SU1742389A1 - Method for restoring design state of stress of a string of welded rails for continuous welded railway track - Google Patents

Abstract

The invention relates to railway transport, in particular to the operation of a railway track. The aim of the invention is to improve the quality of restoring the calculated stress state of a rail scourge. After detecting a section with actual voltage deviations from the calculated value on the rail scourge and determining zones with stresses greater and less than the calculated values in this area, these zones are divided into sub-areas with different values of stresses. Subs 2–3 and 3–4, and Zone 4–6 on Sub Subs 4–5 and 5–6, weaken the rail connections of the section with the cross ties between sections 2–6. Then, the section between sections 2–4 is simultaneously heated, at the sub-section 2-3 by a larger amount than at the sub-section 3-4, and the section between sections 4–6 is cooled, and at the sub-section 4-5 by a smaller value, than on sub-site 5-6. In this case, heating is carried out in the direction from section 2 to section 4, and cooling in the direction from section 6 to section 4. As a result, not only the control section 4, but also sections 3 and 5 are returned to the initial position. 7 ill. k / b

Description

The invention relates to railway transport, in particular to the operation of the railway track.

The purpose of the invention is to improve the quality of restoration of the calculated stress state of the rail lash.

Figures 1, 3 and 5 show diagrams of stresses in a rail lash arising during its operation; in Fig.2 - diagram of stresses in the rail lash after cooling the zone between sections 3-5; figure 4 is the same, after heating the zone between sections 2-4; Fig.6 is the same, after simultaneous heating of the zone between sections 2-4 and cooling of the zone between sections 4-6; 7 is a diagram of the calculated stresses.

The method is as follows.

Rails welded in a whip by the electric contact method are fixed for continuous operation, for example, at a temperature of 20 ° C (taaxp = 20 ° C).

The change in the actual stress state of the rail lashes is controlled, for example, by the movements of the control sections 1-8 relative to the fixed benchmarks. The distance between the benchmarks can be selected with a certain step, for example 25 m. The next time the rail lashes were monitored, the following movements of the control sections were found.

On the first rail lash (Fig. ^ Section 3 moved towards section 2 by 6 mm (Alt = 6 mm), section 4 moved towards section 3 by 2 mm (Δ <2 = 2 mm) while maintaining the position of the remaining sections. at this time, for example, it is equal to 30 ^° C. (tp = 30 ° C.) Therefore, in the section of the rail lash between the control sections 2 and 3, the actual values of the compressive stresses exceed the calculated ones, and in the section 3-5 the actual values of the stresses are less than the calculated ones.

The calculated stress value is determined by the formula σ = 2.5 · Δί = -25 MPa, where Δ t is the difference between the lashing temperature and the actual rail temperature (Δΐ33κρ - Δΐ _ρ ),

The change in the temperature of fastening the rail lash in the areas between the control sections 2 and 3, 3 and 4, 4 and 5 is determined by the formula

ABm = - ^ -.

where Δ I is the amount of movement of the control section mm, in the direction of decreasing (-) or increasing (+) the distance between the sections;

a is the coefficient of linear expansion of rail steel, a = 0.0000118 1 / deg;

L is the length of the lash between the control sections, mm

Δ & Ί? ~ -20 ° C;

DS ~ 14 ° C:

Δ ~ 7 ° C.

The magnitude of the difference between the actual value of the stresses and its calculated values is determined by the formula - 2.5 · Δΐπ3Μ, 'σ ^ ³ ! = -50 MPa:

σ ³ ^! = + 35 MPa;

. <^ ⁵ l = +17.5 MPa; ''

Consequently, in the interval between control sections 2 and 3, the average stress value will be less than the calculated values and equal to

C2-s = (σ + 0¾ = -75 MPa.

In the section between control sections 3 and 4, the average value of actual stresses will be greater than the calculated values and equal to

0z-A = (σ + 0¾ ¹ ]) = +10 MPa.

In the section between control sections 4 and 5, the average stress value will also be greater than the calculated values and equal to σ4-5 = (σ + (Y ^ ⁵ !) = -7.5 MPa.

Thus, after identifying the movements of the control sections of the rail lash section with the actual deviations of the stresses from the calculated value and determining in this section two zones with voltages less than and greater than the calculated values, these zones are divided into sub-sections with different voltage values, if necessary (in this case, the zone 3-5 on sub-sections 3-4 and 4-5), weaken the ties of the rails of this section with the sleepers between sections 2-5. Then, the section is cooled between sections 3-5, and in this case, the temperature of the rails on the subsection 3 4 is reduced by a factor of 2 less than on the lodge

4-5, and the temperature change of the rails is made in the direction from section 5 to section 3. This ensures the return to the starting position not only of control section 3, but also. control section 4, i.e. increase the quality of restoration of the calculated stress state of the rail lash.

