A Method for Fast Obtaining of Soil Shear Strength Index Based on Dem Free-Fall Cone Penetration Simulation

Soil shear strength is an important index of soil mechanical properties, which is of great significance in fields such as rock and soil stress analysis, agricultural machinery farming, seabed exploration, and vehicle trafficability evaluation. In order to improve the problems existing in the existing methods of obtaining soil shear strength index, such as low accuracy, demanding experimental site conditions and long periodicity, this paper constructed a model of free-fall cone penetration into the soil based on the discrete element method (DEM) simulation, and the corresponding relationship between moisture content and penetration depth was obtained. In addition, the corresponding relationship between the moisture content and the soil shear strength index was obtained from the triaxial compression test. Combining these two relational equations, this paper finally summarized the equation about the relationship between the penetration depth in the simulation and the soil shear strength index in the test. It was verified that the errors of internal friction angle (φ) and internal cohesion (c) obtained by the equation were only 3.45% and 6.68%. It shows that the DEM free-fall cone penetration simulation can replace the triaxial compression test to obtain soil shear strength index with very low error, and it is a quick and accurate new method to acquire the soil mechanical parameters.