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心墙是否会发生水力劈裂关系土石坝的安全,该问题的难点和关键之一是水力劈裂的发生机制和条件。利用自制模型,在2种不同加压速率条件下,对有无初始裂缝和5种不同初始裂缝深度的试样进行了水力劈裂试验;结合数值模拟和CT观测试验,验证了水力劈裂的楔劈效应机制—当水压力作用在初始裂缝形成的劈背上,引起劈刃上的力超过临界值时就可能导致发生水力劈裂。研究结果表明:初始裂缝深度越大、加压速率越高,越容易发生水力劈裂。为避免土石坝发生水力劈裂破坏,应注意心墙迎水面的施工质量和平整性,宜采用较慢的蓄水方案。
Whether the hydraulic wall splitting will affect the safety of earth-rockfill dam is one of the cruxes and key points of the hydraulic splitting mechanism and conditions. Hydraulic fracturing tests were carried out on the samples with or without initial fracture and five different initial fracture depths under self-made model at two different pressurization rates. The hydraulic fracturing test was carried out on the specimens with two different pressurization rates. The numerical simulation and CT observation tests verified that the hydraulic fracturing Wedge Effect Mechanism - Hydrodynamic cleavage can occur when water pressure exceeds the threshold due to water pressure acting on the cleats formed by the initial cleavage. The results show that the bigger the initial crack depth is, the higher the pressure is and the more prone to hydraulic fracturing. In order to avoid the hydraulic fracturing of earth-rock dam, it is necessary to pay attention to the construction quality and the flatness of the water-to-water surface of the heart wall. A slower water storage plan should be adopted.