Numerical study on deformation around underground mining structures (Algeria)

Purpose. To study the stability of underground mining structures using numerical method based on finite elements, two-dimensional (2D), Finite Element (FE) modeling using GEO5 calculation model. Methodology. To consider the influence of geotechnical parameters, the tunneling is carried out by the NATM method. In order to check settlements in soft ground and to carry out the work in complete safety, we used software based on the finite element method. Findings. Determination of the range and prediction of subsoil displacements are necessary when designing this type of structure due to the need to ensure the safety of the active environment located in the zone of influence. Originality. The originality of this work is the characterization of the soil of the studied region, determining of the different physical and mechanical properties as well as the modeling with a recent calculation model based on the Mohr-Coulomb behavior mode. Practical value. Given the characteristics of the current section, this study illustrates that the results obtained using the GEO5 calculation code, show the movement exceeding the permitted threshold; its values are 47.80 and 46.6 mm respectively in the first and second step, which can induce significant ground movements. As a solution, there are possibilities of reducing the current declivity within the limits authorized for this type of line (maximum = 40) in order to increase the cover (height of earth on the key) of the tunnel and consequently reduce surface settlements.