基于微极亚塑性本构的地基沉降模拟

Simulation of foundation settlement with a micropolar hypoplastic constitutive model

本文基于ABAQUS开发的微极亚塑性本构模型有限元程序,模拟了砂土的平面应变试验和地基沉降变形。结合微极理论特有的内部尺度参数,分析了该参数对局部变形规律、剪切带角度和厚度等特征的影响。通过提取地基模型剪切带内外单元的微极转动特征,分析了地基沉降和剪切带的变化规律。结果表明,微极理论的引入使得亚塑性本构模型可以更好地捕获应变局部化现象以及研究剪切带的宽度和倾角。微极理论包含单元的旋转自由度可以用来研究剪切带的旋转方向。地基沉降变形的研究发现,剪切带内单元的旋转方向随着剪切带深度的增加而交替变化。剪切带条数和宽度均受到内部长度的影响。地基模型中内部长度越大,剪切带宽度增加,剪切带条数减少。砂土的平面应变试验表明,剪切带宽度与内部长度线性相关,剪切带宽度近似为内部长度的11.6倍。

In this paper,the plane strain test and foundation settlement deformation of sand were simulated based on the finite element program of micropolar hypoplastic constitutive model in ABAQUS.Combined with the unique internal scale parameter of micropolar theory,the influence of this parameter on the local deformation as well as the shear band inclination and width,was analyzed.By extracting the micropolar rotation characteristics of the elements inside and outside the shear band of the foundation model,the variation of foundation settlement and shear band was analyzed.The results show that the hypoplastic constitutive model combined with micropolar theory can better capture the strain localization phenomenon and study the width and dip angle of the shear band.Micropolar theory can be used to study the rotation direction of the shear band by including the rotational degree of freedom of elements.The study of foundation settlement deformation shows that the rotation direction of elements in the shear band changes alternately with the increase of the shear band depth.Both the number and width of shear bands are affected by the internal length.In the foundation model,the width of shear band increases and the number of shear bands decreases with the increase of internal length.The plane strain test of sand shows that the width of shear band is linearly related to the internal length,and the width of shear band is approximately 11.6 times the internal length.