基于自稳式钢支撑基坑支护结构的基坑开挖研究

建筑基坑开挖对周边地表及建筑物影响较大,且其稳定性难以控制。为此,本文提出基于自稳式钢支撑基坑支护结构的建筑基坑开挖方法。以某地铁车站基坑工程为研究对象,采用自稳式钢支撑基坑支护结构——双排围护桩与双排注浆钢管支撑相结合的支护模式,并布设针对建筑物、钢支撑和地表观测点,实时监测基坑开挖后邻近区域地表及建筑物沉降情况。结果表明:三个钢支撑极限承载力均达到1100 kN;采用自稳式钢支撑基坑支护结构邻近建筑物测点地表下沉幅度较小;基坑开挖对周边区域地表沉降影响存在时空效应,在地下水位较高条件下距离较近的周边建筑物受基坑开挖影响沉降显著。

Research on Excavation of Foundation Pit Based on Self-Stable Steel Support Structure

The excavation of building foundation pit has great influence on the surrounding surface and buildings,and its stability is difficult to control.Therefore,the excavation method of building foundation pit based on self-stable steel support structure is proposed.Selecting a station of a certain railway line as the research object,the paper adopted the support mode of self-stable steel support foundation pit support structure—the combination of double row enclosure pile and double row grouting steel pipe support,and the observation points for buildings,steel supports and ground surface were set up to monitor the surface and building settlement in the adjacent area after the foundation pit excavation in real time.The results show that the ultimate bearing capacity of the three observation points of steel support is up to 1100 kN;the surface subsidence of the observation points of adjacent buildings with self-stable steel support structure is small;the excavation of foundation pit has time-space effect on surface settlement in the surrounding area,and the settlement of surrounding buildings is greatly affected by foundation pit excavation under the conditions of high groundwater level.