Analysis of deformations and stresses in the settlement zone of a tunnel constructed according to the new Austrian tunneling method

The specific accidents during the construction process of tunnels are delicate moments that require an examination of behavior and the mechanisms that occur within the structural system. This process allows us to analyse both the collected data from the preliminary design decision preceding the construction stage and the results from the accident investigation. It makes the forecasting process more effective, with a collaborative consideration of information before the start of the construction process and the data gathered at the moment of occurrence and development of the emergency situation. The study seeks potential solutions for analyzing the lining of a shallow tunnel constructed according to the New Austrian Tunneling Method (NATM) after settlement occurs in a part of it. Variant numerical analyses have been conducted using SAP2000 and PLAXIS software, aiming to align model predictions with the actual effects observed during the accident, the measured displacements and settlements in the lining section. The registered measurements after the accident provide initial indications for a well-founded assumption regarding the causes leading to the destruction during the construction phase and the manifested settlements in the infrastructure elements. The presented analyses aim to simulate and trace the tunnel-ground interaction.