基于应力-渗流-损伤耦合模型的重力坝三维水力劈裂数值模拟

Simulation of 3D hydraulic fracturing of concrete gravity dams based on stressseepage-damage coupling model

裂缝的高压水力劈裂是混凝土高坝安全评估的重要部分。目前,重力坝水力劈裂的数值模拟绝大多数是二维的,对于坝体上游面经常出现的竖直裂缝的三维水力劈裂的数值研究几乎为零。本文提出一种应力-渗流-损伤耦合模型,用于混凝土重力坝三维水力劈裂的模拟。采用该耦合模型,模拟了一个内置裂缝的圆柱体试件的水力劈裂,数值结果与试验结果吻合很好,验证了所提耦合模型的合理性。在此基础上,采用该耦合模型,进行了国内某混凝土重力坝三维水力劈裂的模拟,数值模拟得到的损伤区域与设计院根据安全监测实测结果得到的范围基本吻合。研究结果表明:本文耦合模型可以方便、有效地进行重力坝三维水力劈裂的模拟,评估表面裂缝的危险程度。

High pressure hydraulic fracturing is an important part of safety assessment in high concrete dams.At present,most of the numerical simulations of hydraulic fracturing in concrete gravity dams are limited to 2D.There is lack of the simulation of 3D hydraulic fracturing of vertical cracks which often oc cur upstream of the dam.In this study,a stress-seepage-damage coupling model is presented for the simu lation of 3D hydraulic fracturing.By the coupling model,hydraulic fracturing of an internal crack in a cyl inder specimen is simulated.The results are in good agreement with the experimental results,verifying the rationality of the coupled model.Then the coupled model is used to simulate 3D hydraulic fracturing of a concrete gravity dam.The damage region obtained by the simulation is basically consistent with the crack zone predicted by the design institute.The results show that the coupled model can be used to simulate the 3D hydraulic fracturing of gravity dams conveniently and effectively,assess the degree of risk of sur face cracks to take effective measures in time and provide technical support for the safe operation of high dams.