PECASE: Alternatives in Waste Cover Systems and in Engineering Education

cms -0094007标题：“PECASE：废物覆盖系统和工程教育的替代方案”，PI: Jorge G. zornberg摘要：这项PECASE计划的总体目标是研究控制替代性蒸散发覆盖系统的性能的机制，同时，开发替代性教育模块，使更广泛的人群（pre-毕业生、post-毕业生和大学生）接触到环境岩土技术的挑战。预计这一综合研究和教育倡议将通过在以下方面的进步作出重大贡献：(1)对复杂非饱和流动过程的基本认识；(2)离心机与数值模拟的结合；(3)干旱和半干旱环境中废物覆盖系统的设计；(4)将研究与工程教育相结合；(5)设计和环境岩土工程教学；(6)面向少数民族高中生和专业的外展策略。尽管现场监测程序和数值模拟已经为土覆盖系统的行为提供了宝贵的见解，但验证预测数值工具的重要任务充其量仍然是不完整的。本文的研究计划是使用离心机建模作为岩土工程数据的额外来源，以便进一步了解发生在蒸散发覆盖层中的复杂非饱和过程。离心机建模将允许系统地控制相关变量，对设计至关重要的天气和土壤条件的组合，并显着减少获取实验数据所需的时间。最重要的是，离心机模型中使用的不是普通土壤，而是来自美国两个最重要的危险废物填埋场（加利福尼亚州的OII超级基金填埋场和科罗拉多州的落基山兵工厂）的实际土壤。这两个地点目前分别正在实施和寻求实施蒸散发覆盖系统。本研究不是试图在离心机中复制实际的原型盖，而是对盖分析中使用的分析工具进行验证和校准。因此，将对离心机实验进行全面的非饱和流动数值模拟，然后对通用原型盖进行仔细的参数评估。这项调查将利用PI过去作为离心机建模师和OII超级基金场地蒸散发盖的设计和数值建模师的经验。通过离心机和数值模拟相结合的方法研究的一些主要问题包括地表通量边界条件的适当表示，覆盖行为对土壤水力特性滞后的敏感性，以及数值模拟中下边界条件的适当选择。作为教育计划的一部分，将开发两个与研究计划密切相关并从研究计划中汲取主要力量的教育模块。同样的两个模块将用于实现与不同人群相关的四个具体工程教育目标。这项工作将尝试通过开发：(i)多媒体案例历史系列和（ii）现场替代封面演示来“将现场带入校园”。这些教育模块将用于满足以下需求：(1)增强土木工程本科生的设计经验，(2)为研究生开发环境岩土技术课程，(3)有效招募代表性不足的少数民族高中学生进入工程项目，以及(4)积极与本地和国际专业社区进行联系。通过实施替代方案，尽管仍然是结构化的课程，教育计划不仅将促进当前地球环境工程的进展

CMS-0094007Title: "PECASE: Alternatives in Waste Cover Systems and in Engineering Education"PI: Jorge G. ZornbergInstitution: University of Colorado at BoulderAbstract:The overall objective of this PECASE initiative is to investigate the mechanisms governing the performance of alternative, evapotranspirative cover systems for waste containment applications while, at the same time, to develop alternative educational modules that will expose a wide range of populations (pre-, post-, and college students) to the challenges of environmental geotechnics. It is expected that this integrated research and education initiative will provide significant contributions through advancements in: (1) basic understanding of complex unsaturated flow processes, (2) combined centrifuge and numerical modeling, (3) design of waste cover systems in arid and semi-arid environments, (4) integration of research into engineering education, (5) teaching of design and of environmental geotechnics, and (6) outreaching strategies for minority high school students and the profession.Even though field monitoring programs and numerical simulations have provided invaluable insight into the behavior of earthen cover systems, the important task of validating predictive numerical tools remains, at best, incomplete. The research plan herein is then to use centrifuge modeling as an additional source of geotechnical data in order to gain further understanding into the complex unsaturated processes that take place in evapotranspirative covers. Centrifuge modeling will allow systematic control of the relevant variables, combination of weather and soil conditions critical for design, and significant reduction in the time needed for acquisition of experimental data. Of major relevance is the fact that, instead of generic soils, actual soils from two of the nation's most significant hazardous waste sites (California's OII Superfund Landfill and Colorado's Rocky Mountain Arsenal) will be used in the centrifuge models. These two sites are, respectively, currently implementing and seeking implementation of evapotranspirative cover systems. Rather than attempting to replicate actual prototype covers in the centrifuge, this research pursues validation and calibration of analytical tools used in cover analysis. Consequently, comprehensive unsaturated flow numerical simulations of the centrifuge experiments will be undertaken, followed by a careful parametric evaluation of generic prototype covers. This investigation will capitalize on the PI's past experience as centrifuge modeler and as designer and numerical modeler of the evapotranspirative cover at the OII Superfund site. Some of the major issues to be investigated through combined centrifuge and numerical modeling include the proper representation of surface flux boundary conditions, the sensitivity of the cover behavior to hysteresis in soil hydraulic properties, and the appropriate selection of the lower boundary condition in numerical simulations. Two educational modules, which are significantly related to and draw major strength from the research plan, will be developed as part of the education plan. The very same two modules will be used to achieve four specific engineering educational goals relevant to different populations. This effort will attempt to "bring the site to the campus" by developing: (i) a Multimedia Case History Series, and (ii) a Field Alternative Cover Demonstration. These educational modules will be used to address the needs for: (1) enhanced design experience for civil engineering undergraduate students, (2) curriculum development in environmental geotechnics for graduate students, (3) effective recruitment of underrepresented minority high school students into engineering programs, and (4) active outreach to the professional community, both locally and internationally. Through implementation of alternative, though still structured programs, the education plan will not only promote current advances in geoenvironmental engin