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由于坝体、坝基本身的缺陷或者穿坝建筑物的影响,渗透破坏是土石坝常见的一种破坏形式,管涌破坏在渗透破坏中占有很大比例。前人虽对土石坝管涌进行了大量的研究,但对管涌发生后的发展过程及其破坏规律还缺乏深入的研究。首先通过对可动颗粒受力情况的分析,推导出可动颗粒的临界水力梯度和管涌发展过程中土体孔隙率的变化,然后采用水流运动能量方程推导出管涌发展过程中管涌通道流量和流速的发展变化过程,得出了管涌通道流量的计算方法以及孔流转化为堰流的控制条件。在此基础上,提出了一个模拟土石坝管涌发展过程的数学模型,该模型可同时考虑土体的颗粒级配和密实度对管涌发展的影响,建立流量、流速与孔隙率的变化关系,确定管涌过程中的流量过程线,与目前国内外已有的模型相比,更为合理地考虑土石坝筑坝材料性质对溃口发展过程的影响。已有的大坝溃口实测流量过程线证实了该模型的合理性。
Infiltration damage is a common form of failure of earth-rock dam due to the defects of dam body and dam foundation or the impact of crossing dam structures. Piping damage accounts for a large proportion of infiltration and destruction. Though predecessors have conducted a great deal of research on the piping of earth-rockfill dam, there is a lack of thorough research on the development process and the destruction of piping after the occurrence of piping. Firstly, the critical hydraulic gradient of the movable particles and the change of the porosity of the soil during the development of the tube were deduced by analyzing the force of the movable particles. Then, the flow rate and velocity of the tube channel during the development of the tube were deduced by using the flow kinetic energy equation The process of calculating the flow of piping and the control conditions of the flow from hole flow to weir flow were obtained. On this basis, a mathematical model for simulating the development of earth-rockfill embankment is presented. The model can consider the influence of soil particle size distribution and density on the development of piping, establish the relationship between the flow rate, the flow rate and the porosity, and determine Compared with the existing models at home and abroad, it is more reasonable to consider the influence of the material properties of the earth-rock dam on the development of the breach. The existing measured process curve of the dam breach confirmed the rationality of the model.