透水桩坝前冲刷坑深度影响因素探讨

通过模型试验对透水桩坝前冲刷坑深度的影响因素进行研究.受透水桩坝前螺旋环流淘刷,坝前冲刷坑形状为一近乎平行于桩坝的长条状冲坑,与透水桩坝连线方向一致.在来流含沙量及床沙组成不变的情况下,最大冲刷坑深度一般出现在主流顶冲段或稍偏下游部位.透水桩坝的坝前最大冲刷坑深度主要与来流单宽流量、入流角、桩坝透水率等因素有关,其中单宽流量对冲刷坑深度的影响最大.通过试验实测资料进行回归分析,得到最大冲刷坑深度与来流条件之间的无量纲表达式.

Discussion on impact factor of depth of scouring pit in front of permeable pile dike

Based on model test, the impact factor of scouring pit in front of permeable pile dike is studied herein. By the scouting from the spiral-circulation flow, the scouring pit in front of the dike forms a long and narrow scouring pit approximately parallel to the dike with the direction consistent with the axis of the dike. Under the condition of invariable sediment content of inflow and unchangeable bed load composition, the maximum depth of the pit occurs generally at the section facing the mainstream currentrushing or the section slightly deflecting the downstream. The maximum depth of the pit is mainly related to the inflow angle, unit discharge and the perviousness of the dike etc. with the maximum impact from the unit discharge. Regression analysis is made on the basis of the measured data from the test concerned and then the non-dimensional equation for the relationship between the maximum depth of the pit and inflow condition is obtained as well.