湿陷性黄土的变形机理与本构关系

Deformation mechanism and constitutive relation of collapsible loess

基于微结构突变失稳假说,深入研究湿陷性黄土的变形机理,将体积湿陷与剪切湿陷统一到同一个突变模式,给出了黄土湿陷变形的一个完整的本构关系。计算和实验结果都表明:湿陷变形与应力状态及应力路径有很大关系,且体应变与八面体剪应变受球应力与八面体剪应力的交叉影响。发现不同应力比对应的剪切曲线上的交叉现象是湿陷性黄土的物理特征之一。最后。

Based on the hypothesis of the catastrophic instability of microstructure, the deformation mechanism of collapsible loess is researched further in this paper. Proposing a unified catastrophic model, which simultaneously describes the volumetric and shearing collapses, we obtain a complete constitutive relation for collapsible loess. The results of our computations and experiments indicate that the collapsing deformation of loess depends not only on the states but also on the paths of stresses, and that volumetric and shearing deformations are both influenced by the normal component p and the tangential component q of the stress on the octahedral plane. The cross phenomenon of the shear curves with various stress ratio can be regarded as one of natural characters of collapsible loess. Finally,some problems on the collapsing deformation are discussed using the proposed model.