非均匀流与颗粒组成对管涌影响的试验研究

中文摘要: 管涌的发展是个复杂的过程，受多种因素的影响，本文针对水流条件和试样颗粒组成两个因素进行了管涌发展的砂槽模型试验研究，观察并分析了两种典型的非均匀水流条件和三种试样颗粒组成下管涌发生发展的过程。试验结果表明，水流发散时，管涌口流量较小，管涌破坏的临界水力梯度大，侵蚀速度慢，侵蚀发生前试样内的水力梯度沿着水流发散方向逐渐减小；反之，水流汇聚时，管涌口流量大，管涌破坏的临界水力梯度小，侵蚀速度快，侵蚀发生前试样内的水力梯度沿着水流汇聚方向逐渐增大。此外，在相同的水流条件下，当试样中的细颗粒越粗时，管涌发生的临界水力梯度越大，管涌通道发展的速度也就越慢。
Abstract:The evolution of piping is a complex process, which is influenced by many factors. In order to investigate the influence of flow condition and soil particle composition on the piping process, a list of experiments on two typical types of non-uniform flow and three kinds of soil particle composition was carried out using the self-designed apparatus. The results indicated that divergent flow reduced the discharge in the outlet, meanwhile the critical hydraulic gradient for piping was large and the erosion rate was slow. The hydraulic gradient in the soil sample gradually decreased along the divergent flow direction before the erosion. On the other hand, the convergent flow made the discharge in the outlet large, the critical hydraulic gradient small, and the erosion rate fast. The hydraulic gradient in the soil sample gradually increased along the convergent flow direction before the erosion. Furthermore, the coarser the fine particles, the larger is the critical hydraulic gradient and the slower is the developing speed of the piping channel.