# Finite Element Modeling of the Soil-Nailing Process in Nailed-Soil Slopes
## 1 Introduction  
The finite element technique has been accepted as a tool for modeling geotechnical complex processes. The soil-nailing process for slope stability is constructed in sequential stages, as explained by [PERSON] et al. [1], from top to the bottom as the construction proceeds. The soil-nailing process is the most cost-effective and efficient method for stabilizing the natural and engineered slopes [2]. The process can be implemented in small spaces without vibration or disturbing the environment [3]. The numerical methods are best suited to simulate the soil-reinforcement interaction effect and the influence of inhomogeneity of soil on slope instability in a nailed-soil slope, which is not possible to incorporate in analytical methods and laboratory models. The numerical methods can model the non-uniformity of soil medium and soil properties, including strain hardening with time and temperature-dependent properties. The basic concept of a reinforced-soil system depends upon the tensile forces transfer into the soil via friction or adhesion developed at the nail interfaces. The soil mass applies the lateral earth force on the potentially sliding soil mass while providing the resistance due to nail bonding. The interaction between the soil and nails due to friction confines the soil movement in construction of the nailed-soil slope. A state-of-the-art soil stabilization technique using a soil-nailing system, construction parameter influence on the design method and failure modes of the nailed-soil system are summarized by [PERSON] et al. [4]. Among the various methods used for slope stability,three methods are commonly applied to analyze the nailed-soil slopes, namely the limit equilibrium method [5], finite difference method [6] and finite element method [7]. The limit equilibrium method cannot simulate the nail-soil interaction, which impacts nail resistance mobilization. The reduction of the tensile strain due to adhesion and friction between reinforcement and soil adds to the stability of soil mass [8]. [PERSON] et al. [9] have conducted a slope stability analysis of a combined system of soil nails and stabilization piles on loose soil. The soil-nailing system design optimization using the genetic algorithm base is proposed by [PERSON] et al. [10]. The effect of construction process on the behavior of nailed-soil structures using the FE-based software PLAXIS 2D is studied by [PERSON] et al. [11]. [PERSON] et al. [12] have proposed a computational approach based on the material point technique to explore the plate anchor application for stabilization of earth slopes, and the proposed approach results are compared with the results of small-scale laboratory tests. The stabilizing mechanisms of loose-fill slopes using a hybrid nail arrangement have been studied by [PERSON] et al. [13], and they concluded that a hybrid nail arrangement can be used to increase the robustness of the nailing process in soil stabilization. [PERSON] [14] has suggested the nail length requirements to decrease the displacement of the soil slope. In the nailed-soil slope parametric study, namely nail parameters (nails size, length, angle) and soil-nail interface friction coefficient variation on the pull-out force for the grouted soil-nailing system in non-cohesive soil are examined by [PERSON] et al. [15] using the numerical approach. The numerical modeling of layered and homogenous piled stabilized earth slopes is employed by [PERSON] and [PERSON] [16] to study the influence of foundation location and surcharge loading distance from the crest on soil deformation distribution, on the slope stability and on the soil bearing capacity enhancement ratio. The stability and deformation properties of a composite nailed-soil foundation pit were numerically studied by [PERSON] et al. [17]. They have computed the optimum inclination and spacing of the soil nails and the diameter and embedded depth of the mixing pile for stability of the foundation pit. [PERSON] et al.