承压水层圆形基坑悬挂式止水帷幕涌水量解析

Analysis of water inflow in circular foundation pit with suspended waterproof curtain in confined aquifer

针对承压水地层悬挂式止水帷幕基坑的涌水量计算不准确的问题,根据地下水动力学原理,建立了圆形基坑渗流场解析模型,推导了涌水量解析的计算公式.提出了与止水帷幕插入比、承压含水层厚度和基坑半径相关的渗径影响系数,并且采用数值模拟正反分析拟合得到了系数取值,该系数用于修正坑内等效渗径长度并直接影响涌水量计算结果.最后,基于解析解涌水量结果讨论了基坑尺寸止水帷幕控水效果的关系.研究结果表明:本文理论解析结果与数值结果以及现场实测数据有良好的一致性;基坑尺寸过大时不宜选用悬挂式止水帷幕作为控水措施.

This paper aims to solve the inaccurate calculation of the water inflow in the foundation pit of the suspended waterproof curtain in the confined aquifer.According to the principle of groundwater dynamics,the analytical model for the seepage field of the circular foundation pit is established,and the analytical equation of the water inflow is deduced.Then the paper proposes the influence coefficient of seepage diameter related to the waterproof curtain insertion ratio,the thickness of the confined aquifer and the radius of the foundation pit.And the value of the influence coefficient is obtained by the positive and negative analysis of numerical simulation,which is used to correct the equivalent seepage diameter in the pit length,directly affecting the calculation results of water inflow.Finally,based on the calculation results of the analytical solution to water inflow,the relationship between the size of the foundation pit and the water control effect of the waterproof curtain is discussed.The research results show that the theoretical analysis results in this paper are in good agreement with the numerical results and the measured field data.It is concluded that when the size of the foundation pit is too large,it is not suitable to use the suspended waterproof curtain as the water control measure.