基于数值模拟的混凝土坝渗透溶蚀劣化时空特征

针对混凝土坝长期服役过程中的渗透溶蚀问题,在COMSOL平台上分别选用达西定律模块和对流—扩散方程模块,建立了混凝土坝渗流场与钙溶解迁移场的耦合模型,研究了渗透溶蚀作用下混凝土坝劣化的时空分布规律,并对比研究了固液相钙处于平衡态和不平衡态两种情况下混凝土坝渗透溶蚀程度的差异性。数值模拟结果表明,混凝土坝的渗透溶蚀是一个由表及里的过程,主要溶蚀区为坝体上游侧;将基于接触溶蚀试验得到的固液平衡方程用于混凝土坝的渗透溶蚀模拟,得到的坝体渗透溶蚀程度将明显偏大。今后应重点研究固液相钙浓度不平衡态与平衡态之间的偏差距离与流速之间的关系。

Spatio-temporal Characteristics of Leakage Dissolution of Concrete Dam Based on Numerical Simulation

To study the temporal and spatial distribution law of deterioration of concrete dam under leakage dissolution,a coupling simulation model of the leakage field and calcium dissolution-transportation field is established for concrete dams by using the Darcy’s law module and convection-diffusion equation module on the COMSOL platform.The differences of deterioration degree of concrete dam under the balanced and imbalanced assumptions between concentrations of the solid and liquid calcium are compared.The numerical simulation results show that the leakage dissolution of concrete dam is occurred from the surface to inside of the dam body,and the main dissolution area is the upstream side of the dam body.If the solid-liquid equilibrium equation,which is obtained by contact dissolution tests,is used for the leakage dissolution of concrete dams,the dissolution degree will be obviously larger than the actual situation.The future work should be focused on the relationship between the deviation distance between the balance and imbalance states of the solid and liquid calcium and the leakage velocity.