Distribution law of soil deformation caused by decompression of confined water

Land subsidence caused by decompression of confined water is comprised of deformation of aquifer, aquitard and phreatic stratum. When the decompression features short duration, the consolidation deformation of aquitard is little and the aquitard is supposed to be watertight. Based on displacement coordination condition, theory for elastic layered system is adopted to calculate layered soil deformation caused by decompression of confined aquifer, including vertical and horizontal components. The calculated results are compared with numerical simulation and in situ pumping test. Analysis results show that elastic modulus of overlying soil has little influence on ground surface displacement, yet thickness of overlying soil layer should be taken into consideration. Settlement of soils overlying confined aquifer increases up to down nearby the pumping well. Over a certain distance, settlement does not change with buried depth. For unsteady flow of confined wells, the settlement value and region at ground and aquifer surface grows with pumping time increasing. The maximum horizontal displacement value and position at ground surface does not change with time after pumping for a certain time.