CFD-DEM Simulation For Filtration And Penetrability of Cement-based Grout

Grouting is a widely used method for sealing fractured rock masses around underground structures to reduce or stop groundwater inflow. However, even at pre-sent, the filtration and penetration mechanism of cement-based grout have not been clarified sufficiently yet due to complicated physical and chemical processes of grout, such as pressure-dehydration, consolidation, bleeding, clogging, absorption, sedimen-tation and condensation etc. In this research, to better understand the penetration and filtration mechanism of cement-based grout through rock fractures, a two-dimensional numerical model of coupled Computational Fluid Dynamics and the Distinct Element Method (CFD-DEM) had been developed. By using a direct numerical simulation technique, the interaction between fluid and particles can be evaluated. The simulation results were compared with the laboratory injection test to verify the applicability of the newly developed CFD-DEM code. As a result, the simulation results agree qualitatively well with the actual experi-mental results, and the clogging process during the injection of cement-based grout was successfully reproduced by the CFD-DEM code. Moreover, based on these re-sults, the influence of the water/cement ratio of grout on the filtration and penetration mechanism was investigated in detail. The presented numerical model in this paper gives a better understanding for filtration and penetration mechanism of cement-based grout.