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应宏伟, 熊一帆, 李冰河, 吕唯, 程康, 张金红. 软黏土基坑开挖诱发坑外地表沉降的时效解[J]. 岩土工程学报. DOI: 10.11779/CJGE20230727
引用本文: 应宏伟, 熊一帆, 李冰河, 吕唯, 程康, 张金红. 软黏土基坑开挖诱发坑外地表沉降的时效解[J]. 岩土工程学报. DOI: 10.11779/CJGE20230727
Time-dependent solution for ground settlement induced by excavation in soft clay[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20230727
Citation: Time-dependent solution for ground settlement induced by excavation in soft clay[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20230727

软黏土基坑开挖诱发坑外地表沉降的时效解

Time-dependent solution for ground settlement induced by excavation in soft clay

  • 摘要: 对比理论和实测研究成果,发现既有坑外地表沉降计算方法不适用于蠕变效应显著的软土基坑。借助Lame方程和三参量黏弹性地基模型,推导得到柔性挡墙任意变位诱发坑外地表沉降的时效半解析解;将理论计算方法应用于杭州软土地区的两个深基坑工程实例,分析了从基坑开挖到地下室回筑的施工全过程中坑外地表沉降的发展规律。结果表明:(1)软土蠕变诱发不依赖于挡墙附加侧移的地表沉降,不仅导致软土基坑开挖期间的地表最大沉降与挡墙最大侧移之比远大于非软土基坑,而且引起坑外土体在地下室回筑期的持续沉降;(2)软土蠕变诱发的地表沉降随挡墙侧移的增大而增大,表现为凹槽沉降模式;(3)深厚软土深基坑的地表最大沉降与挡墙最大侧移之比主要受软土蠕变性和施工时间等因素的影响,与挡墙侧移量的关系不明显。

     

    Abstract: Upon comparing the theoretical and measured results, it was observed that the current methods need to be revised in predicting ground settlement induced by excavation in soft clay with significant creep effect. With Lame equation and three-parameter viscoelastic foundation model, the time-dependent semi-analytical solution for ground settlement induced by arbitrary displacement of flexible retaining wall was derived. The solution was implemented in two excavations in Hangzhou soft clay, analyzing both the developments of ground settlement from excavation to basement construction and the influences of various factors. The results indicate that: (1) ground settlement induced by soft soil creep does not depend on extra lateral displacement of retaining wall. Soft soil creep not only leads to a much greater δvm/δhm during excavation compared to excavation in non-soft clay, but also causes continuous ground settlement during basement construction. (2) Ground settlement induced by soft soil creep increases with lateral displacement of retaining wall, showing a concave settlement mode. (3) δvm/δhm of deep excavation in soft clay is primarily affected by creep characteristics of soft soil and construction time, and seems independent of lateral displacement of retaining wall.

     

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