Hydraulic head difference at two sides of suspended waterproof curtain during multi-grade dewatering of excavation  

作　　者：Tao Yang Li-yuan Tong M.Hesham El Naggar Xin Yan 

机构地区：[1]School of Transportation,Southeast University,Nanjing 21000,China [2]Department of Civil and Environmental Engineering,Western University,London N6A 5B9,Canada

出　　处：《Underground Space》2023年第3期137-149,共13页地下空间（英文）

基　　金：the National Natural Science Foundation for Surface Project of China(Grant Nos.51878157,41572273);the Jiangsu Natural Science Foundation,China(Grant No.BK20181282).

摘　　要：This paper proposes an approach to calculate the head difference at two sides of suspended waterproof curtains during multi-grade dewatering.The seepage during the dewatering process can be subdivided into three regions:(i)seepage in pit,(ii)seepage between cur-tains,and(iii)seepage outside the pit.The flow rate of the first region is equal to the pumping rate,and the flow rate of the second and third regions can be obtained by numerical analysis.A numerical model is established to simulate the seepage in the second and third regions and its performance is validated by using the measured data of a series of field tests.The flow rate of each region is then used to derive formulae for the head difference in conventional dewatering,which can be used to determine the head difference at two sides of each waterproof curtain during multi-grade dewatering.The proposed formula expresses the head difference as a function of the relative depth of the curtain inserted into the confined aquifer,the thickness of the aquifer,the distance between two curtains,and the anisotropy of the hydraulic conductivity of the aquifer.The proposed numerical approach is further validated by using data derived from numerical analysis.The validation results demonstrated that the predictions of the proposed approach are acceptable and convenient.

关 键 词：Head difference Multi-grade dewatering Suspended waterproof curtain Confined aquifer 

分 类 号：TU753[建筑科学—建筑技术科学]