Grouting mechanism in fractured rock considering slurry-rock stress coupling effects

The slurry-rock stress coupling effects have a great influence on the grouting process in fractured rock. In order to describe the dynamic grouting process, a piecewise equation is used to govern the deformation process of rock fissure, and a theoretical model for fissure grouting considering slurry-rock stress coupling effects is established with the slurry being assumed as Bingham liquid. A step-wise calculation method is established, in which the tracing of grouted zone front and distribution of grouting flow rate are realized by using the mass conservation condition. The try out method is adopted to compute the pressure and velocity fields in the grouted zone. The distribution of the pressure field and fracture aperture in the grouted zone and the effect degree of slurry-rock stress coupling on the grouting process with different fracture apertures are analyzed. The results show that in the micro-fracture grouting process, the slurry-rock stress coupling has greater effect on the grouting process when the fracture aperture becomes smaller. At the same time, the grouting pressure, replacing the fracture aperture, becomes the main controlling factor for the grouting radius. By comparing the theoretical results with the measured ones in a grouting project, the validity of the theoretical model and calculation method is verified.