深大基坑联合支护环境效应实测分析

FIELD MEASUREMENT ANALYSIS OF ENVIRONMENTAL EFFECTS OF COMBINED SUPPORT FOR DEEP AND LARGE FOUNDATION PITS

依托杭州湾智慧谷二期深大基坑工程,对基坑施工全过程中的地表沉降、地表水平位移、邻近建筑物、道路沉降及地下水位变化进行实测分析。结果表明:在基坑施工过程中应加快开挖速度,避免基坑在无支撑的情况下长期暴露,以此达到控制基坑变形在允许范围内的目的,同时在无支撑期间应适时提高地表沉降观测频率及时发现地表沉降值突变,提前做好应对措施,减少基坑开挖过程中周边土体的变形;基坑周边建筑物及道路的沉降主要随地下水位的变化而改变;因联合支护具有高稳定性,地下水位变化较为稳定,最大累计降深不超过1 m。

Relying on the second stage deep foundation pit project of Hangzhou Bay Wisdom Valley,the ground settlement,horizontal displacement of ground surface,settlement of nearby buildings,road settlement and groundwater level changes during the whole process of foundation pit construction are measured and analyzed.the result shows the excavation should be speeded up during the construction of the foundation pit,to avoid longterm exposure of the foundation pit without support and to achieve the purpose of controlling the deformation of the foundation pit within the allowable range,at the same time,during the unsupported period,the frequency of observation of surface subsidence should be increased in a timely manner to detect sudden changes in the value of surface subsidence in time,and countermeasures are prepared in advance,and the excessive deformation of the surrounding soil is reduced during the excavation of the foundation pit;the settlement of buildings and roads around the foundation pit mainly changes with the change of groundwater level;and due to the stability of the combined support,the groundwater level changes relatively stable,and the maximum cumulative descent does not exceed 1 m.