Numerical Analysis of Direct Shear Test Based on Change of Force Chain
The connection between macro-mechanics and meso-mechanics is always a hot topic in the field of geotechnical mechan-ics.Flow software PFC2D was used to simulate the direct shear test from the macro-meso-view,and each stage of the direct shear test was carried out.The direction of the force chain was described by the wind rose diagram.A comprehensive test was carried out by dis-crete element particle flow simulation and meso-view theory.The distribution change and evolution law of the force chain in the direct shear test were studied.The results show that the results of the indoor test and numerical simulation test are consistent.Before the shear stress reaches the peak value,the internal force chain structure is reconstructed regularly,and the strength chain gradually leans against the angular bisector.When the shear stress reaches its peak value,the angle between the shear stress and the horizontal direc-tion is close to 45°.In the stage of unloading instability,the weak force chain will redistribute,some of the strong force chains will transform and dissipate,and most of them will remain around the shear band.This study can better understand the meso-mechanical mechanism of soil and provide reference for related numerical simulation tests.