Research on Mesoscopic Characteristics of Limestone Grouting Diffusion Based on Discrete Fracture Network

The limestone stratum has well-developed rock fissures and abundant groundwater. Under extreme rainstorm conditions, tunnel surrounding seepage is serious especially. In order to reveal the grouting diffusion mechanism of karst fractured mass realize effective water plugging, in this paper, basic mechanical parameters are obtained by laboratory triaxial test, porosity distribution nuclear magnetic resonance test. PFC2D discrete element software used simulate characteristics compressive deformation fracture propagation pattern compared with test results. Discrete network theory establish numerical simulation model mass. And filling stress variation rule cement slurry under different pressure studied. results show that (1) During process, micro-cracks expand along tip existing cracks, extend cracks finally form through so as achieve effect reinforcement. (2) With increase pressure, maximum displacement particles increases continuously, but prolongation time, reaches a stable state no longer increases. (3) process mass, state. This study provides an important reference for setting