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 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Lightweight Geomaterials for Bridge Approach Utilization on Soft Ground Area) ผู้เขียน: ดร.ธวัชชัย ตันชัยสวัสดิ์, อาจารย์ ,  D.T. Bergado, Taweesak Kanjananak สื่อสิ่งพิมพ์:pdf AbstractConstruction of bridge approach highway embankment using strong but lightweight geomaterials over soft ground will alleviated problems of instability and long-term settlement. Backfills of retaining structure can also be constructed using lightweight materials resulting in lower earth pressure and improved economics. There is a variety of lightweight geomaterials available. However, large volume needed in embankment and backfill construction often places limits on the use of costlier manufactured lightweight materials. This study is aimed on used rubber tire-sand mixtures reinforced with geogrid for embankment on soft ground. The test embankment is constructed in the campus of Asian Institute of Technology (AIT). The geogrid reinforced embankment system is extensively instrumented in the subsoil and within the embankment itself in order to monitor the behavior of the wall both during construction and in the post-construction phases, and thereby to evaluate its performance. The unit weight of rubber tire sand mixture 30:70 by weight is 13.6 kN/m3 compare to conventional backfill sand of 18.0 kN/m3, it is lighter by about 75 %. The settlement magnitude of 122 mm at original ground is less when compare to conventional backfill. Differential settlements are small, so this type of lightweight material is appropriate for highway bridge approach utilization. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Interaction between Geogrid Reinforcement and Tire Chip-Sand Mixture) ผู้เขียน:ดร.ธวัชชัย ตันชัยสวัสดิ์, อาจารย์, D.T. Bergado, ดร.สุริยน เปรมปราโมทย์, ผู้ช่วยศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractThe interaction between reinforcing and backfill materials is a significant factor for analysis and design of reinforced earth structures. It can be simplified as pullout resistance and direct shear resistance, which depend on both reinforcing and backfill materials. This study is aimed at studying the interaction between geogrid and tire chip-sand mixture. Numerous experiments including index tests, compaction tests, pullout tests and large-scale direct shear tests were conducted to meet the mentioned objectives. Saint-Gobain and Polyfelt geogrids were selected as reinforcing materials whereas tire chipsand mixtures at the mixing ratios of 30:70, 40:60 and 50:50 % by weight were used as fill materials. The mixture at the mixing ratio of 30:70 % was found to be the most suitable fill material. The pullout resistance and the pullout interaction coefficients of Saint-Gobain geogrids were higher than those of Polyfelt geogrids. In contrast, the direct shear resistance, the direct shear interaction coefficients, and the efficiency values of Polyfelt geogrids were higher than those of Saint-Gobain geogrids. The ultimate tensile strength of Polyfelt geogrid was slightly lower than that of Saint-Gobain geogrid. Finally, Polyfelt geogrid and the tire chip-sand mixture at the mixing ratio of 30:70 % by weight were recommended as reinforcing and backfill materials for field applications. |
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