JP7612152B2 - How to build slab track - Google Patents

Description

Article 30, paragraph 2 of the Patent Act applied. Test construction was carried out on June 4, 2019 at the Technical Research Institute of Toa Road Industry Co., Ltd.

The present invention relates to a method for constructing slab track for railways such as the Shinkansen, and is concerned with a method for constructing slab track in which a filler injection bag is inserted between the roadbed concrete or the like and the track slab.

In railways, track construction generally involves the use of ballast track, which is a trackbed. However, in recent years, the increase in train speeds and the number of routes has led to an increase in the labor and expense required for trackbed destruction and maintenance work. In response, slab track was developed with the primary goal of making the track maintenance-free, and is already in use on Shinkansen and conventional lines.

As shown in FIG. 1, a slab track is constructed by placing a track slab 13 on a concrete roadbed 12, which is poured on a concrete floor slab 11, which is the surface layer of an embankment, tunnel, bridge, etc., and laying rails 14 on the track slab 13. A horizontal layer 15 made of a filler such as cement asphalt mortar or synthetic resin is provided between the concrete roadbed 12 and the track slab 13, so that the track slab 13 is set at a constant height. In addition, a locking projection 16 is provided on the concrete roadbed 12, and a vertical layer 17 made of a filler is provided between the side of the locking projection 16 and the side of the track slab 13, so that the track slab 13 does not easily shift in the traveling direction of the vehicle.

Conventionally, filler injection bags have been used to provide the horizontal layer 15 made of filler. That is, the filler is injected into the injection bag to provide the horizontal layer 15. Nonwoven fabric is used as the material for this injection bag (Patent Documents 1 and 2). However, with typical nonwoven fabric, the filler leaks, contaminating the roadbed concrete 12 and making it difficult to install the track slab 13 at a constant height. In particular, the injection bag described in Patent Document 2 is characterized by covering the sides of the injection bag with asphalt, assuming that the cement asphalt will leak (Patent Document 2, claims 1 and 2).

Japanese Patent Application Publication No. 1-271501 Patent No. 5329263

The objective of the present invention is to provide a method for constructing slab track that prevents leakage of filler such as cement asphalt mortar from injection bags, prevents contamination of the roadbed concrete when constructing slab track, and makes it easy to install track slabs at a constant height.

The present invention solves the above problem by adopting specific materials for the injection bag body and the injection port. That is, the present invention relates to a method for constructing a slab track, which comprises the steps of: preparing an injection bag body for slab track construction comprising a laminated nonwoven fabric in which a long-fiber nonwoven fabric in which thermoplastic long fibers having a finer diameter than the thermoplastic ultrafine fibers are accumulated is bonded to both sides of an ultrafine fiber nonwoven fabric in which thermoplastic ultrafine fibers are accumulated, by the adhesiveness of the thermoplastic ultrafine fibers or the thermoplastic long fibers themselves; and an injection port formed of a woven or knitted fabric having a higher tensile strength than the laminated nonwoven fabric; inserting the injection bag for slab track construction between concrete or the roadbed concrete laid thereon and the track slab; and injecting a filler material through the injection port by pressure. The present invention also relates to a method for constructing a slab track in which the injection bag for constructing a slab track is inserted between the locking protrusions installed on the concrete deck or the roadbed concrete laid on top of it and the track slab, and then the filler is pumped and injected from the injection port.

The infusion bag for slab track construction used in the method for constructing a slab track according to the present invention has an infusion bag body made of a laminated nonwoven fabric, and an infusion port made of a woven or knitted fabric having a higher tensile strength than the laminated nonwoven fabric. Therefore, when the filler is pressure-fed and injected from the infusion port, the infusion port is less likely to break, and the effect of preventing the filler from leaking out is achieved. In addition, the ultrafine fiber nonwoven fabric in the laminated nonwoven fabric is made of an accumulation of ultrafine fibers with a small fiber diameter, so the fiber gaps are very small, making it difficult for the liquid components in the injected filler to leak out. The long fiber nonwoven fabric in the laminated nonwoven fabric has a large fiber diameter, so it has excellent mechanical strength and is less likely to break or burst during and after the injection of the filler. In addition, the laminated nonwoven fabric has gaps between the fibers, so it is breathable, and air mixed in the filler can be released to the outside when the filler is injected. Therefore, by adopting the method for constructing a slab track according to the present invention, it is possible to prevent the roadbed concrete from becoming dirty and to make it easier to install the track slab at a constant height. Furthermore, the injection bag for constructing a slab track used in the present invention is less susceptible to the infiltration of rainwater from the outside, so the filler is less likely to deteriorate, and a slab track with a long life is obtained.

FIG. 1 is a schematic perspective view showing a conventional slab track structure. FIG. 1 is a plan view of an example of an infusion bag for constructing a slab track used in the present invention, and an infusion bag of this shape is used for constructing a flat track slab. This is another example of a plan view of an infusion bag for constructing a slab track used in the present invention, and an infusion bag of this shape is used to construct a frame-shaped track slab. FIG. 4 is a plan view of an infusion bag piece used when creating the infusion bag for slab track construction of FIG. 2 or FIG. 3.

