U.S.-Japan Cooperative Science: Use of Reinforcement-Drainage Geosynthetics in Embankment/Wall Construction with Marginal Backfill

该奖项支持由美国宾夕法尼亚州切斯特威德纳大学的韩杰教授、美国特拉华大学的Dov Leshchinsky教授和日本佐贺大学的J. C. Chai教授共同开展的为期三年的国际合作研究项目。他们将进行一项研究，研究在边缘填土的路堤/墙建筑中使用加筋排水土工合成材料。土工合成材料已成功地用作以下功能之一或组合：加固、排水、分离、过滤和/或遏制土方结构。在目前的路堤/墙建设中，土工合成材料主要用于加固路堤/墙的稳定性。目前的规范要求使用高质量、自由排水、粒状回填体来建造机械稳定土（MSE）挡土墙。然而，由于经济和可用性的限制，包括粘性回填在内的边缘回填已越来越多地用于建造堤防/墙。许多研究表明，充填体中细粒颗粒的增加将使充填体更容易受到水分/水的影响。水在充填体中的有害影响是降低强度和模量，增加变形（包括蠕变变形），并通过增加土压力和诱导渗透力来破坏土工结构。当使用边缘回填时，使用土工合成材料进行排水和加固对堤防/墙的性能至关重要。研究方向为：1)土工合成材料的排水特性，特别是在边缘土中土工合成材料的长期透过率；2)土工合成材料层间边缘土的固结特性；3)土工合成材料与边缘土的直接滑动和拉拔相互作用行为；4)土工合成材料加固堤/墙的稳定性，无论是否具有排水功能。该项目汇集了具有互补专业知识和研究能力的实验室的努力。本研究将对加筋排水土工合成材料在边缘土路堤/墙施工中的应用产生影响，并为使用这些双重功能土工合成材料的土工结构设计提供指导。该项目通过一名博士后和一些本科生的参与来促进国际人力资源的发展。通过思想和技术的交流，该项目将扩大我们的基础知识基础，促进国际了解与合作。研究结果将在科学会议和科学期刊上传播。这项研究也将在互联网上公布。

0355430HanThis award supports a three-year international collaborative research project between Professor Jie Han at Widener University in Chester, Pennsylvania, Professor Dov Leshchinsky at the University of Delaware and Professor J. C. Chai at Saga University in Japan. They will undertake a study on the use of reinforcement-drainage geosynthetics in embankment/wall construction with marginal backfill. Geosynthetics have been successfully used as one or a combination of the following functions: reinforcement, drainage, separation, filtration, and/or containment in earth structures. In current embankment/wall construction, geosynthetics have been mostly used as reinforcement for the stability of embankments/walls. Current specifications require the use of high-quality, free-draining, granular backfill for constructing mechanically stabilized earth (MSE) retaining walls. However, marginal backfill including cohesive backfill has been increasingly used to construct embankments/walls due to economic and availability constraints. Many studies have indicated that an increase of fine-grained particles in backfill would make the backfill more susceptible to moisture/water. The detrimental effects of water in the backfill are to reduce strength and modulus, increase deformations (including creep deformation), and destabilize earth structures by increasing earth pressures and inducing seepage forces. When marginal backfill is used, use of geosynthetics for drainage as well as reinforcement becomes critical to the performance of embankments/walls. The researchers will be studying the following areas: 1) the drainage behavior of the geosynthetics, especially the long-term transmissivity of geosynthetics confined in marginal soil; 2) the consolidation behavior of marginal soil between layers of geosynthetics; 3) the interaction behavior between geosynthetics and marginal soil including direct sliding and pullout; and 4) the stability of embankments/walls using geosynthetic reinforcement with or without a drainage function. The project brings together the efforts of laboratories that have complementary expertise and research capabilities. The research will have an impact on the use of reinforcement-drainage geosynthetics in embankment/wall construction with marginal soil and provide guidance for the design of earth structures using these dual function geosynthetics. The project advances international human resources through the participation of a postdoc and a number of undergraduate students. Through the exchange of ideas and technology, this project will broaden our base of basic knowledge and promote international understanding and cooperation. Results of the research will be disseminated at scientific meetings and in scientific journals. The research will also be made available on the Internet.