Effect of Fines Type and Content on Liquefaction Resistance and Ground Failure Potential

[0218365], chang H. Juang， Clemson University《粉粒类型和含量对液化阻力和地面破坏潜力的影响》，准确评估液化潜力和液化诱发的地面破坏潜力在震区结构的工程规划和设计中具有重要意义。本研究主要针对地震液化危害缓解中的两个重要问题，即粉粒类型和含量对液化抗力的影响，以及液化诱发的地面破坏潜力。第一个主题涉及液化的触发，第二个主题涉及液化的后果。关于第一个主题，最近许多研究者的研究得出结论，细粒含量和细粒类型都影响土壤的抗液化能力，但这些影响在现有的简化设计方法中没有得到充分考虑。来自最近地震的数据提供了一个难得的机会来调查这些影响，并改进液化触发分析的当前状态。第二个主题更具挑战性，因为目前还没有现成的适用于特定地点的模型来评估液化诱发的地面破坏潜力。然而，最近地震的历史案例的数量现在足以建立经验模型来估计特定地点的地面破坏潜力。该项目正在收集液化触发和地面故障的额外案例历史数据。该案例历史数据与现有数据库一起用于改进液化触发分析的现状，并开发评估液化诱发地面破坏潜力的新经验模型。研究了逻辑回归分析、基于人工神经网络的映射函数方法和贝叶斯更新技术等先进的数据分析技术，并利用这些技术建立了实证模型。确定性模型和概率模型都在开发中。由于岩土工程专业倾向于确定性方法，因此将开发确定性模型，但配备建议的指导方针，包括风险校准的安全系数。正在开发的概率模型用于基于性能的地震工程，以及用于绘制液化引起的地面破坏。

0218365, Charng H. Juang, Clemson University"Effect of Fines Type and Content on Liquefaction Resistance and Ground Failure Potential"The ability to accurately evaluate the liquefaction potential and the liquefaction-induced ground failure potential is important in the engineering planning and design of structures in seismic regions. This research project addresses two important issues in the mitigation of earthquake-induced liquefaction hazards, namely the effect of fines type and content on liquefaction resistance, and the liquefaction-induced ground failure potential. The first topic concerns the triggering of liquefaction, and the second addresses the consequence of liquefaction.With respect to the first topic, recent studies by numerous investigators have concluded that both fines content and fines type affect the liquefaction resistance of soils, but these affects are not fully accounted for in the existing simplified design methods. Data from recent earthquakes offers a rare opportunity to investigate these effects and to improve on the current state of the art on liquefaction triggering analysis.The second topic is more challenging, as reflected in the fact that no readily applicable site-specific model is currently available for evaluating liquefaction-induced ground failure potential. However, the number of case histories from recent earthquakes is now sufficient to establish empirical models for estimating site-specific ground failure potential. This project is collecting this additional case history data on liquefaction triggering and ground failure. This case history data, together with the existing databases, is used to improve the current state of the art on liquefaction triggering analysis, and to develop new empirical models for evaluating liquefaction-induced ground failure potential. Advanced data analysis techniques, including logistic regression analysis, mapping function approach based on artificial neural network, and Bayesian updating technique, are examined and utilized for developing the empirical models.Both deterministic and probabilistic models are being developed. Since the geotechnical engineering profession prefers the deterministic approach, the deterministic models will be developed, but equipped with suggested guidelines including risk-calibrated factor of safety. The probabilistic models are being developed for use in performance-based earthquake engineering, as well as for mapping liquefaction-induced ground failure.