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天然岩土材料具有结构性和各向异性。在岩土破损力学的理论框架下,建立了初始应力各向异性结构性土的二元介质模型。岩土破损力学把结构性岩土材料抽象成由胶结强的胶结块(胶结元)和无胶结的软弱带(摩擦元)组成的二元结构体,变形过程中胶结块逐步破损并向软弱带转化。假定胶结块为横观各向同性的理想弹脆性体,胶结块破损后转化成的软弱带为可用邓肯-张模型描述的非线性弹性体。通过引入考虑各向异性影响的破损率和局部应变系数,建立了初始应力各向异性结构性土的二元介质本构模型,并给出了模型参数的确定方法。最后给出了模型的表现,且通过人工制备初始应力各向异性结构性土的三轴压缩试验结果验证了模型的适用性。计算结果表明,所提出的本构模型可以较好地模拟初始应力各向异性结构性土的应力-应变和体积变形特性。
Natural geomaterials are structural and anisotropic. Under the theoretical framework of geotechnical failure mechanics, a binary medium model of initial stress-anisotropic structural soil is established. Geotechnical failure mechanics abstracts the structural geomaterials into a binary structure consisting of cemented cements (cemented elements) and non-cemented soft bands (friction elements). During the deformation process, the cemented blocks gradually break down and move toward the weak zone Conversion. Assuming that the cement is ideal transverse elastic isotropic brittle body, the soft belt transformed into the damaged cementitious mass is a non-linear elastic body that can be described by Duncan-Chang model. By introducing the damage rate and the local strain coefficient which affect the anisotropy, the constitutive model of binary medium with initial stress-strain anisotropy soil is established and the method to determine the model parameters is given. Finally, the performance of the model is given, and the applicability of the model is verified by the triaxial compression test results of the artificial anisotropy soil with initial stress. The calculated results show that the proposed constitutive model can simulate the stress-strain and volume-deformation of the initial stress-anisotropic structured soil well.