# Finite Element Modeling of the Soil-Nailing Process in Nailed-Soil Slopes
## 1 Introduction
[18] have modeled the soil nails in a soil mass under different overburden pressures using the FE method and studied the nails' pullout performances. The constitutive relation of soil follows the modified Drucker-Prager/Cap model, while the Coulomb friction model describes the soil-nail interface. [PERSON] [19] has developed FE 2D and 3D models for unreinforced and reinforced slopes. The 2D models use four node bilinear quadrilateral elements to discretize the slope domain in conjunction with Drucker-Prager failure-yielding criteria for slope soil, whereas the 3D models implement eight node linear brick elements in conjunction with the Mohr-Coulomb failure-yielding criteria. He found that the results of FE models and the results of the limit equilibrium method were in good agreement. [PERSON] et al. [20] have analyzed the steep soil-nailed slope using the finite element method to investigate the range of the nail parameters, i.e., nail spacing and inclination, appropriate to various slope angles. They have recommended that the range of nails parameters in the existing specification are applicable only to the slope angles of \(55^{\circ}\) and lower. [PERSON] and [PERSON] [21] proposed a comparative study using limit equilibrium and FE approaches to examine the influence of various slope angles and nail inclinations on safety factors and critical slip surfaces of nailed-soil slopes. Compared to the FE method, the limit equilibrium method gives higher values for the factor of safety for slope and nail parameters. [PERSON] et al. [22] have compared between the results of the 2D FEM and results of the 3D FEM for assessment of the factor of safety of clay slopes stabilized with vertical piles. The increase in the factor of safety (FSI) of the stabilized clay slope is investigated considering the slope width, location of the piles, pile diameter, pile spacing and shear strength of the clay. [PERSON] and [PERSON] [23] have investigated the behavior of soil-nailed structures, considering orientation and vertical spacing of nails and bas heave. They have found that lateral deformation is reduced by about 41 percent using nails and the factor of safety is increased by almost 1.2 times that of the slope without nails. [PERSON] and [PERSON] [24] have conducted finite element simulation of soil-nailing support for deep foundation pits using PLAXIS software. The numerical and experimental study on the ground improvement through the implementation of a soil-nailing system has been presented by various researchers. [PERSON] et al. [25] have analyzed the stability of slope under varying anti-slip pile conditions (pile spacing, row spacing and pile locations) using Midas GTS NX software. FE analysis results of the earth pressure on pile-side and thrust on landslide were compared the results obtained from earth pressure theory and field observations. [PERSON] et al. [26] have stabilized the tunnel face under the drainage condition using a new type of soil nail of fiberglass pipe, with improved performance for coupled reinforcement and drainage action of the nails. [PERSON] et al. [27] used finite element analysis to explore the deformation behaviors in tunnel excavation in the presence of rock. The optimization study of soil-nailing parameters using finite element and multi-regression analysis is due to [PERSON] and [PERSON] [28]. They have also developed a correlation between the geotechnical properties, nail parameters and the serviceability conditions using multi-regression analysis. [PERSON] and [PERSON] [29] investigated the influence of nail spacing on soil-nailed walls using hybrid limit equilibrium and finite element methods. [PERSON] et al. [30] have presented numerical modeling using FLAC3D to study the nailed-soil slope behavior under varying surcharge pressure. A limit equilibrium and finite difference coupled approach was used by [PERSON] et al. [31] for stability analysis of nailed-soil slopes.