论文部分内容阅读
预变形过程可以认为是应力历史的作用,为了探明预变形对兰州黄土应力松弛特性的影响,开展了一系列室内侧限松弛试验,研究了不同预变形量条件下黄土的应力松弛过程曲线。试验结果表明:预变形量愈大,起始松弛应力愈大,在试验历时内的应力松弛量也较大。根据松弛曲线特征,提出松弛程度的概念,试验发现,预变形量愈大,达到同一松弛程度所需时间较短;随应力松弛进一步发展,这种时间差别愈明显。从试验出发,探讨了松弛过程的阶段性,将全过程分为瞬时松弛阶段、衰减松弛阶段和稳定松弛阶段3个阶段。预变形选择恒变形速率加载过程,研究了不同变形速率对松弛过程的影响。在分析松弛试验数据基础上,获得了一种能够描述卸载过程的流变关系,并对其可靠性进行了验证。
In order to find out the effect of pre-deformation on the stress relaxation characteristics of loess in Lanzhou, a series of indoor relaxation experiments were carried out. The stress relaxation curves of loess under different pre-deformation conditions were studied. The experimental results show that the greater the pre-deformation, the greater the initial relaxation stress and the greater the amount of stress relaxation during the test duration. According to the characteristics of relaxation curve, the concept of relaxation degree is proposed. It is found that the larger the amount of pre-deformation, the shorter the time required to reach the same degree of relaxation. With the further development of stress relaxation, the time difference is more obvious. Based on the experiment, the stage of relaxation process is discussed. The whole process is divided into three stages: instantaneous relaxation stage, relaxation relaxation stage and stable relaxation stage. Pre-deformation selection constant deformation rate loading process, the effect of different deformation rate on the relaxation process. Based on the analysis of the relaxation test data, a rheological relationship that can describe the unloading process was obtained and its reliability was verified.