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李航, 李泽文, 廖少明, 李志义, 钟铧炜. 上海超深基坑环境变形时空分布特性实测分析[J]. 岩土工程学报, 2023, 45(8): 1595-1604. DOI: 10.11779/CJGE20220661
引用本文: 李航, 李泽文, 廖少明, 李志义, 钟铧炜. 上海超深基坑环境变形时空分布特性实测分析[J]. 岩土工程学报, 2023, 45(8): 1595-1604. DOI: 10.11779/CJGE20220661
LI Hang, LI Zewen, LIAO Shaoming, LI Zhiyi, ZHONG Huawei. Field measurement of time-space distribution behaviors of environmental settlement of an ultra-deep excavation in Shanghai soft ground[J]. Chinese Journal of Geotechnical Engineering, 2023, 45(8): 1595-1604. DOI: 10.11779/CJGE20220661
Citation: LI Hang, LI Zewen, LIAO Shaoming, LI Zhiyi, ZHONG Huawei. Field measurement of time-space distribution behaviors of environmental settlement of an ultra-deep excavation in Shanghai soft ground[J]. Chinese Journal of Geotechnical Engineering, 2023, 45(8): 1595-1604. DOI: 10.11779/CJGE20220661

上海超深基坑环境变形时空分布特性实测分析

Field measurement of time-space distribution behaviors of environmental settlement of an ultra-deep excavation in Shanghai soft ground

  • 摘要: 基于工程现场实测数据,对深度为31.3 m的上海某超深基坑开挖引起的环境变形特性进行了研究分析。结果表明,与上海常规深度(12~20 m)的软土基坑工程相比,超深基坑的环境影响明显偏大,表现出显著的时空分布特性:①坑外地表沉降规律随墙体侧向变形的空间分布形态差异而变化,墙体侧向变形由中部向角部变化越平缓,坑外的地表沉降影响范围越大,由中部至坑角收敛越快,坑外地表沉降影响区域则越集中,影响范围也相对较小;②受坑角效应影响,平行于基坑围护结构的地表沉降由中心向坑角沉降迅速减小,并呈高斯分布规律,影响范围延伸至坑角后1.5He (He为基坑深度);③建筑物变形表现出显著的三维特性,靠近基坑围护结构中部的建筑物沉降量显著大于基坑角部,同时均伴随较大的扭转变形;④当平行于基坑围护结构的建筑物横跨坑角区域时,最危险点均位于坑角附近0.5He范围内,其损伤程度与建筑物和基坑的位置关系和建筑物刚度有密切关系;⑤相对于常规深度基坑,本工程对地表沉降的主要影响范围偏大,达到3He左右,但最大地表沉降位置偏小,位于墙后0.5He附近;⑥地表沉降最大值δvm介于0.03%~0.50% He之间,且与墙体最大侧移值δhm之间的关系平均为δvm=0.6δhm

     

    Abstract: Based on the extensive field observations, the environmental deformation characteristics of a 31.3 m-deep excavation in Shanghai soft ground are investigated. The results show that compared with the general excavations with a depth ranging from 12 to 20 m, the ultra-deep excavation presents significant environmental effects and time-space distribution behaviors: (1) The influence zone of settlement near the long side of the excavation is related to the wall deflection distribution on the plane. The more gently the lateral wall displacement changes from the middle area to the corner, the more extensive the influence zone is. The faster the lateral wall displacement transits from the middle to the corner of the excavation, the more concentrated the influential zone is. (2) Due to the corner effects, the ground surface settlement decreases rapidly from the center to the corner, and exhibits a Gaussian distribution law, with the influence range extending to 1.5He (depth of excavation) behind the excavation corner. (3) The deformation of buildings exhibits distinct three-dimensional characteristics. The buildings located near the excavation corner have less settlement than those near the center of the excavation, accompanied by a certain torsional deformation. (4) When the buildings paralleling to the retaining wall cross the corner of the excavation, the most dangerous point is located within 0.5He near the corner of the excavation, and its damage degree depends on the relative location between the buildings and the excavation and their stiffness. (5) Compared with the conventional deep excavations, the ultra-deep excavation leads to a larger primary influence zone for ground surface settlement, reaching about 3He, but the location of the maximum surface settlement is closer to the wall, nearly 0.5He behind the retaining wall. (6) The maximum ground surface settlement δvm is about 0.03%~0.50%He, and the relationship between the maximum ground surface settlement δvm and the maximum lateral wall displacement δhm can be expressed by δvm=0.6δhm averagely.

     

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