【摘要】 平面应变条件下土体中主应力之间的关系,其实质是特定应变路径条件下土的应力-应变关系,为土的一个重要力学特性。在平面应变条件下将土体的变形和强度特性简化为二维问题处理时,其关键就在于如何简单、合理地确定平面应变方向上的主应力大小。基于弹塑性理论及土的试验规律,在平面应变的简单加载条件下,假定主应力之间的关系为双线性函数,并利用一维固结和破坏时的主应力状态,确定双线性函数的系数,得到平面应变方向上主应力计算公式的一个较合理形式,为应力状态和材料性质的函数。建议的主应力关系体现土体在平面应变条件下的变形机制,在b-R坐标内通过3个天键点：初始点（1,1）、一维固结应力状态点（b_c,R_c）、破坏应力状态点(b_PS,R_PS)。通过与试验数据的比较证明所提双线性主应力函数的合理性,它可合理地描述平面应变方向上主应力的变化趋势,并且形式简单,易于工程应用。更多还原

【Abstract】 The relationship between principal stresses in the plane strain state is the stress-strain relationship of soil with a certain strain path.The characteristics of deformation and strength of soils under the plane strain condition can be simplified as a two-dimensional problem.How to easily and reasonably determine the value of principal stress in the direction of plane strain is the key point.Based on the elastoplastic theory and test data under the plane strain condition,it is assumed that the relationships between the principal stresses in plane strain direction and those in the other directions are bilinear.The parameters of bilinear function are determined by one-dimensional consolidation and failure state.The principal stress in the plane strain direction is expressed as a function of stress states and material properties.Substantially,the proposed relationship of the principal stresses embodies the characteristics of deformation of soils in plane strain state.The function of this relationship passes three key points,that is the original point（1,1）,the state point of one-dimensional consolidation（b_c,R_c） and failure point(b_PS,R_PS).Compared with test results,the validity and practicality of the proposed bilinear principal stress function are testified.更多还原