航道开挖对上跨桥梁桩基影响及控制措施研究

Study on the Influence of Channel Excavation on Upper Span Bridge Pile Foundation and Its Control Measures

以京杭运河二通道海宁段东西大道桥某桥梁桩基为研究对象,针对陆上航道开挖穿越密集交叉点重要桥梁工程的建设施工和安全防护的科学技术难题深入开展研究。针对目标研究区软黏土特殊地质条件,运用FLAC 3D软件,分析了航道直接开挖和采取支护结构的航道开挖对上跨桥梁桩基影响,对航道开挖控制措施效果进行了评价。结果表明:(1)采取支护结构后再进行航道开挖,可以大大减小上跨桥梁桩基顶部的倾斜,更加有利于桥梁桩基的稳定性;(2)航道开挖过程中,采取支护结构后,可以大大减小桩基所受到的水平应力、桥梁桩基顶部偏斜,且各减小量分别可达33%和66%。

In this paper,the pile foundation of a bridge in Haining Section of the Second passage of Beijing-Hangzhou Canal is taken as the research object,aiming at the scientific and technical problems of the construction and safety protection of important bridge projects crossing dense intersections during the excavation of overland waterway.According to the special geological conditions of soft clay in the target study area,FLAC 3D software is used to analyze the influence of channel excavation directly and channel excavation with support structure on the pile foundation of the upper span bridge,and the effect of channel excavation control measures is evaluated.The results show that:(1)The slope at the top of the pile foundation of the upper span bridge can be greatly reduced and the stability of the bridge pile foundation can be improved by using the support structure before the channel excavation;(2)In the course of channel excavation,the horizontal stress of pile foundation and deflection of bridge pile foundation can be greatly reduced by 33%and 66%,respectively.