Analysis of reasonability of several assumptions used in typical limit equilibrium methods based on progressive failure feature of slope

作者：Zeng Zeng^*; Zhang Ze Hui; Yang Hong Li; Yin Xiao Tao; Dang Fa Ning

来源：Yantu Lixue/rock and Soil Mechanics, 2012, 33(SUPPL. 1): 146-150.

• Assumption
• Limit equilibrium methods
• Numerical tests
• Particle flow code
• Progressive failure
• Slope

Progressive failure feature of slope is difficult for numerical simulation of slope. Also practical slope failure process is rarely a whole and sudden slipping one, is often step by step one from local deformation to final and overall instability, which is a chain domino style failures triggered by small disturbance under critical condition. Here by particle flow code (PFC), a numerical slope with cohesion between particles being 36 kPa, friction coefficient between particles being 0.36, 0.1 m particle size and 10 m height is designed, initial models damage will not occur under gravity condition. Slope failure is done by cohesion strength between particles reduced to half of initial one. Slope shapes of each 20000 steps, total steps being 200000, are obtained by monitoring change of vertical particle groups at horizontal intervals of 1m, which directly reveals progressive failure of slope. Found that failure is always beginning from local part, movement of slope body material results in secondary damage in slope, which forms final arc sliding surface. These account for sliding isn't a whole declining of slope body, the body isn't a rigid one. Stress conditions along slip surface don't reach limit state at the same time. Change of stress in slope body isn't a monotonous one, but a process with rises and falls. All these conclusions contradict assumptions in current limit equilibrium methods such as rigidity of finite slice, simultaneously reaching limit sate on slip surface, making statically indeterminate problem solved by force transfer mode between slices given, overall analytical method not presenting localization and progressive feature of failure, which hints future of slope computing method lies in discrete element methods can present dynamic practical problem and material real failure characteristics.

• 出版日期2012