软弱地层管棚施工中失水引起的地表沉降计算

管棚支护是浅埋暗挖法施工中的一种辅助工法。它对于城市地下工程的建设，不失为一种较好的方法，但是由于城市地下工程施工中对地表沉降控制极其严格，这种方法因此带来了一些问题。在软弱地层管棚的施工中，管棚成孔过程中产生水的渗流通道，地下水的流失引起土的固结而导致地表沉降。文章通过计算分析，比较在地层渗透系数、管棚参数、施工参数不同的情况下地表沉降的变化，得出这几种因素影响地表沉降的规律和大小，可为施工提供参考和指导依据。

Calculation of Ground Surface Settlement Resulted by Water Loss During Pipe-roof Construction in Soft Ground

Pipe roof support is an assisted method of shallow tunneling. It can be well used in the city underground construction. However, it also brings some questions due to the control demand of ground surface settlement in the city. In the construction process of the pipe roof in soft ground, the ground surface settlement was resulted by water loss and consolidation, which was induced by the drilling process of pipe roofs, in which the seepage paths were formed. In this paper, the ground surface settlement was calculated and the effects of the seepage coefficient of ground, the numbers and the diameter of pipe roof and construction parameters on the ground surface settlement are compared. The law and extend of the influence of these factors on ground surface settlement are presented. These conclusions can be used as reference and guide during the construction.