Abstract. The stability of excavated slopes in grounds consisting of soil or rock is one of the important topics in geotechnical engineering. The present paper deals with the global stability of a completely vertical wall excavated in non-cohesive ground reinforced by the soil nailing method. The effect of various parameters on the variation of nail length is studied based on the limit equilibrium approach by analysis of 17496 models using the SLOPE/W program. The results indicate that the length of nails increases with the reduction of internal friction angle of soil, surcharge distance from the edge of the wall, tensile strength of the nail material, and number as well as the diameter of rebars used for each nail. However, any increase in groundwater depth, the wall height, surcharge magnitude, soil unit weight, and nails spacing leads to the increased soil nail length. The novelty of current research is the derivation of empirical correlations between the system variables and the optimum length of the nail when the global factor of safety tends to a minimum required value. The relations were verified for four cases properly, which demonstrates the advantages of this study for the design of soil nailed walls.

Keywords