深基坑近距离侧穿高层民房施工技术研究

摘要

The reinforcement scheme of pre-grouting + real-time tracking grouting of large settlement points of high building is proposed.The differential settlement and horizontal displacement of the building is effectively reduced by Soletanche grouting to 2 m below foundation of the building;the ground surface around the building and the horizontal displacement of foundation pit supporting pile are obviously reduced;and the axial force of steel support is improved;the inclination of the building and the differential settlement of the foundation can meet relevant requirements.Some appropriate key construction and control technologies for different deep foundation pit construction phases are proposed;and the cracks of the building are monitored.The monitoring results show that the sizes of the existing cracks of the building are essentially invariant;and 45 increased cracks occurred to wall belong to temperature shrinkage cracks.The calculation and monitoring results show that the differential settlement and deformation of the building can be effectively controlled by pre-grouting and real-time tracking grouting of large settlement points of the high building;the safety of the building and the foundation pit can be guaranteed;the calculation results of the model coincide with the monitoring results well;and the grouting scheme adopted is rational and economical.%为解决深基坑近距离(基坑距房屋4.1 m)侧穿高层民房施工难题,结合数值分析,首次提出了在房屋沉降较大的部位采取预注浆和适时跟踪注浆相结合的加固方案,在袖阀管注浆加固至房屋基础下2m后,有效地减少了房屋的差异沉降和水平位移,并对房屋附近地表沉降、基坑支护桩桩身水平位移和钢支撑轴力等都起到了明显的改善作用,满足了房屋整体倾斜0.6‰和基础差异沉降10 mm的控制值要求.针对深基坑施工的不同阶段,制订了相应的关键施工技术控制措施,并对房屋的裂缝进行了监测,施工前房屋原80处裂缝在施工过程中基本未出现加宽和加长的现象,施工后新增的45处裂缝主要发生在墙体部位,新增的墙体裂缝基本属于温度收缩裂缝.计算和监测结果表明:对房屋沉降较大的地方采取预注浆和适时跟踪注浆相结合的加固方案可以有效地减少房屋的差异沉降和变形,基坑和房屋是安全的,模型计算与实测结果相符,该方案不仅安全可靠,而且十分经济.