JP7345451B2 - Tunnel waterproofing method - Google Patents

Description

The present invention relates to a tunnel waterproofing method, and particularly to a tunnel waterproofing method that allows construction of a composite waterproof layer with high workability in a method of rolling out a long waterproof sheet.

In mountain tunnel construction, sheet waterproofing is used to ensure the waterproofness of the tunnel, in which a waterproof sheet is pasted onto the shotcrete surface of the tunnel.
In recent years, in sheet waterproofing, long waterproof sheets with a width of about 10 m have been developed and utilized for the purpose of improving workability. Since this long waterproof sheet cannot be handled in its unfolded state, it is folded back multiple times in the width direction and then folded into a long strip in the longitudinal direction, and placed on a sheet truck along the circumferential direction of the tunnel.
During installation, the fixed pieces (called ``fins'') on the back of the tarpaulin sheet were nailed to the shotcrete surface at predetermined intervals along the circumference of the tunnel, and then the sheet truck was moved to the face side and folded. Unroll the tarpaulin and repeat these steps to apply the entire length of the tarpaulin to the shotcrete surface.

Patent Document 1 describes a method for unwinding a long waterproof sheet, in which a tube-shaped inflatable body is arranged along the pedestal of a sheet truck, and the waterproof sheet is pasted while being pressed against a shotcrete surface with the inflated body. A tunnel waterproofing method is disclosed.

JP2019-199688A

The conventional technology had the following problems.
<1> Workability.
In the case of unrolling a long tarpaulin sheet, when installing the tarpaulin sheet, the worker stands on the face side of the folded tarpaulin sheet, grasps the fixed piece on the back of the tarpaulin sheet, presses it against the shotcrete surface, and stretches it in the circumferential direction of the tunnel. Hammer nails at specified intervals along the line.
Here, the distance between the fixing pieces in the seat width direction is 1 m or more, and it is impossible to reach the fixing pieces in the second row through the folded waterproof sheet, so it is difficult to nail the fixing pieces in two or more rows at a time. Can not.
Therefore, every time the waterproof sheet is nailed in one row in the circumferential direction, it is necessary to move the sheet truck and feed out the waterproof sheet to the position of the next fixing piece.
Furthermore, when nailing, the worker must move up and down on the sheet truck from the ceiling to the ground.
Therefore, the conventional technology has room for improvement in workability.

<2> Issues associated with application to composite laminated structures.
In recent years, with the aim of improving construction quality, waterproof sheets with a composite laminated structure in which a waterproof sheet and a back cushioning material such as a nonwoven fabric are integrated have been frequently used.
However, when a long waterproof sheet has a composite laminated structure, the back cushioning material is thick and bulky, so it must be folded at the factory, transported to the site, placed on a sheet trolley, rolled out on the sheet trolley, and sprayed onto the shotcrete surface. It is difficult to handle the tarpaulin sheet during each process of nailing it to the roof, resulting in poor workability.
In particular, when nailing to a shotcrete surface, the heavy, laminated waterproof sheet is grabbed by the fixing pieces and pressed onto the shotcrete surface, which places a great physical burden on the worker.

The tunnel waterproofing method of the present invention includes a back cushioning material fixing step in which the back cushioning material is spread and fixed on the shotcrete surface, and a plurality of electromagnetic induction heating elements are fixed at predetermined intervals on the back cushioning material. a heating element fixing process; a waterproof sheet placement process in which the waterproof sheet, which is folded multiple times in the width direction and folded into a long strip in the longitudinal direction, is placed on a sheet trolley along the circumferential direction of the tunnel; A start end fixing step in which the starting end of the direction is fixed onto the back cushioning material at a predetermined interval in the circumferential direction of the tunnel, and a step in which the waterproof sheet is paid out from the seat cart by moving the sheet cart in the face direction. During the process, an electromagnetic induction device is brought close to the surface of the tarpaulin sheet fed out from the sheet trolley, and the electromagnetic induction heating element on the back cushioning material is heated by electromagnetic induction through the tarpaulin sheet, causing the tarpaulin sheet to generate electromagnetic induction heat. A welding step of welding the waterproof sheet to the body is repeated, and the feeding step and the welding step are repeated a predetermined number of times to bond the waterproof sheet over the entire width onto the back cushioning material.

