区域地下水开采与地面沉降控制三维全耦合数值模拟

Three-dimensional full coupling numerical simulation of groundwater exploitation and control of land-subsidence in region

针对第四纪松散沉积层中地下水开采所引起的地面沉降问题,以比奥固结理论为基础,考虑到土体的非线性特征及土体的渗透性随应力状态的动态变化,引入邓肯-张非线性模型和渗透率动态模型,将地下水渗流场和土体应力场耦合起来,并以江阴市浅层地下水开采为例,建立了浅层地下水开采与地面沉降三维全耦合数值模型。在对模型进行校正、识别的基础上,以第Ⅰ承压含水层未来10年内地下水位埋深不低于含水层顶板埋深一半,地面沉降量不超过50mm为约束条件,预测了江阴市各镇的地下水可采资源量以及地面沉降量。实践表明,该模型不仅稳定性好,且收敛速度快。

Aimed at the land-subsidence cased by groundwater exploitation in Quaternary loose sediments, based on Biot＇s consolidation theory, took the shallow groundwater exploitation in Jiangyin as the case study, a three dimensional full coupling numerical model between the hydraulic action of the seepage field and the stress field was established, in which Duncan-Chang non-linear model and the dynamic models of permeability were introduced with considering the non-linear characteristics and the dynamic variation of hydraulic conductivity of soils with stress. Based on identification and verification of the model, with the constraint conditions that the groundwater level would not be lower than half of the roof depth of the first confined aquifer and the land-subsidence wound not exceed 50mm, the allowable yield of groundwater and the land-subsidence in each town were predicted. It shows that this model has fast converged speed and runs steadily in practice.