Numerical Investigation of Grout Diffusion Accounting for the Dynamic Pressure Boundary Condition and Spatiotemporal Variation in Slurry Viscosity

Abstract This paper proposed an improved stepwise algorithm to simulate the grout diffusion in a single fracture considering the dynamic grouting parameter boundary condition and the spatial- and time-dependent viscosity of the grout. The method was more effective and could result in variation in key output parameters at any measurement point/time (in space and time). Based on the algorithm, three types of dynamic pressure boundary conditions, which are more applicable in grouting engineering practice, were designed to illustrate the grouting process. Compared with constant pressure grouting, the dynamic adjustments of pressure grouting were found to be beneficial to grout propagation in most cases. Some other factors were also studied under dynamic pressure boundary conditions, such as the spatiotemporal variation in the slurry viscosity and fracture aperture, which demonstrate a significant influence on the grout migration. Finally, a dynamic pressure grouting system was prepared, and the accuracy of the algorithm was successfully validated using a series of laboratory tests.