堤防管涌试验研究与分析

he theory definition of piping is the phenomenon that the fine particles of the soil move in pore space passage and are taken away under the effect of seepage; in engineering, piping effect commonly means the contact washout destruction between the hydraulic structure and the groundwork. In order to determine the hydraulic gradient under which the inner particles of dike foundation can be dragged to outlet and the piping appears, For obtaining the critical hydraulic gradient of piping in theoretically, the device of flume model test is improved in order to avoid the phenomenon of contact erosion and the critical hydraulic gradient of piping under different conditions such as different content of fine particles, packing density and length of seepage path is studied. It shows that the results of test are almost coincided with the value by formula. Under this precondition, the influence of seepage channel in inner dike foundation to critical hydraulic gradient of piping and the influence of different size of diameter of seepage channel and different distance between the channel and outlet to critical hydraulic gradient are studied and some reasonable conclusions are derived.