## 1 Introduction
These types of methods can model both continuous and discontinuous slopes using the techniques of the finite element method (FEM) for continuum modelling [31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43], discrete elements method (DEM) for discontinuum modelling [44; 45; 46] and the hybrid/coupled method which combines FEM and DEM [47; 48; 49; 50; 51]. [PERSON] et al. [52] reviewed the wide range of computer programs available to engineers for the analysis of slopes, emphasizing the emerging powerful numerical modelling codes that enable the realistic simulation of slope failure. However, it was found that each method and every software has its own advantages and limitations, so there is no accepted standard imposed, to date, requiring the choice of a particular software product or analysis method. The COMSOL Multiphysics software and its geomechanics module [53] (part of the structural mechanics module) proved to be a reliable tool for the scope of the paper, given the type of simulation involved. This is a versatile multiphysics piece of software [54; 55] that differs from niche programs in user interface, model building capabilities, solvers available, mesh generation complexity and also the possibility to solve coupled models (fluid flow and structural mechanics in this case). COMSOL provides multiple ways to define geometries using strong user or physics-controlled mesh generation tools; the soil plasticity can be simulated either by internal available models or by user-defined yield functions; it also offers either direct or iterative solvers and can generate results as charts, graphs, tables, animated outputs, or data that can be exported and handled in postprocessing tools. There are several simulations in geoengineering carried out with COMSOL. [PERSON] et al. [56] calculated several safety factors of a high southwest rock slope of the Dagushan iron mine under various rainfall conditions using the nonlinear strength reduction method. A study for the assessment of slope stability was developed by [PERSON] et al. [57] where the COMSOL numerical model considered the coupled thermal (temperature variation), hydraulic (pore water pressure), and mechanical (stress and displacement) processes, obtaining results that coincided well with those given by the limit equilibrium method. Again, COMSOL Multiphysics software was used by [PERSON] et al. [58] to compute a coupled dual-permeability model with a soil mechanics model for landslide stability evaluation on a hillslope and to compare the model with two existing solutions. [PERSON] [59] conducted a study that focused on comparisons between safety factors calculated utilizing computer modeling (COMSOL) for simple slopes using the extensively used limit equilibrium methods and the less common finite element approach. The comparative analysis is based on a multitude of slope geometry and material property combinations. In their paper, [PERSON] et al. [60] proposed a numerical approach using the same software of seepage analysis where soil moisture distribution, water movement phenomena and slope stability characteristics in an unsaturated soil slope were analyzed based on the strength reduction method using a two-step approach: pressure-head analysis, and static analysis. A multifield coupling theory was proposed by [PERSON] et al. [61] to solve the coupled partial differential equations for soil slopes under rainfall infiltration using COMSOL. [PERSON] et al. [62] combined Plaxis, Matlab and COMSOL Multiphysics for an optimized approach to the modified shear strength reduction method (SSRM) used for slope stability analysis and determination of the factor of safety and related failure zones. The purpose of this work is to assess the stability of a TP/TD for a tailings pond situated in Coroiesti, Romania. In order to do so, a stability analysis was conducted on a section of the tailings dam, with the determination of the FOS in various scenarios using the commercial software COMSOL Multiphysics.