电杆基础冲刷及防护措施效果的数值分析

Numerical analysis of the scouring of electric pole foundations and the effectiveness of protective measures

目前考虑一定坡度下基础局部冲刷的研究很少,并且缺乏探讨山洪灾害下电杆防护措施的效果研究。基于FLOW-3D软件对电杆基础冲刷进行三维数值模拟,分别对水头(4~6 m)、坡度(10°~20°)、电杆距坡脚距离(6~9 m)和初始流速(1~3 m·s^(-1))4个变量进行了参数敏感性分析,对照工况的水头、坡度、电杆距坡脚距离和初始流速分别设置为4 m、20°、6 m和2 m·s^(-1),通过控制变量法进行试验。随后在对照工况基础上分别设置牺牲桩群和杆前分流板,计算电杆基础的最大冲刷深度和水流冲击电杆的压力,并对比分析2种防护措施的防护效果。结果表明:随着水头、坡度和初始流速的增大及电杆距坡脚距离的减小,电杆基础的最大冲刷深度和水流冲击电杆的压力均随之增大。在水头、坡度、电杆距坡脚距离和初始流速分别取6 m、20°、6 m和3 m·s^(-1)的工况下,电杆基础的最大冲刷深度和水流冲击电杆的压力最大;设置牺牲桩和分流板均可降低水流冲击电杆的压力,其中设置牺牲桩降低冲击压力的幅度更大;设置牺牲桩可有效降低电杆基础的最大冲刷深度,相比之下,设置分流板只能降低电杆前侧基础的冲刷深度,但对电杆后侧基础的防护效果不明显。

At present,there are limited studies considering the local scour of foundations under a certain slope,and there is a lack of research on the effect of protection measures for electric poles under the mountain flood disaster.In this study,the three-dimensional numerical simulation of the scour of an electric pole foundation has been conducted using FLOW-3D software,and the sensitivity analysis of four parameters,including water head(4-6 m),slope(10°-20°),distance between pole and slope foot(6-9 m)and initial velocity(1-3 m·s^(-1)),has been carried out.Meanwhile,the water head,slope,distance between pole and slope foot and initial velocity were taken as 4 m,20°,6 m,and 2 m·s^(-1),respectively,as the reference condition.Finally,the control variable method was used to conduct numerical simulation experiments.Subsequently,on the basis of the reference condition,the sacrificial piles and a splitter plate in front of the pole were respectively set up,the maximum scouring depth of the pole foundation and the water pressure impacting the pole were calculated,and the protective effects of these two protective measures were compared and analyzed.The results showed that:the maximum scouring depth of the pole foundation and the pressure of water impacting the pole increase with the increase in water head,slope and initial velocity as well as the decrease in distance between pole and slope foot.When the water head,slope,distance between pole and slope foot and initial flow rate were set to 6 m,20°,6 m,and 3 m·s^(-1),respectively,the maximum scouring depth of the pole foundation and the pressure of water impacting pole were the largest.The setting of sacrificial piles and splitter plate can reduce the pressure of water impacting the pole,and the sacrificial pile can reduce the impact pressure more greatly.