JPS6024243B2 - Roadbed mud spray prevention method on railway tracks - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a construction method for forming an impermeable layer for preventing counterfeiting on the surface layer of a railway track bed.

In recent years, with the speeding up of railway transportation and the increase in the number of passing weight vehicles,
Subgrade mud, which causes the track level to sink and impedes track function, has become a major problem for track maintenance. Roadbed mud phenomenon is a phenomenon in which muddy substances in the roadbed are ejected into the gaps between ballasts in the ballast roadbed, especially when a train passes by.The causes of this phenomenon include poor drainage of the roadbed and roadbed, and the quality of its materials. There are many factors involved, including the cause of the problem, but the most important cause is that the roadbed surface layer becomes muddy (slurry) due to rainwater that accumulates due to poor drainage and groundwater that rises. Therefore, preventing the roadbed surface layer from becoming muddy leads to preventing the roadbed sludge phenomenon, and for this purpose, it is necessary to provide a water-blocking layer on the roadbed surface layer. Figure 1 shows a cross-sectional view of a railway track in which the subgrade method has been used to prevent the muddying phenomenon of the roadbed. 1 is the roadbed, 2 is the drainage layer formed on the surface layer of the roadbed, and 3a and 3b are the drainage layers formed on both sides of the roadbed 1. The drainage ditch has drainage holes 3, and the drainage layer 2 and perforated drainage ditches 3a, 3b are for draining groundwater inside the roadbed 1.

The surface layer of the roadbed 1 has a slope of 3/100 or more to accommodate drainage of rainwater within the roadbed 6. Reference numeral 4 denotes a water-blocking sheet with a protective layer 5 for preventing rainwater from entering the roadbed 1, and is laid on the drainage layer 2.

Reference numeral 6 denotes a trackbed provided on the water-blocking sheet 4 with the protective layer 5, and sleepers 7 and seals 8 are laid on it.

Conventionally, the impermeable layer is in the form of a sheet, so it is damaged by the biting of pebbles in the road bed 6, making it impossible to maintain the impermeable layer, which not only lacks the mud blowing prevention effect and the durability of this effect, but also damages the surface layer of the roadbed 1. Since the water-shielding sheet 4 is laid in the area, the ballast of the roadbed 6 must be removed to prevent mud from forming on the roadbed of the existing track, which is disadvantageous in terms of economy and construction.

In addition, styrene maleate/
There is also a method of forming soil particles that are difficult to turn into mud on the roadbed surface using styrene itaconate copolymer, etc., but this method does not have a durable water-shielding effect under conditions such as the caustic vibrations of the trackbed. You can't get it.

The present invention solves the above-mentioned drawbacks and provides a roadbed counterfeit mud prevention method that is excellent in mud prevention effect and durability, is economical, and is easy to implement. First, the gist of the construction method of the present invention will be explained with reference to FIG. 2.
A undiluted solution of hydraulic urethane resin or a dispersion of water added thereto is injected or sprayed into gravel, etc., and permeated or mixed, and the water contained in the gravel or newly added water causes a hydraulic reaction. A roadbed for railway tracks, characterized in that a continuous water-blocking layer (consolidated layer) 9 having elasticity and having a desired thickness with good water-blocking properties is formed on the surface layer of the roadbed 1 by causing This is the correct method for preventing lanterns.

The hydraulic Witan resin stock solution used in the present invention is mainly composed of a polyurethane compound that has good affinity for water and has the property of curing by reaction with water.
Its composition consists of a urethane prepolymer obtained from a polyisocyanate compound and a polyether polyol compound, and a polyisocyanate compound.

Polyisocyanate, which coexists with urethane prepolymer, is important for producing crosslinked gel by hydraulic reaction, and is used in large excess than the equivalent amount when reacting polyether polyol compound and polyisocyanate to obtain urethane prepolymer. It may be left as an unreacted component by adding it to the urethane prepolymer, or it may be further added after obtaining the urethane prepolymer, as long as it is present together during the hydraulic reaction with water.

