考虑颗粒破碎的动力UH模型
Dynamic UH model considering particle crushing
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摘要: 在已发展的考虑颗粒破碎效应的静力UH本构模型基础上,采用变换应力方法,将原模型拓展为适用于无黏性土的动力统一硬化模型(DUH模型)。具体做法:①针对静力模型中屈服面形状随当前应力状态变化而改变的现状,采取含有 p 变换的变换应力方法,将原真实应力空间中变化的屈服面变换为变换应力空间中的椭圆屈服面;②采用旋转硬化规则,在变换应力空间中椭圆的位置以及形状由旋转轴来确定,并建立了一并考虑等向硬化以及旋转硬化的混合硬化参数;③在变换应力空间中,参考屈服面与当前屈服面之间通过应力比参数 R 来建立联系。模型参数较少。通过3种不同岩土材料在高围压下的单调以及循环加载试验结果的比较,验证了所提DUH模型的合理性。Abstract: The UH model considering particle crushing is expanded to dynamic UH (DUH) model by using the transformed stress (TS) method. There are three aspects developed in the proposed model: (1) the shape of yielding surface in UH model changes with the change of current stress state. The yielding surface in ordinary stress space is transformed into the ellipse yielding surface by adopting the TS method including p transformation; (2) the rotational hardening rule is adopted. The position and the shape of ellipse yielding surface are determined based on the value of rotational axis. The mixed hardening parameter considering isotropic hardening and rotational hardening is established; (3) the relationship between the reference yielding surface and the current yielding surface is established by means of the stress ratio R in TS space. There are fewer parameters in the proposed model. The reasonability of the proposed model is demonstrated by comparing with the test results of three kinds of geomaterials under monotonic and cyclic loading conditions.