断层影响区内隧道涌水的Goodman解析解

Goodman analytical solution of tunnel inflow in fault-affected area

隧道在富水地层穿越断层影响带时,往往伴随着突水的风险,给施工和结构安全带来极大隐患,因此有必要对断层影响区域内隧道涌水量进行预测。在Goodman井流假定的基础上,利用镜像叠加原理,推导隧道在断层影响区内开挖引起的地下水头分布的半解析公式,得到隧道涌水量的半解析解;经过对不同工况进行解析计算,并与数值计算的对比,证明所推导的半解析公式具有较好的适用性;通过将该公式应用于多种工况条件,充分探讨隧道和断层位置关系的几何参数对隧道涌水量的影响。研究结果表明:隧道与地下水位线之间的垂直距离对涌水量的影响最大,且当其他参数不变时,涌水量呈现出与该垂直距离近似线性增长的趋势。此外,横断面内隧道中心到断层面与水位面交点的水平距离以及断层倾角也会影响涌水量的大小。当水平距离越小,且断层倾角越大时,隧道涌水量变大,反之则变小。计算与分析结果可为后续隧道涌水量计算与控制提供指导。

When a tunnel passes through a fault-affected zone in a water-rich stratum, it is often accompanied by the risk of large water inflow, which brings about great hidden dangers to construction and structural safety.Therefore, it is necessary to predict the water inflow of the tunnel in the fault-affected area. Based on the assumption of Goodman well flow theory, the semi-analytical formula for the distribution of the underground water head caused by the excavation of the tunnel in the influence zone of the fault was derived by using the principle of mirror superposition. Thus, the semi-analytical solution of tunnel water inflow was obtained. After comparing the analytical calculation with the numerical calculation for different working conditions, it was considered that the derived semi-analytical formula had good applicability. Finally, by applying the formula to various working conditions, the influence of geometric parameters representing the positional relationship between tunnel and fault on the tunnel water inflow was fully discussed. It is found that the vertical distance between tunnel and groundwater level line has the greatest effect on water inflow when other parameters remain unchanged. The water inflow exhibits a linear growth trend similar to the vertical distance. In addition, other geometric parameters also affect the size of water inflow, such as the horizontal distance between the center of tunnel and the intersection of fault plane, water level surface, and the dip angle of fault. When the horizontal distance is smaller, and the dip angle of fault is larger, the water inflow of tunnel will also increase, and vice versa. The results of calculation and analysis can provide guidance for the subsequent calculation and control of tunnel water inflow.