In the present invention, a polyether polyol compound is particularly used because the ether bonds in the main chain of the urethane resin tend to form a hydrated gel in the surface layer due to the action of water, and this gel is subjected to loads from railway tracks. This is because it is suitable for forming a durable water-blocking layer that is particularly resilient to special conditions such as gravity and vibration of trains.

Further, the urethane resin stock solution may be mixed with a solvent if necessary, and the urethane resin stock solution may be mixed and dispersed in water when used at a construction site.

Considering the workability during construction and the strength of the formed water-blocking layer 9, it may be composed of 60 to 9% by weight of urethane prepolymer, 1 to 2% by weight of polyisocyanate compound, and 0 to 2% by weight of solvent. preferable.

The solvent is preferably one with high solubility in water in order to make contact between the urethane resin and water efficient. If the polyisocyanate compound exceeds 2% by weight, it will sufficiently penetrate into the surface layer of the roadbed 1, that is, the gelation rate will become too fast, making it difficult to obtain a water-blocking layer of desired quality or thickness. Waterproof performance and strength against train weight are poor. On the other hand, if the amount is less than 1% by weight, gelation is insufficient for use in railway track roadbeds, making it difficult to obtain a stable impermeable layer and resulting in insufficient strength against train weight. If the weight percent of solvent 2 is exceeded, when the urethane resin stock solution is used by directly permeating into the roadbed, the permeability to soil, gravel, etc. is too high, making it difficult to obtain a stable water-blocking layer, and the strength against the train weight is insufficient. do. Furthermore, when using such a urethane resin stock solution dispersed in water, the contact efficiency between water and the urethane resin will not be further improved even if the solvent exceeds 2% by weight, so 2% by weight is sufficient. It is. In the present invention, the polyisocyanate compound is a compound having two or more isocyanate groups, and examples include tolylene diisocyanate, difunylmethane diisocyanate, diphenyl diisocyanate, naphthalene diisocyanate,
Polyhydric isocyanates such as xylylene diisocyanate, hexamethylene diisocyanate, triphenylmethane triisocyanate, tetramethylene diisocyanate, cyclohexane diisocyanate, methylene bis(cyclohexyl isocyanate), and phenylene diisocyanate may be used alone or in mixtures.

A polyether polyol compound is a compound having a primary mirror formed by an ether bond and having two or more hydroxyl groups, and preferably has a molecular weight of 1,000 to 20,000.

Examples include ethylene glycol, glycerin, trimethylolpropane, trimethylolethane, diethanolamine, triethanolamine, bentaerythritol, solpitol, seuclose, methyl glucoxide, propylene glycol, hexanetriol, and maleic acid, fumaric acid, It can be obtained by adding polyol-modified castor oil, tall oil, etc., or alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, etc. singly or in combination. The affinity of the urethane resin for water can be controlled by using alkylene oxides having 3 or more carbon atoms alone or in combination. The urethane prepolymer is prepared by mixing a polyether polyol compound and a polyisocyanate compound weighed so that the number of isocyanate groups is in excess of the hydroxyl groups of the polyol, and the mixture is typically 30 to 120 qo.
It is produced by reacting at a temperature of 30 minutes to 7 days. As a result, free polyisocyanate compounds can remain. Catalysts such as tertiary amines and metal anchors may be added as necessary during production. Suitable solvents are those that have no activity against isocyanates and have high solubility in water; examples include methyl ethyl ketone, ethyl acetate,
- A water-dropping solvent for urethane such as butyl lactone, tetrahydrofuran, etc. alone or as a mixture.

In the method of the present invention, auxiliary agents may be added for the purpose of controlling the curing time in consideration of workability during construction, such as organic chlorides such as ethyl chloride and benzyl chloride, These include curing retarders such as slip-off surfactants and isocyanate masking agents such as phenol, diketone, and acidic sodium sulfite, alone or in combination, and curing accelerators such as tertiary amines and organic tin compounds.

