Finite Layer Formulations for Land Subsidence due to Groundwater Withdrawal

Abstract

A finite-layer method (FLM) based on consolidation theory is presented for land subsidence due to groundwater withdrawal. The groundwater flow in aquifer systems and the displacement within soil skeletons are approximated by an integration of the standard finite-element method (FEM) in the vertical direction and analytical techniques in the other two spatial directions. By virtue of the analytical eigenfunctions introduced in the formulation, the FEM-weighted residual equations can be decoupled into small-scale linear subsystems, and the formulas for coefficient matrices and flow vectors can be obtained explicitly. Numerical examples are presented to verify the validity of the presented solution through comparisons with available analytical and experimental results. The study also shows that the compressibility of pore water has a significant influence on the pumping-induced subsidence process. The numerical applications to multilayered aquifer systems and horizontal wells are presented to demonstrate the applicability and efficiency of the present method.