Influence of the soil properties on meso-mechanical behaviors of Soil-rock mixtures

Abstract Soil-rock mixtures (S-RMs) are widely distributed in nature that extensively encounter geohazards as landslides and debris flows. The meso-mechanical behaviors of such geomaterials are quite complex due to varying rock block content and soil composition. This study considers two types of S-RM samples with varying physical properties. A series of triaxial tests under different consolidated drained (saturated and unsaturated) and undrained conditions with varying confining stresses are performed, and the influence of soil properties on the meso-mechanical response of S-RMs are studied. The experimental investigations revealed that the soil properties, even with the similar percentage of rock content, significantly influence the mechanical behaviors of S-RM. The findings indicate that the strength parameters and rock block breakage ratio of S-RM samples with non-cohesive soil exhibit decreased susceptibility to influence compared to S-RM samples with cohesive soils. Both samples (S1 and S2) exhibited an apparent hardening trend in their stress-strain mechanism under consolidated drained unsaturated conditions without reaching a peak stress. Furthermore, the modified Mohr-Coulomb relationship with a power law function is suggested to obtain the p-qlinear relationship of shear strength parameters of S-RM after the particle breakage in the tests of different types of samples. The present study paved the way for new insights into meso-mechanical behavior and deformation mechanisms in S-RMs existing in nature.