Influence of type of geosynthetic material interaction on shallow anchor pullout capacity

Abstract

A series of laboratory model pullout tests were performed in the present study on poorly graded sands having different properties of S1 and S2, at a relative density (Rd) of 70%. The tests were performed in a test tank having a size of 1000 mm × 1000 mm × 1000 mm using a circular-shaped anchor size (D) of 100 mm. The depth (L) of the anchor plate during the model tests was maintained as shallow i.e., L/D = 4. To improve the plate anchor uplift capacity, the lab scale model tests were performed in sand beds of S1 and S2 using low tensile strength polypropylene geotextile (PPGT) as a reinforcement material. Furthermore, a series of openings were made to the PPGT which is named GOP (geotextile with openings) to act as a geogrid material. Irrespective of the type of sand and reinforcement, a single number of reinforcement layers having a size of 5D was used and placed directly above the anchor plate for all the model tests. The test results revealed that sand S1 shows higher improvement compared to sand S2 for both the cases of unreinforced and PPGT geotextile reinforced conditions. It happened due to the soil physical property of higher unit weight of soil of S1. Furthermore, the anchor ultimate pull-out capacity of sand S1 with GOP is 1.63 and 1.15 times higher than that of unreinforced and PPGT geotextile-reinforced sands. Even though, the tensile strength and stiffness of GOP in comparison with PPGT is almost lesser than a factor of 3. It could be happened due to the difference in the soil-geosynthetic interactions and reinforcement mechanisms.