多沙河流中群桩塔基局部冲刷平面尺度模型试验研究

局部冲刷平面尺度是对塔基附近可能受冲床面进行精准防护的指导依据,也是预测群桩局部冲刷结果的重要组成部分。结合泥沙运动学理论,根据试验观察分析规则分布的群桩局部冲刷平面形态演变及其干扰因素,提出了一个可综合反映水流强度与塔基结构影响的局部冲刷强度指标。在此基础上,采用物理模型试验方法,通过统计不同强度指标下的塔基局部冲刷平面结果,回归分析得到了二者之间的相关关系。最后,采用黄河下游两组工程实例对局部冲刷平面尺度关系式进行了试验验证。其结果表明,拟合公式的计算值与实测值比较符合,误差不大于10%,可为多沙河流中规则分布群桩塔基周围的床面防护提供参考。

Experimental study on local scour plane size around the pile groups of tower foundation in sandy rivers

The plane size of local scour pit is the guiding basis for protecting the riverbed that may be scoured in sandy rivers,and it is also an important component for predicting the local scour results of pile groups. Based on the theory of sediment kinematics, this paper analyzed the evolution and influencing fac-tors of regularly distributed pile groups in the local scour process, and put forward a local scour intensity index which can comprehensively reflect the influence of water flow intensity and tower foundation structure. On this basis, the physical model test method is adopted, and the correlation between local scour intensity index and plane size was obtained through statistical analysis. Finally, the regression equations were veri-fied by two groups of river-crossing engineering examples. The results show that the calculated value of the fitting formula is in good agreement with the measured value with an error of less than 10%, which can provide a technical reference for the protection of the bed surface around regularly distributed pile groups in sandy rivers.