大跨浅埋公路隧道下穿既有建筑施工的沉降控制

Settlement Control for a Shallow Long-span Multi-arch Tunnel Under-passing Existing Buildings

厦门机场下穿34号楼隧道工程,隧顶到建筑结构底3 m,属浅埋大跨下穿既有建筑物连拱隧道工程。论文根据工程类比法,采用CRD法优化隧道施工步骤;借助数值分析方法,分析既有建筑的沉降规律,把握了CRD法重点施工步骤。根据现场实测及数值模拟结果,提出了超前注浆、地面硬化及补偿抬升注浆、洞内全断面帷幕注浆、大管棚超前支护等多种施工辅助措施。实践表明,施工过程中既有建筑结构沉降得到有效控制,最终沉降量小于40 mm。

Xiamen Airport Expressway under-passes No.34 building by a shallow-buried long-span multi-arch tunnel with 3 m cover from tunnel crown to the bottom plate of buildings.Based on engineering analogy,CRD method was adopted to optimize construction procedures.Settlement regularity of existing buildings was determined by numerical analysis method to control key procedures of CRD method.Several auxiliary measures were adopted to control settlements based on measured results and simulation results,including pre-grouting,ground strengthening and surface height compensation grouting,full-face curtain grouting and advance support by large pipe-roofing.Results showed that the settlements of existing buildings were controlled effectively in the construction process and the final settlement was less than 40 mm.