JP7589097B2 - Repair method for fill layer on slab track - Google Patents

Description

The present invention relates to a technology for repairing slab track, and in particular to a method for repairing a CA mortar layer (cement asphalt mortar) layer that serves as a filling layer between the roadbed concrete and the track slab.

In slab track, a filling layer made of CA mortar is provided between the roadbed concrete and the track slab made of concrete plates laid above it, providing a buffer layer. Conventionally, this CA mortar layer has been made using a formwork method in which a formwork is set up and a filler is poured into the inside of the formwork and hardened, and a long tube method in which mortar is poured into a nonwoven fabric bag.
Among these, an invention relating to a method for constructing a track slab with a long-tube type CA mortar layer interposed therebetween is described in, for example, Patent Document 1.

In recent years, in slab track in snowy and cold regions, water sprayed to melt snow and rainwater seep into the CA mortar layer, causing repeated freezing and thawing, which causes the CA mortar layer to deteriorate. Therefore, in slab track parts where the CA mortar layer is less deteriorated, measures have been taken to prevent water from seeping into the CA mortar layer by coating the side parts where the CA mortar layer is exposed with resin.
On the other hand, in slab track sections where the CA mortar layer has deteriorated considerably, excavators are used to excavate and remove the mortar from the side of the CA mortar layer to a relatively deep area, and then repair the CA mortar layer by injecting repair materials.In the case of long-tube CA mortar layers, the nonwoven fabric covering the surface must also be removed, so a suitable grinding device for slab track repair has also been developed.

Furthermore, there are conventional inventions relating to repair devices and methods for the filled layer (CA mortar layer) in slab track, such as those described in Patent Documents 2 and 3.
Of these, the invention of Patent Document 2 involves excavating the filling layer between the roadbed concrete and the track slab from the side, setting up a formwork on the outside of the track slab, and then injecting a two-component mixed filler into the formwork from the mixer nozzle of a traveling filling layer repair device mounted on a rail, allowing it to harden, and then removing the formwork.

The invention in Patent Document 3 involves removing the deteriorated CA mortar layer from around the track slab to an appropriate horizontal depth to form a gap that opens to the outer periphery of the track slab, filling the gap with a repair bag from the outside, and then injecting a repair filler into the repair bag to expand it and secure it tightly to at least the top and bottom surfaces of the gap.

JP 2010-203178 A JP 2015-224418 A JP 2012-180634 A

However, in the case of the filling layer repair method described in the above Patent Document 2, since it is necessary to install and remove formwork on the roadbed concrete, there are many work steps, which requires a considerable amount of time and cost.
On the other hand, the filling layer repair method of Patent Document 3 has the advantage that it does not require the installation and removal of formwork, but it requires the repeated insertion of multiple repair bags into the voids created by partially removing the CA mortar layer and the sequential injection of filler into the repair bags.

In addition, in the filling layer repair method of Patent Document 3, in order to fill the gap remaining at the back of the gap where the repair bag was inserted, injection holes are first provided in the track slab in the vertical direction and the filler is injected, so it still takes a lot of time and does not reduce costs sufficiently. Moreover, because it takes time for the filler to harden, when carrying out work to repair a wide area of the CA mortar layer at night when commercial trains are not running, work must be carried out to prevent the slab track from sinking, which is an issue as it is not suitable for large-scale repairs.

The present invention has been made against the background described above, and aims to provide a method for repairing a filling layer in a slab track, which enables extensive repair work to be carried out on the CA mortar layer serving as a filling layer between the roadbed concrete and the track slab of a slab track during the nighttime hours when no commercial trains are running.
Another object of the present invention is to provide a method for repairing a filling layer in an existing slab track, which can repair a CA mortar layer as a filling layer in a short period of time without installing a large-scale formwork in the roadbed concrete.

In order to achieve the above object, the present invention provides:
A method for repairing a filling layer in a slab track, in which a filling layer provided between a roadbed concrete and a track slab in a slab track is excavated from the side of the slab track and filled with a repair material,
A first step of excavating the filling layer from a side of the slab track to a predetermined depth;
a second step of inserting the block packings, each of which is a plurality of bags having a width substantially equal to the depth of the excavated portion excavated in the first step, a length 1/n (n is a positive integer) of the length of the track slab, and a filler injection port, into the excavated portion excavated in the first step in a line; the block packings each contain a block having a predetermined shape and a predetermined strength or more, the block packings being filled with the block packings being filled with the block packings and having a width substantially equal to the depth of the excavated portion excavated in the first step, the length 1/n (n is a positive integer) of the length of the track slab, and a filler injection port;
A third step of injecting a hardening type repair agent into the bag;
The above is included.

