CT Testing Analysis And Constitutive Model Study Of Unsaturated Slates

Fracture rock mass is one of the common and complex rock masses encountered in hydroelectricity, mining and petroleum engineering. The strength, deformation and seepage characteristics of the fracture rock mass are critical to the design, construction and maintenance of the relevant projects.In the field of microscopic rock mechanics study, one of the hottest and most important topics is the proposal of the microscopic damage constitutive model, in which different microscopic damage mechanisms can also be figured out, to represent the microscopic damage evolution of rock mass structure.In this study, unsaturated slate from Jinping Second Stage hydropower station site will be tested; the evolution mechanism of micro cracks in fractured rock mass will be investigated. The achievements are as follows:(1) With ISRM standard rock samples cut with a pair of cracks, uniaxial compression tests are conducted to study the 3D crack evolution mechanism in different lithology rocks. It is shown that, the crack's initiation, propagation and coalescence are influenced by crack angle, depth, distance and angle of crack bridges, and the failure pattern and reasons of rock samples are given.(2) Using the X-ray horizontal screw CT machine and the corresponding loading systems in the State Key Laboratory of Frozen Soil Engineering, the real-time CT uniaxial compression tests of two unsaturated jointed slate samples with different bedding distribution are conducted. The failure mode and mechanism with different bedding distribution are explained in the microscopic scale, and the damage evolution stages are figured out. Based on the principle of CT, the scalar damage variable of unsaturated rocks is formulated with the CT values. Then several computations and analysis are carried out.(3)The real-time CT tests of two unsaturated jointed slate samples with two man-made cracks are conducted, the damage evolution mechanism is studied, and the process of...