Physical Model Test of Land Subsidence Caused by Groundwater Withdrawal

In this study, a physical model test was conducted to investigate the relative settlement of the aquifers and the aquitards during the pumping test. The soil layers in the physical model were simulated from practical (SU-XI-CAHNG) pumping strata. The dimensions of the cubical model tank were 0.6m in length, 0.5m in width and 1.0m in height. The model soils consisted of four layers with two aquifers and two aquitards alternating placed. The pumped aquifer was located at the bottom of the tank, and the thickness of each layer varied. The hydraulic head and the deformation of each soil stratum were monitored during pumping test by small diameters pore pressure tubes and settlement telltales. Throughout the pumping test, the compression of the pumped aquifer at bottom consisted of 50% of the overall observed settlement measured at surface of soil (land subsidence). The time effect of the sandy aquifer deformation was also observed. A bilinear relationship between the land subsidence and the decrease of the hydraulic was verified in this experiment. It is confirmed that, although the recharge had a significant effect on the land subsidence potential reduction, the subsided ground would not rebound due to the recharge. The model test improved the understanding of the land subsidence due to groundwater withdrawal.