In the tunnel waterproofing method of the present invention, in the back cushioning material fixing step, a plurality of back cushioning materials corresponding to the length in the width direction of one waterproof sheet are laid on the shotcrete surface along the tunnel axis direction. You can also fix them side by side.

In the tunnel waterproofing method of the present invention, a reference line parallel to the tunnel axis direction may be drawn on the surface of the back cushioning material fixed on the shotcrete surface.

In the tunnel waterproofing method of the present invention, the waterproof sheet may have translucency.

The tunnel waterproofing method of the present invention has at least one of the following effects.
<1> High workability.
At the mine entrance side of the folded tarpaulin sheet, the tarpaulin sheet is pasted from the sheet surface side by electromagnetic induction, so even though a long tarpaulin sheet is installed, it is possible to waterproof a large area at once without moving the sheet cart frequently. A sheet can be attached.
In addition, at this time, workers can weld multiple locations in the tunnel axis direction at once on a stage at the same height on the seat truck, reducing the number of times the worker lifts and lowers the seat truck to a fraction of that of conventional technology. be able to.
For this reason, workability is extremely high and the physical burden on workers is low.
<2> Compatibility with composite laminated structures.
By combining split nailing of the back cushioning material and welding of the waterproof sheet, a waterproof sheet with a composite laminated structure consisting of the waterproof sheet and the back cushioning material can be applied efficiently with simple work.

FIG. 2 is an explanatory diagram of the tunnel waterproofing method according to the present invention. An explanatory diagram of a composite waterproof layer. An explanatory diagram of a back cushioning material fixing process. An explanatory diagram of a heating element fixing process. An explanatory diagram of a starting end fixing step. An explanatory diagram of a feeding process. An explanatory diagram of a welding process.

Hereinafter, the tunnel waterproofing method of the present invention will be explained in detail with reference to the drawings.
In addition, in this specification, the "width direction (width)" of the waterproof sheet and back cushioning material is the direction (width) parallel to the tunnel axis direction at the time of completion of construction, and the "longitudinal direction (length)" is the direction (length) perpendicular to the width direction on the waterproof sheet.
Further, the "back" of the waterproof sheet and the back cushioning material means the surface that faces the shotcrete surface during installation, and the "front" means the opposite surface to the back.
"Extending" the back cushioning material means spreading and pressing the back cushioning material onto the shotcrete surface.
The dimensions and ratios of each component in the drawings are changed as appropriate for the purpose of explanation, and do not represent actual dimensions or ratios. Furthermore, in the drawings, the tunnel, waterproof sheet, and back cushioning material are shown in cross section along the tunnel axis direction.

[Tunnel waterproofing method]
<1> Overall configuration (Figure 1).
The tunnel waterproofing method of the present invention is a method for constructing a composite waterproof layer 10 on a shotcrete surface A in mountain tunnel construction.
The tunnel waterproofing method includes at least a back cushioning material fixing step S1, a heating element fixing step S2, a waterproof sheet placement step S3, a starting end fixing step S4, a feeding step S5, and a welding step S6. The composite waterproof layer 10 is provided on the shotcrete surface A by repeating step S5 and welding step S6 a predetermined number of times.
In addition, below, one construction cycle in which the composite waterproof layer 10 is newly provided on the face side of the composite waterproof layer 10 provided on the shotcrete surface A in the previous construction cycle will be explained.

<2> Composite waterproof layer (Figure 2).
The composite waterproof layer 10 is a waterproof layer with a composite structure consisting of a back cushioning material 12 fixed on the shotcrete surface A and a waterproof sheet 11 pasted on the surface of the back cushioning material 12.
In the tunnel waterproofing method of the present invention, instead of attaching the composite waterproof layer 10 as an integral sheet, the waterproof sheet 11 is attached to the surface of the back cushioning material 12 fixed to the shotcrete surface A. A composite waterproof layer 10 is constructed on the shotcrete surface A.

