The aim of this study is to understand the local mechanisms related to creep behavior of a typical clay under triaxial loading. The investigation concerns both normally consolidated and overconsolidated specimens of remolded kaolin clay. The macroscopic results showed that both dilatancy and contractancy could occur during creep depending mainly on the clay behavior prior to the creep test. The magnitude of the dilatancy/contractancy was controlled by the stress level, on one hand, and by the overconsolidation ratio which governed the sign of the volumetric strain variation during triaxial loading, on the other hand. At the microscopic scale, the dilatancy/contractancy phenomena were analyzed using the scanning electron microscopy (SEM). The results indicated that the microstructural evolution of the clay along mechanical loading depended on the stress history. The structural evolution during the creep phases followed the structural pattern developed under monotonic loading. The creep dilatancy phenomenon appeared strongly related to the expansion of micro pores and micro cracks within the overconsolidated clay specimens.

这项研究的目的是了解与典型粘土在三轴载荷下蠕变行为有关的局部机理。研究涉及重塑高岭土的正常固结和超固结标本。宏观结果表明，蠕变过程中可能同时发生膨胀性和收缩性，这主要取决于蠕变试验之前粘土的行为。膨胀/收缩的大小一方面受应力水平控制，另一方面受过固结率控制，该过固结率决定了三轴加载过程中体积应变变化的迹象。在微观尺度上，使用扫描电子显微镜（SEM）分析了膨胀/收缩现象。结果表明，粘土沿机械载荷的微观结构演变取决于应力历史。蠕变阶段的结构演变遵循单调加载下的结构模式。蠕变膨胀现象似乎与超固结黏土样品中的微孔和微裂纹的扩展密切相关。