US-Egypt Cooperative Research: Physical and Numerical Modeling of Geogrid-Soil Cyclic Interaction

该奖项支持佛罗里达州坦帕市南佛罗里达大学（USF）土木与环境工程系的Alaa Ashmawy博士和埃及开罗国家研究中心（NRC）土木工程系的Ahmed Abdel-Rahman博士的联合研究项目。他们建议研究土工格栅-土壤循环相互作用的物理和数值模拟。在美国和埃及，土工格栅作为机械内含物在土方施工中的使用一直在上升。然而，颗粒土与土工格栅之间的相互作用机制尚未完全了解，特别是在循环荷载条件下，如交通和地震荷载。在早期的一个项目中，主要研究人员设计并制造了一种新的多用途土工合成测试设备，能够对土-土工格栅界面进行拉拔和直剪测试。pi计划利用目前安置在开罗NRC的新设备来研究颗粒土和土工格栅内含物之间的循环相互作用。埃及团队将进行一项全面的实验计划，以检查土工格栅开口尺寸与颗粒尺寸之间的静态和循环拉拔强度的依赖关系。USF的团队将使用离散元法（DEM）对系统的微观力学进行数值模拟，以验证和校准实验数据。将对现行加筋土设计和土工格栅制造标准进行相应修改。范围：PI最近开发了一种使用DEM方法对角粒子进行数值模拟的新技术。这项计划中的研究活动将允许通过与埃及小组收集的实验数据进行比较来验证和改进这项技术。开罗的NRC拥有实验研究所需的基础设施，而DEM软件、算法和数值研究工具可以在USF获得。研究结果有望推进土工合成-土壤相互作用的知识状态，以及增强颗粒土系统的离散元建模。该项目将涉及一名美国研究生，她将通过访问合作科学家在开罗的实验室并在那里工作，获得独特的学习机会。参与该项目的一名本科生也将通过USF工程学院的REU项目获得支持。这两个学生都是代表性不足的群体的成员。研究成果将通过在期刊、会议记录和互联网上发表来广泛传播。

0310183AshmawyDescription: This award supports a joint research project between Dr. Alaa Ashmawy, Department of Civil and Environmental Engineering, University of South Florida (USF), Tampa, Florida and Dr. Ahmed Abdel-Rahman, Civil Engineering Department, the National Research Center (NRC), Cairo, Egypt. They propose to investigate the physical and numerical modeling of geogrid-soil cyclic interaction. The use of geogrids as mechanical inclusions in earth construction has been on the rise in both the US and Egypt. However, the interaction mechanisms between granular soils and geogrids are not yet fully understood, especially under cyclic loading conditions such as traffic and earthquake loading. In an earlier project, the principal investigators designed and manufactured a new multi-purpose geosynthetic testing apparatus capable of performing pullout and direct shear testing on soil-geogrid interfaces. The PIs plan to utilize the new apparatus, currently housed at the NRC in Cairo, to investigate the cyclic interaction between granular soils and geogrid inclusions. The Egyptian team will carry out a comprehensive experimental program to examine the dependence of static and cyclic pullout strength on geogrid opening dimensions in relation to grain size. The team at USF will conduct numerical modeling of the micromechanics of the system using the Discrete Element Method (DEM) to verify and calibrate the experimental data. Modifications to the current reinforced earth design and geogrid manufacturing standards will be proposed accordingly. Scope: The PI has recently developed a new technique for numerical modeling of angular particles using the DEM method. This planned research activity will allow validation and improvement of the technique through comparison with experimental data collected by the Egyptian team. The NRC in Cairo possesses the necessary infrastructure for the experimental study, and the DEM software, algorithms, and numerical research tools are available at the USF. The findings are expected to advance the state of knowledge with respect to geosynthetic-soil interaction as well as discrete element modeling of reinforced granular soil systems. The project will involve an American graduate student who will have a unique learning opportunity through her visit to and work at the cooperating scientist's laboratory in Cairo. An undergraduate student working on the project will also be supported through a REU program at the USF's College of Engineering. Both students are members of underrepresented groups. Broad dissemination of research findings will be done through publication in journals, conference proceedings, and the Internet.