水闸侧墙与土体接合部渗透破坏过程模拟试验

为深化对穿堤涵闸土石接合部渗透破坏发展机理的认识,研发了试验装置,实现了水闸侧墙与土体接合部渗透破坏过程的室内模拟。通过对黏粒质量分数分别为4.6%、12.3%及22.6%的土体开展试验,分析了接触冲刷的破坏特征及其发生发展规律,探讨了土体性质、水力比降、接触带压实度等因素对渗透破坏的影响。试验结果表明:土石接合部接触冲刷破坏过程分为稳定渗流阶段、管涌形成发展阶段和冲蚀破坏发展阶段;土体黏粒质量分数越大、压实度越大,土体稳定时间及破坏时间越长,抗冲蚀能力越强;冲蚀量与土体黏粒质量分数、水力比降及压实度均呈现明显的反比关系;水力比降较小时,压实度对土体抗冲性能影响显著,但随着水力比降的逐渐增大,土体性质起主导作用;初始破坏阶段土体细颗粒的流失受土体性质、压实度及水力比降各因素的综合作用,表现出不同的规律性。

Simulation test on seepage failure process of junctions between sluice side wall and soil mass

To deepen the understanding for the seepage failure mechanism of earth rock junctions for crossing-dyke sluices, a testing apparatus was designed to accomplish the indoor simulation for the seepage failure process of the junctions between sluice side wall and soil mass. Then, the failure characteristics of contact scouring and its development were analyzed with the clay mass fractions of 4. 6%, 12. 3% and 22. 6%. The effects of soil properties, hydraulic gradient and compactness of the contact zone on seepage failure were studied. The results show that the typical contact scouring process can be divided into three stages, i. e. , stable seepage, piping formation development, and erosion failure. The higher the clay content and compactness, the longer duration will be for stable and failure stages with stronger erosion resistance. There is a significant inverse relationship between erosion and clay mass fraction, hydraulic gradient and compactness. The compactness effect on soil erosion resistance is significant under weak hydraulic gradient. However, with the increase of hydraulic gradient, soil properties play a leading role. At the initial stage of failure, the loss of fine soil particles shows different regularities under the comprehensive effect of soil properties, compactness and hydraulic gradient.