failure ◽  
Survey Period ◽  
Mass Model ◽  
Before And After ◽  
Close Range ◽  
Point Detection

Characterizing the surface deformation during the inter-survey period could assist in understanding rock mass progressive failure processes. Moreover, 3D reconstruction of rock mass surface is a crucial step in surface deformation detection. This study presents a method to reconstruct the rock mass surface at close range in a fast way using the improved structure from motion—multi view stereo (SfM) algorithm for surface deformation detection. To adapt the unique feature of rock mass surface, the AKAZE algorithm with the best performance in rock mass feature detection is introduced to improve SfM. The surface reconstructing procedure mainly consists of image acquisition, feature point detection, sparse reconstruction, and dense reconstruction. Hereafter, the proposed method was verified by three experiments. Experiment 1 showed that this method effectively reconstructed the rock mass model. Experiment 2 proved the advanced accuracy of the improved SfM compared with the traditional one in reconstructing the rock mass surface. Eventually, in Experiment 3, the surface deformation of rock mass was quantified through reconstructing images before and after the disturbance. All results have shown that the proposed method could provide reliable information in rock mass surface reconstruction and deformation detection.

Embankment failures at Vernon, British Columbia

1995 ◽  
Vol 32 (2) ◽  
pp. 271-284 ◽  
Author(s):  
C.B. Crawford ◽  
R.J. Fannin ◽  
C.B. Kern
Keyword(s):  
Case History ◽  
Field Observation ◽  
Factor Of Safety ◽  
Strain Softening ◽  
Progressive Failure ◽  
Back Analysis ◽  
Site Investigation ◽  
Silty Clay ◽  
Pore Pressures ◽  
Similar Materials

A section of Highway 97, west of Vernon, B.C., is located over a soft-to-firm, compressible, silty clay subsoil. In addition to an extensive site investigation, the performance of two test embankments was observed for 2 years before construction was begun on the highway grade between them. When the highway fill reached a maximum thickness of about 10 m a failure occurred. The design was then changed to include berms on either side, but a second failure occurred when the grade was rebuilt. An undrained back-analysis of the first failure shows the influence of various variables on the factor of safety and illustrates the difficulty of choosing appropriate strength values for design when the site has a strong crust overlying a weaker layer and there is potential for progressive failure. Observations of settlements, pore pressures, and lateral movements in the subsoil describe the performance of the embankment during construction and reveal the importance of strain softening as a factor in the failures. Comparisons with a variety of similar failures in Canada, Scandinavia, and southeast Asia provide some guidance for future construction over similar materials. Key words : case history, embankment failure, field observation, pore pressures, stability, strength, undrained analysis.

scholarly journals Study on Failure Process and Permeation Evolution of Single-Cracked Rock

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Xiangxi Meng ◽  
Weitao Liu
Keyword(s):  
Rock Mass ◽  
Crack Propagation ◽  
Pore Pressure ◽  
Failure Process ◽  
Confining Pressure ◽  
Propagation Mode ◽  
Abrupt Decrease ◽  
Pore Pressures ◽  
Failure Evolution ◽  
Macroscopic Crack

To evaluate the mechanical properties and permeation evolution of cracked rock mass, failure evolution tests were designed by RFPA software for single-cracked rock mass with (i) different inclination angles under uniaxial compression and (ii) different confining pressures and pore pressures under triaxial compression. The results show the following: (1) Angle of the crack significantly affects the crack propagation mode and slightly affects the bearing capacity of rock. During the crack propagation, the peak of permeation is delayed at the peak of stress. The stress-strain curve shows a different behavior in the postcritical part of the curve, especially in the case of 45°, where a smooth postcritical curve was clearly observed instead of an abrupt decrease in the stress of other two cases. (2) When the confining pressure is constant, the trend is almost the same when varying pore pressures, and with the increase in pore pressure, crack propagation is accelerated. At a low confining pressure, the crack is extended vertically to the upper and lower ends of the specimen, forming a longitudinal macroscopic crack. At a high confining pressure, the crack gradually extends to the left and right boundaries of the specimen, forming a transverse macroscopic crack. (3) The rate of crack initiation and destruction first decreases and then increases with the increase in confining pressure when pore pressure is constant.

scholarly journals Microseismic Monitoring, Positioning Principle, and Sensor Layout Strategy of Rock Mass Engineering

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Tianhui Ma ◽  
Daoyuan Lin ◽  
Chun’an Tang ◽  
Kedar Prasad Yadav ◽  
Zhiqiang Feng ◽  
...  
Keyword(s):  
Rock Mass ◽  
Progressive Failure ◽  
Failure Process ◽  
Microseismic Monitoring ◽  
Underground Engineering ◽  
Monitoring Technology ◽  
Sensor Arrangement ◽  
Initial Stage ◽  
Practical Engineering ◽  
Scientific Nature

Microseismic monitoring technology can start from the most initial stage of rock deformation and track and monitor the progressive failure process of rock mass from the fracture of rock blocks to the instability of rock mass. Thus, the scientific nature of monitoring work is greatly promoted, and the accuracy and advance of the prediction of engineering and geological disasters are improved. In this paper, the fracture and instability of rock can be analyzed by analyzing the microseismic signals produced by rock failure; The location of microseismic source can be determined by multipoint synchronous data acquisition to determine the time when each sensor (at least 5) receives microseismic signals; Combined with practical engineering experience for underground engineering in growth, heading tunnel, put forward only sensor arrangement to take mobile, follow the semienclosed layout network. We hope to give some reference to the researchers who are concerned with microseismic monitoring technology.

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