Helical soil nails have been developed recently to stabilize soil slopes, excavations, roadway cuts, retaining walls, etc. Installation of such nails is carried out by the application of torque and crowd, unlike conventional drilled and grouted soil nails. However, numerical studies on the performance of helical soil-nailed slopes are limited. This study presents the finite-element (FE) modelling of the exact field installation procedure and the pull-out response of helical soil nails. A coupled Eulerian–Lagrangian (CEL) approach employed in ABAQUS has been adopted for the numerical simulation. Traditional finite-element methods depend on a Lagrangian framework, leading to issues such as contact problems and distortion in the FE mesh when dealing with large deformation geotechnical problems. In the Lagrangian formulation, the motion of the continuum is described in terms of material coordinates and time. Conversely, in the Eulerian method, the continuum's motion is characterized by spatial coordinates and time. As a result, materials can freely traverse in the Eulerian mesh without causing element distortion. Thus, in the modelling process, the helical soil nail was discretized using Lagrangian elements, while the soil material was represented within the Eulerian domain. Validation of the adopted method was carried out by performing a model experiment of the installation and pull-out loading of single-helix soil nails. Results showed that the CEL approach can model the installation and pull-out response of helical soil nails with reasonable accuracy. Neglecting the installation process when modelling helical soil nails can result in an overestimation of their capacity.