Simulating Strength Parameters and Size Effect of Stochastic Jointed Rock Mass using DEM Method

Abstract

The strength parameters and the size effect of stochastic jointed limestone rock mass is investigated in this paper. Based on extensive statistics of joint parameters of rock mass in the research region, the probable distribution of geometric characteristic parameters of discontinuities are obtained by the probability graph method. Then the Monte-Carlo method is used for discontinuities network modeling. In addition, 3DEC software and its built-in FISH programming language are used to establish the stochastic jointed rock mass network model based on discrete element method. Triaxial numerical simulation tests under variable confining pressure are conducted with different model sizes and dip angles of bedding planes. The numerical simulation results indicate that the jointed rock mass exhibits weak anisotropy property and significant size effect when it is cut by stochastic discontinuities; the mechanical strength parameters of rock mass begins to fluctuate distinctly as the model size increases, and tend to be stable once the model size reaches or exceeds 4 m × 4 m × 8 m. Besides, the comprehensive mechanical parameters of rock mass in the research region are determined and failure modes of rock mass are analyzed as well based on the numerical simulation results.