Opportunity Constraint Evaluation Method for Bottom Stability of Foundation Pit

The limit equilibrium theory is employed to analyze the bottom stability of foundation pit, a method that is used to calculate stability coefficient of resisting upheaval in accordance with deterministic mass property and sliding mode. The deterministic model for the analysis of bottom stability that can adapt to different types of slip surface is established by applying the motion-unit method to limit equilibrium theory and taking into account the strength reduction principle. Given the randomness of soil mechanical properties at the pit bottom and the failure of intensity parameter to meet the randomness of constraint conditions, the reliability analysis method for chance constraint is set up. The calculation and comparison between circular sliding surface and Prandtl's sliding surface offers an analysis of the influence of circle center position of different sliding surfaces, load of pit bottom and bracing load on the insertion ratio of supporting structure and the control of confidence level of random constraint function on insertion ratio. The above-mentioned analysis thoughts and methods are achieved through an engineering example