粗粒土的剪胀方程及广义塑性本构模型研究

以剑桥模型的剪胀方程为基础,引入曲线形态调节因式,提出了一个新的剪胀方程,并依此构建了一个适用于粗粒土的广义塑性模型。主要结论如下:(1)所提剪胀方程能够反映粗粒土剪胀比和应力比之间的非线性关系,且参数定义明确、确定方法简单,并通过试验验证了其对粗粒土的剪缩和剪胀特性的描述能力较好;(2)所构建的广义塑性本构模型参数为9个,并给出了通过室内常规试验确定参数的方法;(3)推导了该模型在一般应力状态下的刚度矩阵,并证明了其对粗粒料普通三轴CD试验具有良好的拟合效果,进一步地,利用三轴等p试验和两段等应力比试验验证了模型的适用性。

Dilatancy equation and generalized plastic constitutive model for coarse-grained soils

A new dilatancy equation is proposed by adding a factor to the dilatancy equation of Cambridge model, and this factor can adjust the shape of curve between the dilatancy ratio and the stress ratio for coarse-grained soils, and can reflect the nonlinear relationship. Thus a new constitutive model based on the generalized plastic theory is proposed. The main conclusions are as follows: (1) The method of determining the parameters of the proposed dilatancy equation is simple, and its capability to reflect the dilatancy properties of coarse-grained soils is verified by CD tests; (2) There are 9 parameters in this model and their definitions are clear, and the methods to determine parameters through the indoor tests are given; (3) According to the generalized plastic constitutive model, the stiffness matrix under the general stress state is deduced, and the triaxial constant p tests and two-stage constant-stress-ratio tests are carried out to verify its rationality.