断续节理直剪试验与PFC(上标 2D)数值模拟分析

The research results of model tests and numerical simulation in two different loading conditions, triaxial and direct shear, are summarized. By conducting model tests on integrated samples and intermittent joints samples, shear strengths under different normal stresses are obtained. Also, the changing trends of shear strength under various connectivity rates are analyzed. The entire process of direct shear test is numerically simulated using particle flow code in 2 dimensions (PFC(superscript 2D)). In order to make the stress-strain curve of numerical simulation accord with experimental one about both integrated samples and through samples, the mechanical parameters between particles are adjusted. Through adopting the same particle geometric parameter, the numerical models of intermittent joints under different connective conditions are rebuilt. At the same time, the rock bridges and joints in testing samples with the fixed particle contacting parameters are endowed, and a series of direct shear tests are conducted. Then the failure process and mechanical parameters in both micro-prospective and macro-prospective are obtained. By synthesizing the numerical and testing results and analyzing the evolutionary process of stress and strain on intermittent joints plane it is concluded that the shear strength of rock bridges is increased due to the centralization of compressive stress on it. At last, the failure mechanism of intermittent joints rock under direct shear condition is discussed, meanwhile, the whole shear process is divided into five phases, i.e. linear elastic phase, fracture initiation phase, peak value phase, after-peak phase and residual phase.