权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Evaluation of Liquefaction Potential of Saturated Granular Soils under Partial Drainage Conditions

部分排水条件下饱和粒状土的液化势评价

基本信息

批准号：
1728612
负责人：
Usama El Shamy
金额：
$ 22.89万
依托单位：
Southern Methodist University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-01 至 2022-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1728612&HistoricalAwards=false
关键词：
Evaluation Liquefaction Potential Saturated Granular

项目摘要

The U.S. and other seismically active areas around the world have sustained considerable damage resulting from earthquake-induced site liquefaction that was associated with very costly damage to port facilities, bridges, dams, buried pipes, and buildings of all types. The Earthquake Engineering Research Institute reports that the direct cost of losses in the built environment and the indirect economic cost of a major earthquake that strikes a major urban area could easily exceed 100 billion dollars. Such losses could be significantly reduced if the performance of soil systems could be reliably predicted and current design and remediation measures improved. This project addresses a critical gap in engineering knowledge related to the evaluation of the liquefaction potential of soil deposits under realistic drainage conditions. This undertaking will help in reducing the uncertainty and large costs associated with site liquefaction hazards. The research and education activities fall within the national interest. They have the potential to achieve increased economic competitiveness through better assessment of liquefaction potential. The knowledge gained from this research would prevent future loss of lives and contribute to the welfare of the American public. The research will contribute to the progress of earthquake engineering and science. The activities would also lead to a globally competitive American STEM workforce equipped with the latest development in high-performance computational modeling.Liquefaction is a result of water pressure build-up due to squeezing of pore space during rapid earthquake loading that, in turn, reduces soil strength. The mechanism of pore-pressure development during cyclic loading has been mainly explained based on the analogy between cyclic contraction of fully drained sands and pore pressure generation in undrained conditions. However, depending on several factors such as external loading rate, soil permeability and in-situ pore-pressure boundary conditions, different drainage conditions are expected in the field. These conditions may lead to a partial drainage situation in which simultaneous change in pore volume and in pore water pressure may occur during shearing. Under these conditions, soils originally believed to be non-liquefiable such as dense sand, may actually experience instability. This project aims at providing accurate characterization of pore fluid migration during seismic loading of a soil deposit and assessing liquefaction potential under realistic drainage conditions. The high-performance computing (HPC) resources of the cyberinfrastructure component of the NSF-supported NHERI enable the development of a universal predictive tool capable of seamless modeling of soil systems at an unprecedented resolution. High-fidelity fully-coupled micromechanical computational simulations utilizing parallel computing are planned in this effort to provide much-needed answers to questions related to understanding the mechanical processes that control the evolution of pore pressure during seismic loading.

美国和世界上其他地震活跃地区遭受了地震引起的场地液化造成的相当大的破坏，这与港口设施、桥梁、水坝、埋地管道和所有类型的建筑物的非常昂贵的破坏有关。地震工程研究所报告说，建筑环境损失的直接成本和袭击主要城市地区的大地震的间接经济成本很容易超过1000亿美元。如果能够可靠地预测土壤系统的性能，并改进目前的设计和补救措施，就可以大大减少这种损失。该项目解决了与评估现实排水条件下土壤沉积物液化潜力相关的工程知识中的一个关键空白。这项工作将有助于减少与场地液化危险有关的不确定性和巨额费用。研究和教育活动符合国家利益。通过更好地评估液化潜力，它们有可能提高经济竞争力。从这项研究中获得的知识将防止未来的生命损失，并有助于美国公众的福利。该研究将有助于地震工程和科学的进步。这些活动还将培养出具有全球竞争力的美国STEM人才队伍，并配备高性能计算建模方面的最新发展。液化是由于快速地震荷载期间孔隙空间受到挤压而导致水压积聚，进而降低土壤强度的结果。基于完全排水砂土的循环收缩与不排水条件下孔隙水压力产生的相似性，对循环荷载作用下孔隙水压力的形成机理进行了解释。然而，取决于几个因素，如外部加载速率，土壤渗透性和原位孔隙压力边界条件，不同的排水条件预计在该领域。这些条件可能会导致局部排水的情况下，在剪切过程中，孔隙体积和孔隙水压力可能会同时发生变化。在这些条件下，最初被认为是不可液化的土壤，如密实的沙子，实际上可能会经历不稳定。该项目旨在提供土壤存款地震荷载过程中孔隙流体迁移的准确表征，并评估现实排水条件下的液化潜力。 NSF支持的NHERI的网络基础设施组件的高性能计算（HPC）资源能够开发一种通用预测工具，能够以前所未有的分辨率对土壤系统进行无缝建模。高保真度完全耦合微机械计算模拟利用并行计算计划在这方面的努力，以提供急需的答案，了解有关的机械过程，控制孔隙压力的演变在地震荷载。