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粗粒土具有明显的剪胀剪缩性,为非虎克材料。对8种颗粒材料进行了11组三轴试验,将体应变分为球应力和偏应力引起的体应变两部分,并假定弹性变形泊松比为常数,对实测体应变两部分大小进行了分离。假定三轴试验的轴向应变和剪应力引起的体应变服从Rowe剪胀方程,分析表明,对任一种颗粒材料而言,Rowe剪胀方程参数Kf的归一性良好,即不同应力状态下参数Kf均近似为一个常数。在此基础上,基于邓肯–张模型和Rowe剪胀方程,建立了体变模量KP、剪胀模量Kq、剪切模量G三参量与应力状态的关系,初步提出了一种新的非线性剪胀模型。该模型可视为邓肯–张模型的改进型模型。经验证,该模型能比较准确地描述各种颗粒材料的体变过程,是一种物理概念明确,简单实用的非线性剪胀模型。
Coarse grained soil has obvious dilatancy shear, non-Hooke material. Eleven sets of triaxial tests were carried out on eight kinds of granular materials, and the body strain was divided into two parts of the body strain caused by the ball stress and the deviatoric stress. The Poisson’s ratio of the elastic deformation was assumed to be constant, and the two parts of the measured body strain were separated . Assuming that the axial strain and the shear strain induced by the triaxial tests are in line with Rowe’s dilatancy equation, the analysis shows that for any granular material, the Rowe dilatancy parameter Kf has a good normality, that is, under different stress states The parameters Kf are approximated as a constant. On this basis, based on the Duncan-Chang model and Rowe’s dilatancy equation, the relationship between the three parameters of bulk modulus KP, dilatancy modulus Kq, shear modulus G and stress state is established, and a new Nonlinear dilatancy model. The model can be regarded as an improved model of Duncan-Chang model. The model has been proved to be able to describe the volume change process of various granular materials more accurately. It is a nonlinear dilatancy model with clear, simple and practical physics concept.