隔水帷幕绕流长度对基坑降水影响研究

RESEARCH ON THE INFLUENCE OF THE DEPTH OF WATERPROOF CURTAIN ON THE DEWATERING OF FOUNDATION PIT

利用有限元数值计算软件建立了巨厚承压含水层条件下悬挂式隔水帷幕基坑减压降水的三维水文地质概念模型。通过该模型模拟计算了基坑减压降水过程中绕流长度、降水时间等因素对基坑坑外水位降深的影响。结果表明降水前期承压水水位下降迅速,而后逐渐变缓直至接近稳定;在相同的坑内水位降深下,坑外水位降深随绕流长度增加而减小,不同时空的坑外降深的减小幅度十分接近;但随着绕流长度的增加,减小坑外水位变化的效果逐渐衰减;增加隔水帷幕的插入深度控制坑外水位降深,在长期降水时效果更为明显。

By using finite element numerical calculation software,a three-dimensional hydrogeological conceptual model is established for decompression dewatering of suspended water-proof curtain foundation pit under the condition of huge confined aquifer.The model is used to simulate and calculate the influence of bypass length,and dewatering time on the drawdown of confined water outside the foundation pit during the process of decompression dewatering.The results show that the water level of confined water rapidly drops in the early stage of dewatering,and it slows down gradually until it approaches stability.Under the same drawdown in the pit,the drawdown outside the pit decreases with the increase of the bypass length,and the reduction range of drawdown outside the pit is very close in different time and space.However,the effectiveness of reducing the drawdown outside the pit gradually decreases with the increase of bypass length.Increasing the insertion depth of water-proof curtain controls the drawdown outside the pit,especially during long-term precipitation.