Study on mechanical properties and mesoscopic simulation of coarse-grained soil subgrade

In order to study the variation of mechanical properties of coarse-grained soil under load and rainfall infiltration, Autotriax fully automatic triaxial test system was used to conduct static triaxial test on coarse-grained soil filler. Based on the parameter of test, the mesoscopic simulation of triaxial test was carried out with particle flow software PFC3D. Contact bond model was introduced by self-programming, the mechanical properties and variation of coarse-grained soil under different confining pressures, moisture contents and degrees of compaction were compared and analyzed. The results show that using the PFC3D software for simulation of static triaxial, the trend of stress-strain curves are consistent with the experimental curves. The body strain of specimens appear shear contraction under high confining pressure, and display shear contraction first and then dilatation under low confining pressure. As the strain increases, the bond fracture point develops rapidly in the sample. The sample is extruded from a single intermediate part to multiple potential shear planes, and the bond failure between the particles has hysteresis, and the law of internal evolution is consistent with the law of variation of stress-strain curve. © 2020, Central South University Press. All right reserved.