Numerical and Experimental Studies of Diffusion Law of Grouting with Expansible Polymer

Polyurethane has been widely used as new chemical grouting material. Expansion characteristics caused by chemical reactions make polymer grout different from other types of grout. To throw light on the diffusion process of polymer grout in a fracture, a density model was derived by fitting the experimental data based on the polymerization mechanism of polyurethane. In addition, a numerical simulation of polymer diffusion in a single fracture was developed to predict the pressure distribution. An experiment was carried out to analyze the diffusion distance and pressure field under different grouting masses. Comparison of results from numerical calculation and experiments indicates that the numerical approach is able to predict polymer diffusion in the fracture. The numerical simulation is suitable for rapid determination of the grouting mass, diffusion shape, flow-front position, and pressure distribution, which could provide guidance on assessing polymer grouting parameters.