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在临界状态弹塑性力学的框架内,建立了可以考虑循环荷载作用下各向异性对饱和软土力学特性影响的边界面塑性模型。该模型采用非关联的流动法则,引入了反映土体各向异性的内变量,利用该内变量的初始值描述初始各向异性,采用一种理论更为严谨、模型参数确定更为恰当的旋转硬化法则描述循环加载过程中各向异性的演化,利用更新映射中心的径向映射法则和与塑性偏应变路径长度有关的塑性模量插值规律,保证模型能够模拟循环加载时应力-应变响应的非线性、滞回性、应变累积性等基本特性,解释了模型参数的物理意义和确定方法,特别是给出了一种合理确定描述土体初始各向异性状态变量方法。通过文献中等压固结和偏压固结饱和黏土的循环三轴试验结果与模型预测结果的对比验证了模型的合理性。
In the framework of critical state elasto-plastic mechanics, a plastic boundary model of interface can be established which can consider the effect of anisotropy on the mechanical properties of saturated soft soil under cyclic loading. The model uses the non-associated flow rule to introduce the internal variable that reflects the anisotropy of soil. The initial value of the internal variable is used to describe the initial anisotropy. A rigorous theory and a more appropriate rotation of the model parameters are determined The hardening law describes the evolution of anisotropy during cyclic loading. By using the radial mapping rule of updated mapping center and the plastic modulus interpolation law related to the length of plastic partial strain path, the hardening law can guarantee that the model can simulate the stress-strain response of cyclic loading Linearity, hysteresis, and strain accumulation, the physical meaning and determination method of model parameters are explained. In particular, a method to reasonably determine the initial anisotropy state variables of soil is given. The validity of the model is verified by the comparison of the cyclic triaxial test results of medium pressure consolidation and bias consolidation of saturated clays with the model predictions.