| At present,there is no corresponding maintenance specification for 250m radius sharp curve CWR(Continuously Welded Rail)track.It lacks the research on the range of rail maintenance temperature of CWR track for the sharp radius curve,and the theoretical and experimental basis is insufficient.This paper analyses the temperature range of maintenance and stability enhancement measure based on the research of the China Railway and the Beijing Railway Bureau which the author participated in and some 250m sharp radius curves of CWR laid.Through the theoretical analysis,test,field detection and monitoring,the study of rail temperature range of maintenance work and Stability enhancement measures for the sharp radius curve CWR track was carried out for 2 years.The finite element model of CWR track for the sharp radius curve under various conditions of maintenance is established,including replacing sleeper,respacing sleeper,large machine maintenance,track lifting,and track lining.Analysis of the effect of strengthening measures such as the replacement of the cross shaped sleepers,reducing sleeper spacing,the anchoring rods arrangement and so on are carried out.Based on the monitoring system of track condition of the test section,and a series of parameters of the CWR track for the sharp radius curve are analyzed.After replacing sleeper and machine maintenance,the geometries of the track in the test section are inspected,and the data of detection and monitoring are processed and analyzed.The main conclusions are as follows:(1)The finite element analysis of the CWR track for the 250m sharp radius curve shows that has the whole "respiration",which may weaken the ballast resistance to a certain extent.The difference of temperature force and radial force between 250m sharp radius curve CWR and 300m,400m and 800m radius curve are extremely small.(2)Compared with 400m radius curve specified in the Railway Line Maintenance Rules,the range of rail temperature of maintenance of continuously replacing two sleepers,respacing no more than four sleepers uncontinuously(in the way of replacing or respacing one by two intervals),large machine maintenance and track lifting all the way of the 250m sharp radius curve CWR,it is suggested to reduce the range of rail temperature 7℃,8℃,6℃,8℃,respectively.(3)Because of the structural characteristics,the replacement of the cross shaped sleeper plays an important role in improving the stability of the track.Under the normal ballast resistance condition,compared with the line of Type-Ⅲ concrete sleeper,the allowable temperature rise range is increased by 11.68%when the track is smooth,and the allowable temperature rise range is increased by 10.46%when the track is irregular.The effect of reducing sleeper spacing on the stability of the track will increase with the increase of the radius of the curve,but the effect is not obvious.The layout of the anchor rod is 5m/piece of the transition curve and 5m/piece of the circular curve,which will obviously improve the stability of the track,and its effect will increase with the decrease of the ballast resistance.(4)Through the on-the-spot monitoring data of the track state monitoring system,the lateral displacement of the sleeper is in the stage of elastic deformation.The base line of the displacement is stable.There is no worsening trend in the stability of the CWR;the parameters of track are not more than their respective safety limit value.The versine of curve measured shows that there is no phenomenon of track deformation exceeding the limit on most area of the test track after replacing sleeper and the large machine maintenance.The data measured by the instrument of track inspection showed that the alignment of the track kept good. |
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