膨胀土变形特性和基于Mohr-coulomb准则本构关系

Research on Deformation Characteristics of Expansive Soil and Constitutive Relationship based on Mohr-Coulomb Criterion

膨胀土是一种强度较高的可塑性特殊黏土,其变形特性在力学上表现为球应力与偏应力的交叉作用,其硬化规律应遵循非关联塑性流动法则。本文通过侧限压缩试验和固结排水试验,对膨胀土的剪缩性、压硬性及两者的耦合关系作了阐述,并采用Mohr-Coulomb屈服条件,假定其屈服函数公式与塑性势函数公式相同,只是将内摩擦角φ替换成剪胀角ψ,从而推导了膨胀土的弹塑性本构关系,研究表明:Mohr-Coulomb本构模型高度适用于正常固结膨胀土土体,可以较精确地描述膨胀土的变形特性与本构关系。

Expansive soil is a kind of plastic special clay with higher strength.Its deformation characteristics are mechanically manifested as the cross action of spherical stress and deviatoric stress,and its hardening law should follow the law of non-associated plastic flow.In this paper,through the confined compression test and the consolidation drainage test,the shear shrinkage,compressibility and the coupling relationship of the expansive soil are described,and the Mohr-Coulomb yield condition is adopted,and the yield function formula and the plastic potential function formula are assumed.The same,except that the internal friction angle is replaced by the dilatancy angle,thereby derives the elastoplastic constitutive relationship of expansive soils.The study shows that the Mohr-Coulomb constitutive model is highly suitable for normally consolidated expansive soils and can be described more accurately Deformation characteristics and constitutive relationship of expansive soil.