Simulation of liquefaction of unsaturated soil using critical state soil model
Simulation of liquefaction of unsaturated soil using critical state soil model
复制标题
利用临界状态土模型模拟非饱和土的液化
DOI：
10.1002/nag.2669
复制
发表时间：
2017
影响因子：
4
通讯作者：
M.
中科院分区：
文献类型：
--
作者：
Komolvilas;V. and Kikumoto;M.
一些研究人员报道，饱和度相对较高的非饱和土在完全不排水循环荷载条件下的平均有效应力逐渐减小，最终可以像饱和土一样液化。本文采用非饱和土弹塑性模型，对非饱和土体进行了一系列完全不排水循环荷载模拟。该模型是用有效应力张量建立的非饱和土临界状态土模型，它包含以下概念：(A)由于饱和度的变化，包含临界状态线的状态界面的体积运动；(B)考虑比容和水力滞后影响的土壤水分特征曲线；以及(C)考虑密度影响的次加载面概念。虚空气被认为是一种符合波义耳定律的理想气体。通过与以往结果的比较，验证了该模型的有效性。模拟结果表明，该模型较好地描述了非饱和土液化、压缩和饱和度增加等不排水循环特性。最后，根据模拟结果，描述了饱和度、孔隙率和围压对非饱和土循环强度的影响。非饱和土抗液化能力随饱和度和孔隙率的减小而增大，随围压的增大而增大。此外，饱和度对液化抗力的影响大于围压和孔隙比。版权所有©2017 John Wiley&Sons，Ltd.
Several researchers have reported that the mean effective stress of unsaturated soils having a relatively high degree of saturation gradually decreases under fully undrained cyclic loading conditions, and such soils can be finally liquefied like saturated soils. This paper describes a series of simulations of fully undrained cyclic loading on unsaturated soils, conducted using an elastoplastic model for unsaturated soils. This model is a critical state soil model formulated using effective stress tensor for unsaturated soils, which incorporates the following concepts: (a) the volumetric movement of the state boundary surface containing the critical state line owing to the variation in the degree of saturation; (b) the soil water characteristic curve considering the effects of specific volume and hydraulic hysteresis; and (c) the subloading surface concept for considering the effect of density. Void air is assumed to be an ideal gas obeying Boyle's law. The proposed model is validated through comparisons with past results. The simulation results show that the proposed model properly describes the fully undrained cyclic behavior of unsaturated soils, such as liquefaction, compression, and an increase in the degree of saturation. Finally, the effects of the degree of saturation, void ratio, and confining pressure on the cyclic strength of unsaturated soils are described by the simulation results. The liquefaction resistance of unsaturated soils increases as the degree of saturation and the void ratio decrease, and as the confining pressure increases. Furthermore, the degree of saturation has a greater effect on the liquefaction resistance than the confining pressure and void ratio. Copyright © 2017 John Wiley & Sons, Ltd.