考虑两种不同性质超固结的土体本构模型

A Constitutive Model for Structured Clays based on Two Different Types of Overconsolidation

结构对土体的变形特性有强烈影响,土体本构模型应该反映土体的结构性。通过调研分析将土体变形表现出的超固结划分为结构超固结与应力超固结这2种不同性质的超固结,从而使结构超固结与应力超固结统一起来。土体结构超固结采用结构超固结参数来表示。模型对修正剑桥模型进行扩展,模型的屈服面形状与修正剑桥模型一致,而屈服面的大小由结构超固结和应力超固结ps之和决定,而屈服面的变化由体积硬化与结构损伤共同来描述,模型采用相关联流动法则;从而提出了一个可考虑结构性的粘土本构模型。模型概念明确,参数简单并有物理意义。初步验证表明,模型可以较好的反映结构性土体的变形特性。

Structure has a major influence on the stress-strain relation of soil, which implies that the constitutive model should reflect the its structure. Based on the investigation , the over-consolidation （OC） of the soils was made up of two different types, which were structure-induced OC and stress-induced OC. And then the structure-induced OC and stress-induced OC were united. Structure-induced OC index was used to represent the degree of structure and the cam clay model was extended. The shape of the yield surface was the same as cam clay model, whise the size was equal to the sum of the structure-induced OC and stress-induced OC. And the change in size of the yield surface was decerminated by the volume-harden function and the structural damage function. The associated flow rule was adopted in the model. Afterwards constitutive model for structured clavs was presented.