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.

在由土壤或岩石组成的地基中开挖边坡的稳定性是岩土工程中的重要课题之一。本文研究了在非粘性地基中开挖的完全垂直墙体的整体稳定性，该墙体采用土钉加固法。使用SLOPE/W程序对17496个模型进行分析，基于极限平衡法，研究了各种参数对钉子长度变化的影响。结果表明，钉子的长度随着土壤内摩擦角、距墙边缘超载距离、钉子材料的抗拉强度以及每个钉子所用钢筋数量和直径的减小而增加。然而，地下水深度、墙高、附加费大小、土壤单位重量的任何增加，和钉间距导致土钉长度增加。当前研究的新颖之处在于，当全局安全系数趋向于最小要求值时，系统变量与钉子的最佳长度之间的经验相关性的推导。对4个案例的关系进行了正确验证，证明了本研究在土钉墙设计中的优势。