Numerical Analysis Method for Dynamic Stability of a High and Steep Rock Slope in the Sichuan Wenchuan Earthquake

2011 ◽  
Vol 261-263 ◽  
pp. 1182-1190 ◽  
Author(s):  
Shi Guo Xiao ◽  
Wen Kai Feng

Near-field ground shock features are analyzed according to the seismological record of the May 12 Wenchuan earthquake made at the Wolong observation station. A numerical analysis model is established by taking the record as the input seismic load and a real high and steep rock slope on the bank of the Zipingpu Reservoir. The acceleration response and shear strain increment distribution features at different locations of the slope under horizontal seismic force are analyzed using Plaxis software. The moment when the widest plastic zone occurs for the slope is obtained by time history analysis. The corresponding stability factor of the slope at that moment is calculated using the strength reduction method (including shear strength and tensile strength). The above is the Time History Analysis–Strength Reduction Method presented in this article. In addition, the stability factor of the slope can be calculated using the pseudostatic method by taking the seismic force as the external load. This is the Time History Analysis–Pseudostatic method put forward in this paper. Analysis results demonstrate that, as far as the studied high and steep slope is concerned, at 31.89 s, the stability factor calculated with the Time History Analysis–Strength Reduction Method is 1.004, which is slightly larger than the 0.833 obtained using the Time History Analysis–Pseudostatic Method (Spencer method). Both results demonstrate that there is collapse and sliding failure of the localized rock mass at the top of the slope at that moment because of joint fracture. Field investigation after the earthquake further verified the calculation result, proving to a certain degree the rationality of the analysis method presented.

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Ruili Lu ◽  
Wei Wei ◽  
Kaiwei Shang ◽  
Xiangyang Jing

In order to study the failure mechanism and assess the stability of the inlet slope of the outlet structure of Lianghekou Hydropower station, the strength reduction method considering the ubiquitous joint model is proposed. Firstly, two-dimension numerical models are built to investigate the influence of the dilation angle of ubiquitous joints, mesh discretization, and solution domain size on the slope stability. It is found that the factor of safety is insensitive to the dilation angle of ubiquitous joints and the solution domain size but sensitive to the mesh discretization when the number of elements less than a certain threshold. Then, a complex three-dimension numerical model is built to assess the stability of the inlet slope of the outlet structure of Lianghekou Hydropower station. During the strength reduction procedure, the progressive failure process and the final failure surface of the slope are obtained. Furthermore, the comparison of factors of safety obtained from strength reduction method and analytical solutions indicates that the effect of vertical side boundaries plays an important role in the stability of jointed rock slope, and the cohesive force is the main contribution to the resistant force of vertical side boundaries.


2013 ◽  
Vol 639-640 ◽  
pp. 593-597
Author(s):  
Lin Chen ◽  
Yong Yao ◽  
Jiong Yang ◽  
Zhao Qiang Zhang

According to finite element strength reduction method,the article has discussed the failure mechanism of anti-sliding pile by using finite element software MIDAS /GTS ,exploration report and anti-sliding pile design data.The comparative analysis shows that the failure of anti-siding pile is contributed by the slope excavation and rainwater.The analysis method and results can provide reference significance to other anti-sliding pile design.This paper also provide a feasible method for prediction of consequence in slope excavation.


2012 ◽  
Vol 166-169 ◽  
pp. 2164-2170
Author(s):  
Xu Jie Sun ◽  
Hou Zhang ◽  
Da Gang Lu ◽  
Feng Lai Wang

The design process of the 100 m high reinforced concrete masonry building in China was firstly presented, deformation check calculation under earthquake action by mode-superposition response spectrum method and time-history analysis method were detailed and deformation under wind load was also checked. Then elastic-plastic deformation under earthquake action was checked by time-history analysis method and pushover analysis method with both under uniform load and reverse triangle load. The conclusion is construct 100 m high office building built in Fortification intensity 6 by reinforced concrete masonry is feasible. Then the building was redesigned as built in fortification 7, the same check was performed as that have been done in fortification 6, it is feasible too.


