地铁盾构近距离下穿既有建筑结构影响分析

Effect of Shielded Excavation in the Metro Tunnel on the Adjacent Existing Building Structures

建筑结构与城市地铁交叉时,地铁盾构区间施工对建筑结构安全产生一定的影响,合理选择施工顺序及设计方案是保证先期施工结构安全的有效措施。通过武汉地铁11号线盾构区间对即将施工的某些建筑结构的安全影响进行分析,比较了与底板相连的桩基础位于盾构区间上方的原设计方案与采用桩＋梁结构、桩端位于盾构区间下方的优化方案。结果可知,采用桩＋梁结构、桩端位于盾构区间下方的设计方案更能保证上部结构的安全,该方案合理可靠。

When the proposed shielded tunnel excavation is close to or underneath the existing or proposed building structures,the safety of these buildings is very important and shall be warranted.The reasonable design and excavation sequence are the effective aspects of ensuring the building structure safety.This paper presents a case history of safety evaluation of Wuhan Metro No.11 Line shielded excavation on the proposed BMW and Mercedes vehicle service buildings.Two different approaches,the short-piled raft foundations with pile tip above the shielded excavation zone and the long pile supported ground beams with pile tip below the shielded excavation zone are compared.The results indicate that the long pile supported ground beam approach is a better way ensuring the building safety.