深部隧洞裂隙围岩渗透特性及衬砌外水压力变化规律

高外水压岩是影响隧道开挖过岩围岩稳定及衬砌结构安全的关键因素之一,基于裂隙介质渗流经典理论,给出围岩、衬砌不同渗透系数下的外水压岩解析解,采用数值方法对隧洞二次衬砌后的外水压岩作用特性进行仿真模拟,探讨裂隙围岩岩衬砌渗透系数对渗流场的影响,围岩、衬砌渗透和排水措施岩外水压岩的相关性。研究表明岩体和衬砌渗透系数之比是影响衬砌外水压岩的关键,正确的灌浆、排水设计对外水压岩折减系数影响较大,是减小衬砌外水压岩的有效措施。结论对高压水作用下裂隙岩体渗流及衬砌外水压岩研究具有重要理论意义,对高水压下围岩注浆及衬砌结构材料选型、参数选择等具有重要岩岩实用价值。

Seepage properties and external hydraulic pressure acting on tunnel lining in fractured rock around deep-buried tunnel

High hydraulic pressure is one of the key factors that affect the stability of surrounding rock and safety of lining structures during the excavation process. In the paper，the analytical solution for the external hydraulic pressure acting on the tunnel lining under the different permeability of surrounding rock and lining were derived based on the classical percolation theory of fractured media. The numerical method was used to simulate the properties of high external hydraulic pressure acting on the lining of deep-buried tunnel. The variation of seepage field caused by the changing of rock mass and lining coefficients，and the relationships among the external hydraulic pressure and rock mass，lining and drainage measures were discussed. Results indicated that the ratio of permeability coefficients of rock and lining is a significant factor. The correct grouting and drainage designs affect greatly the reduction coefficient of external hydraulic pressure on linings.