Study on Mechanical Characteristic and Deformation Failure Mechanism of Rock-Soil Aggregate Sampled from Sliding Mass

The mechanical characteristics and deformation failure mechanisms of dolomite rock-soil aggregate obtained from the sliding mass of Jinpingzi landslide are studied. Laboratory triaxial tests show that the stress–Cstrain curves of rock-soil aggregate are non-linear and can be categorized as strain-hardening typed. The curves of volumetric strain to axial strain exhibit shear contraction behavior under high confining pressure. Under low confining pressure, the curves firstly show shear contraction and then shear dilation. The envelope line of antishear strength is linear. The variation of gradation of rock-soil aggregate leads to little change in its internal frictional angle while has considerable influence on its cohesion value. When the rock proportion in rock-soil aggregate varies within 60%∼80%, the stress–Cstrain curves do not change significantly. Particle breakages are observed during the deformation failure process of rock-soil aggregates, thus causing shear contraction deformation of samples under high confining pressure.