基于Hardin曲线的土体边界面本构模型在ADINA软件中的实现

Hardin curve based boundary surface constitutive model of soil and implementation in ADINA software

为了提出一种适合于岩土地震数值模拟的土体本构模型,基于土体动应力-应变关系的Hardin曲线及其在非等幅往返荷载下的Pyke修正,采用von Mises准则在偏应力平面上构造边界面,以反向加载点和当前应力点的连线在边界面上投影的比例作为硬化参数,推导了塑性硬化模量并给出该边界面本构的具体增量表述。在有限元软件ADINA中通过自定义材料的二次开发实现了该本构模型,并利用动三轴试验对该本构模型进行了验证。数值模拟与试验结果的对比表明,本构模型能如实反映土体的应力-应变关系。针对实际工程场地的地震反应,应用边界面本构模型在ADINA中进行了二维数值模拟,与SHAKE91的计算结果进行了对比,说明了该本构模型应用于岩土地震工程问题的合理性。

This paper proposes a soil constitutive model suitable for geotechnical earthquake simulation. The Hardin curve of soil dynamic stress-strain relationship and its Pyke’s modification for irregular cyclic loading are used. The boundary surface is established on the deviatoric stress plane according to von Mises criterion. After connecting reverse loading point and the current stress point for boundary surface projection, a plastic hardening modulus is derived regarding projection ratio as hardening parameter. The specific increment formulation is given. This constitutive model is implemented by customizing the secondary development of materials in finite element method software ADINA and verified with dynamic triaxial test. The comparison of numerical simulation and test results illustrates that this constitutive model can truthfully reflect the stress-strain relation of soil. For seismic responses of a site, a 2D numerical simulation is executed using the boundary surface constitutive model in ADINA. The results are compared with those of SHAKE91 to illustrate the rationality of adopting this constitutive model to geotechnical earthquake engineering problems.