扩展剑桥模型在深基坑有限元分析中的应用

Application of Extended Cambridge Model in Finite Element Analysis of Deep Foundation Pit

剑桥模型适用于正常固结和弱超固结粘土,经修正后的模型应用范围扩大,但仍未考虑第三应力不变量的影响。扩展剑桥模型允许屈服面扩张或收缩,硬化定律形式多样,可考虑第三应力不变量的影响,目前该模型的应用较少。为验证扩展剑桥模型分析基坑的可行性,以某深基坑为例,利用有限元计算支护结构位移、坑底回弹、坑周地表沉降等。实例分析表明,扩展剑桥模型分析粘土基坑时,符合粘性土的力学性状,计算结果与实际情况相符,可供类似工程参考。

Cambridge model can be used in analyzing normally consolidated and feeble-overconsolidated clay. After Modified, the model is broader in application field, but the third stress invariant can not be considered. Extended Can-bridge model not only allows the yield surface to grow or shrink, but also has several formats to define the hardening rule. Besides, as the third stress invariant can be considered. In fact, the model was not applied widely. In order to verify the feasl＇bility of analyzing pit by using the extended Cambridge model, taking a deep foundation pit as an example, the level-displacement of surrounding frame, the feedback of pit bottom, the sedimentation of earth surface around pit, and so on were studied with the finite element method. Analysis shows that the model accords with mechanical properties of cohesive soil and the calculating results agree well with the practical case, thus it will provide useful reference for similar projects.