考虑含水层渗透系数各向异性的深基坑降水优化设计

Optimization Design of Dewatering in Deep Foundation Pit Considering Anisotropy of Hydraulic Conductivity of Aquifers

某船闸基坑承压含水层存在夹层及互层,地层渗透系数表现为竖向小于水平向的各向异性特征。充分利用这一特性,将隔水帷幕与降水井设计同步考虑,建立三维数值分析模型,改变地下连续墙与滤管插入承压含水层深度,计算不同插入深度组合工况基坑内外承压水位降低情况,得出了经济、安全的地墙与滤管插入深度,不但满足了设计降深要求,且坑外水位降深较小,还保护了周边已有的构筑物。

The confined aquifers of a ship lock foundation pit have interlayers and interbeds so that the stratum hydraulic conductivity presents the anisotropy in the vertical direction weaker than that in the horizontal direction. With this feature, given simultaneous design of impermeable curtain and dewatering well, 3D numerical model was established. Then by changing the depth of underground diaphragm wall and filter tube inserted into the confined aquifers, how the level of confined water reduces inside and outside the foundation pit in different combinations of inserting depth cases were calculated. As a result, the economic and safe value of the inserting depth of diaphragm wall and the filter tube was obtained, which not only met the design requirement of dewatering depth, but also due to the shallow dewatering depth outside the foundation pit, the existing structures surrounded could be protected.