Numerical Simulation of Grout Curtain in a DEWPR Tunnel
Grouting is often adopted in a tunnel to resist high external water pressure; the tunnel is defined as External Water Pressure-Resistant Tunnel (EWPR Tunnel). When the grouting reinforcement does not seal the high pressure groundwater completely and the leakage groundwater is drained by drainage system, the tunnel can be called a Drained External Water Pressure -Resistant Tunnel with limited Drainage (DEWPR Tunnel), the grouting reinforcement and waterproof/drainage system of which are great important and should be considered specially. Take the traffic tunnels of Jinping Second Cascade Hydropower Station as an example, a numerical method is adopted to simulate the influence of grouting reinforcement thickness on the distribution of external water pressure. The results indicate that the discharge rate per unit length is 7.82m2/d with single tunnel drainage and 5.28m2/d with double-tunnel drainage, and the external water pressure can be reduced less than 0.6MPa when the thickness of grouting reinforcement is 12m based on the control factor of volume of water discharge.
Guangfan Li, Yong Huang and Chaohe Chen
J. X. Wang et al., "Numerical Simulation of Grout Curtain in a DEWPR Tunnel", Advanced Materials Research, Vols. 250-253, pp. 1873-1876, 2011