基于广义塑性本构模型的饱和多孔介质应变局部化分析

Generalized plastic constitutive model based on strain localization analysis of saturated porous media

给出基于平均化原理的多孔介质动力学分析的基本理论与控制方程,采用适用于饱和砂土的广义塑性本构模型(PastorZienkiewicz模型)进行多孔介质的应变局部化数值模拟,分别对中等松散砂土与密实砂土两类介质进行了应变局部化数值模拟,并进一步对剪切带内孔隙水压力的数值结果进行了分析。可以发现,对密实砂土的模拟孔隙水将会出现负压(吸力)结果,而对中等松散砂土孔隙水则呈受压现象,这种现象出现的原因与材料的塑性膨胀现象密切相关。

The governing equations for dynamic analysis of saturated porous medium, which are obtained by the general framework of averaging theories, are described in the paper. A generalized plastic constitutive model for fully saturated soils is adopted in the computational process. Samples of medium loose and dense sands are studied. Negative water pressures, which are important for localization phenomena in the shear band of fully saturated dilatant geomaterials, are obtained for dense sands, while positive water pressures are obtained for medium loose sands. All the results obtained by numerical simulation are consistent with the phenomena observed in laboratory test.