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A Mathematical Model for Fracture Grouting in Underground Engineering
1 School of Mining, China University of Mining & Technology 2 State Key Laboratory of Coal Resources and Safe Mining, China University of Mining & Technology 3 School of Resource and Earth Science, China University of Mining & Technology
Abstract Based on research regarding rock fracture propagation in hydro-fracturing, a fluid-solid coupled rock failure process analysis system (RFPA) is used to establish a mathematical model for fracture propagation and slurry diffusion, as well as consolidation during fracture grouting. A numerical analysis is conducted for fracture grouting in a rock mass. The results show that: 1) in the process of fracture grouting, the width of the fracture does not increase indefinitely with rising pressure, and the required pressure for expanding the fracture decreases with an increase of the fracture length; 2) in the same rock mass, the fluid diffusion distance is positively correlated with the grouting time, fracture width and grouting pressure while it is negatively correlated with the resistance coefficient of the rock mass, the fracture length and the grout's kinematic viscosity; and 3) because of the fluid-solid coupling effect of the rock mass, the permeability of the rock mass decreases with a rise in the confining pressure and increases with propagation of the fracture, but when the confining pressure is unloaded, the permeability of the rock mass increases again.
Abstract：
Based on research regarding rock fracture propagation in hydro-fracturing, a fluid-solid coupled rock failure process analysis system (RFPA) is used to establish a mathematical model for fracture propagation and slurry diffusion, as well as consolidation during fracture grouting. A numerical analysis is conducted for fracture grouting in a rock mass. The results show that: 1) in the process of fracture grouting, the width of the fracture does not increase indefinitely with rising pressure, and the required pressure for expanding the fracture decreases with an increase of the fracture length; 2) in the same rock mass, the fluid diffusion distance is positively correlated with the grouting time, fracture width and grouting pressure while it is negatively correlated with the resistance coefficient of the rock mass, the fracture length and the grout's kinematic viscosity; and 3) because of the fluid-solid coupling effect of the rock mass, the permeability of the rock mass decreases with a rise in the confining pressure and increases with propagation of the fracture, but when the confining pressure is unloaded, the permeability of the rock mass increases again.
2015, Vol. 52 