冻结粘性土的变形分析

通过三轴压缩试验条件下冻结粘性土变形分析，发现冻结粘性土的体应变明显不为零，随荷载的变化而变化。加荷初期试样体积收缩。但随着荷载的进一步增大而变为膨胀；轴向应变则随偏应力的增大而磁大，表现出明显的粘塑性特征。应力－应变曲线上的准弹性段、屈服处和粘塑性段刚好分别对应体变曲线上的体缩段、体缩量大处和膨胀段。根据冻结粘性土变形曲线。给出了考虑体变形的应力－应变关系。

Analyses of Deformation in Frozen Clayey Soils

The deformation of frozen soil is closely related to the load, temperature, time or strain rate basically owing to the existence of ice in the frozen soil, which is of strongly rheological property. So, it is of great significance to investigate the deformation behaviours and the stress-strain relation for both evaluating the stress-strain behaviours of frozen soil foundation and structure and developing the theory of frozen soil mechanics. In general, the stress-strain behaviours were sdudied with either constant stress creep tests or constant strain rate tests. Though many stress-strain relations are available to describe the stress-strain behaviours. the volume deformation of frozen soils has not been considered yet. Based on the triaxial constant strain-rate compression tests. in this paper the deformation behaviours of frozen clayey soils are analysesed and discussed . It is found that the volume of specimens contracted at the initial stage of loading, but as the load increased. the volume contracts to a certain value and then expands with the load continuously increasing, and the axial strain increases with the increase of deviatoric stress. The quasielastic , yielding and viscoplastic part in a stress-strain curve just corresponds to the contracting part of the volume, the maximum position of contracting part and the expanding part of the volume. respectively. The volume change is a important fact during the process of deformation. which can not be ignored. So, according to the deformation curves of frozen clayey soils, a stress-strain relation is givening which the volume change of frozen soil is considered.