Abstract:

In order to combine the plan and evaluation of the groundwater exploitable resources with the requirement of the protection of land subsidence in regional loose sediment area, based on the theory of seepage and soil mechanics, a coupling mathematical model between the three-dimensional non-steady groundwater seepage flow and land subsidence which considers the change characteristic of porosity, permeability coefficient and water storage rate of aquifers with consolidation subsidence of aquifer was established. A three-dimensional finite element analysis method was applied to the mining of groundwater in Nantong of Jiangsu Province, based on the control requirements of land subsidence, the groundwater exploitable resources of each aquifer in all the villages was evaluated. It is shown that the total groundwater exploitable resources is 17 870.56×10⁴ m³/a on the basis of the scientific plan of the groundwater exploitation allocation, compared with 10 902.32×10⁴ m³/a of the groundwater exploitation quantity in the present state, the groundwater exploitable resources on the basis of the scientific plan of the groundwater exploitation allocation is increased greatly. The feature of the three-dimensional hydrogeology system is able to be described more accurately by the coupling model between the three-dimensional variable parameters non-steady groundwater and land subsidence, which is more suitable for the practical situation.

Key words: groundwater, land subsidence, three-dimensional non-steady flow, numerical simulation, exploitable resources