According to this method, a block filler loaded with blocks having a certain level of strength or more is inserted into the excavated area of the fill layer (CA mortar layer), so there is no need to maintain the gap between the roadbed concrete and the track slab until the cement asphalt hardens, as is the case when constructing a CA mortar layer using the long tube method. This means that repair work for the fill layer of the slab track can be carried out at night when no commercial trains are running. In addition, since the installation and removal of formwork is required, work time and costs can be reduced.

In addition, since the weight of each block can be reduced, manual handling of the blocks becomes easier, and there is no need to bring large machines or heavy equipment into the track, which shortens the preparation time for repair work. Furthermore, since the hardening repair agent is injected into the inside of the bag, the gaps between the blocks and between the bag and the wall surface of the excavation section become narrower, which increases the strength of the filling layer, and since the weight of each individual block inserted into the bag can be reduced, manual handling of the blocks becomes easier, and there is no need to bring large machines or heavy equipment into the track, which shortens the preparation time for repair work.

Here, it is preferable that the bag is formed from a sheet-like material that does not allow the filling material inside to seep out, and that a valve is provided on the inner surface facing the back of the excavated space formed in the first step.
According to this method, the hardening repair agent injected into the inside of the bag overflows from the valve on the inside surface and fills the back of the excavated space and the gaps above and below, thereby preventing the intrusion of rainwater and suppressing deterioration of the filling layer (CA mortar layer).

Alternatively , the bag is formed from a nonwoven fabric that allows the filler inside to seep out, and the outer surface is made of or attached to a fabric material that prevents the injected filler from seeping out.
According to this method, the hardening type repair agent injected into the bag seeps out from the surface of the bag and fills the inner part of the excavation space and the gaps above and below, preventing the intrusion of rainwater and suppressing the deterioration of the filling layer (CA mortar layer). In addition, it is possible to prevent the repair agent from seeping out from the outer surface of the bag and protruding out to the side of the track slab.

Also, preferably, the bag has a filler injection port on the outer surface thereof.
According to this method, the operation of injecting the repair agent into the inside of the bags (short tubes) constituting a plurality of block packings can be carried out efficiently.

Furthermore, it is preferable that the length of the block fillers corresponding to one track slab should be the length of one track slab plus the gap between the track slabs, and that the block fillers at the ends inserted between adjacent track slabs and roadbed concrete be arranged so as to come into contact with each other.
The track slabs that make up the slab track are divided into units of several meters, so according to the above method, when repairs are carried out on the filling layer (CA mortar layer) for each track slab, adjacent block fillers between adjacent track slabs can be connected, preventing lateral shifting of the block fillers and preventing blocks from popping out.

The method for repairing the filling layer in a slab track according to the present invention makes it possible to carry out repair work over a wide area of the CA mortar layer serving as a filling layer between the roadbed concrete and the track slab of a slab track during the nighttime hours when no commercial trains are running. In addition, there is an effect that the CA mortar layer serving as a filling layer can be repaired in a short time on an existing slab track without the need to install large-scale formwork on the roadbed concrete.

FIG. 1 is a perspective view showing the structure of a slab track to which the repair method for a CA mortar layer as a filling layer according to the present invention is applied. FIG. 1 is an explanatory perspective view showing an example of a slab track structure after large-scale repair to which the present invention is applied. FIG. 2A is an oblique view showing the inner surface of a short tube inserted into an excavated portion of a CA mortar layer, and FIG. 2B and FIG. 2C are oblique views showing examples of the configuration of valves provided on the inner surfaces of the short tubes. 13 is an explanatory perspective view showing the filler injection process performed after the CA block is inserted into the excavated portion. FIG. FIG. 11 is a plan view showing another example of the configuration of a CA block used to repair a CA mortar layer in an embodiment. FIG. 11 is a plan view showing another example of the configuration of a CA block used to repair a CA mortar layer in an embodiment.

Hereinafter, an embodiment of a repair method for a CA mortar layer serving as a filling layer in a slab track according to the present invention will be described in detail with reference to the drawings.
Figure 1 shows the structure of a slab track to which the method for repairing the filling layer according to the present invention is applied. As shown in Figure 1, the slab track has a structure in which a roadbed concrete 11 of a given thickness is laid along the track extension direction on a concrete floor slab (not shown), and a track slab 13 (length 4.95 m, width 2.34 m, thickness 16 cm) is laid on the roadbed concrete 11 via a CA mortar layer 12. The width of the CA mortar layer 12 is the same as that of the track slab 13.