The infusion bag for slab track construction used in the present invention includes an infusion bag body 1 and an infusion port 2. The infusion bag body 1 is made of a laminated nonwoven fabric. The laminated nonwoven fabric is made by laminating and bonding a long fiber nonwoven fabric made of thermoplastic long fibers having a finer diameter than the thermoplastic ultrafine fibers on both sides of an ultrafine fiber nonwoven fabric made of accumulated thermoplastic ultrafine fibers. As the material for the thermoplastic ultrafine fibers, polyolefin resins such as polyethylene, polypropylene, or ethylene-propylene polymer, polyester resins such as polyethylene terephthalate, and polyamide resins such as nylon 6 or nylon 66 are used. The fineness of the thermoplastic ultrafine fibers is about 0.001 to 1 decitex. By accumulating such ultrafine fibers, microvoids are formed between the ultrafine fibers, and although the ultrafine fibers have air permeability, the water permeability is extremely reduced, making it difficult for the injected filler to leak. The ultrafine fiber nonwoven fabric can be obtained by the so-called melt blown method, and has a basis weight of about 10 to 100 g/m ² .

As for the material of the thermoplastic long fibers constituting the long fiber nonwoven fabric laminated and bonded on both sides of the ultrafine fiber nonwoven fabric, polyolefin resin, polyester resin, polyamide resin, etc. are used, as in the case of the thermoplastic ultrafine fibers. The materials of the thermoplastic ultrafine fibers and the thermoplastic long fibers are preferably the same type, for example, polyolefin resins. This is because the affinity between the ultrafine fibers and the long fibers is good when the materials are the same type, and they are easier to bond. The fineness of the thermoplastic long fibers is higher than that of the ultrafine fibers, about 1 to 30 decitex. Since the fineness of the thermoplastic long fibers is higher than that of the thermoplastic ultrafine fibers, the mechanical properties such as the tensile strength of the laminated nonwoven fabric are improved, and the infusion bag body 1 is less likely to break or burst. The basis weight of the long fiber nonwoven fabric is about 5 to 100 g/ ^m2 . The long fiber nonwoven fabric can be obtained by a conventionally known method, and it is preferable to obtain it by the so-called spunbond method.

To laminate and join ultrafine fiber nonwoven fabric and long fiber nonwoven fabric, for example, the following method is used. That is, after obtaining a long fiber nonwoven fabric by the spunbond method, the surface of this long fiber nonwoven fabric is sprayed with thermoplastic ultrafine fibers by the meltblown method to form an ultrafine fiber nonwoven fabric. Then, by accumulating thermoplastic long fibers on the surface of the ultrafine fiber nonwoven fabric by the spunbond method to form a long fiber nonwoven fabric, a laminated nonwoven fabric can be obtained in which the long fiber nonwoven fabric is laminated and joined to both sides of the ultrafine fiber nonwoven fabric. The ultrafine fiber nonwoven fabric and the long fiber nonwoven fabric are bonded to each other by the adhesiveness of the thermoplastic ultrafine fibers themselves, by spraying thermoplastic ultrafine fibers that are still in a softened state onto the surface of the long fiber nonwoven fabric and accumulating thermoplastic long fibers on the surface of the still softened ultrafine fiber nonwoven fabric. If it is desired to further advance the bonding, the laminated nonwoven fabric can be passed between a pair of heated rolls to soften the thermoplastic ultrafine fibers and/or thermoplastic long fibers, and the bonding can be performed by the adhesiveness of the thermoplastic ultrafine fibers and/or thermoplastic long fibers themselves. In this case, the thermoplastic ultrafine fibers can be sprayed in two or three or more stages by the meltblown method to form a two-layer or three or more layers of ultrafine fiber nonwoven fabric. In addition, after obtaining a long-fiber nonwoven fabric by the spunbond method, two two-layer laminates of ultrafine fiber nonwoven fabric and long fiber nonwoven fabric obtained by spraying thermoplastic ultrafine fibers on the surface of the long-fiber nonwoven fabric by the meltblown method can be prepared, and the ultrafine fiber nonwoven fabrics can be laminated so that they are in contact with each other, to obtain a laminated nonwoven fabric in which the long-fiber nonwoven fabric is laminated and bonded to both sides of the ultrafine fiber nonwoven fabric.

The basis weight of the laminated nonwoven fabric is about 30 to 150 g/ ^m2 . This laminated nonwoven fabric is resistant to leakage of liquid components in the filler and has excellent water resistance. For example, when a water pressure of 500 _mmH2O is applied for 30 minutes using a water pressure resistance tester, the amount of water seeping out is about 50 cc or less. It is also preferable to incorporate weathering agents such as ultraviolet absorbers and light stabilizers into the thermoplastic ultrafine fibers and thermoplastic long fibers that make up the laminated nonwoven fabric. This is to prevent deterioration, since injection bags for slab track construction are often used outdoors for long periods of time.

