Abstract

The mechanical behavior of soils can be modeled using a non-linear elastic part showing an incremental response depending on current stress state, while the plastic part can be described appropriately by a smoothed Drücker-Prager based plastic criterion. In order to reproduce the behavior of such media under prescribed loading, a new constitutive model is proposed as a combination of a hyperelastic formulation and a plastic criterion within the elastoplasticity framework. In this new model, both inherent and induced anisotropies are taking into account in the elastic part by mean of a pressure exponent parameter. The tangent stiffness matrix of the elastoplastic model varies as a function of current state of stress which is in accordance with experimental observations of soils and leads to define only one set of parameters for the different initial mean stresses. It is found that the stress-strain responses including hardening tendencies are affected by different values of the pressure exponent which accords to different levels of anisotropy, and the level of influence of anisotropy is related with density and the drainage condition of soils.

摘要

土壤的力学行为可以使用非线性弹性部分来模拟，该部分显示出取决于当前应力状态的增量响应，而塑料部分可以通过基于平滑 Drücker-Prager 的塑性标准适当地描述。为了重现这种介质在规定载荷下的行为，提出了一种新的本构模型，它结合了超弹性公式和弹塑性框架内的塑性准则。在这个新模型中，通过压力指数参数在弹性部分考虑了固有的和诱导的各向异性。弹塑性模型的切线刚度矩阵作为当前应力状态的函数而变化，这与土壤的实验观察结果一致，并导致只为不同的初始平均应力定义一组参数。研究发现，包括硬化倾向在内的应力-应变响应受不同压力指数值的影响，压力指数值对应于不同的各向异性水平，而各向异性的影响程度与土壤的密度和排水条件有关。