Mechanical Properties of Soil-Rock Mixture Filling in Fault Zone Based on Mesostructure

Abstract

Soil-rock mixture (SRM) filling in fault zone is an inhomogeneous geomaterial, which is composed of soil and rock block. It controls the deformation and stability of the abutment and dam foundation, and threatens the long-term safety of high arch dams. To study the macroscopic and mesoscopic mechanical properties of SRM, the development of a viable mesoscopic numerical simulation method with a mesoscopic model generation technology, and a reasonable parametric model is crucially desired to overcome the limitations of experimental conditions, specimen dimensions, and experiment fund. To this end, this study presents a mesoscopic numerical method for simulating the mechanical behavior of SRM by proposing mesoscopic model generation technology based on its mesostructure features, and a rock parameter model considering size effect. The validity and rationality of the presented mesoscopic numerical method is experimentally verified by the triaxial compression tests with different rock block contents (RBC). The results indicate that the rock block can increase the strength of SRM, and it is proved that the random generation technique and the rock parameter model considering size effect are validated. Furthermore, there are multiple failure surfaces for inhomogeneous geomaterial of SRM, and the angle of the failure zone is no longer 45°. The yielding zones of the specimen are more likely to occur in thin sections of soil matrix isolated by blocks with the failure path avoiding the rock block. The proposed numerical method is effective to investigate the meso-damage mechanism of SRM.