The hydraulic urethane resin of the present invention has a large liquid permeability coefficient and good permeability into soil, gravel, etc., and is particularly suitable for use in pongee granular soils such as areas where mud is generated, and does not react with moisture in the soil. The formed impermeable layer 9 prevents rainwater from entering the roadbed 1 and has a small deformation coefficient compared to its compressive strength (i.e., has elasticity). This not only helps to alleviate vibration propagation, but also strengthens the roadbed by forming it to a desired thickness to withstand an increase in the tonnage of passing trains. This is to prevent counterfeiting over a long period of time.

Next, a typical construction method of the present invention will be illustrated.

The portion where the water-blocking layer 9 is formed by a hydraulic reaction is common to each construction example, so it will be omitted.

The first construction example is a method of inserting an injector such as a funnel from the trackbed surface until the nozzle tip reaches the surface layer of the roadbed 1 without removing the trackbed 6, and then injecting a dispersion of hydraulic urethane resin. .

In order to improve the permeability of the hydraulic urethane resin dispersion to the earth and sand on the surface of the roadbed, it is recommended to perform pre-treatment to loosen the layer to be treated and increase the void ratio using a vibrating rope sander, etc. prior to installing the injection machine. . In this method, the concentration of the hydraulic urethane resin dispersion is between 3 and 4% by weight, preferably 5% by weight.
It is preferable to set it to 2% by weight.

That is, if the concentration is less than 3% by weight, the concentration of the resin component will be too low and a hydrated gel will not be formed, and if the concentration is more than 4% by weight, the viscosity of the dispersion will become high and penetration will be insufficient. It is. This method can be applied to places where the roadbed is sunken into the roadbed surface layer, or where the roadbed surface layer is sandy and has relatively good water permeability, and the equipment is simple and there is no need to remove the roadbed. It is characterized by points.

In the second construction example, a vibrating injection machine is used from the surface of the road bed 6 to insert the tip nozzle to a depth that reaches the surface layer of the road bed 1, and while injecting the hydraulic urethane resin stock solution, it is inserted into the surface layer of the road bed 1. This is a method of mixing. The vibration-type injection machine may be a known one, and vibrates the hydraulic urethane resin stock solution and water in the hydraulic urethane resin stock solution tank and water tank through hoses using a urethane pump and a water pump, respectively, using a vibrator. It has a structure that allows it to be injected from the nozzle of the vibrating part. As the vibrator, either one that generates vibration, such as a titan bar, or one that generates both vibration and rotation, such as a hammer drill, may be used.
It is preferable that the vibrating part be shaped like a spade, such as the tip of a titan bar, or shaped like the tip of a drill, from the viewpoint of workability and mixing effect. Regarding the nozzle structure, either a system in which the hydraulic urethane resin stock solution and water are mixed near the outlet at the tip or a system in which the hydraulic urethane resin stock solution and water are mixed immediately after exiting from independent exits may be used. In the case of this method, the mixing ratio of the hydraulic urethane resin stock solution and water is such that the concentration of the hydraulic urethane resin stock solution is in the range of 3 to 9% by weight, preferably in the range of 10 to 3% by weight, considering workability and effectiveness. It is desirable to set it as follows. If it is less than 3% by weight, the permeability to earth and sand becomes too high, and there is a great possibility that it will escape along the slope of the roadbed outside the area where the impermeable layer is to be formed.

When the amount exceeds 9% by weight, the viscosity of the mixed liquid increases,
Permeability into soil and sand may decrease.

The amount of hydraulic urethane resin stock solution to be used needs to be set at the optimum value depending on the properties of the person to be treated, but it is usually 2 to 6 days per day.
The water-blocking layer 9 can be formed to have a thickness of 5 mm or more.
This method is suitable for soils in which natural penetration of the hydraulic urethane resin dispersion is difficult due to reasons such as the subject being treated is a viscosity engineer, or the soil has a high water content.

