Design Methods of Reinforced Earth Embankments Reinforced by Soil Nails

• Main Authors: Chin-Chung Hsieh, 謝至忠
• Other Authors: Chia-Cheng Fan
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/95890128457408568426

碩士 === 國立高雄第一科技大學 === 營建工程所 === 95 === The application of reinforced earth embankment in mountain areas is easily restricted by available space. It raises difficulty for allocating length of reinforcement. If we add soil nails on the back side of reinforced earth embankment, the soil nails could provide extra force as compensation for the lack of sufficient length of reinforcement embankment. This paper analyze applications of reinforced embankment system for different geometric slopes via the Limit Equilibrium Analysis computer program – ReSSA. Deduce length of reinforcement from safe factors of research result. In addition, Compound Construction Method combined soil nails and reinforcement retaining structure has been proven to be highly feasible. In order to solve the problem of mentioned above in mountain areas, this paper also uses the Compound Construction Method to design, and analysis via Finite Element Method program – PLAXIS. The geometric conditions of reinforced earth embankment include: (1) height of reinforcement earth embankment; (2) angle of reinforcement slope; (3) length of reinforcement material. Besides, this paper also has an emphasis on different weight loadings, both in static and dynamic states, on reinforced embankment. In order to build design chart of soil nail force for Reinforced Earth Embankments Reinforced by Soil Nails system as a basis. For different geometric conditions, this paper takes 7 meters, 9 meters, and 12 meters height into consideration. The result shows that the higher the embankment, the more tensile force the soil nails endures. As for the angle of embankment slope, we study it under 60 degree, 70 degree, 80 degree, and 90 degree, and find that the steeper the reinforced embankment, the more tensile force the soil nails takes. Besides, the angle of reinforcement slope influences tensile force distribution from each step of soil nails. While above one-third of embankment height, the bigger the angle of embankment slope, the more tensile force the soil nails takes; surprisingly, while below one-third of embankment height, the bigger the angle of embankment slope, the less tensile force the soil nails sustains. As for the length of reinforced materials, the longer the reinforced materials, the less the maximum tensile force of soil nails bears. Moreover, this paper studies friction angle of backfill in 25 degree, 30 degree, and 35 degree, to understand influences on stability of reinforced area from different backfill. The result shows when the friction angle of backfill is higher, reinforced earth embankment maintains higher stability and soil nails endure less tensile force. For mastering the tensile force needed from soil nails in different geometric conditions, this paper categorizes results of mechanics analysis from reinforced earth embankment connected with soil nails under static weight loadings in different geometric conditions, and establishes design chart of tensile force from soil nail to normalize the maximum tensile force.