基于三维蠕变模型的基坑开挖长时位移预测  

Prediction of Long-term Displacement in Excavation of Foundation Pit Based on 3D Creep Model

作　　者：王荣勇[1,2] 陈立生 王颖轶[2] 黄醒春[2] 

机构地区：[1]上海城建市政工程(集团)有限公司,上海市200018 [2]上海交通大学,上海市200040

出　　处：《城市道桥与防洪》2017年第6期244-249,286,共7页Urban Roads Bridges & Flood Control

摘　　要：针对流变性软土地层大型深基坑开挖扰动位移的时效特性及长时位移的预测计算,开展系统研究。提出了融合基坑开挖卸载弹塑性动态位移、土体蠕变位移及其相互作用模式的长时位移计算概念化本构模型并建立了相应力学表达式;分析了软土蠕变模型的适用性并推导了长时位移计算关键参数--蠕变位移时效系数的计算公式。基于FEM与地层蠕变模型的时间增量法,建立了基坑开挖卸载位移和土体蠕变位移相结合的基坑开挖长时位移统一计算方法。研究成果适用于软土地层任意形式基坑工程设计阶段、施工阶段、基坑挖方完成等土体扰动长时位移的预测计算。工程实例的比较分析表明,计算方法具有良好的可靠性和工程适用性。Aiming at the aging characteristics of disturbance displacement and the prediction calculation of long time displacement in the excavation of large deep foundation pit in the rheological property soft soil stratum, a systematic study is carried out. The article puts forward the calculation conceptualization constitutive model of integrating the excavation unloading elastic plastic dynamic displacement of foundation pit, creep displacement of soil body, and the long time displacement of its interaction mode. And the corresponding mechanical expression is established. The article analyzes the applicability of soft soil creep model, and deduces the key calculation parameters of long time displacement-the calculation formula of creep displacement aging coefficient. Based on the time incremental method of FEM and stratum creep model, the unified calculation method of foundation pit excavation long time displacement combined with foundation pit excavation unloading displacement and soil creep displacement is established. The study result is appropriate for the prediction calculation of soil body disturbance long time displacement in the engineering design stage and construction of the different foundation pits, and the completion of foundation pit excavation in the soft soil stratum. The comparison and analysis results of engineering cases show that the calculation method has good reliability and the engineering applicability.

关 键 词：蠕变地层 基坑开挖长时位移 卸载与蠕变位移统一模型 时间增量解法 

分 类 号：TU46[建筑科学—结构工程]