浅埋大断面软岩隧道施工影响下建筑物 安全性控制的试验研究

 厦门机场路一期工程在大跨、浅埋及复杂地质等工程条件下穿越地表密集的建筑物群，受隧道施工影响的建筑物多达90余栋。在隧道施工过程中，既要保证新建隧道结构的安全，同时还要保证地表既有结构的安全，而后者显得更加重要。隧道施工面临着全风化花岗岩遇水软化、隧道结构整体沉降、地层大变形、建筑物差异沉降及裂缝控制等诸多难题。在对该工程特点和控制方案系统分析的基础上，为保证控制方案的可靠性，对拟拆迁的104#和105#楼房进行试验研究，通过施工过程的注浆抬升和变形监测结果，论述地层沉降、建筑物沉降及裂缝产生、发展随隧道开挖的变化规律，并提出优化洞内施工与地面注浆抬升建筑物相结合方案，控制围岩大变形和有效保护建筑物的工程措施。试验数据表明，将核心控制指标—建筑物差异沉降量控制在20 mm以内可保证建筑物的安全；地表注浆与洞内注浆相结合可实现对建筑物的抬升，并有效地减小建筑物的差异沉降并控制裂缝的发展。研究结果为机场路隧道后续穿越重点建筑物的施工提供了技术支撑和安全保障，也为今后类似工程的设计、施工和研究提供了有益的借鉴和参考。

EXPERIMENTAL STUDY ON SAFETY CONTROL OF BUILDINGS DURING CONSTRUCTION OF SHALLOW-BURIED SOFT ROCK TUNNEL WITH LARGE-SECTION

The first-stage project of Xiamen Airport Road contains large-section tunnel with span of 34 m in shallow depth，which passes through the bottom of more than 90 existing buildings. During its excavation process，the safety of the tunnel itself must be guaranteed，while more attentions should be paid to the safety of the existing buildings. As to this tunnel construction，it is faced with many technical difficulties，especially softening of fully-weathered granites in groundwater，settlement of the whole tunnel structure，large deformation of strata，and differential settlements and cracking of buildings，etc.. Based on systematic analysis of the project features and its control scheme，buildings #104 and #105 planned to be removed are reserved as experimental building for ensuring the reliability of this scheme. Through the uplift grouting and in-situ deformation monitoring during tunnel construction，it is discussed how the strata subsidence，settlement and cracks of buildings develop with excavation step. Besides，the method of optimizing construction scheme combined with surface uplift grouting is proposed to control the large deformation of strata and to protect buildings. In-situ data show that the differential settlements of buildings should be controlled within 20 mm；the synchronous measure of grouting from surface and from inside tunnel can control the buildings uplift，reduce their differential settlements，and hold their cracking development. The research results can provide technical support and insurance for subsequent construction when more important buildings exist，as well as favorable reference for design，construction and study of future similar projects.