软硬交界隧道近距离下穿建筑物注浆控制及监测管理

城市浅埋隧道在砂类土与基岩交界地层中近距离下穿建筑物,受上部建筑超载、下部基岩爆破扰动等因素的影响,极易诱发各类安全事故。以青岛地铁区间下穿商业建筑为工程依托,通过对地质条件及工程资料的深入分析,提出了"复合锚杆桩+超前深孔注浆+强化补偿注浆"的联合注浆加固技术,并通过精细化数值模拟与现场监测验证,分析了浅埋隧道穿越施工的结构与地层变形规律。结果表明:在基岩上部的软弱砂层中进行高压注浆,易诱发隧道上部的地层出现"M"形抬升变现,导致基础与梁柱构件形成由两边至中间折弯的正曲率形态;超前深孔注浆是改善施工面前方地质条件的重要措施,虽然注浆引起上部地层产生持续隆升,但总体变形量仍在可控限值内;在施工影响敏感区域开展现场监测管理,能够识别和规避地下工程现场作业中出现的不利因素,对注浆工艺和注浆参数进行反向调控,减小因注浆引起的建筑和地基变形问题。

Grouting reinforcement and Monitoring Management for A Tunnel Undergoes the Building closely in Soft and Hard Interface Strata

The shallow buried tunnel in the city passes through the building closely in the boundary layer between sand soil and bedrock. Based on the project of subway undergoes commercial building of Qingdao, through the deep analysis of geological conditions and engineering data, the joint grouting reinforcement technology of "compound anchor pile + advanced deep hole grouting + reinforced compensated grouting" is put forward. Through fine numerical simulation and field monitoring verification, the structure and formation deformation rules of shallow buried tunnel crossing construction are analyzed. The results show that high pressure grouting in the soft sand layer on the upper part of the bedrock can easily induce the stratum on the upper part of the tunnel to realize the "M" type uplift, resulting in the positive curvature of the foundation and the beam and column members bending from both sides to the middle. Advanced deep hole grouting is an important measure to improve the geological conditions before construction. Although grouting causes continuous uplift of the upper strata, the overall deformation is still within the controllable limit. On-site monitoring and management in sensitive areas affected by construction can identify and avoid the adverse factors in underground engineering site operation, reverse control the grouting process and grouting parameters, and reduce the building and foundation deformation problems caused by grouting.