浅覆土盾构隧道近距离侧穿地下承重桩施工技术

Construction technology of shallow earth shield tunnel passing through underground bearing pile in short distance

济南地铁某盾构区间近距离侧穿紧邻车站主体结构尚未施工完成的地下承重桩基,承重桩基底板距离区间隧道拱顶最近处3.3m。盾构穿越区域采用三重管高压旋喷注浆对地层进行预加固,衬砌结构采用冗余注浆孔管片,采用土压平衡掘进和足量同步注浆,管片脱出盾尾后及时二次注入双液浆以进一步提高管片的稳定性等技术措施,这些技术措施可有效控制地面沉降,规避盾构掘进对地下承重桩基的不利影响。

A shield section of Jinan metro underpasses the underground bearing pile foundation adjacent to the main structure of the station which has not been completed yet.The base plate of the bearing pile is 3.3 m away from the vault of the tunnel.In the shield crossing area,triple pipe high-pressure rotary jet grouting is used to pre-strengthen the stratum,redundant grouting hole segments are used in the lining structure,balanced earth pressure tunneling and suffi cient synchronous grouting are used,and double liquid grouting is injected in time to further improve the stability of the segments after the segments come out of the tail end of the shield.These technical measures effectively control the ground settlement to avoid the adverse effect of shield tunneling on the underground bearing pile foundation.