Multi-field Coupling Strength Reduction Method of RCC Gravity Dam on Thick Overburden Layer

The strength reduction method is more strict than the limit equilibrium method in theory.Compared with the overall strength reduction method,the local strength reduction method is closer to the actual geotechnical engineering destruction.In order to solve the calculation problem of the anti-slide stability calculation of the roller compacted concrete gravity dam on the thick overburden layer,the local strength reduction method is further improved.In view of the problems of the numerical morbid of the local strength reduction method,the multi-field coupling solution,the initial parameter determination and the dynamic change of the relevant parameters and reduction region in the course of reduction,a series of measures are adopted respectively,such as H type adaptive grid,COMSOL Multiphysics multi-physical field coupling finite element,particle swarm partition inversion,permeability variation with confining pressure,and obtaining the size of the reduction area according to the degree of strain state and the rate of yield dynamically,and then a modified local strength reduction method is proposed.In the actual project,the three-dimensional finite element simulation results of the overflow dam section of the river bed and the bank slope in the left bank show that the proposed method can overcome the calculation abnormality caused by the conventional local strength reduction method and reasonably obtain the anti-sliding stability safety factor of the dam after danger-elimination and reinforcement for emergency. © 2020, The Editorial Board of Journal of Basic Science and Engineering. All right reserved.