Rail track sleeper block schemes influences on rail bridge switch
In order to improve the lateral passing speed of the railway switch of the high-speed railway, engineers always adopts large railway turnout Numbers such as no. 38, no. 42 and No. 62. The lateral passing speed can reach 140 km/h, 160 km/h and 220 km/h. Relatively more, at present, no 42 railway switch application demand and its bifurcation area rail track sleeper buried type without a frantic jumble, and its length could be as long as more than 160 meters.
In this section, rail track sleeper and bridge (base) could be relative sliding, bridge road bed board and railway switch rail coupling each other and influence each other under the action of a temperature change and stress is complex, it is necessary to study its working principle under the temperature load bifurcation area without a frantic jumble ballast bed decorate the bifurcation a board bridge the influence law of longitudinal interaction, 42 to guide the bridge rail bifurcation area without a frantic jumble of ballast design.
Calculation parameters of Rail Track Sleeper
For example, a group of 60 kg/m no 42 track movable ballastless turnout is arranged on a (7 × 32.7) m continuous beam of a high-speed railway. The seamless railway turnout is 157.2m in length and located in the middle of the continuous beam. The distance between the head and tail of the railway turnout is 47m and 24m respectively from both ends of the turnout beam, and the fixed support of the turnout beam is 10 m in front of the theoretical turnout. The position arrangement of turnout, bridge and pier is shown in table. The fixed support of turnout beam is located in the front plate and the base of turnout center of turnout theory.
The sliding layer of "two cloth and one film" is laid between the turnout bed and the base. A certain number of longitudinal and transverse grooves are set on the base to limit the position of the pavement bed board. The rest of the sections are paved with CRTS 1 type double-block ballastless track and WJ 1 type 8 type constant resistance fasteners.
Structural parameters of no. 42 turnout can be selected according to figure No. "Passenger dedicated line (07) 006" turnout; Parameters such as turnout fastener resistance, turnout limiter and spacing iron resistance
Calculation Model of Rail Track Sleeper Block Plan
According to the design and the principle of interaction between beam and rail of bifurcation area rail track sleeper buried without a frantic jumble roadbed structure, the seamless without a frantic jumble rail bridge structure is regarded as a 3 layers structure of rail switch, bed board, the beam body, double block bifurcation area before and after the bridge without a frantic jumble orbit as a rail, the beam body composed of two layers of structure system, establish a integration model of "seamless rail turnout, rail track sleeper, bridge beam and piers".
|Check item||Rail Sleeper block plan|
|3 block||4 block||5 block||6 block|
|Maximum telescopic additional pressure of straight basic rail/kN||809.2||815.6||811.7||806.6|
|Maximum force of tip rail heel limiter/kN||0||0||0||0|
|Maximum force of spacer iron at wing rail end/kN||-111.7||-121.9||-117.6||-119.4|
|Longitudinal force of pier with fixed bearing of turnout continuous beam/kN||-2623.5||-2786.4||-2713.8||-2755.1|
|Maximum telescopic displacement of straight basic rail/mm||-22.9||-23.2||-23.0||-22.8|
|Straight tip rail tip relative to basic rail displacement/mm||-14.4||-13.7||-12.1||-11.8|
|Displacement of core rail tip relative to wing rail/mm||0.36||-0.32||0.02||-0.14|
|The maximum relative displacement between the basic rail and the bridge at the traction point of the switch rail/mm||-2.6||-2.5||-2.3||-1.2|
|Maximum relative displacement between the basic rail and the bridge at the core rail traction point/mm||-4.1||-0.5||-2.2||-1.4|
|Maximum force of transverse groove/kN||1912||1830||632||714|
|The maximum force groove corresponds to the number of the track bed plate (sequence from fork to fork)||Board 3||Board 4||Board 2||Board 3|
The rail fastener between 0 turnout and track bed plate is simulated with spring. The rail track sleeper and beam, beam and fixed pier are connected by spring, and the double-block ballastless track and beam anchor are connected. According to the technical conditions of elastic cushion rubber rail pad, the rigidity of rubber pad for transverse groove is 700kN/mm. Reference to specification for seamless railway line diagram design, frantic jumble rail bridge free day temperature 30 ℃, as railway jumble bed board located on the deck, and as a result of the box girder "greenhouse effect", the railway switch was frantic jumble that tao bedplate rise cool more than Bridges, so without a frantic jumble ballast bed temperature 35 ℃, in order to make the adaptability of this research is more wide, rail 45 ℃ heating or cooling rate; The span of each beam is an integral box beam, and the fixed pier stiffness of the turnout beam is 2× 100000 kN/m.
