Based on a subway station excavation construction project in the soft soil area in Nanjing, an informationized monitoring scheme was conducted during the construction of excavation, and the theories of displacement prediction were introduced into the scheme for the evaluation of the horizontal displacement of the retaining structure and the settlement of the surroundings around the excavation. Based on these theories and the monitoring data, a numerical simulation based on the commercial FEM numerical analysis software, Midas GTS NX, was conducted to simulate the whole construction process. To handle the large displacement of the retaining structure observed during the construction, the actual soil layers’ status discovered by excavating, which can reflect the physical characteristics of the soil, the construction condition, and the variation trend of the monitoring data, was used in the back analysis of the factors that induced the large deformation of the retaining structure, and the analysis result was fed back to the countermeasurement organization and design such as erecting temporary steel strut. The effectiveness of these measurements in the aspect of the reduction of the deformation rate was verified, which can provide reference to the design and construction of a similar project in soft soil area.

中文翻译：

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软土地区开挖异常大位移的系统分析方法

以南京某软土地区地铁站基坑开挖工程为基础，在基坑施工过程中进行信息化监测，将位移预测理论引入到方案中，对支护结构水平位移进行评价以及挖掘周围环境的沉降。基于这些理论和监测数据，基于商用有限元数值分析软件Midas GTS NX进行数值模拟，对整个施工过程进行模拟。为处理施工过程中观察到的挡土结构位移较大，开挖发现的实际土层状况，能够反映土体的物理特性、施工条件、并利用监测数据的变化趋势，对引起支护结构大变形的因素进行反分析，并将分析结果反馈给架设临时钢撑杆等对策组织和设计。验证了这些测量在降低变形率方面的有效性，可为软土地区同类工程的设计和施工提供参考。