The track slab 13 is constructed by arranging multiple concrete slabs, each of which is rectangular in top view, in the direction in which the rails extend. A rail 20 is extended onto the track slab 13 and fastened to the track slab 13 by rail fasteners 21.
More specifically, cylindrical locking projections 14 are provided at a specified interval in the center of the roadbed concrete 11, and semicircular notches having a diameter slightly larger than that of the locking projections 14 are formed in the center of the front and rear ends of each of the rectangular concrete plates that make up the track slab 13, and the concrete plates that make up the track slab 13 are positioned by the locking projections 14 engaging with these notches. Note that gaps between the track slab 13 and the locking projections 14 are filled by injecting and hardening filler 15.

There are two types of CA mortar layer 12: those made by the formwork method, and those made by long tubes with CA mortar injected into nonwoven bags. The long tube method CA mortar layer 12 is constructed by placing a long tube in the gap between the roadbed concrete 11 and the track slab 13, injecting a cement asphalt mixture from an injection port on one side of the tube so that it fills the entire tube, and cutting off the end of the injection port that protrudes to the side from the track slab 13 after hardening. The long tube is made of long fiber nonwoven fabric made of polyester, polyethylene terephthalate, etc., for example.

The cement asphalt mixture injected into the long tube contains, for example, a specified ratio of cement, asphalt, and fine aggregate. The asphalt component is added as an asphalt emulsion, and when the moisture is removed and the tube hardens, it becomes an elastic body that exhibits toughness. In addition, the sides of the long tube may be treated to make them light-resistant in order to improve their weather resistance.

Examples of light resistance treatment include a method for improving the light resistance of the fibers constituting the nonwoven fabric, a method for covering the surface including the side surfaces of the long tube with a light-resistant resin, and a method for completely covering the side surfaces of the long tube with asphalt.
Among these, a method for improving the light resistance of the constituent fibers of the nonwoven fabric is to mix a light-resistant agent into the constituent fibers to form a fiber, while a method for covering the surface including the side surface of the long tube with a light-resistant resin is to inject a cement-asphalt mixture into the long tube and then apply an acrylic light-resistant paint to the exposed side surface of the long tube.

When the CA mortar layer 12 having the above-mentioned structure deteriorates, as described above, partial repair or large-scale repair (large cross-section chipping repair) is performed depending on the degree of deterioration. The present invention is directed to large-scale repair. In the embodiment, large-scale repair is performed by excavating the CA mortar layer 12 below the track slab 13, which is about 2.5 m wide, to a depth of about 70 cm on both sides, and forming a new filling layer. The excavation depth of the CA mortar layer 12 is not limited to around 70 cm.

The structure and methods of large-scale repair of slab track are explained in detail below.
An example of a slab track structure by large-scale repair using the present invention is shown in Fig. 2. As shown in Fig. 2, the repair of the slab track in this embodiment involves excavating both sides of the CA mortar layer 12 below the track slab 13 over the entire rail extension direction, inserting a plurality of blocks 16B rectangular in top view loaded in a slightly larger bag-shaped short tube 16A (hereinafter referred to as block fillers) in contact with each other and lining up the short tubes 16A, and sequentially injecting a filler such as cement asphalt into the inside of the tubes through the injection ports 16c of the short tubes 16A.

In FIG. 2, the track slab 13 is shown separated from the CA mortar layer 12, but in actual construction, the track slab 13 is not lifted, and both sides of the CA mortar layer 12 are excavated to form a space for inserting the block filler 16. In addition, the length of each block 16B is shortened to reduce its weight, and multiple blocks loaded with the blocks 16B in the short tubes 16A are inserted under one track slab 13, making it easy to transport the block filler 16 manually and eliminating the need to bring large or heavy machinery into the track. The blocks 16B may be loaded into the short tubes 16A on-site, but the blocks 16B may also be loaded into the short tubes 16A in advance at a factory or the like and then transported to the site.

The block 16B is made of a sheet of material such as polyester or polyethylene terephthalate, which is used in conventional long tubes, and is designed to prevent the cement asphalt injected inside from seeping out from the surface, and as shown in Figure 3(A), multiple valves 16b are provided at regular intervals on the surface facing the back of the excavation space. Also, a cement asphalt injection port 16c is provided on the front side of the short tube 16A, for example at the center.