In the third construction example, after the roadbed 6 is removed, a hydraulic urethane resin stock solution or dispersion is sprayed on the surface layer of the roadbed 1, and the hydraulic urethane resin stock solution or aqueous solution is mixed with the roadbed surface layer in a concentrated manner to block water. This is a method for forming layer 9.

In this case as well, the amount of the hydraulic urethane resin stock solution used is approximately 2 to 6 m/m. In this construction method, mixing the hydraulic urethane resin stock solution or dispersion with the subgrade surface layer requires a small treatment area;
For large areas, it is convenient to use a manual mixer, and for large areas, it is convenient to use a mechanical mixer such as a stirrer or cultivator.

Also, if the subgrade soil is thoroughly loosened before mixing, it will be easier to form a homogeneous impermeable layer. Although this construction method requires additional work to remove the road bed 6 compared to the first and second construction examples, it is possible to form a water-blocking layer even on roadbeds where the permeability of the hydraulic urethane resin stock solution and dispersion is extremely poor. This is a feature. Fourth
In the construction example, after replacing the surface layer of roadbed 1 with crushed stone, a hydraulic urethane resin dispersion is sprayed on this surface layer and allowed to penetrate.
This is a method of forming a water-blocking layer 9. As for the crushed stone, if you use one decorated with on-site generators, 0 to 40 grain size crushed stone, or a single grain size stone of about 6, either alone or in combination, the hydraulic urethane resin stock solution can penetrate well and form a water barrier. The performance of the layer is also good. The suitable concentration of the hydraulic urethane resin stock solution to be sprayed is 3 to 3% by weight, preferably 7 to 2% by weight. In addition, when spraying hydraulic urethane resin liquid, if the area to be treated is small, it is easy to mix the undiluted solution and water in a funnel-type container, or if the area is large, use an automatic metering type metering pump to spray the undiluted solution. It is convenient to use a device that discharges undiluted solution and water at a fixed ratio, and uses a tip nozzle to mix and spray the undiluted solution and water. In this construction method, the roadbed 6 sinks into the surface layer of the roadbed 1, and is firmly consolidated by the roadbed ±.
Alternatively, it may be applied in cases where natural permeation of the undiluted solution and mixing with the undiluted solution are difficult due to the loamy nature of the roadbed surface.

In any of the construction methods of the present invention, as shown in the second figure, a drainage layer 2 of sand, a water-permeable nonwoven fabric mat, a foam having open cells, etc. is preferably placed at the bottom of the water-blocking layer 9, preferably from 1 to 30%.
Drainage grooves 3 with holes formed on both sides of the roadbed 1 are formed to the thickness of an arc.
a and 3b, even if groundwater rises from the lower part of the roadbed, this groundwater can be drained along the drainage layer 2 into the perforated drainage ditch 3.
By discharging the water to drains a and 3b, a good effect of preventing sludge can be expected.

The construction method of the present invention will be illustrated in more detail with reference to Examples below.

Example 1 A vibrating drill with a diameter of 4 mm is inserted into the surface of a roadbed made of viscous sandy soil with a water content of 20%, and a roadbed surface layer with a thickness of about 10 mm is damaged. .

This treatment takes about 3 to 5 minutes per end and is performed evenly over the entire area to be treated. Next, funnels with nozzles at their tips from the track bed surface are placed at the apex positions of an equilateral triangle with sides of 85 mm, and a 2% by weight dispersion of hydraulic urethane resin stock solution is poured into each of the three funnels. Make 10 injections per funnel and withdraw each funnel after injection.
The hydraulic urethane resin stock solution consists of 10 parts of polyoxyethylene glycol (weight unit, same as below) with an average molecular weight of 1000 and 55 parts of tolylene diisocyanate in 90 parts and 2 parts.
An 85% solution of methyl ethyl ketone produced by reacting for a period of time was used. With this implementation method, the thickness is 1
A waterproof layer was formed. Example 2 A vibrating injector with an injecting nozzle attached to the tip of a titan bar was inserted into the surface of a roadbed laid on a roadbed made of viscous material with a moisture content of 19%, and while vibrating, the weight of hydraulic urethane resin was injected. % dispersion was injected into the subgrade surface layer.

