Groundwater Inrush Control and Parameters Optimization of Curtain Grouting Reinforcement for the Jingzhai Tunnel

Abstract

Based on the systematic study on the characteristics of water and mud inrush during the excavation of Jingzhai tunnel, the mechanism of water inrush seepage transformation caused by excavation disturbance is analyzed. By means of electromagnetic geophysical prospecting, the potential water bearing area of the tunnel was analyzed. The constitutive model of rock mass and grouting parameters are considered in the numerical simulation. The law of tunnel crack initiation and expansion under different curtain grouting parameters is proposed. The characteristics of seepage water inrush caused by excavation are described. It is considered that there are three stages in the seepage characteristics of tunnel: incubation, sudden, and stable. Numerical simulation was used to analyze the crack propagation track and water inflow characteristics under the grouting thickness of 3 m, 5 m, and 7 m. When the curtain grouting thickness was 3 m, the fracture field penetrated the curtain grouting area. The dominant seepage channel is formed, which greatly increases the probability of water inrush. When the curtain thickness is 5~7 m, the expansion of the crack zone can be controlled basically, so that the fracture and water bearing rock layer cannot form a seepage channel. At last, the grouting scheme of 6 m thick grouting and 20 m advanced grouting was selected, and the water seepage was reduced by 83%.

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Investigation on Rock Strata Fracture Regulation and Rock Burst Prevention in Junde Coal Mine

“…According to the strength theory, if the local stress of coal and rock mass is too large and exceeds its own strength, rock burst will be induced. According to energy theory, rock burst will be induced when the energy of mechanical system of stope surrounding rock exceeds the energy needed to maintain the equilibrium state [23,24].…”

Influence of Water-Resisting Layer Thickness on Fracture Evolution in Karst Tunnel and Control Measures

“…The treatment methods include selecting the advanced geological prediction method according to the risk degree of different sections of the tunnel, determining the prediction items, and selecting the appropriate methods, namely, drainage guidance method, blockage guidance method, or drainage blockage method. Li et al [9] analyzed the transformation mechanism of water inrush and seepage caused by excavation disturbance and analyzed the potential water-bearing area of the tunnel by using the electromagnetic geophysical exploration method. The constitutive model of rock mass and grouting parameters is considered in the numerical simulation.…”