Reliability assessment of soil nailed slopes under surcharge loading: a numerical and experimental investigation with theoretical aspects

Soil nailing is a slope stabilisation technique used for strengthening of natural as well as manmade earth/soil slopes. Nowadays, this technique is commonly used worldwide in civil engineering projects like highways, railways, tunnelling processes, etc. It plays a very effective role in slope stabilisation in hilly or landslide-prone areas. Because of the ease of construction and due to the economic benefits, this technique is more popular than other slope stabilisation techniques. In this paper, considering slope stabilisation issues, a Three-Dimensional Finite Element Method (3D-FEM) model has been developed for simulation to investigate the behaviour of the entire structure under the surcharge loading. Consequently, the slope failure surface is classified into different areas/zones based on the outcomes of the 3D-FEM analysis. The reliability of various elements like soil slope, soil nailed wall, soil nails, and bearing plate at the facing has been studied in detail. The contribution of effective parameters in grouted nails has been obtained. An experimental investigation was carried out to identify the effects of surcharge load on the soil-nailed slope and wall. Based on the analytical and experimental observations, it is found that grouted nails play an important role in slope stabilisation, reducing settlement and wall deflection. The overall stability is found satisfactory at 15 degrees nail inclination.