JP7582900B2 - 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 grinding device suitable for this purpose has also been developed for slab track repair.

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, 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 , as a repair material , a plurality of blocks having a predetermined strength or more, the blocks being prefabricated to have a predetermined shape and a width in a direction perpendicular to the rail that is the same as the depth of the portion excavated in the first step, into the portion excavated in the first step;
a third step of performing post-treatment so that the block inserted into the portion does not come out;
The above is included.

According to the method following the above procedure, blocks with a specified strength or more are inserted into the area where the filling layer (CA mortar layer) has been excavated, 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 filling layer of the slab track can be carried out at night when no commercial trains are running. In addition, since it is necessary to install and remove formwork in the roadbed concrete, work time and costs can be reduced.

Here, preferably, the plurality of blocks are blocks having the same shape,
In the second step, a predetermined number of the blocks are inserted into the portion where the filling layer has been excavated, for the track slab having a predetermined length.
According to this method, the weight of each block can be reduced, making it easier to handle the blocks manually and eliminating the need to bring large or heavy machinery onto the track, thereby shortening the preparation time for repair work.

Also, preferably, each of the blocks is provided with an engaging portion that can mesh with an engaging portion of an adjacent block.
With this method, adjacent blocks are connected to each other, so that the lateral force generated by the vibrations caused by the running train can be distributed among multiple blocks, thereby increasing resistance to lateral slippage and preventing the blocks inserted into the excavation from flying out.

Moreover, preferably, the total length of the multiple blocks inserted corresponding to one of the track slabs is the length of one of the track slabs plus the gap between the track slabs, and the blocks are arranged so that the ends of the blocks inserted between adjacent track slabs and roadbed concrete come into contact or engage with each other.

The track slabs that make up the slab track are divided into several-meter intervals, so with the above method, when repairs are made to the filling layer (CA mortar layer) for each track slab, adjacent blocks between adjacent track slabs can be connected, further preventing lateral displacement of the blocks.

Furthermore, preferably, the post-treatment in the third step is a treatment of injecting a hardening type repair agent into the gap between the surface of the block inserted into the excavated portion of the filling layer and the surrounding components.
According to this method, the gap between the surface of the block and the surrounding components is filled with a hardening repair agent, thereby preventing rainwater from entering the filling layer and suppressing deterioration of the filling layer (CA mortar layer).

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. 2 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. 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 semi-cylindrical 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 are filled between the outer periphery of the locking projections 14 and the track slab 13 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, in repairing a slab track in this embodiment, both sides of a CA mortar layer 12 below a track slab 13 are excavated along the rail extension direction to create a space, and a number of blocks 16, rectangular in top view, are inserted in a line in contact with each other.

In addition, in Figure 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, but rather both sides of the CA mortar layer 12 are excavated to create space for inserting the blocks 16. In addition, because each block is made shorter and lighter, and multiple blocks 16 are inserted under one track slab 13, the blocks 16 can be easily transported by hand, eliminating the need to bring large or heavy machinery into the track.

The blocks 16 are made by pouring the cement asphalt material into a predetermined formwork in a factory or the like and hardening it to form a rectangular plate (hereinafter referred to as CA blocks). This shortens the construction time at the site and prevents the cement asphalt from being left unhardened on the track for a long period of time, so there is no problem even 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.
Furthermore, in the case of the repair method of Patent Document 3, in which a repair bag is inserted into the excavated area of the CA mortar layer and a filler is injected, if a train runs after the work is completed while the CA blocks are still unhardened, there is a risk that the track slab 13 will sink and harden in that state. However, the repair method of this embodiment makes it possible to avoid such a risk.

Furthermore, as shown in FIG. 2, a plurality of CA blocks 16 may be inserted in a space created by excavating both sides of the CA mortar layer 12, and then, as shown in FIG. 3, a seal-type formwork 17 may be provided to cover the entire outer surface of the inserted CA block 16, and a filler such as cement asphalt may be injected into the gap inside the formwork 17 and allowed to harden, thereby filling the gaps between the CA blocks 16 and the gaps between the CA blocks 16 and the side of the excavated CA mortar layer 12 at the back of the CA block 16. In this way, it is possible to prevent rainwater from entering the gaps in the CA mortar layer 12 created by the repair work and accelerating deterioration. After injecting the filler, a light-resistant resin or paint may be applied to the end surface of the repair layer to form a coating layer. Since the amount of filler injected into the gap inside the formwork 17 is small, it hardens in a relatively short time.

