Study on Stability of Unstable Rock Masses on Right Bank Slope of JinPing I Stage Hydropower Station, Southwestern China

2011 ◽  
Vol 243-249 ◽  
pp. 3036-3042 ◽  
Author(s):  
Da Huang ◽  
Yong Xing Zhang ◽  
Run Qiu Huang
Keyword(s):  
Failure Mode ◽  
Calculation Method ◽  
Limit Equilibrium ◽  
Rock Block ◽  
Southwestern China ◽  
Hydropower Station ◽  
Rock Masses ◽  
Limit Equilibrium Theory ◽  
Earthquake Force ◽  
Unstable Rock

A lot of investigations showed that unstable rock masses (URM) could be classified into four failure modes：whole slide，rock block landslide，whole shear fall，and compress-rip-slide. Unloading cracks forming URM failure boundary don¢t store water usually，so the main loads to cause URM failure in dam region are weight and earthquake force. According to limit equilibrium theory, Authors put forward different calculation method of stability and criterion of stability state class to different failure mode. The corresponding treatments and cure to URM of different scale and stability state are presented, too.

Analysis of Unstable Rock-Mass Stability Based on Limit Equilibrium Method and Strength Reduction Method

2016 ◽  
Vol 858 ◽  
pp. 73-80
Author(s):  
Ying Kong ◽  
Hua Peng Shi ◽  
Hong Ming Yu
Keyword(s):  
Rock Mass ◽  
Failure Mode ◽  
Posterior Margin ◽  
Reduction Method ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Strength Reduction ◽  
Strength Reduction Method ◽  
Rock Masses ◽  
Unstable Rock

With the slope unstable rock masses of a stope in Longsi mine, Jiaozuo City, China as the target, we computed and analyzed the stability of unstable rock masses using a limit equilibrium method (LEM) and a discrete element strength reduction method (SRM). Results show that the unstable rock masses are currently stable. Under the external actions of natural weathering, rainfall and earthquake, unstable rock mass 1 was manifested as a shear slip failure mode, and its stability was controlled jointly by bedding-plane and posterior-margin steep inclined joints. In comparison, unstable rock mass 2 was manifested as a tensile-crack toppling failure mode, and its stability was controlled by the perforation of posterior-margin joints. From the results of the 2 methods we find the safety factor determined from SRM is larger, but not significantly, than that from LEM, and SRM can simulate the progressive failure process of unstable rock masses. SRM also provides information about forces and deformation (e.g. stress-strain, and displacement) and more efficiently visualizes the parts at the slope that are susceptible to instability, suggesting SRM can be used as a supplementation of LEM.

scholarly journals Geotechnical Characteristics and Stability Analysis of Rock-Soil Aggregate Slope at the Gushui Hydropower Station, Southwest China

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Jia-wen Zhou ◽  
Chong Shi ◽  
Fu-gang Xu
Keyword(s):  
Limit Equilibrium ◽  
Triaxial Compression ◽  
Friction Angle ◽  
Soil Aggregate ◽  
Equilibrium Analysis ◽  
Hydropower Station ◽  
Small Scale ◽  
Rock Masses ◽  
Geological Processes ◽  
Toppling Failure

Two important features of the high slopes at Gushui Hydropower Station are layered accumulations (rock-soil aggregate) and multilevel toppling failures of plate rock masses; the Gendakan slope is selected for case study in this paper. Geological processes of the layered accumulation of rock and soil particles are carried out by the movement of water flow; the main reasons for the toppling failure of plate rock masses are the increasing weight of the upper rock-soil aggregate and mountain erosion by river water. Indoor triaxial compression test results show that, the cohesion and friction angle of the rock-soil aggregate decreased with the increasing water content; the cohesion and the friction angle for natural rock-soil aggregate are 57.7 kPa and 31.3° and 26.1 kPa and 29.1° for saturated rock-soil aggregate, respectively. The deformation and failure mechanism of the rock-soil aggregate slope is a progressive process, and local landslides will occur step by step. Three-dimensional limit equilibrium analysis results show that the minimum safety factor of Gendakan slope is 0.953 when the rock-soil aggregate is saturated, and small scale of landslide will happen at the lower slope.

