Simulation On Ground Subsidence In Fuyang, Anhui Province

Geological disaster caused by unreasonable exploitation of groundwater has become a global issue. The ground deformation has serious implications on the buildings in the subsidence areas. Ground subsidence also caused elevation reduction result in lowering flood control standards. Elevation reduction may lead to loss area of mainland in coastal areas. Therefore, the scientific community now has been great concern on the problem of ground subsidence.During simulation on ground subsidence in Fuyang, as a typical example that exploitation of groundwater leaded to the consolidation in adjacent aquifer, the groundwater flow change in the aquifer must be considered. When you simulate groundwater flow change in aquifer, the "consolidation water" releasing from adjacent clay layer can not be ignored. At present, the theory of fluid-solid coupling is the effective way to research the ground subsidence and Biot fluid-solid coupled is used widely. However, the parameters of Biot fluid-solid coupled are excessive, and some parameters are difficult to determine. Thus, it is considerable difficulty to be widely applied in practice. In addition, the filtration in clay layer is not fit to the Darcy flow. Therefore, the Biot fluid-solid coupled also is difficult to direct application. In addition to Biot theory, other fluid-solid coupled methods are more biased towards the mechanism of consolidation and the change of process. The simulation of seepage will be only used as a supplement way to calculate the consolidation. In fact, to achieve this simulation under such conditions of the groundwater flow system is more difficult.When this paper studied the problem of ground subsidence in Fuyang City, the relationship equation between "consolidation water" and consolidation volume are established, and decoupled method is used for computation. As a result, the one-dimensional consolidation and three-dimensional flow equations achieve indirect coupling. The monitoring data of water level and the measured data of ground subsidence from January in 1997 to December in 1999 are used for model identifying. In the course of identifying, the water level in July, 1997 is taken as the initial head and the calculation step is 4 months. At last, use the identified coupled model to forecast for the next eight years of subsidence.