Response of Building Adjacent to Stiff Excavation Support System in Soft Clay
Response of Building Adjacent to Stiff Excavation Support System in Soft Clay
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DOI：
10.1061/(asce)0887-3828(2002)16:1(10
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发表时间：
2002-02
影响因子：
2.5
通讯作者：
R. Finno;L. Bryson
中科院分区：
文献类型：
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作者：
R. Finno;L. Bryson
一所由浅地基支撑的三层学校受到邻近 12.2 米深的软粘土基坑的影响，其中基坑支撑系统是由跨地段支柱和拉杆支撑的 0.9 米宽的割线桩墙。学校为钢筋混凝土框架结构，外墙为钢筋混凝土基础墙。本文总结了现场情况，并介绍了施工活动、测量到的变形和扭曲以及学校随之而来的损坏之间的相关性。通过放置在学校周围的四个测斜仪来监测与挖掘相关的横向地面运动。通过在内柱、外墙和屋顶上建立的光学测量点以及在外基础墙上安装的倾斜计来监测建筑物的运动。学校受损主要为非承重墙300至500毫米长的细缝裂缝。只有少数裂缝的宽度大于 6 毫米。学校变形，最靠近挖掘处的部分下垂，其余部分拱起。当角度变形达到 1/940 且开挖深度约为 5.5 米时，首先在下垂区域观察到损坏。项目结束时观察到角度扭曲高达 1/300。数据表明，角度扭曲必须小于 1/1000，才能防止对学校造成任何损坏。
A three-story school supported by shallow foundations was affected by an adjacent 12.2-m-deep excavation in soft clay in which the excavation support system was a 0.9-m-wide secant pile wall braced by both cross-lot struts and tiebacks. The school is a reinforced concrete frame structure with exterior reinforced concrete foundation walls. This paper summarizes the conditions at the site and presents correlations among construction activities, measured deformations and distortions, and attendant damage in the school. The lateral ground movements associated with the excavation were monitored with four inclinometers placed around the school. The building movements were monitored with optical survey points established on interior columns, exterior walls and on the roof, and with tiltmeters installed on the exterior foundation walls. The damage to the school mainly consisted of 300 to 500-mm-long hairline cracks in nonload bearing walls. Only a few cracks had widths greater than 6 mm. The school deformed such that the portion closest to the excavation sagged and the remainder hogged. Damage was first observed in the area of sagging when angular distortions reached 1/940 and the excavation was approximately 5.5-m deep. Angular distortions as large as 1/300 were observed at the end of the project. The data suggest that angular distortions had to be less than 1/1000 to preclude any damage to the school.