深圳某地铁隧道下穿桥梁桩基托换技术研究

Study on pile foundation underpinning of Shenzhen subway funning tunnel passing under bridge

发展地铁建设与保证既有交通桥梁安全问题的矛盾日趋明显.依托工程为深圳地铁8号线梧桐山站至沙头 角站区间隧道穿越罗沙高架桥处桥梁粧基托换工程,该处地铁区间为盾构法施工的双线并行隧道,穿越处有两处桥 梁粧基础与隧道存在冲突,需进行粧基托换.被托换的既有桥梁部为异型钢筋混凝土连续箱梁,受力复杂,结构变形 敏感,桥墩墩底轴力大;新建托换梁跨度约18 m,如此大跨度、大轴力的桩基托换工程实例很少.以罗沙高架桥梁粧 基托换设计为依托,通过对托换方案、关键连接节点、荷载转移机理的分析、研究,详细介绍大轴力粧基托换思路、托 换体系转换,给出托换关键节点的施工方案及监测技术要求,可为类似工程提供借鉴.

With the development of subway construction,the cross interference between the subway and the exist- ing traffic bridges is inevitable, and the contradiction between the development of subway construction and the guarantee of the safety problems of existing traffic bridges is becoming more and more obvious. This paper relies on the project of Shenzhen Metro Line 8 Wutong Mountain station to Sha Tau Kok Station Tunnel through Rosa Viaduct Bridge Pile Foundation Underpinning Engineering, the subway shield construction for double parallel tunnel, crossing conflicts two pile foundation of bridge and tunnel, the need for pile foundation underpinning. Is the underpinning of existing bridges for special-shaped reinforced concrete continuous box girder, complex stress, deformation sensitive, pier bottom shaft force; the new underpinning beam span of about 18m, so the large span and large axial force of pile underpinning project rarely. The pile foundation underpinning Rosa viaduct is based on the design of the underpinning scheme, key joints, load transfer mechanism analysis and research, introduces the axial force of pile foundation underpinning ideas underpinning system transformation, are supporting con-struction scheme and technical requirements for monitoring of key nodes, which can provide reference for similar engineering.