مهندسی عمران شریف (Feb 2019)
FINE-GRAINED INFLUENCE ON THE BEHAVIOR OF REINFORCED SAND WALLS UNDER SURCHARGE LOAD USING CENTRIFUGE
Abstract
Modern methods of reinforcing walls were used in the 60s by Henry Vidal. Reinforced soil wall is an alternative to retaining walls and traditional embankments. The use of geosynthetics as reinforcement in reinforced soil walls has been significant in recent years. Reinforced soil walls have been used in Iran since 70s. Accordingly,in some areas, due to the lack of access to suitable materials and high cost of material supply from far zones, fine-grained soils may be used for wall backfill. Reinforced slopes and walls come with various applications, including its use in bridge abutment. In this study, the effect of fine-grained soils, strip surcharge, and wall angle on behavior of geosynthetic reinforced soil walls using centrifuge modeling has been studied. In this study, a set of 8 centrifuge testes on saturated fine-grained walls reinforced with geotextile was performed using the geotechnical research center of Iran University of Science and Technology centrifuge, and behavior of physical models using digital image processing technique was studied. The comparison between place of rupture on geotextile and slid surface obtained from digital image processing was a good matched. Therefore, combination of centrifuge modeling with digital image processing is a good way to study the behavior of geosynthetic reinforced soil walls.The results showed that with increasing load of strip footing, the amount settlements of top of wall increased, and this effect on vertical walls is more than the battered walls. Moreover, stains of reinforced layers and deformation of facing wall also increase when fines in backfill increased from %10 to %20. It was observed that slide surfaces were entry from behind of strip footing and developed to the toe of the walls. With increasing percent of fine-grained in backfill from %10 to %20, sliding surfaces were deeper. In addition, with the decreasing of angle of face, the models were stable. In addition, existence of %10 fines in sand backfill improves performance of geosynthetic reinforced soil wall (GRSW). If fines in the backfill increased to %20, GRSW would have poor performance.
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