Back Analysis and Application of Confined Aquifer Hydrogeological Parameters Based on Pumping Test

Abstract

Hydrogeological parameters are important factors for engineering dewatering design. There is often a big difference in calculated hydrological parameters value due to the complexity and diversity of calculation of hydrogeological itself. In order to offset the disadvantage of low search efficiency and large amount of calculation by the traditional back analysis methods in geotechnical engineering, the back analysis method combining the Nelder–Mead algorithm and finite element method is studied. The back analysis code is developed by the software MATLAB, in which the finite element code of ABAQUS is embedded as a module. Using the proposed method in this paper, the hydrogeological parameters of the confined aquifer were calculated and compared with the theoretical analytic solution according to unsteady pumping test data. The results show that the parameter searching efficiency and the convergence precision of the proposed method have an obvious improvement and the inverse results meeting accuracy requirements can be obtained with less iterations. And results of theoretical method and numerical back analysis method are basically in the same order of magnitude, but the inverse result is smaller than the theoretical. The method proposed in this paper is effective. The proposed method is a feasible method for back analysis of stress, seepage and displacement in geotechnical engineering.