Effect of installation angle on pull-out resistance of nails in soil slopes

Abstract

Abstract In this study, the effect of the nailing angle on the pull-out capacity of nails in soil slopes was investigated using the finite difference method with the help of FLAC3D software. Initially, the geometric model was created at three different angles of the excavation slope (45°, 63°, and 80°). Considering the Mohr–Coulomb behavioral model and applying the physical and geometric parameters of the model in order to model the nail in the nailing system, five rows of nails at different angles, relative to the horizon, which included 5°, 10°, 15°, 20°, 25°, 30°, and 35° were used to evaluate the effect of change in the angle of the nail and the different angles of the excavation slope on the pull-out capacity of the nails. The results showed that the magnitude of the nail pull-out force, at slopes of the same level, increases as the angle of the excavation slope increases. Also, the maximum force is generated at the level range of 0.7 of the height from the upper edge of the slope and the nails situated at an angle of about 30° relative to the horizon. Therefore, according to the soil conditions, the angle of nail, and the factor of safety, the optimal implementation angle of the nail on the slope can be calculated in different designs.

Keywords

• Soil nailing
• Pull-out resistance
• Nail angle
• Numerical modeling
• FLAC3D