Pullout Behavior of Nail Reinforcement in Nailed Soil Slope

Abstract

The pullout resistance and displacement performance of reinforcement have significant effects on the safe and economic design of a reinforced-soil system. In this study, the nail pullout tests are conducted to assess the pullout behavior of soil nail reinforcement at different levels in the soil slope of granular materials. The similitude laboratory models of a reinforced soil system with a scale of 1:10 are prepared. The construction sequence used in a full scale slope was precisely followed in the laboratory model. The models consist of a Perspex wall box filled with sand and steel bars as a reinforcement. The models of sand beds are formed using an automatic sand raining system. Devices and instruments are installed to record the nails pullout resistance and displacement. The tests are carried out at variable footing pressures to get the pullout force of the nails based on a strain control technique. The finite element models of nailed soil slope are also analyzed to validate the laboratory model results. It infers from the numerical model results that the laboratory models underestimate the pullout behavior of nail reinforcement in nailed soil slope. The pull-out force in nail reinforcement increases as the displacement increases and then decreases slightly and becomes constant with an increase in displacement in the case of deeper placed nails, but it becomes constant immediately for upper nails.

Keywords

• soil nailing system
• nails characteristics
• soil slope
• footing pressure
• nails orientation
• pullout force