Preliminary Study On Laying Technical Index Of Rubber Isolation Layer Of CRTSⅢ Type Ballastless Track On Bridge

The development and application of ballastless track on long-span bridges has become an important measure for technological innovation of high-speed railways in my country,and has been successfully applied on long-span cable-stayed bridges ranging from 300m to 350m.However,there is a lack of in-depth research on the laying conditions of the rubber isolation layer.In this regard,based on the type of CRTSⅢ ballastless track,this paper adopts the finite element numerical method to analyze three bridges with different spans and structural types,and compares the geotextile isolation layer and the rubber isolation layer.To explore the technical conditions for laying the rubber isolation layer of the CRTSⅢ ballastless track of the long-span bridge.The main contents and achievements are:1)A 32m double-track standard simply supported box girder bridge-track finite element model of ballastless track slab with geotextile isolation layer and 0.05N/mm~3,0.10N/mm~3,and 0.15N/mm~3 rubber isolation layers with different body stiffness was established.The deformation compatibility between various ballastless tracks and beams under the action of load combination is compared and analyzed.2)The unit models of the main span 2×90m arch-bearing tower cable-stayed bridge and the main span 300m composite cable-stayed bridge were established respectively,and the most unfavorable local flexural deformation and load conditions in typical intervals such as the cable interval were analyzed.3)Refined finite element models of arch-bearing tower cable-stayed bridge-track and composite cable-stayed bridge-track were established.the beams under various load combinations of ballastless tracks using geotextile isolation layers and the above-mentioned rubber isolation layers with different body stiffnesses-deformation coordination between rails were analyzed.4)For the above three ballastless track bridges,the axle load loading mode of the operating train is adopted,combined with other unfavorable load conditions,and the local flexural deformation characteristics of the beam body along the bridge direction and the void volume between the slabs of the ballastless track of different isolation layers are compared and analyzed.The applicability of geotextile isolation layer and rubber isolation layer is analyzed based on the local deflection deformation of the main beam plate length and the local deflection rate of the main beam plate length proposed in this paper.The results show that the rubber isolation layer has better beam-rail deformation coordination than the geotextile isolation layer.5)Considering the economy and the difficulty of construction,the technical conditions for the rubber isolation layer to be laid on the CRTSⅢ ballastless track bridge are proposed:the construction error is controllable;the deflection-span ratio is less than 1/800;The local deflection rate of m plate length is greater than 1/12500 and 1/15000 respectively,and the local deflection rate of plate length when the main beam is bent downward is greater than 1/9000.The thesis includes 56 figures,31 tables,and 77 references.