邻近桥桩暗挖地铁车站施工方案及桥桩保护措施研究

RESEARCH ON CONSTRUCTION METHOD OF METRO STATION ADJACENT TO BRIDGE PILES AND REINFORCEMENT MEASURES FOR BRIDGE PILES

北京地铁十号线呼家楼站邻近京广桥,受桥桩位置制约,车站主体结构采用分离结构型式,原设计施工方案为CRD法,由于车站主体结构沿走向邻近桥桩(距桥桩最近距离仅为2.16m),施工风险大,因此所选施工方案必须能够确保邻近桥桩的安全。通过工程类比和有限元数值分析,选择对邻近桥桩保护最为有利的洞桩法(PBA)方案。根据邻近桥桩与地铁空间位置关系,将邻近桥桩划分不同的风险等级,采取相应的控制措施。在车站施工期间对桥桩变形和地表沉降进行跟踪监测。监测结果表明:车站主体结构的施工方案合理,对邻近桥桩的保护措施有效,能够确保邻近桥桩和地铁车站施工的安全。

Hujialou metro station of Beijing metro No. 10 is designed to be adjacent to the Jingguang Bridge. Restricted by the bridge piles,the metro station structure is divided into two detached tunnels. In the primary design,the cross diaphragm(CRD) method is adopted. In view of the metro station structure adjacent to the Jingguang Bridge piles(the shortest distance between metro main structure and bridge piles is only 2.16 m) and the risk for metro station construction being great,the adopted metro station construction method should ensure the safety of adjacent bridge piles. According to similar engineering construction experience and finite element numerical analysis,the PBA(pile-beam-arc) construction method is adopted. The adjacent bridge pile risk grade is classified according to the bridge piles spatial location. The corresponding reinforcement measures are adopted according to bridge risk grade. The stratum subsidence and bridge pile displacement are measured during construction period. The monitoring result indicates that the PBA construction method for metro station is reasonable and the reinforcement measures for the adjacent bridge piles are effective.