Finite Element Method for Designing Large Section Underground Works by Sequential Excavation Method. Study Case: Lugoj-Deva Road Tunnel

Any underground work requires the knowledge and application of appropriate techniques and technologies in all stages of implementation of such a project. An important problem in the design of underground works is the knowledge of the characteristics and behaviour of the massif in which the work will be carried out. It depends on the choice of the excavation solution appropriate to the existing real conditions, which will influence the duration of the work and the costs associated with it. The objective of this paper was to analyse and compare the total deformations of the contour of the underground work, assuming that the work is performed by sequential excavation method (S.E.M.): excavation in the horizontal direction and in the vertical direction. The finite element numerical simulation method was used for the convergence analysis, which showed that the total displacements of the tunnel gallery wall are smaller for the horizontal sequential excavation (SEM) variant, both for the hypothesis of coefficient of pressure in state of rest having the value K₀ = 0.6, as well as for the hypothesis in which K₀ = 2.27.