## 5 Conclusions  
The earth nailing system is an earth slope stabilization technique accomplished by installing in situ closely spaced nails in the ground. In the present study, an experimental investigation of earth nailing system models of non-cohesive soil, having different nailing parameters, such as nail spacing and orientations and length of nails, was carried out. The distribution of the mobilized tensile force in the nail and the slope face horizontal pressure is nonlinear with different nailing parameters. The nail tensile force approaches zero at the ends and increases toward the middle third of the nail. The maximum lateral displacement and slope face horizontal pressures of the slope occur in the middle third, and minimum lateral displacement and slope face horizontal pressures, the lower third of the slope with different surcharge loading and nailing parameters. The minimum and maximum vertical and horizontal pressures behind the soil mass occur in the upper third and lower third of the slope, respectively, with different nailing parameters.  
There is a reduction in the lateral movement of the slope and footing settlements with an increase in the length and inclination of the nails and with a decrease in the nail spacing. The mobilized tensile forces in the nails are increased due to the increase in the nail length and spacing, while tensile forces reduce with the increase in the inclination of the nails.  
The vertical stresses under the soil mass are not much affected by changing the nail parameters, i.e., length, inclination, and spacing. The horizontal stresses at the slope face decrease with the increase in the nail inclination, while they are increased with the increase in nail length and spacing.  
The vertical and horizontal stresses behind the soil mass increase with the increase in the spacing of the nails, while the vertical and horizontal stresses decrease with the increase in nail inclination. The increase in the length of the nails causes a decrease in the vertical and horizontal stresses behind the soil mass, up to the length of the nail of about the slope height, while further increases in the nail length increase the vertical and horizontal stresses behind the soil mass.  
Conceptualization, M.H.M. and M.A.; methodology, M.H.M. and M.A.; resources, J.M. and P.V.H.; writing--original draft preparation, M.H.M. and M.A.; writing--review and editing, J.M. and P.V.H.; project administration, P.V.H.; funding acquisition, M.A. All authors have read and agreed to the published version of the manuscript. Funding for this research was given under award numbers R.G.P2/73/41 by the Deanship of Scientific Research; King Khalid University, Ministry of Education, Kingdom of Saudi Arabia.  
Not applicable.  
Figure 31: Footing settlement from laboratory and numerical model.  
**Acknowledgments:** The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through the General Research Project under grant number (R.G.P2/73/41). The authors acknowledge the Dean of the Faculty of Engineering for his valuable support and help.  
**Conflicts of Interest:** The authors declare no conflict of interest.