Influence of time effects on instability of granular materials
Influence of time effects on instability of granular materials
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DOI：
10.1016/s0266-352x(97)00002-5
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发表时间：
1997
影响因子：
5.3
通讯作者：
P. Lade;J. Yamamuro;Paul A. Bopp
中科院分区：
文献类型：
--
作者：
P. Lade;J. Yamamuro;Paul A. Bopp
先前进行的一系列三轴压缩试验的结果表明，表现出非关联流动的材料不遵守德鲁克和希尔的稳定性假设，这些试验旨在揭示粒状材料所表现出的行为类型。在排水和不排水条件下，对完全饱和和部分饱和砂土试件进行了三轴试验，以研究稳定和不稳定特性的区域。如果应力状态位于材料的失稳线和破坏面之间，则颗粒材料可能在破坏面内部变得不稳定。这里介绍的是三个系列的实验进行的砂土，在剪切压缩。在一个系列中，进行实验来研究应变率对不稳定线位置的影响。在第二个系列中，允许砂土在排水条件下蠕变，导致屈服面向外移动，因此砂土在应力点以上的区域中变得痛苦。因此，蠕变量的增加需要越来越高的应力差来使砂不稳定。在第三组实验中，饱和砂土在不排水条件下允许蠕变，这导致孔隙压力增加和可能的不稳定，因为应力可能被带入潜在的不稳定区域。因此，时间效应在土的稳定性中起着重要的作用。
Results of previously performed series of triaxial compression tests designed to expose the type of behavior displayed by granular materials have shown that materials that exhibit non-associated flow do not obey the stability postulates by Drucker and by Hill. Triaxial tests on fully and partly saturated specimens of sand have been performed under drained and undrained conditions to study the regions of stable and unstable behavior. Granular materials may become unstable inside the failure surface if the state of stress is located between the instability line and the failure surface for the material. Presented here are three series of experiments conducted on sands that compress during shear. In one series, experiments are performed to study the effect of strain rate on the location of the instability line. In the second series, the sand is allowed to creep under drained conditions resulting in outwards movement of the yield surface, and the sand consequently becomes suffer in the region above the stress point. Increasing amounts of creep therefore require increasingly high stress differences to render the sand unstable. In the third series of experiments, the saturated sand is allowed to creep under undrained conditions, and this results in increasing pore pressures and possible instability because the stresses may be brought into the region of potential instability. Thus, time effects play important roles in the stability of soils.