Experimental investigation on the sealing of flowing water by cement-sodium silicate slurry in rough single fracture

With the rapid development of underground engineering, the problem of sudden surge water has become one of the main problems that restrict engineering safety. Grouting method is commonly used to seal the fracture water flow. However, grouting in flowing water streams still faces many challenges. In this study, a rough fracture model is established based on the Barton curve, and the effects of fracture roughness, water flow rate, fracture inclination, and grouting pressure are considered, and orthogonal tests are used to study the diffusion pattern of slurry under the four factors. According to the observed phenomena, there are four main diffusion patterns of the slurry: (1) full slurry coverage with no water passing through; (2) little coverage with watercourses and cavity areas along both sides of the fracture; (3) partial slurry coverage with no obvious watercourses but some cavity areas; and (4) less coverage with larger watercourses and cavity areas. The reduction rate of flow rate at the outlet before and after grouting was used to express the sealing effect. The results show that the degree of influence on the slurry sealing effect from strong to weak is fracture roughness, water flow velocity, grouting pressure, and fracture angle in order. A method to characterize the sealing effect by slurry coverage is proposed based on the final distribution of residual slurry. Considering the mutual influence between different factors, the sealing effect of two factors is analyzed in order to provide reference for engineering practice.