Numerical analyses for the design of fiber reinforced precast concrete lining segments for ram thrust forces

Abstract: Fibre reinforcement is increasingly used in civil works to improve materials strength against brittle failure mode. In mechanized tunnelling, precast concrete lining design and reinforcement dimensioning is carried out according to various loading schemes covering to the entire service life of segments and rings. One of the most onerous load conditions is related to the longitudinal ram forces need to the TBM advancement, which determines a considerable amount of localized reinforcement. This paper describes the design of two sets of precast concrete lining of approximately 10m diameter which differ for segment geometry and number of rams. The paper highlights how the use of steel-fibre reinforcement against the ram thrust forces load can provide several advantages and economies, not just regarding TBM advance stage but also for production and logistic, i.e. easier production and assembly of the conventional reinforcement cage due to simpler geometry, and higher performance during handling and positioning.Fibre reinforced concrete, Constitutive model, Numerical simulation, Non-linear analysis.