# Finite Element Modeling of the Soil-Nailing Process in Nailed-Soil Slopes
## 1 Introduction
The stability analysis of soil slope reinforced with pre-stress anchors, including an anchor parameter optimization study, was conducted by [PERSON] et al. [32] using the limit equilibrium method. The slope sliding for shear failure of the slip surface has been described according to the nonlinear Mohr-Coulomb yielding criterion. [PERSON] and [PERSON] [33] have reviewed the various aspects and restrictions related to soil-nailing systems. They have also presented the design of a soil-nailing system for landslide prevention and mitigation. [PERSON] et al. [34] have carried out shaking table tests to study the dynamic behavior of nailed-soil slopes. They infer from the study that smaller nail inclination provided better reinforcement action for stabilizing the soil slopes than the horizontal nails and nails of large inclination. Centrifuge tests were carried out by [PERSON] et al. [35] to determine the impacts of overburden pressure on the performance of nailed vertical excavations. It is clear from the literature review that the various development stages of the soil-nailing process have not been modeled numerically. The analytical models are unable to incorporate the soil-reinforcement interaction and inhomogeneity of soil mass. The laboratory models are difficult to construct and are not cost effective. Moreover, the behavior of the soil-nailing process is affected by various nail, soil and slope parameters, and parameters are difficult to implement in analytical models and laboratory models. Therefore, numerical models need to be developed to investigate the behavior of the soil-nailing process at construction and overburden stages. In this study, finite element (FE) modeling of various stages of the soil-nailing process, i.e., construction stages and overburden pressure stages, is carried out considering different soil parameters simulated by in-house developed laboratory models [33]. The soil-nailing process built in the laboratory models is idealized as a plain strain problem and modeled in PLAXIS 2D and 3D software. The 15-node triangular elements and 5-node plate elements are employed, respectively, for soil and foundation modeling. The 2-node elements are taken to simulate the nail reinforcements. The elements at the interface are employed to simulate the soil-reinforcement interactions. The laboratory models of the soil-nailing process consist of a Perspex sheet box filled with sandy soil, a Perspex sheet facing, steel bars for reinforcement and a steel plate for foundation. The stress-strain behavior of the sand is represented by a Hardening-Soil model. The interface at soil and nails is defined by the Coulomb friction law. The behavior of the soil-nailing process during the construction stage and under overburden pressure are investigated in terms of lateral/vertical displacement of slope and stress conditions in slope soil mass. The results of the FE models of various stages of the soil-nailing, process, i.e., construction stages and under overburden pressure stages, are also compared with the laboratory model results. The numerical simulation using PLAXIS 3D were developed for laboratory model dimension sensitivity by varying the extents of the nailed-soil model. The sensitivity analysis of the experimental model was conducted for the toe soil depth variation and for plain strain condition validity.