牺牲桩截面特性对圆柱桥墩局部冲刷的影响试验研究  

Experimental study on the influence of sacrificial pile section characteristics on the local scour of cylindrical pier

作　　者：魏凯[1] 冉彭鑫 裘放 洪杰 WEI Kai;RAN Pengxin;QIU Fang;HONG Jie(National Key Laboratory of Bridge Intelligent and Green Construction,Southwest Jiaotong University,Chengdu 611756,P.R.China)

机构地区：[1]西南交通大学桥梁智能与绿色建造全国重点实验室,成都611756

出　　处：《土木与环境工程学报（中英文）》2024年第5期152-159,共8页Journal of Civil and Environmental Engineering

基　　金：国家自然科学基金(U21A20154、52222804)。

摘　　要：墩前牺牲桩防护是减小桥墩局部冲刷的主要措施之一,现有的牺牲桩防护桥墩局部冲刷研究主要集中在圆形截面,关于牺牲桩截面特性对桥墩局部冲刷的影响关注较少。通过单向流循环水槽构建冲刷环境,开展不同直径与不同截面牺牲桩防护单桩桥墩局部冲刷物理模型试验,并通过水下高清摄像以及倾斜摄影测量技术实现对局部冲刷深度发展历程和冲刷平衡时刻冲刷坑形态的精准测量,进而探究牺牲桩直径与截面形式对单桩桥墩局部冲刷防护效果的影响规律。试验表明:牺牲桩直径与截面形状是影响桥墩局部冲刷防护效果的关键因素,牺牲桩的防护效果随牺牲桩直径的增大而增强,相比方形和圆形截面牺牲桩,菱形截面牺牲桩对桥墩的冲刷防护效果更好;牺牲桩防护会影响后方桥墩冲刷坑变化的剧烈程度,防护效果越好,后方冲刷坑变化越平缓;牺牲桩防护会缩短冲刷达到平衡状态的时间,牺牲桩直径越大,到达冲刷平衡状态的时间越短。采用牺牲桩开展桥墩局部冲刷防护时,应合理确定牺牲桩尺寸和截面特性,从而提高冲刷防护效果。The protection of sacrificial piles is one of the main measures to reduce the local scour on bridge piers.Existing research on the protection of local scour by sacrificial piles mainly focuses on circular sections and pays less attention to the influence of the section characteristics of sacrificial piles on local scour.In this study,physical model experiments with sacrificial piles of different diameters and cross-sections were carried out to protect a single bridge pier from local scour in a unidirectional flow circulating flume.During the experiment,the development of the local scour depth and the shape of the scour pit at the scour balance were accurately measured by an underwater high-definition camera and tilt photogrammetry.The study investigated the influence of sacrificial pile diameter and section shape on the protective effect of sacrificial piles for a single pier against local scour.The results show that the diameter and section shape of the sacrificial pile are key factors affecting the local scour protection effect of the bridge pier.The protective effect of the sacrificial pile on the rear pier increases with increasing diameter of the sacrificial pile.Compared with square and circular cross-section sacrificial piles,rhombus section sacrificial piles have a better scour protection effect on bridge piers.The sacrificial pile protection will affect the severity of the scour pit change around the rear pier,and the better the protection effect is,the gentler the change is in the rear scour pit.Additionally,the protection of the sacrificial pile shortens the time for the scour to reach the equilibrium state,and the larger the diameter of the sacrificial pile,the shorter the time is to reach the scour equilibrium state.Therefore,when using sacrificial piles to protect against local scour of bridge piers,the section characteristics of sacrificial piles should be reasonably considered to improve the scour protection effect.

关 键 词：桥墩 局部冲刷 冲刷防护 牺牲桩 水槽试验 

分 类 号：U443.22[建筑科学—桥梁与隧道工程]