Development and Calibration of a Discrete Element Model for Penetration Test in Cohesive Soil

Cone penetration test is one of the methods widely used for measuring the soil mechanical strength. It can also be used as a simple method to calibrate soil parameters in the discrete element method (DEM) simulations. In this study, a DEM model for the interaction of a cone penetrometer with a clay loam soil was developed and the possibility of finding relationships between the cone index and the parameters of the model for different levels of moisture and soil density was investigated. A hybrid contact model, hysterical spring - linear cohesion was used to simulate the soil. Sensitivity analysis of the model parameters showed cohesion, coefficient of internal friction and particle yield strength are the most important parameters affecting the cone index. Laboratory cone penetration tests using a tension-compression loading frame were performed in remolded soil at two moisture contents of 11 and 16% each at two bulk densities of 1000 and 1150 kg m-3. By fitting the measured and simulated cone index- depth profiles, values ​​for particle yield strength were obtained which showed a strong correlation (R2 = 0.97) with the maximum cone index in the tested soils. The results were validated using plate sinkage test. As a general conclusion, the cone penetration test can be used to calibrate the yield strength of soil particles in the discrete element simulations.