江苏松散沉积层地区地下水资源评价模型发展趋势

Development trend of groundwater resources evaluation model in loose sediments in Jiangsu

江苏松散沉积层厚度大、结构复杂、容易发生固结压缩,地下水可采资源量评价具有较大的不确定性,容易造成重复或缺失,地下水的过量开采又容易引发地面沉降地质灾害。针对以上问题,提出了地下水资源评价的地下水渗流三维数学模型及其地下水渗流与地面沉降耦合模型。地下水渗流三维数学模型可以将整个松散沉积层作为一个统一的水文地质体进行计算,对不同水力性质的含水层同时进行刻画描述,克服了以往二维或准三维模型将各含水层之间的粘性土层概化为越流层给评价结果带来的重复或缺失。地下水渗流与地面沉降耦合模型可以结合地面沉降环境控制,评价出地下水的可采资源量,尤其是以比奥固结理论为基础,考虑了土体的非线性特征及土的渗透性随应力状态的动态变化的全耦合模型,使评价结果更趋科学、合理。

The loose sediments of large thickness and complexed structure can be easily consolidated and compressed are widely distributed in Jiangsu Province, the uncertainty in the evaluation of groundwater resources may easily leads to duplication or deletion. In addition, land subsidence and other geological disasters were mostly caused by excessive extraction of groundwater. Accordingly, a three-dimensional mathematical model of groundwater seepage and groundwater flow model coupled with land subsidence evaluation were adopted in the evaluation of the groundwater resources. Three-dimensional mathematical model of groundwater seepage was able to count the whole layer of loose sediments as a unified hydro - geological body, and describe the aquifer of different hydraulic properties at the same time. Compared with the two-dimensional or quasi-three-dimensional model which generalized the clay layers between the aquifers for leaky aquifer in the past, the model could overcome the duplication or deletion brought about by the evaluation results. Groundwater flow model coupled with surface subsidence could evaluate the groundwater availability combined with land subsidence environment. Particularly based on Biot＇s consolidation theory that considered the entire coupled model of the nonlinear characteristics of soil and the dynamic change of soil permeability under stress state, it could make the results more scientific and rational.