2013 ◽  
Vol 351-352 ◽  
pp. 849-853
Author(s):  
Lan Chen ◽  
De Long Lu ◽  
Xiao Gang Yin

Based on the vertical seismic information, the vertical seismic response spectrum was calculated by Matlab Lsim function. The seismic effect of Kiewitt-Lamella suspended-dome was measured by dynamic to static ratio. According to the EL-Centro seismic wave, it analyzed and compared the dynamic to static ratios which were calculated by the following four vertical seismic calculation methods respectively: the simplified method of specification, the mode-superposition response spectrum methods based on the horizontal earthquake affecting coefficients and the vertical acceleration response spectrum respectively, and the time history analysis method. Analysis shows that: For the seismic effect, the time history analysis method is larger than the other three methods, and the method based on the vertical acceleration response spectrum is closer to the time history analysis method. Owing to large difference of the four methods for seismic effect, various methods should be adopted to ensure the safety of vertical seismic design.


2014 ◽  
Vol 501-504 ◽  
pp. 51-55 ◽  
Author(s):  
Chao Peng ◽  
Dong Ji ◽  
Liang Zhao ◽  
Zhen Yu Qian ◽  
Fen Hua Ren

An analysis on safety factor of slope through c - φ reduction algorithm by finite elements method is presented. When the system reaches instability, the numerical non-convergence occurs simultaneously. The safety factor is then obtained by c φ reduction algorithm. This paper, which combines with the actual situation of Jinduicheng open pit mine, analysis the stability of the limit height of the dump based on strength reduction of finite element method. And the value of slope safety factor is 1.25 to 1.30. The results show that calculating safety factors of the slope by ANSYS is in full conformity with the basic requirement of safety. That means, the dump is stable, which can reduce the production costs and benefit the enterprise.


2012 ◽  
Vol 424-425 ◽  
pp. 1187-1190
Author(s):  
Yue Zhai ◽  
Kun Long Yin

With the anti-shear parameters reduction, the nonlinear strength reduction FEM model of slope turns to unstable status and the numerical non-convergence occurs simultaneously. Hence, the safety stability factor obtained based on c-φ reduction algorithm can be regarded as equal to stability factor obtained using limit equilibrium method. In this paper, stability analysis of one reservoir slope is made and the calculation results show that the strength reduction method matches the traditional grid limit equilibrium method well, yet with much more available information. Efficient and accurate, the strength reduction FEM is feasible to examine slope stability and analyze slope movement patterns.


2012 ◽  
Vol 260-261 ◽  
pp. 907-911
Author(s):  
Yu Chen ◽  
Hui Yun Duan ◽  
Cheng Tao Zhou

The slope deformation and instability caused by rainfall is the most common geological hazard in the highway slope landslide hazards. This paper used the finite element method to analyze the stability of slop in a variety of water-saturated conditions based on the strength reduction method, and to get the mechanism of rainfall weakening the strength of landslide. The results shows that the slope landslide in the fully saturated state would be instability when the surface was muddy geotechnical (thickness about 5 m), but it could remain stable when the saturated rate was under 80%. Under the action of rainfall, the maximum shear stress of potential slip plane in this kind of slopes was in the landslide’s lower edge which has obvious stress concentraten. Therefore, slope control measures should be strengthened to prevent the occurrence of the landslide hazard in the lot of long rainy season.


2021 ◽  
Author(s):  
Tianbai Zhou ◽  
Lingfan Zhang ◽  
Jian Cheng ◽  
Jianming Wang ◽  
Xiaoyu Zhang ◽  
...  

Abstract Due to long-term mining, a series of high and steep rock slopes have been formed in the open-pit mine. For high rock slopes, rainfall infiltration is the main cause of landslide. Therefore, the stability analysis of high rock slope under rainfall has become a key issue in the open-pit mine engineering. In this work, aiming at the high stress condition of high rock slope, the instantaneous internal friction angle and instantaneous cohesion of rock mass under different stress states are deduced, and the a nonlinear strength reduction method for high rock slope is established according to the relationship between normal stress and shear stress of rock mass under the Hoke-Brown criterion. The numerical calculation results show that the factor of safety (FOS) for high rock slope calculated by the proposed method is more reasonable. Taking the southwest slope of Dagushan Iron Mine as the research background, the safety factors of high rock slope under different rainfall conditions are calculated by COMSOL Multiphysics. And the stability analysis of high rock slope in open-pit mine under rainfall are carried out.


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