Analysis Of CWR Tram Track Stability With Sharp Radius Curve

The tram track structure is diversified,compared with railway and subway,the radius of the curve and vertical curve of tram track could be smaller.The minimum allowed curve radius of Code for Design of Railway Continuous Welded Rail is 300m,but the curve radius of tram can reach 30m.The minimum allowed vertical curve radius of Beijing Modern Tram Technical Standard is 300m under operating speed of 30km/h in difficult condition,far less than 2500m in Code for Design of Metro.Therefore,it is not possible to apply the regulation of CWR track,new study must be done on the tram.At present,there is no comprehensive research on the CWR tram track stability with sharp radius curve in China.Therefore,it is necessary to study the CWR track stability with sharp radius curve of various types of tram track.In this thesis,the finite element analysis method is used to establish the analysis model of the plane curve and the vertical curve,including the straight line,the transition curve,the circle curve and the vertical curve.The stress and deformation analysis,the lateral stability analysis and the vertical stability analysis of various types of tram track under temperature rise are carried out.Finally,according to the track stability analysis results,the proposed parameter range is obtained.The main conclusions are as follows:(1)Curve radius has a significant effect on the lateral stability of the CWR tram track,and the stability of rails decrease rapidly with the decrease of the curve radius.When the radius of the curve decreases from 300m to 30m,the maximum rail lateral displacement of ballast track,fastener embedded track,non-fastener embedded track,and rubber-tyred tram track increase by 4.8 times,8.6 times,10.9 times,and 8.3 times.(2)Curve radius has a significant effect on the axial compressive force of the rail if the curve radius is less than 100m,and the difference of the force between the middle of the curve and the straight line increases rapidly with the decrease of the curve radius.R=30m,the of the rail decreases by 15.16%for ballasted track,and the stress-free temperature has been increased by 4.49℃.The smaller radius curve,the greater reduction proportion of the axial compressive force of the rail,also there are greater impact on stress-free temperature.(3)The key factor that influent the lateral stability of the CWR tram track is lateral resistance of ballast bed for ballasted track,elastic modulus of filling material for non-fastener embedded track and rubber-tyred tram track,lateral stiffness of fastener for fastener embedded track.In order to ensure the lateral stability of the CWR tram track,we must pay attention to the corresponding key parameter’s value.(4)Under the same conditions,when the lateral stability of the CWR tram track can be ensured,the vertical stability can also be satisfied.But when the filling material fails,the vertical stability of the CWR tram track will decrease rapidly.The failure length of the filling material has a significant effect on the vertical stability of CWR non-fastener embedded track and rubber-tyred tram track.Therefore,it must be ensured that the filling material is within operating range in operation.