Incidentally, the CA block 16 shown in Figure 2 has a rectangular shape when viewed from above. Therefore, if there is even one CA block 16 with weak joining strength, there is a risk that the repeated vibrations of a running train will cause the block to shift laterally and gradually protrude to the side.
Figures 4 and 5 show examples of CA blocks 16 equipped with a function to prevent such protrusion. Of these, the CA block 16 in Figure 4 has a convex portion 16a formed on one side of the front or rear end in the rail direction, and a concave portion 16b engageable with the convex portion 16a formed on the other opposing side, so that adjacent CA blocks 16 are arranged side by side with the convex portions 16a and the concave portions 16b meshed with each other.

The CA block 16 in Figure 5 has a step of the same height in the center of the front and rear end sides, and engagement step portions 16c, 16d having a length that is half the length of the side are formed on each side, so that the engagement step portions 16c, 16d of adjacent CA blocks 16 are arranged side by side in an engaged state.
By forming the CA blocks 16 in the shape shown in Figure 4 or Figure 5, even if a lateral force acts on a CA block 16 due to the repeated vibrations of a running train, the multiple CA blocks 16 (eight in the figure) that engage with each other can resist the force as a whole, preventing lateral slippage and preventing the track slab from protruding sideways.

4 and 5, the length of the blocks is set and arranged so that the convex portion 16a (or engagement step portion 16c) of the CA block 16 below the front track slab 13 and the concave portion 16b (or engagement step portion 16d) of the CA block 16 below the rear track slab 13 can mesh with each other at the boundary between the front and rear track slabs 13. In other words, the total length of n CA blocks 16 (eight in the figure) corresponding to one track slab 13 is set to be longer than the length of one track slab 13 by the gap between the track slabs.
This further increases the resistance to lateral forces acting on the CA block 16, making it possible to more reliably prevent lateral displacement.

The invention made by the inventor has been specifically described above based on an embodiment, but the present invention is not limited to the above embodiment. For example, in the above embodiment, a CA block 16 is inserted into the excavated portion of the CA mortar layer 12, but a block made of a material other than cement asphalt may be inserted as long as it has the same or greater strength as the CA block.

In the above embodiment, n (e.g., 8) CA blocks 16 are inserted into the excavation formed in the CA mortar layer 12 corresponding to one track slab 13, but one block having the same length as the track slab 13 may be inserted into the excavation. Even in this case, the length of one block should be set to the length of one track slab 13 plus the gap between the adjacent track slabs, and the ends of the blocks inserted between the adjacent track slabs and the roadbed concrete should be in contact or engaged with each other. This increases the resistance to the lateral force acting on the inserted block due to the vibration of a running train, and prevents the CA block from slipping out to the side.

11 Roadbed concrete 12 CA mortar layer (filling layer)
13 Track slab 14 Locking projection 15 Filler 16 CA block 16a Convex portion (engagement portion)
16b Recess (engagement portion)
16c, 16d Engagement step part (engaging part)
17 Formwork 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 , as a repair material , a plurality of blocks having a predetermined strength or more, the blocks being prefabricated to have a predetermined shape and a width in a direction perpendicular to the rail that is the same as the depth of the portion excavated in the first step, into the portion excavated in the first step;
a third step of performing post-treatment so that the block inserted into the portion does not come out;
A method for repairing a filling layer in a slab track, comprising: The plurality of blocks are blocks having the same shape,
The method for repairing a filling layer in a slab track according to claim 1, characterized in that in the second step, a predetermined number of the blocks are inserted into the portion where the filling layer has been excavated for the track slab having a predetermined length. The method for repairing a filling layer in a slab track as described in claim 2, characterized in that the blocks are provided with engaging portions that can mesh with the engaging portions of adjacent blocks. The method for repairing the filling layer in a slab track as described in claim 2 or 3, characterized in that the total length of the multiple blocks inserted corresponding to one of the track slabs is the length of one of the track slabs plus the gap between the track slabs, and the blocks are arranged so that the ends inserted between adjacent track slabs and roadbed concrete come into contact or engage with each other. A method for repairing a filling layer in a slab track as described in any one of claims 1 to 4, characterized in that the post-treatment in the third step is a process of injecting a hardening type repair agent into the gap between the surface of the block inserted into the portion where the filling layer was excavated and the surrounding members.

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