Impact of Ballastless Rail Track Bed Block Number
Considering the need of rail switch sensitive equipment, the length of rail track sleeper should be divided according to the switch area, guide curve area and frog area to ensure that all signal switch machine equipment is on the same rail track bed plate; Due to the equipment installation requirements of the point machine, the track bed board in the switch area needs to design multiple points machine connecting rod groove, which weakens the strength of cross section of the rail track bed. In order to reduce the stress concentration of the rail track bed and ensure the strength of the track bed, the transverse groove position should avoid the link groove area of the point machine. Therefore, the following 4 schemes are considered for the division of ballastless bed:
- Scheme 1: 3 rail track bed boards, with transverse grooves at the end of the track board in the point machine area and other track bed boards with transverse grooves in the board, each board is about 49.4m, 56.9m and 62.3m in length respectively (from the fork head to the fork tail, the same below);
- Scheme 2: 4 rail track bed boards, with transverse grooves at the end of the track bed board in the point machine area, transverse grooves in the guide curve area, and transverse grooves at the front of the other track bed boards, each board is about 49.4m, 56.9m, 36.5m and 25.8m long respectively.
- Scheme 3: 5 rail track bed board, the track bed board of switch and frog area sets transverse groove on the tail, the other track bed board sets transverse groove on the board, each plate is different. The length is 49.4m, 28.2m, 28.9m, 36.5m, 25.8m;
- Scheme 4: 6 rail track bed boards, the track bed boards in the point machine area are provided with transverse grooves at the end, and the other track bed boards are provided with transverse grooves in the board, each board is about about the length respectively 36.2m, 26.2m, 26.2m, 24.2m, 28.0m, 27.7m; The results of the four schemes are shown in Table 1.
It can be seen from Table that the number of blocks on the track bed plate has little influence on the maximum expansion displacement of the basic rail with additional pressure, the reason is that the railway turnout arrangement is far away from the continuous beam joint. The larger the number of rail track bed blocks, the lower the displacement of the straight rail tip relative to the basic rail track, the lower the displacement of core rail tip relative to the wing rail, and the lower the maximum relative displacement at the core rail - traction point, indicating that it is more favorable for the operation of the signal point machine.
The number of blocks of the pavement bed board has the greatest influence on the transverse groove stress, which can be reduced from 1,912 kN to the minimum of 632 kN, which is very beneficial to the groove stress and can also reduce transverse grooves number. Based on the analysis of various factors, it is reasonable to use 5 ballastless track bed boards for no. 42 railway turnout.
Influence of Transverse Groove Position on Ballastless Bed
The railway turnout area ballastless track bed board is divided into 5 pieces, and the transverse groove position is studied in the following 4 schemes:
- Scheme 5: The transverse groove of the rail track bed board on the switch and frog area is set on the tail, and the transverse groove of the other track bed board is set on the board;
- Scheme 6: The transverse groove of the rail track bed board on the switch and frog area is set at the head, and the transverse groove of the rest of the track bed board is set in the board;
- Scheme 7: The transverse grooves of the rail track bed board are all set in the board;
- Scheme 8: The transverse grooves of the rail track bed board in the point machine area are set at the end, and the transverse grooves of the other track bed board are set at the head, that is, all the transverse grooves of the track bed board are set at one end of the fixed support of the adjacent switch beam.
The Calculation Results of 4 Rail Track Sleeper Schemes
|Check item||Horizontal groove position|
|Scheme 3||Scheme 5||Scheme 6||Scheme 7|
|Maximum telescopic additional pressure of straight basic rail / kN||811.7||796.0||806.6||84.6|
|Maximum force of the tip rail heel limiter / kN||0||0||0||0|
|Maximum force of the spacer iron at the end of the wing rail / kN||-117.6||-121.8||-120.2||-122.2|
|Longitudinal force of turnout pier with fixed bearing of continuous beam / kN||-2713||-2810||-2770||-2789|
|Maximum telescopic displacement of straight basic rail/mm||-23.0||-22.2||-22.7||-23.1|
|Displacement of straight tip rail relative to basic rail/mm||-12.1||-13.5||-12.6||-11.6|
|Displacement of core rail tip relative to wing rail/mm||0||-0.3||-0.2||-0.3|
|Maximum relative displacement between the basic rail and the bridge at the traction point of the switch rail / mm||-2.3||2.2||-1.0||-2.3|
|The maximum relative displacement between the basic rail and the bridge at the core rail traction point / mm||-2.2||-0.8||-1.4||-0.4|
|Maximum force of transverse groove N||632||378||622||1825|
|The maximum force groove corresponds to the number of the track bed plate (sequence from fork to fork)||Board 2||Board 1||Board 5||Board 5|
In scheme 8, the transverse grooves bear the largest force, indicating that the transverse grooves are arranged in accordance with the fixed support of the adjacent continuous beam, which is not favorable for the grooves to bear the force, so the number of transverse grooves should be increased. Schem 5 and 3, the results are mostly the same, Scheme 5 tongue rail, rail heart towing point maximum relative displacement of basic rail and bridge is smaller , which is advantageous to the signal of the switch machine operation, but as the railway switch and the frog area possessed transverse grooves in board, switch machine in weak link rod groove area, stress concentration has weakened roadbed section strength. Based on the analysis of all factors, it is reasonable to choose according to scheme 3, which is to set transverse groove of 5 ballastless track bed board at No. 42 switch.
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