Głuchowski Andrzej, Sas Wojciech
Water Centre, Warsaw University of Life Sciences-SGGW, 02787 Warsaw, Poland.
Materials (Basel). 2020 Sep 3;13(17):3907. doi: 10.3390/ma13173907.
Long-term cyclic loading is observed in a wide range of human activities, as well as in nature, such as in the case of ocean waves. Cyclic loading can lead to ratcheting which is defined as progressive accumulation of plastic deformation in a material. Long-term cyclic loading causes a time effect (creep), which is a secondary compression effect. In this article, we conducted 15 triaxial tests on four types of cohesive materials in undrained conditions to evaluate the damage and failure mechanism. To characterize the strain and pore pressure development, we modified the Yanbu resistance concept. On the basis of the static creep tests, we concluded that the stress paths for undrained creep behavior have to take into account the pore pressure developed during long-term cyclic loading. Pore pressure build-up and plastic strain accumulation during long-term cyclic loading are dependent on the number of loading cycles. Finally, we proposed the failure criterion, which was based on the Modified Cam-Clay constitutive model.
在广泛的人类活动以及自然界中，如海浪的情况，都能观察到长期循环加载。循环加载会导致棘轮效应，棘轮效应被定义为材料中塑性变形的渐进累积。长期循环加载会引起时间效应（蠕变），这是一种二次压缩效应。在本文中，我们在不排水条件下对四种粘性材料进行了15次三轴试验，以评估损伤和破坏机制。为了表征应变和孔隙水压力的发展，我们修改了延布阻力概念。基于静态蠕变试验，我们得出结论，不排水蠕变行为的应力路径必须考虑长期循环加载过程中产生的孔隙水压力。长期循环加载过程中的孔隙水压力积累和塑性应变积累取决于加载循环次数。最后，我们提出了基于修正剑桥黏土本构模型的破坏准则。
