Grouting rock fractures under condition of flowing water

Abstract

Grouting is generally applied as an effective way to seal rock fractures, reduce permeability, decrease deformation, increase strength of rocks, and to stop the water flow through the jointed rock mass. But grouting rock fractures under condition of flowing water depends greatly on experiences of professional engineers, without sufficient theoretical guidance to refer to, as no commonly accepted and reasonable theoretical models are available. To describe the grouting process of fractures in flowing water, and put forward reasonable grouting guidance suggestions. The present work established a theoretical model for grouting into a fracture with flowing water. Considering boundary conditions, a streamline equation of grouting diffusion trajectory with flowing water was derived, and analyzed the influence of boundary effect on grouting diffusion law. The simulation tests of grouting rock fracture with flowing water were carried out on the self-developed fracture grouting experimental platform, and the results were compared with the theoretical prediction results, which verified the rationality of the theoretical model. The results show that there are three types of diffusion of quick-setting slurry under condition of flowing water. The existence of boundaries can increase the penetration along the direction of the flowing water both downstream and upstream, but it weakens the penetrability in the vertical flow direction. Rock fractures with a high water velocity require a high grouting flow rate, however, it is not the higher the better for determining the relevant grouting flow rate, a decrescent ratio between these two parameters should be ensured as a precondition.