盾构区间下穿异形板桥梁桩基托换研究

Pile Foundation Underpinning of Special Shaped Bridges in Shield Section

石家庄建和桥环形高架桥共分为4个异形板块,盾构区间下穿建和桥桩基托换工程需托换南侧和北侧异形板块,工程周边及地下环境复杂,托换过程中既有交通不得中断,对变形要求非常严格,设计采用主动托换方案。通过分析周边条件,以南异形板块桩基托换为例介绍相关设计和关键控制措施,包括托换设计、预支顶措施、施工步序、主要监测项目及控制值等。实践表明,托换施工满足设计和工前评估要求,桩基托换设计合理,结构安全可靠。

By using the active underpinning project"Shield Section under the Pile Foundation of Jianhe Bridge"as an example,the Ring Bridge of Jianhe Bridge was divided into four special-shaped plates.The project needed to replace the plates in the south and north sides,but the traffic could not be interrupted in the process of underpinning.Complex situations existed around the project and in the underground environment,so the active replacement scheme was adopted to meet the strict requirements for deformation.Through analysis of surrounding conditions,the related design and key control measures of the underpinning were introduced,including underpinning design,pre-supporting measures,pile foundation construction under the bridge,key construction procedures,and main monitoring items and control values.Currently,the replacement on the south and north sides has been completed,and the replacement process meets the requirements of design and pre-work evaluation.The practice shows that the replacement is reasonable in design and is safe and reliable in structure.