近邻地铁隧道深基坑的流变效应研究
Rheological effects of deep foundation pits near metro tunnels
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摘要: 利用室内三轴蠕变试验结果,分析和研究了上海软黏土不同应力下的变形时间效应。试验表明,在弹性范围内软土可以用五元件黏弹性模型进行模拟。将建立的黏弹性元件模型应用到近邻地铁的深基坑开挖,分析了基坑支护结构倾斜、墙间留土与不留土流变速率的影响以及隧道不均匀沉降的规律,并与实测数据进行了对比。结论表明五元件黏弹性模型可以模拟软土深基坑的开挖流变效应。Abstract: The time-dependent properties of Shanghai soft soils under different loadings are studied based on indoor creep tests. The tests show that the creep curve can be simulated by means of the viscoelastic model which is composed of five elements when the loading is below a certain load limit. The creep effects of deep foundation pits are analyzed by using the viscoelastic model. The incline change of support construction by the excavation, the creep rate and non-uniform settlement of the metro tunnel are compared with the measured data. The results show that the viscoelastic model with of five elements can reflect the creep effects of deep foundation pits.