区域地下水开采与地面沉降控制三维全耦合数值模拟

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。

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

Railroad gauge standards, from the initial several hundred to about 30 and finally an international standard of 1435 millimeters, have evolved for a long time. This paper discusses the evolution process viewing from transaction cost perspective of institutional economics. It is indicated that the transaction cost is continuously reduced and the economic efficiency is greatly promoted. According to the North economic theory, the evolution of the standardization is the process of institutional change. However, standardization is easier to be implemented than the system change, and standardization greatly reduces the transaction costs, saves the transaction time and increases the efficiency of railway transportation.