DEVELOPMENT DESIGN AND TESTING OF A NEW LOW MAINTENANCE HIGH FIXITY TRACK FORM FOR RAILWAY TUNNELS

摘要

There is an immediate demand for low maintenance high fixity track forms in the UK and elsewhere. Historically concrete based solutions have been used to provide low maintenance, high fixity track. Modern geocomposites can offer an alternative to concrete by creating a reinforced ballasted railway track. This paper presents the measured horizontal and vertical deflection and settlement results of full scale modelling and testing of a geocomposite railway track. The measurements were recorded under laboratory conditions, using the GRAFT II (Geopavement and Railways Accelerated Fatigue Testing) facility. A full scale model representative of the conditions found in Toadmoor Tunnel was designed and built for the modelling. The testing replicated 25 tonne axle loads at 80mph on 1200m radius track with 55mm cant, for 11 million cycles. The geocomposite track is observed to provide levels of fixity normally associated with concreted slab tracks. The effect of high dynamic wheel loads associated with wheel flats on the track structure is observed. The free draining properties of the geocomposite are also highlighted. The paper comments on the drivers for such an approach and the potential use in the UK.