The injection rate was 3 minutes/minute, and the injection time was about 4 minutes per injection. By this method, a water-blocking layer with a thickness of 10 mm was formed. Example 3 A hydraulic urethane resin stock solution was sprinkled on a clay roadbed with a moisture content of 26%, which was becoming muddy, at a ratio of 4:4 and 4:3. A water-blocking layer of about 10 skins was formed.

The hydraulic urethane resin stock solution was obtained by reacting 20 parts of a copolymer diol of 85 parts of ethylene oxide and 15 parts of propylene oxide with an average molecular weight of 2000 with 55 parts of tolylene diisocyanate at 90 qo for 3 hours. be. Example 4: The bed of the railway track where the mud phenomenon occurred was removed, and a roadbed surface layer with crushed stone embedded in it was excavated to a thickness of 10 mm, and then 0 to 4 dawn crushed stone was laid to a thickness of 10 mm. .

Next, a 1% by weight dispersion of a hydraulic urethane resin was sprayed onto the crushed stones in the surface layer of the roadbed at a ratio of 40 mm by weight using an automatic metering spreader to form a water-blocking layer with a thickness of 10 mm. The table below shows the hydraulic urethane resin compositions used in Examples 1 to 4, the properties of the water-blocking layers formed, and Comparative Examples 1 and 2 for reference.

The thickness of the water-blocking layer formed in Comparative Examples 1 and 2 is as follows:
10 skins and 10 skins, respectively. Note 1 Ichiyanagi Ti; Shrinkage strength: JIS-AI216 Note 2 Coefficient of permeability: JIS-AI
218 Note 3 Wave Labor Characteristics: Rotate the cam on the rail/sleeper around the l rib in the horizontal direction, and repeatedly apply 1 to 3 K ties to the bottom of the sleeper and the surface of the water barrier layer. is applied at a repetition rate of 500 times.

As is clear from the above detailed explanation, according to the construction method of the present invention, a stock solution or an aqueous solution of hydraulic urethane resin is injected or sprayed into the roadbed surface layer to infiltrate or mix.
This method uses water to cause a hydraulic reaction and forms a continuous impermeable layer of the required thickness on the surface layer of the roadbed, so it can be applied to prevent the formation of fin mud on newly constructed tracks, and it can also be applied to hydraulic urethane resins. Because of its high water gel (consolidation) ability, it can be applied to the roadbed of existing tracks where mud has formed and the water in the mud is used for hardening or hydrated gel to create a water-blocking layer. By forming a water-shielding layer made of hydraulic urethane resin that has not only water-shielding performance but also elasticity to the required thickness (5 skins or more), it is possible to prevent muddy phenomena when trains pass. It can reduce the propagation of vibrations to the roadbed, prevent the movement of dirt and pebbles, and prevent the cracking of pebbles, and strengthen the roadbed so that it can withstand an increase in the tonnage of trains passing through it. Not only can the prevention effect be maintained over a long period of time, but since the undiluted solution or dispersion of hydraulic urethane resin can be injected or sprayed onto the surface of the roadbed, construction is easy and economical. be.

Note that, of course, if a drainage layer and a perforated drainage groove are provided together as shown in the second figure, the effect of preventing counterfeiting can be further improved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a railway track to which an example of the conventional construction method is applied, and FIG. 2 is a cross-sectional view of a railway track to which an example of the construction method of the present invention is applied. 1...Roadbed, 6...Road bed, 9...Waterproof layer. Figure 1 Figure 2

Claims (1)

[Claims] 1. On the surface layer of the roadbed below the ballast track bed on railway tracks,
Penetrate or mix the stock solution or water dispersion of hydraulic urethane resin, cause a hydraulic reaction with water, and apply it to the surface layer of the roadbed.
A roadbed mud spray prevention method for railway tracks, which is characterized by forming a continuous impermeable layer of a required thickness.