FIG. 3B shows a specific example of the structure of the valve 16b.
The valve 16b shown in FIG. 3(B) is provided on the inside of each opening hole 16a formed on the back surface (inner surface) of the short tube 16A, and a check valve having a structure that allows the filler in the short tube 16A to flow out to the outside but makes it difficult for the flowed-out filler to return is used.

FIG. 3C shows another example of the structure of the valve 16b.
The valve 16b shown in Fig. 3(C) is a disk-shaped elastic body with a diameter slightly larger than the opening 16a, which is formed on the back surface (inner surface) of the short tube 16A and has a diameter of several mm to several cm, and has a cross-shaped cut in the center to cover the opening 16a. The material of the valve 16b may be any material that is elastically deformable and strong, such as polyethylene terephthalate, which is the material used for PET bottles. Note that the configuration of the valve 16b is merely an example and is not limited to the above configuration.

When using the short tube 16A as described above, the side of the CA mortar layer 12 is excavated, and multiple block fillers 16 are lined up and inserted into the excavated portion, and then cement asphalt is injected through the injection port 16c. Then, the short tube 16A is filled with cement asphalt, and the valve 16b on the back side is deformed outward by the internal pressure, opening a slit, and the cement asphalt flows out and fills the gap between the back of the excavated space and the block filler 16. In addition, once the gap at the back is filled, the cement asphalt moves to the outer surface side and fills the gap between the upper and lower walls of the excavated portion and the block filler 16. As a result, it is possible to prevent rainwater from entering the gap between the excavated portion of the CA mortar layer 12 and the block filler 16, which would hasten deterioration.

The short tubes 16A may be made of long fiber nonwoven fabric, similar to the long tubes used to provide a filling layer when constructing the initial slab track. Tubes made of long fiber nonwoven fabric have the property of allowing injected cement asphalt to seep out from the surface. Therefore, in this embodiment, when cement asphalt is filled into the short tubes 16A of the block filler 16 inserted into the space created by excavating the CA mortar layer 12, it seeps out from the surface and fills the gaps with the track slab 13 above and the roadbed concrete 11 below.

In addition, the gaps between the block fillers 16 and between the sides of the excavated CA mortar layer 12 at the back of the block fillers 16 can be filled, preventing rainwater from entering these gaps and accelerating deterioration. Since it is expected that there will be more gap space at the back of the excavation than above or below the block fillers 16, valves may be provided at a specified pitch on the back side of the short tubes 16A so that more filler (cement asphalt) can be poured through the valves into the gaps at the back of the excavation.

A fastener may be provided on one side of the short tube 16A to make it easier to load the block 16B. This fastener is made of a material that does not allow the cement asphalt to seep out, and by inserting the block filler 16 into the excavated portion of the CA mortar layer 12 with the fastener facing outward, it is possible to prevent the cement asphalt from seeping out to the outside of the track slab even without a formwork. The outer surface of the short tube 16A may be made of or attached to a cloth material that does not allow the filler to seep out, rather than a fastener.

According to the repair method of this embodiment, which uses a block filler 16 consisting of short tubes 16A and blocks 16B as described above, the amount of cement asphalt filled into the short tubes 16A is small, so the amount of water brought in is small, reducing the burden on workers and shortening the time required for the cement asphalt to harden. This makes it possible to avoid leaving the cement asphalt on the track in an unhardened state for long periods of time, so there is no problem if trains run on the track immediately after construction. This makes it possible to carry out repair work during the night when no commercial trains are running.

In addition, in the case of the repair method of Patent Document 3, in which an empty repair bag is inserted into the excavated area of the CA mortar layer and filler is injected, if a train runs after the work is completed while the CA block is still unhardened, there is a risk that the track slab 13 will sink and harden in that state. However, with the repair method of this embodiment, such a risk can be avoided because the amount of filler is small and the time required for the effect is short. After the filler is injected, a light-resistant resin or paint may be applied to the end surface of the repair layer to form a coating layer.

Furthermore, after inserting the block filler 16 consisting of the short tube 16A and the block 16B into the excavated portion of the CA mortar layer 12, and before injecting the filler into the short tube 16A, as shown in FIG. 4, a seal-type formwork 17 may be provided to cover the entire outer surface of the inserted block filler 16, and then the filler may be injected into the short tube 16A to fill the gaps around the block filler 16. In this way, when the entire short tube 16A is made of nonwoven fabric or the like that allows the filler to seep out, it is possible to prevent the filler from seeping out from the outer surface of the short tube 16A and spilling out to the side of the track slab 13.

