Research On Three-Dimensional Discrete Maneuver Analysis Method Of Slope And Its Application

A common concern in the field of geotechnical engineering is how to perform stability analysis for slopes based on the limit analysis theorem considering the mechanical characteristics of the soil.In this paper,the upper limit analysis of the stability of threedimensional slope is carried out based on the discrete technique and the rotating damage mechanism.Taking the "bull's-horn" three-dimensional discrete damage mechanism as the main object of study,the energy dissipation law and the energy balance equation inside the soil slope under the Mohr-Coulomb criterion are derived.By considering the special geometry of the slope and the spatial variability of the geotechnical parameters,the universality of the model is verified by using FLAC3 D software.Finally,different from the safety coefficient as the traditional evaluation index,the probability of failure is used as an index to evaluate the stability of slopes based on the construction of a random field using the reliability analysis method.The research contents of this paper are as follows.(1)According to the actual three-dimensional damage of the slope,we adopt the idea of discretization to construct a 3D discrete damage mechanism with "bull-horn type" as the basic framework,derive the "point-to-point" control equation on the interrupted velocity surface,and clarify the boundary and constraints of the mechanism.Based on the construction of the disruptive mechanism,the power equation of internal energy dissipation on the disruptive surface is derived.The dichotomous method and the strength reduction method are combined to write a program using MATLAB,and the calculation results are compared with those of the traditional three-dimensional damage mechanism to prove the reliability of the model.(2)Using the discretization technique to establish the transfer equation of discrete points and derive the energy dissipation power equation in non-homogeneous slopes,which solves the problem of complicated calculation of integration in the traditional upper limit method when analyzing the change of friction angle and cohesion.This method breaks the limitation that the traditional continuous type damage mechanism is only applicable to homogeneous slopes,and ensures the accuracy of calculation results while improving the calculation efficiency.(3)Considering the spatial variability of the slope soil,the random field is constructed by Karhunen-Loeve expansion method on the basis of the three-dimensional discrete damage model for simulation.Finally,the implicit approximate functional function of the slope is solved based on the response surface method,and the failure probability is calculated by combining with the reliability analysis.