Residual deformation assessment of earth structure against earthquake and its application for design

本文提出了土结构抗震稳定分析的新方法和刚塑性动力变形分析方法，并讨论了它们在实际工程中的适用性.土结构抗震安全系数的考虑基于安定理论的稳定性分析方法准确地考虑了地震加速度时程。该方法的适用性进行了检查，为正弦和不规则的加速度波在基岩处执行。研究结论如下：1）合理评价了加速度周期对路堤稳定性的影响。其稳定性不仅取决于强迫加速度，而且取决于地基的动力特性。2)通过与传统地震系数法的比较，探讨了新方法的适用性.刚塑性动力变形分析方法的发展基于刚塑性假设的动力变形分析方法是为了评价土工结构物在地震作用下的残余变形而发展起来的。研究结果表明：1）刚塑性动力变形分析能够较好地模拟岩土结构在刚体和塑性流动之间的动态变化。2)利用粘土重复荷载的应力历史模型，通过刚塑性动力变形分析较好地模拟了平面应变重复试验的液化过程。

This study presents new stability methods of earth structures against earthquakes and rigid-plastic dynamic deformation analysis, and discusses their applicability in practice.1. Consideration on safety factor of earth structure against earthquakesA new stability method based on the shakedown theory considers the acceleration time history of earthquake exactly. The applicability of this method is examined for both sine and irregular acceleration waves enforced at the bedrock. The conclusions in this study were as follows : 1) The effects of periods in enforced accelerations on embankment stability were suitably evaluated. The stability depended on not only the enforced acceleration, but also the dynamic properties of the ground. 2) The applicability of new method is discussed in comparison with the conventional seismic coefficient method.2. Development of rigid-plastic dynamic deformation analysisThe dynamic deformation analysis based on rigid-plastic assumption was developed in purpose of residual deformation assessment of earth structure against earthquakes. The results obtained in this study were as follows : 1) THe rigid-plastic dynamic deformation analysis could simulate the behavior of the geotechnical structures properly which changes their states between rigid body and plastic flow. 2) With the use of the stress history model of clays for repeated loads, the liquifaction process of plane strain repeated test was fairly simulated by rigid-plastic dynamic deformation analysis.