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现行《公路工程抗震设计规范》(JTJ044-89)对地震动力荷载作用主要是以区域地震烈度作为唯一的参考依据,没有考虑地震振动频率、次数和地震持续时间等特性,因此无法真实反映路基在地震作用时的反应特性,迫切需要对路堤填土在地震动力荷载作用下的动力特性进行研究。文章针对干旱地区路堑边坡在地震荷载下的动力特性的研究,基于边界面的概念,以Mohr-Column屈服函数为基础,介绍了边界面弹塑性模型,建立了路堤土的动力本构模型。利用该模型研究地震作用下路堤的残余变形及整体稳定性分析。通过室内动三轴试验的模拟验证了该模型的可靠性和模型的表现。文章介绍了该模型在ABAQUS中的二次开发实现的技术。利用自编程序模拟了动三轴剪切试验结果,并与ABAQUS采用本模型的计算结果比较,证明了开发成果的正确性。最后以某一理想路基工程算例说明了所添加的本构模型进行路基动力分析的方法,并给出了相应的结果。计算结果符合土体在地震荷载作用下的动力特性规律,验证了该模型的可行性,拟补了现行规范的不足。
The current Code for Aseismic Design of Highway Engineering (JTJ044-89) is mainly based on the regional seismic intensity as the only reference and does not consider the characteristics of seismic frequency, frequency and duration of earthquake, so it can not truly reflect the subgrade It is urgently necessary to study the dynamic characteristics of embankment fill under earthquake dynamic load. In this paper, based on the concept of boundary surface and the Mohr-Column yield function, a dynamic constitutive model of embankment soil is established to describe the dynamic characteristics of cutting slope in arid areas under earthquake load. This model is used to study the residual deformation and overall stability of embankment under earthquake action. The reliability of the model and the performance of the model are verified by the simulation of indoor dynamic triaxial test. This paper introduces the technology of secondary development of this model in ABAQUS. The self-programmed program was used to simulate the moving triaxial shear test results and compared with the ABAQUS calculation results of this model to prove the correctness of the development results. At last, an example of an ideal subgrade construction is given to illustrate the method of subgrade dynamic analysis of the added constitutive model, and the corresponding results are given. The calculated results are in accordance with the dynamic characteristics of the soil under earthquake load. The feasibility of the model is verified and the deficiency of the existing codes is proposed.