NEESR-CR: Seismic Response of Landfills: In-Situ Evaluation of Dynamic Properties of Municipal Solid Waste, Comparison to Laboratory Testing, and Impact on Numerical Analyses

该奖项是美国国家科学基金会09-524计划征集活动的成果。地震工程模拟(NEES)研究网络(NEESR)“竞赛，包括密歇根大学(牵头机构)、洛杉矶加州州立大学(次级奖项)和地球合成技术咨询公司(次级奖项)。该项目将利用德克萨斯大学奥斯汀分校的NEES设备场地。每年产生的越来越多的城市固体废物(MSW)大多被填埋。现代(自20世纪90年代以来)城市生活垃圾填埋场是对环境敏感的复杂设施，其大小类似于大型大坝。最近的美国地震(例如1994年的北岭地震)突出了MSW垃圾填埋场潜在的地震脆弱性。震动时移动过多可能会损坏垃圾填埋场？S安全壳或覆盖系统或导致稳定性故障。这类故障对环境的影响可能是毁灭性的。准确、具有代表性的城市生活垃圾的动力特性是进行可靠的抗震工程分析和设计的要求，但我们对城市生活垃圾的动力特性的了解还处于起步阶段。该项目的智能优点是首次使用可在NEES@UT获得的T-Rex移动振动台来评估城市垃圾的现场非线性动力学特性。移动式振动筛是一种车载大容量振动筛，可在废料中产生显著的循环应变。加速度计被用来记录振动筛附近深度处废物质量的加速度，并得出废物的动力学性质。使用T-Rex的测试将在四个地点进行，在四个精心挑选的城市垃圾填埋场(一个在德克萨斯州，三个在加利福尼亚州的地震高发区)，重点记录城市垃圾的变异性和捕获因素，如年龄、降解和水分含量的影响。随后，将挖掘测试坑，并在密歇根大学的大型实验室测试设施和洛杉矶加州州立大学的较小规模测试设施中收集和测试废物。实验室测试将使调查人员能够研究影响废物动态特性的各种因素(例如，围压、密度、成分)，并将结果与现场测试进行比较。将进行数值分析，以评估垃圾填埋场的抗震性能，并为抗震设计提供建议。这项研究有可能改变垃圾填埋场设计中的地震工程实践，为固体废物的现场测试提供一种新的方法，验证城市生活垃圾大规模实验室测试的适用性，产生急需的现场和实验室数据，并为城市垃圾填埋场的地震分析制定推荐的方法。该项目更广泛的影响是在地震区设计更安全、更可靠的城市垃圾填埋场。该项目还将通过积极让本科生和高中生参与研究和辅导活动来整合研究和教育。计划在垃圾填埋场举行示威和学习活动期间，向更广泛的高中生和社区进行宣传。建议的研究将为至少一篇博士论文(在密歇根大学)提供基础，并将促进主要研究机构和主要教学机构之间的合作。还概述了向技术界传播广泛数据和研究成果的综合计划。该项目的数据将被存档，并通过NEES数据库向公众提供。该奖项是国家减少地震灾害计划(NEHRP)的一部分。

This award is an outcome of the NSF 09-524 program solicitation ''George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) Research (NEESR)" competition and includes the University of Michigan (lead institution), California State University in Los Angeles (subaward) and Geosyntec Consultants (subaward). This project will utilize the NEES equipment site at the University of Texas at Austin.The increasing amounts of municipal solid waste (MSW) generated every year are, in their majority, landfilled. Modern (since the 1990s) MSW landfills are environmentally sensitive, sophisticated facilities and are similar in size to large dams. Recent U.S. earthquakes (e.g. 1994 Northridge Earthquake) highlighted the potential seismic vulnerability of MSW landfills. Excessive movement during shaking may damage the landfill?s containment or cover system or cause stability failures. The impact of such failures on the environment can be devastating. The use of accurate and representative dynamic properties of Municipal Solid Waste is a requirement to reliable seismic engineering analyses and design, but our understanding of the dynamic properties of MSW is rudimentary and lacking. The intellectual merit of this project is in evaluating, for the first time, the in-situ nonlinear dynamic properties of MSW using the T-Rex mobile shaker available at NEES@UT. The mobile shaker is a truck mounted, high capacity shaker that can induce significant cyclic strains in the waste material. Accelerometers are used to record the accelerations of the waste mass at depths in the vicinity of the shaker and derive the dynamic properties of the waste material. Testing using T-Rex will be performed at four locations, at four carefully selected MSW landfills (one in Texas and three in areas of high seismicity in California) with emphasis on documenting the variability of MSW and capture factors such as effect of age, degradation and moisture content. Subsequently, test pits will be excavated and waste material will be collected and tested in large-scale laboratory testing facilities at the University of Michigan and smaller scale testing facilities at California State University in Los Angeles. The laboratory tests will allow the investigators to study the various factors (e.g. confining stress, density, composition) that affect the dynamic properties of waste and compare the results with the field testing. Numerical analyses will be performed to evaluate the seismic behavior of landfills and provide recommendations for use in seismic design. This investigation has the potential to transform seismic engineering practice in landfill design by providing a new methodology for field testing of solid waste, validating the applicability of large-scale laboratory testing of MSW, generating much needed field and laboratory data, and developing recommended methodologies for the performance of seismic analyses of MSW landfills. The broader impact of this project is the safer, more reliable, designs of Municipal Solid Waste landfills in seismic regions. The project will also be integrating research and education by actively involving undergraduate and high school students in research and mentoring activities. Outreach to a broader population of high school students and the community is planned during a demonstration and learning event at a landfill site. The research proposed will provide the basis for at least one Ph.D. dissertation (at U-M) and will promote collaboration between primarily research and primarily teaching institutions. A comprehensive plan for broad data and research results dissemination to the technical community is also outlined. Data from this project will be archived and made available to the public through the NEES data repository. This award is part of the National Earthquake Hazards Reduction Program (NEHRP).