The inlet 2 is the part where the filler is injected, and is the part where pressure is applied to pump the filler into the infusion bag body 1. Therefore, it is made of a material with higher mechanical strength, such as tensile strength, than the infusion bag body 1. For example, it is preferable to form it from a woven or knitted fabric such as nylon taffeta.

The method of making the infusion bag for slab track construction in the shape shown in FIG. 2 can be, for example, the following method. That is, two infusion bag pieces shown in FIG. 4 are prepared. This infusion bag piece is made of an infusion bag main body piece 1a made of laminated nonwoven fabric, and an infusion inlet piece 2a made of woven or knitted fabric is sewn with a thread 5 such as a sewing thread. Of course, instead of sewing with the thread 5, it may be bonded with a hot melt adhesive or the like. Note that 4 is a recess for fitting the locking protrusion. By overlapping two such infusion bag pieces and sewing the overlapping periphery with a thread 3 such as a sewing thread, it is possible to obtain an infusion bag for slab track construction. Of course, in this case, it is also possible to adhere with a hot melt adhesive or the like instead of sewing with the thread 3. Also, it is possible to make an infusion bag for slab track construction in the shape shown in FIG. 3 by folding one of the infusion bag pieces shown in FIG. 4 in the vertical direction and overlapping it, and sewing the overlapping periphery with a thread 3 such as a sewing thread. In this case, there is no need to sew or glue the folded edges.

The injection bag for slab track construction shown in FIG. 2 has a body that is almost the same shape as the flat track slab, so it is used when constructing a slab track using a flat track slab. That is, the injection bag for slab track construction shown in FIG. 2 is inserted between the roadbed concrete and the flat track slab, and a filler such as cement asphalt mortar or urethane resin is injected into the injection bag body 1 from the injection port 2. Then, when the cement asphalt mortar or urethane resin hardens, the slab track structure can be constructed. In addition, the injection bag for slab track construction shown in FIG. 3 is used when constructing a slab track using a frame-shaped track slab. That is, the injection bag for slab track construction shown in FIG. 3 is inserted between the left and right frame parts of the rail and the roadbed concrete, and the filler is injected into the injection bag body 1 from the injection port 2, so that the slab track structure can be constructed.

The infusion bag for slab track construction used in the present invention can also be applied between the locking protrusion and the track slab. That is, the infusion bag for slab track construction can be inserted into the vertical gap between the locking protrusion and the track slab, and the filler can be injected into the infusion bag body 1 from the injection port 2 to construct a slab track structure. The infusion bag for slab track construction to be applied to this location is not shown, but for example, one with a shape as shown in Figure 3 can be wrapped around the side of the locking protrusion. After the slab track is constructed, the injection port 2 can be cut off or tied off.

Reference Signs List 1 Injection bag body 1a Injection bag body piece 2 Injection port 2a Injection port piece 3 Thread for sewing the overlapping periphery of the injection bag body piece and the injection port piece 4 Recess for fitting the locking protrusion 5 Thread for sewing the injection bag body piece and the injection port piece 11 Concrete floor slab 12 Subgrade concrete 12
13 track slab 14 rail 16 locking projection

Claims (5)

A process of preparing an infusion bag for slab track construction, comprising: an infusion bag body made of a laminated nonwoven fabric in which a long-fiber nonwoven fabric made of thermoplastic long fibers having a finer diameter than that of the thermoplastic ultrafine fibers is bonded to both sides of the ultrafine fiber nonwoven fabric by the adhesiveness of the thermoplastic ultrafine fibers or the thermoplastic long fibers themselves; and an infusion bag for slab track construction, comprising an infusion bag body made of a laminated nonwoven fabric in which a long-fiber nonwoven fabric made of thermoplastic long fibers having a finer diameter than that of the thermoplastic ultrafine fibers is bonded to both sides of the ultrafine fiber nonwoven fabric by the adhesiveness of the thermoplastic ultrafine fibers or the thermoplastic long fibers themselves; and
A method for constructing a slab track, comprising the steps of: inserting the injection bag for slab track construction between concrete or roadbed concrete laid on top of it and a track slab; and injecting filler by pressure from the injection port. The method for constructing a slab track as described in claim 1 employs a step of inserting the injection bag for slab track construction described in claim 1 between a locking protrusion installed on a concrete slab or the roadbed concrete installed on the concrete slab and the track slab, instead of the step of inserting the injection bag for slab track construction between the concrete or the roadbed concrete installed on the concrete slab and the track slab. The method for constructing a slab track according to claim 1 or 2, wherein the thermoplastic ultrafine fibers are polyolefin ultrafine fibers, and the thermoplastic long fibers are polyolefin long fibers. The method for constructing a slab track according to claim 1 or 2, wherein the woven or knitted fabric is nylon taffeta. The method for constructing a slab track according to claim 1 or 2, wherein the track slab is a flat track slab or a frame track slab.

Images