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

对更新世和全新世两种自然沉积的原状粘土进行了不排水三轴压缩试验和测湿仪试验，然后使用超级/次加载屈服面Cam-clay模型（Asaoka， Nakano和Noda，1998年，2000年和Asaoka等人，2002年）模拟了这些粘土的行为，其中将“结构”、超固结、各向异性及其演化规律的概念引入了改进的Cam-clay模型。研究结果表明：1)对于未受扰动的两类粘土，采用单一材料常数，采用超/次加载屈服面Cam-clay模型可以模拟不同各向同性压力下正常固结至超固结的不排水三轴压缩行为；2)此外，该模型可以使用与不排水三轴压缩行为模拟相同的材料常数来模拟一维压缩行为。3)通过改变演化参数，采用超/次加载屈服面cam -粘土模型，模拟了具有不同加载历史和不同老化作用的更新世和全新世两种原状粘土的不排水剪切和一维压缩行为。

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.