非均匀流条件下的管涌试验研究

Laboratory Investigation on Piping Development on the Condition of Non-Uniform Flow

通过自行设计的室内模型试验对非均匀水流条件下堤基管涌破坏规律进行对比研究,结果表明:从小截面进水时,管涌口流量较小,管涌破坏较难发生,临界水力梯度较大,且侵蚀速度较慢,通道发展深度较小;反之,从大截面进水时,管涌口流量较大,管涌破坏容易发生,临界水力梯度小,且侵蚀速度很快,通道发展深度较大。同时对试验过程中累计涌砂量以及孔隙率随时间变化的规律进行了分析,并得到其拟合模型。

Through the design of indoor model experiment, the research of the damage rules of embankment foundation under the action of the non-uniform flow conditions was carried out. The results indicate that divergent flow reduees the discharge of the outlet, meanwhile the critical hydraulic gradient is large, the erosion rate is slow and the depth of channel development is shallow ; on the other hand, the eonvergent flow make the discharge of the outlet large, the critical hydraulic gradient small, the erosion rate is very fast and the depth of channel development is large. Meanwhile the fitting model of cumulative sand gushing amount and the porosity change over times have been determined by analyzing the changing law in the experiment process.