scholarly journals Earthquake Dynamic Failure Mechanism of Dangerous Rock Based on Dynamics and PFC3D

2021 ◽  
Vol 9 ◽  
Author(s):  
Yun Tian ◽  
Yong Wu ◽  
Hongtao Li ◽  
Bangzheng Ren ◽  
Hao Wang
Keyword(s):  
Failure Mechanism ◽  
Failure Mode ◽  
Calculation Method ◽  
Rock Block ◽  
Particle Flow ◽  
Dynamic Failure ◽  
Seismic Acceleration ◽  
Stability Coefficient ◽  
Time Frequency ◽  
The Stability

The dynamic failure mechanism of horizontally layered dangerous rock during earthquakes is complex and only few studies have addressed the combination of particle flow code (PFC) meso-level failure mechanism and mechanical analysis. Based on fracture mechanics and material mechanics we establish a calculation method for the interlayer load and stability coefficient of horizontal layered dangerous rock during strong earthquakes. The method was applied for calculating the stability of a horizontally layered dangerous slope along a highway in the Sichuan Province (China) during earthquakes as a case study. Using a 3D particle flow simulation technology, a PFC3D model of horizontal layered dangerous rock was established. Its dynamic stability, failure mode and Hilbert-Huang 3D time-frequency characteristics are analyzed, and the results of the simulation are largely consistent with the time of the dangerous rock failure as estimated by our new calculation method. Our study documents that as the seismic acceleration gradually increases, the stability coefficient of the rock block fluctuates more violently and the stability coefficient gradually decreases. The stability coefficient of the rock block decreases fastest between 5 and 6 s and the reduction in the stability coefficient is between 0.12 and 0.25. Before the seismic acceleration reaches the maximum, the dangerous rock blocks on the two main controlling structures collapse and get destroyed. 25 s after the earthquake, the failure mode of the dangerous rock is collapse-slip-rotation. We show that earthquakes with frequencies of 0–10 and 250 Hz have the strongest destructive effect on the stability of the horizontally layered dangerous rocks.

Limit equilibrium theory-based investigation on the critical tension crack depth in loess slope

2021 ◽  
Vol 80 (9) ◽  
Author(s):  
Linxuan Zhu ◽  
Zhijun Zhou ◽  
Lei Chen ◽  
Tianyu Xu ◽  
Zhipeng Zhang ◽  
...  
Keyword(s):  
Limit Equilibrium ◽  
Crack Depth ◽  
Equilibrium Theory ◽  
Tension Crack ◽  
Limit Equilibrium Theory ◽  
Loess Slope ◽  
Critical Tension

scholarly journals Study on Failure Plane of Bulk Solid in Squat Silos

2012 ◽  
Vol 6 (1) ◽  
pp. 33-37
Author(s):  
Changbing Chen
Keyword(s):  
Limit Equilibrium ◽  
Large Diameter ◽  
Small Diameter ◽  
Theoretical Method ◽  
Wall Pressure ◽  
Failure Plane ◽  
Limit Equilibrium Theory ◽  
Bulk Solid ◽  
Important Basis ◽  
Key Parameter

With the increasing volume demand of silos, squat silo diameters are bigger and bigger. However, present wall pressure computation methods are mostly based on small diameter silos. To solve this problem, systematical research on the wall pressure in squat silos is of great importance. For now, in the Chinese code the wall pressure computation methods are based on the limit equilibrium theory to be calculated, which define the orientation of the failure plane in the bulk solid within the silo. The rupture angle is a key parameter to silos’ wall pressure. Therefore the value and direction of rupture angle are researched by theoretical method in this paper, which has heavy significance and provide an important basis for the large diameter silo design.

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