洪峰过程非稳定渗流管涌试验研究与理论分析

进行了洪峰过程和潮汐变幅对堤防发生管涌影响的非稳定渗流模型试验。与固定洪峰水头下的稳定渗流管涌试验结果相比，由于洪峰过程高水位历时较短，管涌险情发展的可能性显著减小，同时，管涌险情的发生也与土层的结构、压缩性和透水性有关。结合北江大堤洪峰模拟过程，讨论了砂模型试验的模型相似律和时间比尺的推算问题，给出了管涌险情发展时间的参考值。最后，通过可压缩非稳定渗流方程，导出了正弦型洪峰、潮汐或波浪在堤基中的传播速度、迟后时间、洪峰水头和能量衰减规律的计算公式，并得到试验资料的验证。

Piping experimental study and theoretical analysis of unsteady seepage flow during flood peak

The effect of water level variation in the advance of flood and tide wave on unsteady seepage flow in levee is studied experimentally in laboratory. Since the duration of high water stage in the process of flood is short,comparing with the constant water level,the risk of piping development is remarkably reduced. The similartiy law and time scale of flood process duration for modeling are investigated in the sand model test for levee of Beijiang River, Guangdong Province,and a method for estimating the development duration of piping in levee is deduced. The formulas for calculating propagation velocity, time delay and energy attenuation of unsteady seepage flow under levee in case of the flood peak duration following a sine curve are further analyzed theoretically.