When pumping is conducted in confined aquifer inside excavation pit (waterproof curtain), the direction of the groundwater seepage outside the excavation changes from horizontal to vertical owing to the existence of the curtain barrier. There is no analytical calculation method for the groundwater head distribution induced by dewatering inside excavation. This paper first analyses the mechanism of the blocking effects from a close barrier in confined aquifer. Then, a simple equation based on analytical solution is proposed to calculate groundwater heads inside and outside of the excavation pit with waterproof curtain (hereafter refer to close barrier) in a confined aquifer. The distribution of groundwater head is derived according to two conditions: (i) pumping with a constant water head, and (ii) pumping with a constant flow rate. The proposed calculation equation is verified by both numerical simulation and experimental results. The comparisons demonstrate that the proposed model can be applied in engineering practice of excavation.

在开挖坑（防水幕）内的密闭含水层中进行抽水时，由于存在幕墙，开挖外部的地下水渗流方向从水平方向变为垂直方向。开挖过程中因脱水引起的地下水位分布没有解析计算方法。本文首先分析了密闭含水层中封闭障碍物的阻塞作用机理。然后，提出了一种基于解析解的简单方程式，用于计算密闭含水层中带有防水幕布（以下称为密闭屏障）的开挖坑内部和外部的地下水位。地下水水头的分布是根据两个条件得出的：（i）以恒定水头泵水，和（ii））以恒定的流量泵送。通过数值模拟和实验结果验证了所提出的计算方程。比较表明，所提出的模型可以在开挖工程实践中应用。