中文摘要：

坝基的渗流动态,很大程度上受控于坝基帷幕体的完好程度和止水效果,但是由于地下水长期存在的物理–化学作用,造成帷幕体防渗性能的衰减。为了能够再现坝基帷幕体防渗性能衰减的过程,依据渗流水力学以及水文地球化学的基本理论,建立了反映帷幕体防渗时效的多场耦合作用模型。该模型由渗流模块、溶质迁移模块、地球化学模块及帷幕体侵蚀模块构成,并采用FEM数值法求解。工程实例计算结果表明帷幕体的防渗效果随着时间的推移而弱化,此主要源自帷幕体中Ca（OH）2一类可溶性物质的溶失。在整个模拟时段,帷幕体中的钙质始终处于溶解状态,其不同部位发生溶蚀的强度也不相同,帷幕体底部的溶蚀量要高于其上部的溶蚀量;靠近坝基上游侧的帷幕的溶蚀量要高于下游侧的溶蚀量。钙离子迁移主要由于水动力条件和弥散作用共同引起的,且坝基各点的钙离子浓度随时间呈非线性变化。

英文摘要：

The seepage flow in dam foundation is mainly controlled by the intact degree and the sealing effect of its curtain.Its property is weakened by long-term physical and chemical actions of groundwater.In order to describe the process of the damage to the curtain,a multi-field coupling model for water-rock-seepage curtain of the dam foundation is made up of seepage model,solute transport model,geochemistry model and curtain erosion model,and all the models are calculated by FEM.The results show that the curtain efficiency decrease with the time.Calcium has been always in dissolution during the time stress period for simulation.The erosion extent at the bottom of the curtain is much quicker than that at its top part.And it＇s the same for the upstream and downstream.Calcium dissolution is mainly induced by hydraulic condition and dispersion,and it varies in a non-linear way.