砂土材料状态相关临界状态各向异性模型

A critical state anisotropic model with state-dependent of sand

考虑材料状态对砂土临界状态的影响,采用宏细观结合的方法建立了砂土的各向异性模型。将新的各向异性状态变量引入砂土模型的临界状态方程,增加了各向异性参量、应力状态和应力与材料组构方向关系3个因素对临界状态的影响,扩展了砂土材料状态相关的概念。随应力状态和应力与材料组构方向几何关系变化,π平面上模型的临界状态线、相变状态线和峰值状态线的形状和位置自然产生变化,各向异性越大,状态线偏离的静水压力轴也越远,形状变化也越大。模型的剪胀方程和硬化规律也是状态参量函数,随细观参量的变化,细化和量化了砂土物理状态变量对剪胀性及硬化规律的描述。模型用一组参数可以描述较大围压和密度范围砂土各向异性强度-变形的力学响应。

Considering the impact of sand state on its critical state line,a constitutive model for anisotropic sand is established in the method of macro-micro incorporation.The novel anisotropy state variable is introduced into critical state equation of the model,the influences of anisotropic parameters,stress state and the relationship between stress and fabric direction on the equation is added and the state-dependent concepts of sand is extended. With the changes of stress state and the relationship between stress and fabric direction,the shape and the position of phase transformation-state,peak-state and critical-state of model is changed inartificially on the direction of hydrostatic pressure.The more degree of anisotropy,the further offset from the axes of hydrostatic pressure and the greater change in shape.The hardening law and dilatancy equation of model are the function of anisotropy state variable.The description of sand dilatancy and hardening law are refined and quantified with the change of microscopic quantification parameter.One set of model constants can describe the strength-deformation responses of sand under a large scale of confining pressures and densities.