Dopravní stavby - Fakulta stavební - Vysoké učení technické v Brně

4812th International Scientific Conference, April 20-22, 2009 Brno, Czech RepublicThe Planá nad Lužnicí test track sectionThe second test track section is with the turnout J60-1:12-500-I. The aim is to verify a stability ofthe long bearers with under sleeper pads. A longitudinal level of the track section is assessed. The testtrack section has been constructed in the Planá nad Lužnicí railway station in 2007. The assembly of theunder sleeper pads for the turnout has been designed by a mathematical model [6].Transition zones which allow a smooth transition of a vertical track stiffness between the track withunder sleeper pads and the track without under sleeper pads have been designed. The total length trackwith under sleeper pads is 205 m. The neighboring turnout was chosen as a comparative conventionaltrack section.Discrepancies between the assembly design of under sleeper pads and its execution have beenfound out after a laying of the turnout. These discrepancies have been repaired.Summary of tests and observed parametersLongitudinal levels of the tracks are monitored through a precise levelling. Vertical deflections ofthe track skeletons are measured through displacement sensors. The vertical deflections of rails andsleepers are measured and their relative displacements are calculated. Vibrations of railwaysuperstructure elements and a transfer to a track vicinity are measured according to “A measurementmethodology and a measurement evaluation of vibrations from railway traffic“.Measurements of the longitudinal levels, the vertical deflections both of rails and sleepers and thevibrations have been carried out in the Havlíčkův Brod – Okrouhlice test track section in 2008.The measurements of the longitudinal levels have been were on the 4th of April before the test tracksection repair, on the 11th of April after the repair (only the part with under sleeper pads), on the 17th ofOctober before third tamping and on the 14th of November after the third tamping in the Planá nadLužnicí test section. Furthermore the vertical deflections both of rails and sleepers and the vibrationshave been measured.The Havlíčkův Brod – Okrouhlice test track section was devalued after a year of its observation. Atamping of this section was carried out without a previous notice.The measurement descriptionThe displacement sensors were installed on both sides of each rail foot and at four points of asleeper (on the sleeper ends and in its thirds) in the observed profile.Acceleration transducers was placed on a track skeleton (rails and sleeper) and on measuringpickets which have been beaten in appropriate monitored places. The profile between a cut and anembankment has been chosen in the Havlíčkův Brod – Okrouhlice test section. Two profiles in acommon track have been chosen in the Planá nad Lužnicí test section.The evaluationTrack settlementsA settlements observing of the test tracks with under sleeper pads is the main target of thelongitudinal levels of the tracks monitoring. The settlements of the tracks with under sleeper pads arecompared with the settlements of the comparative track sections (the track section with the turnout no.11 or the section with the rail fastening E 14). Rail levels have been monitored. The elevations are in arelative altitude system. Relative deviations from the optimized track position at the beginningobserving have been calculated.The track level deviations move from +20 mm to -30 mm in the Havlíčkův Brod – Okrouhlice testsection. The greatest deviations are in the area of both superelevation ramps. The transition zones ofboth bridges haven’t became evident along the longitudinal track levels. The track settlements areuniform till this time. The settlement is at the most 8 mm against the starting position (excepting onepoint with the deviation 12 mm).