Incidentally, since the block filler 16 shown in FIG. 2 has a rectangular shape when viewed from above, if there is even one block filler 16 with weak bonding strength, there is a risk that it will shift laterally due to the repeated vibrations of a running train, and gradually jump out to the side.
Figures 5 and 6 show examples of block fillers 16 equipped with a function to prevent such jumping out. Of these, the block filler 16 in Figure 5 has a convex portion 16d formed on one side of the front or rear end in the rail direction of the short tube 16A and the CA block 16B, and a concave portion 16e engageable with the convex portion 16d on the other opposing side, so that adjacent block fillers 16 are arranged side by side with the convex portions 16d and the concave portions 16e meshed with each other.

The block filler 16 in FIG. 6 has steps of the same height in the center of the sides of the front and rear ends of the short tubes 16A and the CA blocks 16B, forming engagement step portions 16f, 16g having a length that is half the length of the sides on each side, and is arranged side by side in a state in which the engagement step portions 16f, 16g of adjacent block fillers 16 are engaged with each other.
By forming the block fillers 16 in the shape shown in Fig. 5 or 6, even if a lateral force acts on a block filler 16 due to repeated vibrations from a running train, the entire block fillers 16 (eight in the figure) that engage with each other resist and prevent lateral displacement and protrusion of the track slab to the side. Note that the short tubes 16A may be formed as rectangular bags without irregularities or steps, so long as they are flexible.

Furthermore, in the embodiment shown in Figures 5 and 6, the total length of n (e.g., eight) block fillers 16 corresponding to one track slab 13 is set to the length of one track slab 13 plus the gap between adjacent track slabs, and the ends of the block fillers 16 inserted between adjacent track slabs and the roadbed concrete are preferably arranged so that they come into contact or engage with each other. This increases the resistance to the lateral force acting on the inserted block fillers 16 due to the vibration of a running train, and prevents the block fillers 16 from slipping sideways and jumping out to the side.

Although the invention made by the inventor has been specifically described above based on the embodiment, the present invention is not limited to the above embodiment. For example, in the above embodiment, a block made of cement asphalt is used as the block 16B to be loaded into the short tube 16A, but a block made of a material other than cement asphalt may be loaded as long as it has a strength equal to or greater than that of the CA block.
In order to connect adjacent block packings 16 to each other, a connecting means such as a hook-and-loop fastener may be provided on the joint surface of the short tube 16A.

11 Roadbed concrete 12 CA mortar layer (filling layer)
13: raceway slab 14: locking projection 16: block filler 16A: short tube 16B: CA block 16a: opening hole 16b: valve 16c: filler injection port 16d: protrusion (engagement portion)
16e Recess (engagement portion)
16f, 16g Engagement step part (engaging part)
20 Rail 21 Rail fastener

Claims (5)

A method for repairing a filling layer in a slab track, comprising excavating a filling layer between a roadbed concrete and a track slab from the side of the slab track and filling the layer with a repair material,
A first step of excavating the filling layer from a side of the slab track to a predetermined depth;
a second step of inserting the block packings, each of which is a plurality of bags having a width substantially equal to the depth of the excavated portion excavated in the first step, a length 1/n (n is a positive integer) of the length of the track slab, and a filler injection port, into the excavated portion excavated in the first step in a line; the block packings each contain a block having a predetermined shape and a predetermined strength or more, the block packings being filled with the block packings being filled with the block packings and having a width substantially equal to the depth of the excavated portion excavated in the first step, the length 1/n (n is a positive integer) of the length of the track slab, and a filler injection port;
A third step of injecting a hardening type repair agent into the inside of the bag;
A method for repairing a filling layer in a slab track, comprising: The method for repairing a filling layer in a slab track as described in claim 1, characterized in that the bag is made of a sheet-like material that does not allow the filling material inside to seep out, and a valve is provided on the inner surface facing the back of the excavation space formed in the first process. The method for repairing a filling layer in a slab track as described in claim 1, characterized in that the bag is formed of a non-woven fabric that allows the filler inside to seep out, and the outer surface is made of or attached to a cloth material that does not allow the injected filler to seep out. The method for repairing a filling layer in a slab track as described in claim 2 or 3, characterized in that the bag has a filler injection port on the outer surface. A method for repairing a filling layer in a slab track according to any one of claims 1 to 4, characterized in that the length of the block fillers corresponding to one track slab is the length of one track slab plus the gap between the track slabs, and the block fillers are arranged so that the ends of the block fillers inserted between adjacent track slabs and roadbed concrete are in contact with each other.

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