滨海地区二元地层明挖隧道基坑施工变形实测分析

The Monitoring Analysis on Construction Deformation of Deep Foundation Pit in Coastal Dual Stratum

为分析滨海地区软-硬二元地层中深长基坑开挖引起的邻近土体变形响应特性及分布规律,以厦门枋钟路隧道明挖基坑为例,采用现场实测方法对基坑开挖引起的邻近土体水平位移、地表沉降及立柱变形分布特性进行了分析。实测结果表明:基坑开挖引起的土体水平位移呈现中间大两头小“鼓胀”式分布,最大水平位移约为基坑开挖深度的0.16%~0.50%,且大致位于开挖面以下10 m深度处;基坑邻近地表沉降呈“凹槽”形分布,最大地表沉降约为基坑开挖深度的0.25%,发生在距坑边0.3倍基坑深度的位置;相较而言,立柱竖向变形分布较为均匀,最大竖向位移约为5~10 mm。

In order to explore the deformation patterns of deep foundation pit in complex coastal soft-hard dual strata, the field monitoring data of the horizontal displacement, surface settlement and pillar heave during the excavation of the open-cut foundation pit of Fangzhong Road tunnel in Xiamen are analyzed. The results show that during the excavation process, the maximum horizontal displacement of the retaining pile is about 0.16% ~ 0.5% of the excavation depth, the maximum horizontal displacement occurs about 10 m below the ground surface, and the horizontal displacement of the retaining pile presents a bulging distribution along the pile. The surface settlement is in a“groove”shape, and the maximum surface settlement occurs at a position 0.3 times the depth of the foundation pit from the side of the pit. Comparatively, the vertical deformation distribution of the column is more uniform, and the maximum vertical displacement is about 5~10 mm.