On the second rail lash (FIG. 3), section 3 moved toward section 2 by 2 mm, section 4 moved towards section 3 by 6 mm. while maintaining the position of the remaining sections. The temperature conditions are the same.

Using the above formulas, we find that in the section between the control sections 2 and 3, the average value of the actual stresses will be less than the calculated values and equal to «z = -42.5 MPa, in the section between the control sections 3 and 4 the average value of the actual stresses will also be less than the calculated values and equal to "s-4 = -60 MPa, and in the section between the control sections 4 and 5, the average value of the actual stresses will be greater than the calculated values and equal to" 4-5 = +25 MPa.

Thus, after identifying on the second rail lash a section of the rail lane with actual voltage deviations from the calculated value, determining zones with voltages in this section more and less than calculated values, dividing these zones into sub-sections with different voltage values (in this case, zone 2-4 sub-sections 2-3 and 3-4), weaken the connection of the rails of this section with the sleepers between sections 2-5. Then, the section is heated between sections 2-4, and in this case, the temperature of the rails in subsection 2-3 is increased by a factor of 2 greater than in subsection 3-4, and the temperature of the rails is changed in the direction from section 2 to section 4. Then they finish back to the starting position not only of control section 4, but. and control section 3, i.e. increase the quality of restoration of the calculated stress state of the rail lash.

On the third rail lash (Fig. 5), section 3 moved toward section 2 by 2 mm, section 4 moved towards section 3 by 6 mm. Section 5 moved towards section 4 by 2 mm while maintaining the position of the remaining sections. The temperature conditions of the rails are the same.

According to the above formulas, we find that in the interval between the control sections 2 and 3, the average value of the actual stresses will be less than the calculated values and equal to <7r-z = -42.5 MPa. in the section between the control sections 3 and 4, the average value of the actual stresses will be less than the calculated values and equal to (73-4 = -60 MPa, in the section between the control sections 4 and 5, the average value of the actual stresses will be more than the calculated values and equal to “4-5 = +10 MPa, and in the section between control sections 5 and 6, the average value of actual stresses will be greater than the calculated values and equal to 05-6 = -7.5 MPa.

Thus, after the identification of a section on the third rail lash with actual deviations of stresses from the calculated value and determination of zones with stresses in this section more and less than calculated values, the breakdown of these zones into subsections with different stresses (in this case, zone 2-4 into subsections 2-3 and 3-4, and zone 4-6 on the sub-sections 4-5 and 5-6), the rails of this section with the sleepers between sections 2-6 are weakened. Then, the section between sections 2–4 is simultaneously heated, and in this case, the temperature of the rails in sections 2-3 is increased by a factor of 2 greater than in sections 3-4, and the section between sections 4–6 is cooled, and in this case reduce the temperature of the rails in sub-section 4-5 by a factor of 2 less than in sub-section 5-6. In this case, heating is carried out in the direction from section 2 to section 4, and cooling is carried out in the direction from section 6 to section 4. This ensures that not only control section 4, but also control sections 3 and 5 are returned to their original position, i.e. increase the quality of restoration of the calculated stress state of the rail lash.

On all three rail lashes, the change in the temperature of the rails on the sections with large values of distortion of the actual stresses from the calculated values will be made by a smaller amount than on the sub-sections with lower values of the distortion of the actual stresses from the calculated values, which ensures safe work on the restoration of the calculated stress state of the rail lash jointless path.

As the control sections return to their initial position, the temperature of the rails of the corresponding sub-sections is stopped and the bonds of these sub-sections with the base are fixed. After the return of all control sections to their original position and fixing the corresponding zones with the base in the lashes there are still stresses that differ from the calculated values (figure 2, 4 and 6). As the temperature of the rails is equalized along the entire length of the lash, its actual stress state will correspond to the calculated values (Fig. 7).

Claims (1)

SUMMARY OF THE INVENTION A method for restoring a calculated stress state of a rail whip of a welded jointless path consisting in detecting a portion of a rail whip with actual deviations of its stress state from the calculated values. define zones with voltages higher and lower than the calculated values in this section, weaken the bonds of this section of the whip with the base, heat or cool the corresponding zones before setting the control sections in the calculated position, and fix previously weakened ties of the rails with the base, which is different from In order to improve the quality of restoration of the calculated stress state of the rail lash, zones with voltages of more and less than the calculated values are divided into sub-sections with different values of the voltage values, and change the temperature of the rails of the corresponding subsections by an amount inversely proportional to the actual deviation from the calculated stress value in the direction from the subsection with less distortion of the actual stresses to the subsection with large distortions of the actual stresses from the calculated values.