JPS5933721B2 - Track construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a track construction method in which an injection layer is placed between track sleepers and the track bed, and when a construction method is used in which the injection material is injected in a heated state, the cooling rate of the heated injection material is accelerated and the This relates to a construction method for shortening the time required for track construction.

BACKGROUND OF THE INVENTION In recent years, as the amount of railway transportation has increased, the amount of trains passing has also increased, and as a result, the frequency of track maintenance work, especially the track bed, has increased.

On the other hand, as the number of trains passing increases, the time required for track maintenance work becomes shorter, so there is a need for a track system that can save labor during track maintenance work.

That is, methods such as replacing the conventional ballast trackbed with a concrete trackbed or integrating the ballast trackbed are being considered.

The purpose of the present invention is to provide a new track system in which a layer of injected material is placed between track sleepers and the trackbed, unlike such improved trackbeds, by a construction method in which the injected material is injected in a heated state.
The aim is to shorten the time required for its construction.

The injected material in this track structure evenly disperses various stresses caused by passing vehicles transmitted through the sleepers to the trackbed, which is the lower structure, and at the same time absorbs as much vibrations transmitted through the sleepers as possible to the trackbed. It is possible to reduce the impact force of the road, protect the trackbed, reduce the wear and tear of crushed stones, and extend the cycle of track maintenance work.

The above-mentioned injection material is required to have the following physical properties.

That is, it is undesirable if the sleeper deforms more than necessary throughout the year in response to the compressive stress transmitted through the sleeper, and on the other hand, if the sleeper is too hard, it will not be able to absorb vibrations sufficiently.

Furthermore, when injecting the material between the sleepers and the track bed, it is difficult to inject the material between the sleepers and the track bed unless it is liquid.

Therefore, there is a need for a material that is liquid during operation, strong after hardening, less deformed by various stresses, and has good vibration absorption properties.

On the other hand, when adopting this track system for newly constructed tracks, it is often possible to take sufficient work time, but when switching to this track system for existing commercial line tracks, extremely difficult problems are encountered. .

In other words, when switching a commercial line to this track system,
Construction work must be carried out within an extremely short period of time, from when the last train passes until the arrival of the first generating car.

Although it varies depending on the line, the work time is generally only about four hours, especially on lines near urban areas that require improved track.

In such a short period of time, the work involved removing the existing rails and sleepers, adjusting and maintaining the track bed surface, bringing in new sleepers and rails,
Adjustment of each location, level, and injection of injection materials must be carried out reliably.

Furthermore, the time required for these construction operations includes not only the operation time required for each of these operations but also the solidification time of the injection material.

In other words, the injection material is liquid and solid when injected, but it is useless as an injection material unless it solidifies after injection.

Therefore, the time required for the injection material to solidify after injection and achieve the required strength must also be considered as the construction work time.

Considering the case where the injection material used is injected in a heated state, if the injection material is thermosetting, the injection temperature should be 10% lower than the injection temperature after injection.
Even if the temperature drops by about 20°C, there is no particular problem as long as it has the required strength, but even if it is a thermosetting injection material, for example, if it has not been sufficiently cured, the temperature of the injection material will be high. In order to put these materials into service, the injected material must be cooled to a temperature at which strength is obtained.

Furthermore, when a thermoplastic material is injected as an injection material at a high temperature, it must be cooled to a temperature at which it solidifies and attains a predetermined strength.

This cooling time actually occupies a very large part of the track construction work, and shortening this cooling time has been found to be an important factor in improving construction speed. Regarding construction T method, for example, there is a method of promoting cooling of the injection material by flowing a coolant etc. after injection of the injection material into a small diameter metal pipe installed in advance in the part that will become the injection layer, or a method of mixing metal pieces into the injection material. Experiments were conducted on various cooling methods, including methods to improve the heat conduction of the injected material.

As a result, if the heated injection material is sprinkled between trackbeds and sleepers to make it wet, if it is sprinkled on the top of the track after injection, or if both are used together, all of these waterings are It became clear that the temperature of the injection material decreased rapidly compared to the case where no injection was performed, and the cooling effect of water spraying was significant.

Therefore, it has been found that applying these cooling methods to orbit construction will result in a new orbit construction method that shortens orbit construction time.

Therefore, an object of the present invention is to construct a track by sprinkling water on the trackbed and sleepers before injecting the heated injection material, and/or by sprinkling water on the sleepers after pouring the heated injection material, in a track construction method in which a layer of injected material is placed between the sleepers and the track bed. The objective is to provide a new trajectory construction method that saves time.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows a sectional view of an embodiment of the present invention, and FIG. 2 shows a plan view of the same.

