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Application of rigid discrete element method in the displacement-based seismic stability analysis of rock slopes |
CUI Zhen,SHENG Qian,MA Yalina |
(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China) |
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Abstract In the present seismic response analysis of rock slopes,the limit equilibrium method is used to analyze the static safety factor and the Newmark dynamic analysis is used to analyze the dynamic permanent displacement. Their use in engineering practice was limited due to the complexity. In this paper,the rigid body discrete element method is introduced into the evaluation of seismic stability of rock slopes. Combining the rigid body discrete element method with the strength reduction method and Newmark method,a static and dynamic stability analysis method for complex rock slopes is presented. Assuming the large stiffness for joints,the contact displacement caused by the elastic deformation of joints was limited so that the rigid discrete element method can be used to solve the static/dynamic stability of rock wedges. The rigid discrete element method does not need to assume the sliding direction and sliding mode in calculating the safety factor of the rock slope and is therefore very useful in engineering practice with the complex rock wedges. The correctness of the proposed method and the programming in the 3DEC code is demonstrated through comparisons with 4 classical static examples and 3 dynamic examples. Parameter studies confirmed that the proposed rigid discrete element method is capable of obtaining the correct trend of variation according to the changing parameters. It was found that under certain conditions the pseudo static safety factor cannot reflect correctly the extent of the earthquake response of the rock slope. In the case study,the seismic stability evaluation of K1 block based on the displacement was carried out with the rigid discrete element method. The results with the rigid discrete element method were better than those from the method of pseudo static safety factor.
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