To obtain deep insight into and understanding of the mechanical behavior and evolution of the lateral interaction between a single pile and soil-rock mixture material (S/RM), parametric two-dimensional discrete element analyses were performed to investigate the effects of different rock proportions. Adequate numerical simulations for the S/RM were first studied and verified by field direct shear tests. The results demonstrated that the binary discrete numerical models were able to capture the relative shear stress-displacement behavior with different rock proportions. Subsequently, the lateral mechanical behavior, as well as the microstructural evolution law, between the pile and S/RM was studied based on the two-dimensional DEM model. The effects of rock block proportion and size on the p-y curves of the single pile in the S/RM were investigated according to micromechanism analyses. Based on the modified initial modulus of the subgrade reaction and the ultimate resistance that can take into account different rock block contents, a new p-y model is proposed for the prediction of static laterally loaded pile response in S/RM.
Keywords: Soil-rock mixture (S/RM), P-y curve, Single pile, Lateral soil resistance, Discrete element method