土壤地盘弹塑性分析及其本构关系之参数研究

从热力学出发,采用连体介质热力学定义,先辨识等温变形条件下系统外力作功产生自由能与耗散能的互补关联;再应用热力学状态变数的概念,在自由能势函数与耗散能势函数中导入有效应力、弹性应变、塑性应变及塑性应变增量等状态变数,将热力学状态函数描述系统内能量转移轨迹的功能等效应用,据以推导临界状态本构模型中屈服条件、流动法则及硬化规律的合理表达形式。研究方向着重在土壤弹塑性本构模型参数的研选与物理性诠释,目的是:在此延展的临界状态本构模型中导入新的参数,据以拓展模型描绘土壤材料本构行为的能力。亦由于关键性的参数导入,使得本研究构建的模型更能合理地描述各类型土壤的异向性本构行为;在本文后续的模型验证研究工作中,该项成果的数值模型已可精确地提供数值分析数据,在与工程监测资料的比对上呈现优于莫尔–库仑模型和修正剑桥模型的符合性。

Studies on parameters in constitutive relation for elastic/plastic analysis of soil mass

Based on the definition of continuous media of thermodynamics, the complementary correlation between free energy and dissipation energy triggered by external forces was identified first under iso-thermal deformation condition. And, the state variables including effective stress, elastic strain, plastic strain, and plastic strain increment were incorporated into both dissipated and free energy potential functions. Then, the equivalent application of the function of state on describing energy locus transfer inside the system was developed to create a more reasonable layout of yield condition, flow rule and hardening law of critical state constitutive model. This paper concentrated on selecting the parameters for the elastic/plastic constitutive model of soils and how to interpret the actual physical phenomena. And, the goal was to improve the ability of this model in describing constitutive behavior of soils through incorporating new parameters into the extended critical state constitutive model. Moreover, through this introduction of critical parameters, the present model was more realistic to describe anisotropic constitutive behavior of different types of soils. The numerical model, based on the effort of model verification, could precisely provide numerical simulation data which provided better consistent simulation with field monitoring data than Molar-Coulomb model and modified Cam-clay model.