Pierre Breul

Numerical modelling of the deterioration of the Parisian metro infrastructures based on a new auscultation method

Abstract Many underground transport systems have aged and need heavy maintenance. Most of these tunnels have been affected by diverse weathering processes that have led to superficial or deep deterioration of the structure. To schedule maintenance operations, managers of these infrastructure networks need to assess the current state of tunnels. However, current diagnostic methods are mainly based on visual observations that cannot completely characterise the current state of these structures and predict the kinetics of degradation and its effect on the structural behaviour over time. In this context, we propose a methodology designed to obtain a state of deterioration of infrastructures and their evolution over time by integrating different parameters into the geometry of the tunnels and the value of the mechanical parameters of each zone (tunnel components and the ground). A numerical modelling procedure based on the parameters derived from a new methodology for auscultation is used to highlight the most damaged areas, which can disrupt the stability of the underground structures. The instantaneous decrease in the mechanical parameters of galleries is considered (from the initial state) to reproduce different states of alteration displayed on different surveys. Several scenarios are proposed to indicate the possible degradation observed on this underground.