摘要
以上海国际金融中心超深大基坑工程为背景,分析了软土层中顺逆作分区交叉实施的坑外土体变形特性及立柱变形和支撑轴力变化等情况。实测结果表明,地下连续墙后的土体侧向位移随施工工况逐步发展,变形形态为"纺锤形";墙后土体侧斜与墙体侧斜相协调,且土体侧斜随距坑边距离增加而减小;此外逆作区受顺作区开挖卸荷及时间效应影响的变形增量及影响范围均较大。墙后土体应变主要发生在基坑开挖面附近,且剪应变值基本处于小应变范围内。立柱的位移表现为隆起,且隆起量随开挖工况逐步发展,随底板浇筑后趋于稳定。支撑轴力增量主要发生在邻近下两皮土方开挖工况下。地下水位监测表明,采用新型TRD工法构建的等厚度水泥土搅拌墙作为悬挂止水帷幕起到了较好的隔水和遮拦作用。围护墙两侧的侧压力分布形态类似三角形分布,侧压力均随着施工工况而逐步减小,且实测侧压力值较理论值偏小。
Based on the monitored data of the super large and deep excavation of Shanghai International Finance Center which was constructed by the combination of top-down method and bottom-up method, this paper analyzed the characteristics of deformation of soil behind the retaining wall, vertical deformation of central columns, and variation of axial force of struts. The results show that the lateral displacement of the soil behind the diaphragm wall developed gradually with construction conditions and the final shape of wall deformation was spindle-shaped. Deformation behavior of soil was quite similar to that of diaphragm walls. Soil deformation decreased with the increase of distance to the diaphragm wall. Deformation of soil behind the top-down area was obviously affected by excavation conducted in the bottom-up area. Soil strain behind the wall mainly occurred near the excavation surface, and the shear strain value was basically in the small strain range. Due to rebound of soil excavation, the columns were all uplifted, and the uplift value gradually increased with the increase of excavation depth. Axial forces of struts obviously increased when the two layer soils bellow the struts were excavated. The waterproof curtain constructed by TRD technique played a good role in water stop. The lateral pressure distribution on both sides of the retaining wall was similar to triangular distribution. The value of lateral pressure gradually reduced with the excavation proceeded, and the measured lateral pressure value was smaller than the theoretical value.
作者
宗露丹
徐中华
王卫东
ZONG Ludan;XU Zhonghua;WANG Weidong(Shanghai Underground Space Engineering Design&Research Institute,East China Architecture Design&Research Institute Co.,Ltd.,Shanghai 200002,China;Shanghai Engineering Research Center of Safety Control for Facilities Adjacent to Deep Excavations,Shanghai 200002,China)
出处
《施工技术（中英文）》
CAS
2021年第13期163-169,181,共8页
Construction Technology
基金
上海市青年科技启明星计划资助项目(19QB1400500)。
关键词
高层建筑
深基坑
顺作逆作结合法
变形
软土
监测
tall buildings
deep foundation excavation
bottom-up and top-down method
deformation
soft soil
monitoring
