限量排放下的隧道地下水渗流分析

Analysis for Underground Water Seepage of Tunnels Under Limited Discharge

以广东某在建高速公路隧道工程为例,通过地下水渗流计算分析,确定隧道富水段注浆后岩体渗透系数,最终实现地下水的限量排放。渗流计算采用连续介质模型,主要考虑泄水孔间距、隧道承压水头以及渗透系数的变化,分析孔隙水压力分布、地下水渗流路径,以及渗透系数与渗流量之间的关系,隧道富水段围岩注浆后,其渗透系数理论上不应超过2×10-5m/s控制指标的结论,可为隧道工程的安全施工提供较好的理论指导。

With some expressway tunnel project under construction in Guangdong as an example, this paper determines the coefficient of permeability of rock mass after grouting at rich water sections of the tunnel via calculation and analysis of groundwater seepage to realize the limited discharge of underground water finally. The calculation of seepage adopts continuum medium model and analyzes pore water pressure distribution, groundwater seepage paths and the relationship between the coefficient of permeability and seepage flow in main consideration of changes of drain hole spacing, confined water head of tunnel and coefficient of permeability. After grouting of wallrock at rich water sections of tunnel, its coefficient of permeability should not be more than 2 x 10-5 m/s control index in theory, this can provide a good theoretical direction for safe construction of tunnel project.