An Elasto-Viscoplastic Model for Clay Considering Destructuralization and Consolidation Analysis of Unstable Behavior
An Elasto-Viscoplastic Model for Clay Considering Destructuralization and Consolidation Analysis of Unstable Behavior
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DOI：
10.3208/sandf.45.2_29
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发表时间：
2005-04
影响因子：
3.7
通讯作者：
S. Kimoto;F. Oka
中科院分区：
文献类型：
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作者：
S. Kimoto;F. Oka
失稳通常被认为是剪切破坏的问题。在固结过程中也观察到不稳定行为，即应力路径偏离破坏线。在本研究中，将弹粘塑性本构模型扩展到描述破坏状态附近和远离破坏线的失稳。失稳与结构退化有关，在本构模型中可表述为超固结边界面和静态屈服面收缩。模拟了粘土的一维固结过程，研究了结构退化对固结过程性能的影响。所提出的模型可以有效地再现固结过程中某些类型的不稳定行为，如停滞，或孔隙水压力的暂时增加，以及沉降速率的突然增加。考虑结构退化时，轴向应变的分布表现出明显的应变局部化。这种压缩应变局部化现象被认为是压实带，它可能引起较大的位移。
Instability is usually considered as a problem of shear failure. Unstable behavior is also observed during the consolidation process, whereby the stress paths depart from the failure line. In the present study, an elasto-viscoplastic constitutive model is extended to describe instability of both around the failure state, and away from the failure line. The instability is connected to structural degradation, and formulated as shrinkage of overconsolidation boundary surface and static yield surface in the constitutive model. One-dimensional consolidation process of clay has been simulated to study the effect of structural degradation on behavior during consolidation. The proposed model can effectively reproduce certain types of unstable behavior during consolidation, such as stagnation, or a temporary increase in pore water pressure, and a sudden increase in the settlement rate. Moreover, the distributions of axial strain exhibit apparent strain localization when structural degradation is taken into account. This phenomenon of the compressive strain localization is regarded as compaction bands, which may cause a large displacement.