An elasto-plastic interpretation on mechanical properties of natural deposited clays

对两种类型的天然沉积原状粘土，即更新世粘土和全新世粘土进行了不排水三轴压缩试验和固结仪试验，然后使用超级/次加载屈服面凸轮粘土模型（Asaoka，中野和野田，1998，2000和Asaoka等人，2002），在修正剑桥模型中引入了“结构”、超固结、各向异性等概念及其演化规律。本研究的结果如下：1）对于两种原状粘土，超/次加载屈服面剑桥模型可以模拟从正常固结状态到超固结状态的不排水三轴压缩特性，对应于不同的各向同性压力，使用一组材料常数; 2）此外，该模型可以模拟一维压缩特性，使用与不排水三轴压缩特性模拟相同的材料常数; 3）对于两种原状粘土，即更新世粘土和全新世粘土，无论是不排水剪切还是一维压缩特性，都可以模拟。不同加载历史、经历不同老化效应的黄土，采用超/次加载屈服面剑桥模型，通过改变演化参数，对黄土进行模拟。

Undrained triaxial compression tests and oedometer tests were carried out on two types of naturally deposited undisturbed clay, Pleistocene clay and Holocene clay, and the behaviors of these clays were then simulated using the Super/subloading Yield Surface Cam-clay model (Asaoka, Nakano and Noda,1998,2000 and Asaoka et al.,2002), in which the concepts of "structure," overconsolidation, anisotropy, and their evolution laws, are introduced into the modified Cam-clay model. The findings of the present study are as follows :1)For the two types of undisturbed clay, the Super/subloading Yield Surface Cam-clay model can simulate undrained triaxial compression behaviors ranging from the normally consolidated state to the overconsolidated state, corresponding to various isotropic pressures using a single set of material constants.2)In addition, the model can simulate one-dimensional compression behaviors using the same material constants as those used for the undrained triaxial compression behavior simulation.3)Both undrained shear and one-dimensional compression behaviors for the two types of undisturbed clay, that is Pleistocene clay and Holocene clay, which have different loading histories and have undergone different ageing effects, were simulated using the Super/subloading Yield Surface Cam-clay model by changing the evolution parameters.