黄河软土地区深基坑阳角区域变形特性分析

Analysis of Deformation Characteristics in External Corner Area of Deep Foundation Pit in Soft Soil Area of YellowRiver

以济南市济洛路穿黄隧道汽修厂站深基坑为例,通过监测手段对获取的地表沉降、地连墙深层水平位移和支撑轴力等数据展开分析,研究了黄河软土地区深基坑阳角区域的变形特性。研究结果表明:基坑标准段地表沉降变形规律呈三角形,最大值发生在距离基坑7 m处,阳角区域地表沉降变形规律呈汤勺形,最大值发生在距离基坑5 m处;基坑开挖地连墙深层水平位移阳角区域的偏移量比标准段偏移量大,最大偏移量为36.10 mm,且整体变化规律表现为“弯弓”形,其最大偏移点随开挖进度的变化逐渐下移,同时整体变形量也随开挖进度的变化在不断增加;首道支撑总体的受力变化形态呈下降趋势,且基本处于受拉状态,与对应的深层水平位移变形特征基本一致,其余3道钢支撑轴力呈波动上升趋势。

Taking the deep foundation pit of Qixiuchang Station of Chuanhuang Tunnel in Jinan City as an example,the data of surface settlement,deep horizontal displacement of ground connecting wall and supporting force were analyzed by monitoring to study the deformation characteristics of external corner area of deep foundation pit in soft soil area of Yellow River.The results show that the surface settlement deformation law of the standard section of the foundation pit is triangular with the maximum deformation occuring at a place of 7 m from the foundation pit.The surface settlement deformation law of the external corner area is in the shape of soup spoon with the maximum deformation occurring at a place of 5 m from the foundation pit;The offset in the external corner of the deep horizontal displacement of the connecting wall is larger than that in the standard section with the maximum offset is 36.10 mm.The overall change rule is“bow”type.The maximum offset point gradually decreases with the change of the excavation progress as well as the overall deformation;The overall stress variation of the first steel support shows a downward trend and is basically in a tension state,which is basically consistent with the corresponding horizontal displacement and deformation characteristics of the deep layer.The axial force variation of the other three steel supports shows a fluctuating upward trend.