Estimation of Cement Grout Penetration Using a Coupled Hydraulic-Mechanical Analysis of Rock Joints

A numerical analysis of coupled viscous fluid flow and joint mechanical deformation was developed to estimate penetration length of cement grout. The coupled analysis was established using discrete element method (DEM) such that parameters of both individual joint and discrete network can be implemented without difficulty in estimating grout penetration in a jointed rock mass. For a verification of the established numerical analysis, the results of penetration length in 1-dimensional linear flow analysis was compared to previous analytical solution. We also showed that the estimated penetration radius in 2-dimensional radial flow analysis was well comparable to our experimental observation of cement grout injection in a rock joint replica. Our simulations of the coupled flow-deformation analysis showed that grout injection-induced joint opening may enhance a penetration and produce a non-linear injection pressure profile within a joint. The effect of parameters on grout penetration length, which investigated in this study, can be usefully informative in designing a cement grout injection in a jointed rock mass.