高压输水隧洞帷幕体防渗性能的数值模拟*

为研究高压输水隧洞帷幕体防渗性能，建立基于渗流场、化学场及帷幕体微观结构等多物理场耦合的数值模型，采用FEM数值法求解并结合工程监测数据对模型进行验证。结果表明:帷幕体在高水头30 a长期侵蚀与溶解作用下，内部Ca2+不断析出，帷幕体溶蚀程度最深处孔隙率较初始孔隙率增加29.38%，渗透系数增大1.95倍，抗渗性和耐久持续衰减；帷幕体溶蚀具有时空变异特性，帷幕体与高压岔管接触部位溶蚀面积最大，其次为底部，顶部几乎未发生溶蚀现象。研究结果可为监测高压输水隧洞帷幕体防渗性能变化及定制专项防渗方案提供参考。

Numerical simulation on anti-seepage performance of curtain body in high-pressure water conveyance tunnel

In order to study the anti-seepage performance of curtain body in the high-pressure water conveyance tunnel,a numerical model based on the coupling of multi-physical fields such as the seepage field,the chemical field and the microstructure of curtain body was established.The model was solved by the finite element method (FEM),and verified by combining with the engineering monitoring data.The results showed that under the effect of long-term erosion and dissolution of curtain body under high water head for 30 years,the internal Ca2+ continuously precipitated.The porosity in the deepest part of dissolution degree of the curtain body increased by 29.38% compared with the initial porosity,the permeability coefficient increased by 1.95 times,and the impermeability and durability continued to decrease.The dissolution of curtain body had the characteristics of temporal and spatial variation.The dissolution area at the contact part of curtain body and high-pressure bifurcated pipe was the largest,followed by the bottom,and there was almost no dissolution at the top.The research results can provide reference for monitoring the change of anti-seepage performance of curtain body in the high-pressure water conveyance tunnel and customizing the special anti-seepage schemes.