Parameters Optimization of Curtain Grouting Reinforcement Cycle in Yonglian Tunnel and Its Application

For practical purposes, the curtain grouting method is an effective method to treat geological disasters and can be used to improve the strength and permeability resistance of surrounding rock. Selection of the optimal parameters of grouting reinforcement cycle especially reinforcement cycle thickness is one of the most interesting areas of research in curtain grouting designs. Based on the fluid-structure interaction theory and orthogonal analysis method, the influence of reinforcement cycle thickness, elastic modulus, and permeability on water inflow of tunnel after grouting and stability of surrounding rock was analyzed. As to the water inflow of tunnel after grouting used as performance evaluation index of grouting reinforcement cycle, it can be concluded that the permeability was the most important factor followed by reinforcement cycle thickness and elastic modulus. Furthermore, pore water pressure field, stress field, and plastic zone of surrounding rock were calculated by using COMSOL software under different conditions of reinforcement cycle thickness. It also can be concluded that the optimal thickness of reinforcement cycle and permeability can be adopted as 8 m and 1/100 of the surrounding rock permeability in the curtain grouting reinforcement cycle. The engineering case provides a reference for similar engineering.