Grouting Diffusion Characteristics in Faults Considering the Interaction of Multiple Grouting

In this study, a testing device was developed to analyze the characteristics of grouting diffusion in faults. To include the interaction of multiple grouting applications, tests consisting of four applications of grout were performed using three sets of grouting pipes. During the grouting process, the real-time injection pressure, injection rate, soil pressure, and seepage pressure were monitored. It was found that the curves of both injection pressure versus time and injection rate versus time showed a wavelike relationship. Soil pressure and seepage pressure showed an obvious response to grouting; both increased continuously during grouting and decreased gradually when grouting was stopped. To expose the diffusion of the grout, 23 sections were cut through the medium, and 2,197 sets of the coordinates and thicknesses of exposed grouting veins were collected. It was found that the grouting veins formed by the first and fourth groutings, respectively, had larger sizes and larger spans. Based on the collected coordinates, the three-dimensional diffusion shape of the grout was sketched for the four grouting tests. Results show that the interactions of multiple groutings are mainly reflected in injection pressure and the distribution of the grouting veins. These conclusions can be used to further develop grouting theory.