Analytical Solution Of Steady Seepage Into Partially Penetrating Cutoff Wall During Excavation Dewatering

In view of the fact that most of the researches on seepage field and water-stop curtain at home and abroad are mainly based on numerical simulation,this paper puts forward an analytical method to obtain the distribution of seepage field in confined aquifer after dewatering of foundation pit with suspended water-stop curtain.Based on Darcy's law,seepage theory equation and other seepage analysis theories,mathematical theories such as conformal mapping theory and Newton iteration method are applied to establish a two-dimensional model for strip foundation pit.The research results include:1.On the assumption that the confined aquifer is homogeneous in soil quality and thickness,regardless of the deformation caused by foundation pit excavation,groundwater seepage conforms to Darcy's law,the permeability coefficient of aquifer is constant k,and the permeability coefficient of suspended water-stop curtain is zero,the mathematical calculation model of confined aquifer of strip foundation pit is established,and the analytic calculation formula of seepage field distribution of foundation pit with suspended water-stop curtain is obtained by repeatedly applying conformal mapping and establishing a one-to-one correspondence between complex physical plane and potential flow plane according to the first and third elliptic integral transformations.2.The mathematical calculation software MATLAB is used to calculate the formula between the complex physical plane and the potential flow plane of the strip foundation pit confined aquifer,then the boundary on the potential flow plane and a plurality of equipotential lines and streamlines are mapped onto the complex physical plane and visualized to obtain the seepage field distribution on the complex physical plane.3.The Seep / W software is used for numerical simulation,and the seepage field distribution obtained by analytical method and numerical simulation method are compared under the same working condition.The seepage field distribution diagrams obtained by the two methods are completely consistent,and the results show that the method is reasonable.The proposed analytical method provides a basis for studying the reasonable design depth of the suspended water-stop curtain.Based on this,more in-depth research can be carried out to explore the relationship between the depth of the suspended water-stop curtain inserted into the confined aquifer and the influence radius,seepage velocity and maximum hydraulic gradient,so as to determine the minimum insertion depth of the water-stop curtain while ensuring safety and ensuring that the surface settlement around the foundation pit meets the requirements.