高混凝土重力坝坝踵裂缝水力劈裂特性分析

高水压作用下常年运行的高混凝土重力坝易存在水力劈裂破坏隐患，对某高混凝土重力坝坝踵裂缝水力劈裂特性进行数值分析，研究了缝内水压对高混凝土坝水力劈裂裂缝扩展的影响，探讨了高混凝土坝水力劈裂裂缝稳定性和坝基面抗滑稳定性。结果表明，当初始裂缝距离坝踵的高度为3.0 m，裂缝深度为2.0 m时，与不考虑缝内水压作用相比，缝内水压作用下坝体极限承载能力降低17.6%；当初始水平裂缝深度为2.0 m，裂缝距离坝踵的高度小于等于5.0 m时，坝体裂缝处于拉剪断裂模式；初始水平裂缝位于坝踵位置，缝内水压作用下坝基面抗滑稳定安全系数下降明显，下降速率为未考虑缝内水压情况的8倍，缝内水压作用对重力坝坝踵裂缝稳定及抗滑稳定不利。

Analysis of hydraulic fracturing characteristics of cracks in a high concrete gravity dam heel

High concrete gravity dams operating perennially under the condition of high water pressure are prone to hydraulic fracturing failure. In this study, the hydraulic fracturing characteristics of the dam heel crack in a high concrete gravity dam were analyzed, the influence of water pressure inside the crack on the expansion of hydraulic fracturing crack was studied, and the stability of hydraulic fracturing crack and anti-sliding stability of dam foundation surface were discussed. The results show that if the initial crack is 3.0 m away from the dam heel and the depth of the crack is 2.0 m,the ultimate bearing capacity of the dam body under the water pressure in the crack decreases by 17.6% compared with that without considering water pressure inside the crack. If the initial horizontal crack depth is 2. 0 m and the distance from the crack to the dam heel is less than 5. 0 m, the crack of the dam body is in the tension shear fracture mode. If the initial horizontal crack is located at the dam heel position, the safety coefficient of anti-sliding stability of dam foundation surface in the joint under the action of water pressure decreases obviously, with a decreasing rate of 8 times compared to the case without considering the water pressure inside the crack. The effect of water pressure inside the crack is unfavorable to the crack stability and anti-sliding stability for gravity dam heel.