复杂地质条件下既有建筑地基基础加固技术研究

Research on strengthening technology of existing building foundation under complex geological conditions

对某发生不均匀沉降的砖混结构住宅楼进行加固,为防止加固时住宅楼产生二次变形,采用微型钢管桩加固条形基础、再新增筏板、最后对地基土进行注浆的加固方法。在现场静载荷试验的基础上,采用ABAQUS对加固方案进行模拟计算,并对加固后的建筑物进行现场沉降监测。结果表明,模拟结果与静载荷试验实测结果基本相符,加固后建筑物的不均匀沉降明显减少,桩顶反力分布呈现出中间小四周大的特点;微型钢管桩承担的荷载占19.43%。实际现场监测最后100 d的沉降速率小于0.01~0.04 mm/d,地基的变形符合GB 50007—2011《建筑地基基础设计规范》的要求,该加固方案可行。

In order to prevent secondary deformation of a brick-concrete residential building when reinforcing a brick-concrete residential building with uneven settlement,the reinforcement method of reinforcing the strip foundation with miniature steel pipe piles,then adding a new raft slab,and finally grouting the foundation soil was adopted.On the basis of on-site static load test,ABAQUS was used to carry out simulation calculations of the reinforcement scheme,and on-site settlement monitoring was carried out for the reinforced building.The results show that the simulation results are basically consistent with the measured results of the static load test,and the uneven settlement of the reinforced building is obviously reduced,and the distribution of the pile top reaction force presents the characteristic of small middle and large surrounding;the load borne by the miniature steel pipe pile accounts for 19.43%.The settlement rate in the last 100 d of actual on-site monitoring was less than 0.01~0.04 mm/d,and the deformation of the foundation was in accordance with the requirements of the specification,which made the reinforcement programme feasible.