上海地区深基坑周围地面沉降特点及预测研究

Characteristics and Prediction of Ground Settlement around Deep Excavation in Shanghai

摘要:

通过研究上海地区32个深基坑工程的监测数据，得到以下地面沉降特点：大多数地面沉降曲线呈凹槽型，存在沉降槽偏心距；最大沉降量 的变化范围在0.4 ～1.9 之间，其平均值和最大侧向位移相等；所有基坑的支撑系统相对刚度都较大，支撑系统相对刚度对最大沉降量影响很小；抗隆起安全系数增大，基坑最大沉降量减小，同时绘制了基于抗隆起安全系数的最大沉降量预测曲线。最后，基于上海地区深基坑的沉降实测曲线特征，提出了考虑沉降槽偏心距的地面沉降预测方法，并结合四个工程实例进行了验证，结果表明，该方法预测精度较高，是一种实用的基坑周围地面沉降预测方法。

Abstract:

Based on the field monitoring data of 32 deep excavations in Shanghai, the main characteristics of ground settlement have been summarized as follows. Firstly, most settlement profiles around deep excavations appear to be grooves with settling tanks. Secondly, the maximum ground settlement, , lies between 0.4 and 1.9 ( for the maximum lateral deflection), and its mean value is equal to . Thirdly, system stiffness of all deep excavations is great and its influence on is small. Fourthly, the maximum ground settlement decreases with the increase of the factor of safety against base heave (FOS), and the FOS-based settlement predictive curve is proposed at the same time. Finally, according to the character of measured settlement profiles in Shanghai, the author proposed a predictive method taking into account effect of the settling tank’s eccentricity. With the verification of the proposed method in four deep excavation cases, the results show a high degree of accuracy, which is proved to be a practical method in ground settlement prediction around deep excavation.