1 is a sleeper, and 2 is a trumpet-shaped inlet for injection material provided in the sleeper, with the upper end being a circle with a diameter of 8 cm, and the lower end being a circle with a diameter of 6 cm.

3 is an injection layer, 4 is a rail, and 5 is a ballast track bed.

FIG. 2 is a plan view of FIG. 1, in which the fastening device 6 also serves as a washer for the rail and fixes the rail to the sleeper.

Sleeper 1 is 2 m long, 73.3 cm wide, and 10 cm apart between sleepers.
m, and the average thickness of the sleepers is approximately 16 cm.

The thickness of the injection layer 3 is approximately 3 cm.

Track bed 5 is made of No. 6 crushed stone (approximately 12 m in diameter) after compacting the ballast track bed.
m) was spread and rolled.

The heated injection material is injected from the injection port 2, and the level of the injection material at the injection port after cooling and solidifying is approximately 10% higher than the top surface of the sleeper.
It was cm.

In order to understand changes in the cooling temperature of the injected material, a thermocouple was inserted from the top of the injection port, and the temperature sensing part was set at a position between the track bed surface and the lower surface of the sleeper at the injection port.

The injection material used was a thermoplastic material, and the injection material was heated to 180°C.

The temperature reading at the temperature measurement point immediately after injection was approximately 160°C, but this is due to heat exchange with the track bed or sleepers, which is about 2.
It is thought that the temperature dropped by about 0℃.

Figures 3 and 4 show how the temperature of the injection layer changes after the injection.

FIG. 3 shows actual measured values of the temperature change of the injection layer under cloudy weather and an air temperature of -2°C, and FIG. 4 shows actual measured values of the temperature change of the injection layer under cloudy weather and an air temperature of 10°C.

Both were made when the Japan National Railways main line switching work was carried out, and the injection materials, injection temperature, and type of improved track are exactly the same.

As is clear from comparing Figures 3 and 4, in Figure 3, which was carried out on a cloudy day, it took 112 minutes for the temperature of the injection layer to drop from 160 °C to 60 °C immediately after injection. In the case of a rainy day shown in Figure 4, the time required for the injection temperature to drop from 160°C to 60°C immediately after injection was 34 minutes, which was more than an hour.

Regarding the difference between the two, the amount of heat from the injected material injected at high temperature evaporates the water adhering to the crushed stones on the road bed, and is replaced by the latent heat of vaporization of the water. The transferred heat also transfers as heat of moisture evaporation to various parts of the trackbed, so the temperature of the trackbed becomes lower than when there is less moisture, and therefore the temperature of the injection layer is cooled more quickly.

Also, regarding the sleepers that are in contact with the upper side of the injection layer,
The temperature of the sleeper rises as the sleeper comes into contact with the high-temperature injection material on the bottom surface, but since there is water on the top surface of the sleeper, the heat transferred to the sleeper is easily removed by the heat of moisture evaporation on the top surface of the sleeper, and the temperature of the sleeper increases. Since the injection layer is cooled more quickly than when there is no moisture, the temperature of the injection layer also decreases more quickly from the top.

In this way, according to the present invention, five injection materials are placed between the track bed and the sleepers.
In the method of injection in a heated state of 0°C or higher, the track bed and/or sleepers are sprinkled with water before the heated injection material is injected, or the top of the sleepers is sprinkled with water after the heated injection material is injected. If only one method is applied, the cooling rate of the heated injection material will be accelerated, the time required for track construction will be shortened, and the amount of work per day can be increased.

Even when this track system is adopted for newly constructed tracks, using this water cooling promotion method will help reduce work time.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of an embodiment of the present invention, Fig. 2 is a plan view of Fig. 1, Fig. 3 is a graph showing the temperature change of the injection layer in cloudy weather, and Fig. 4 is the injection layer for weather use. 2 is a graph showing temperature changes. 1...Sleeper, 2...Material injection port, 3.
...Injection layer, 4...Rail, 5...
・Ballast, 6...Rail fastening device.

Claims (1)

[Claims] 1. In the track construction method in which a layer of injection material is placed between the sleepers and the track bed, water is sprinkled on the track bed and sleepers before the heated injection material is injected, and water is sprinkled on the top of the track after the heated injection material is injected. A track construction method characterized by shortening the time required for track construction by performing at least one water sprinkling.