悬挂式止水帷幕基坑降水引起坑外地面沉降计算方法

悬挂式止水帷幕的挡水效应能够减轻基坑降水对周边环境的影响，但帷幕插入深度与坑外地面沉降之间的定量关系尚不明确.本文基于有效应力原理，并根据渗流场和应力场的部分耦合关系，考虑地下水位下降引起的土体孔隙比和压缩指数变化，通过止水帷幕插入深度与水位降深的关系提出了不同止水帷幕插入深度下潜水含水层中基坑降水引起坑外地面沉降的计算方法.结合室内渗流模型箱试验对所提方法进行验证，结果表明地面沉降的试验监测结果与计算结果基本一致，从而为准确预测地面沉降和设计合理的止水帷幕插入深度提供了重要参考.

Calculation Method for Land Subsidence Induced by Dewatering of Foundation Pit with Suspended Waterproof Curtains

The blocking effect of the suspended waterproof curtain can reduce the impact of foundation pit dewatering on the surrounding environment. However， the quantitative relationship between the insertion depth of the curtain and the land subsidence outside the pit is still unclear. Based on the principle of effective stress， and the partial coupling effect of the seepage field and the stress field where changes in soil void ratio and compression index caused by the drop of groundwater level was considered， a calculation method for land subsidence outside the pit caused by the dewatering of the foundation pit with suspended waterproof curtain in unconfined aquifers considering the relationship between the insertion depth of the waterproof curtain and the drop of groundwater level was proposed. A seepage experiment using a self-designed test model box was adopted to verify and analyze the proposed method. The results show that the calculated values are nearly close to the experimental values. The calculation method provides a significant reference for land subsidence prediction and the design of the insertion depth of rational waterproof curtain.