中国铁路中国铁路发现 (8).ppt

CWR Track and New Type Sub-rail FoundationCWR Track and New Type Sub-rail FoundationCWR tracksTemperature stress typeTemperature stress relieving typeCWR Track and New Type Sub-rail FoundationTemperature stress typeNon-breathing zone:The inextensible part in the middle of a long rail,which shall be not less than 50m longBreathing zone:The part at each end of a long rail extending/contracting in a certain range along with the change of rail temperature,which is typically 50-100m longBuffer zone:The part consisting of 2-4 standard rails or factory-made shortened rails,and serving as a transition section connected with the next long rail or turnoutWelded long railWelded long railNon-breathing zoneNon-breathing zoneBreathing zoneBreathing zoneBuffer zoneCWR Track and New Type Sub-rail FoundationTemperature stress relieving type CWR tracksAutomatic relieving typeRegular relieving typeCWR Track and New Type Sub-rail FoundationAutomatic relieving typeMainly used for super major bridgesWith the temperature expansion joints at both ends of the rail bar,for relieving the temperature stress from time to timePreventing the pier and abutment from bearing large temperature stressCWR Track and New Type Sub-rail FoundationRegular relieving typeMainly used in areas with large temperature differenceThe temperature stress inside the rail shall be adjusted once or twice a year according to the local rail temperatureCWR Track and New Type Sub-rail FoundationBroad concrete sleeperAdvantagesTypically laid in densely arrangement to cover almost the entire top surface of the trackbedNeat and aesthetic appearancePreventing the trackbed from being contaminated,so as to keep it cleanLower compressive stress on the trackbed,resulting in smaller deformation of the trackbed and more stable trackLower workload of track maintenanceCWR Track and New Type Sub-rail FoundationDisadvantagesDifficulties in repair in case of bleeding subgrade or trackbedLack of supporting repair machines and toolsTendency of longitudinal cracking and crazing of the sleepers in case of uneven stressMainly used in stations,yards and long tunnelsBroad concrete sleeperCWR Track and New Type Sub-rail FoundationBallastless trackHigh stabilityHigh smoothnessLower workload of maintenance and repairLonger service lifeNeat and aesthetic trackAdvantagesCWR Track and New Type Sub-rail FoundationHigher requirements for deformation control of the foundationVulnerable track structure,which is difficult to repair once damagedRelatively high investment in the early stageMainly used in tunnels and for HSR linesBallastless trackDisadvantages