<2.1> Waterproof sheet.
The waterproof sheet 11 is a sheet body with a water-blocking function.
The waterproof sheet 11 used in the present invention is a long waterproof sheet that is rolled out from a folded state and applied onto the sheet truck B.
Near the starting end of the waterproof sheet 11 in the width direction, a fixing piece ("fin") for fixing the starting end is attached to the back surface.
The width of the waterproof sheet 11 is arbitrarily selected depending on the construction span. The length of the waterproof sheet 11 is made to correspond to the circumference of the shotcrete surface A.
In this example, a sheet made of ethylene vinyl acetate copolymer resin (EVA) with a width of 9.8 m (effective length of 9.6 m) x length of 21.0 m and a thickness of 0.8 mm is used as the waterproof sheet 11.
However, the waterproof sheet 11 is not limited to this, and may be any other known sheet material as long as it has a predetermined strength and water-blocking performance.
Furthermore, if a sheet material made of a translucent material (transparent or translucent) is adopted as the waterproof sheet 11, the position of the electromagnetic induction heating element 20 on the back side of the waterproof sheet 11 can be adjusted to the position of the electromagnetic induction heating element 20 on the back side of the waterproof sheet Since it can be visually recognized from the surface side, construction efficiency is further increased.

<2.2> Back cushioning material.
The back cushioning material 12 is a sheet body having a shock-absorbing function and a drainage function.
In this example, a long fiber nonwoven fabric sheet of 2.1 m width x 21.0 m length is used as the back cushioning material 12.
That is, in this example, five back cushioning materials 12 (total effective length 10.0 m) are used in combination with one waterproof sheet 11 (effective length 9.6 m).
Further, a three-dimensional mesh body may be installed on the back side of the back cushioning material 12 to improve the drainage function.

<3> Back cushioning material fixing process (Figure 3).
The back cushioning material fixing step S1 is performed, for example, in the following steps.
The back cushioning material 12 rolled from both sides in the longitudinal direction toward the center is carried onto the seat truck B, and the two roll portions of the back cushioning material 12 are rolled down from the center of the sheet truck B to both sides to form the back cushioning material. 12 is unfolded on the sheet trolley B.
The back cushioning material 12 is pressed against the face side of the composite waterproofing layer 10 of the previous construction cycle on the shotcrete surface A.
The longitudinal center of the back cushioning material 12 is aligned with the circumferential center of the shotcrete surface A, and fixed with concrete nails. Subsequently, the back cushioning material 12 is nailed to the shotcrete surface A around the entire circumference at predetermined intervals from the center to both sides.
After one back cushioning material 12 is fixed, the sheet truck B is moved and the next back cushioning material 12 is fixed on the face side of the fixed back cushioning material 12. In this example, an overlap margin of 10 cm is provided between two adjacent back cushioning materials 12.
By repeating the above procedure, five back cushioning materials 12 corresponding to the entire circumference of the waterproof sheet 11 are fixed on the shotcrete surface A.

<3.1> Effects of dividing the back cushioning material.
In this example, the back cushioning material 12 is divided into a plurality of sheets and applied to one waterproof sheet 11.
By setting the division unit of the back cushioning material 12 within the range of weight and width that can be handled by one worker, it is possible to construct the back cushioning material 12 while constructing a long and seamless waterproof sheet 11. can be lifted and moved by one worker. Therefore, it is highly workable and requires less physical strain on workers.
Further, since the back cushioning material 12 is strong and does not require watertightness, it does not require careful handling unlike a composite integrated waterproof sheet, which requires reliable repair even if there is a slight scratch. Therefore, it is easy to handle and can be constructed efficiently.

<4> Heat generating element fixing step (Figure 4).
The heating element fixing step S2 is performed, for example, by the following procedure.
A plurality of electromagnetic induction heating elements 20 are fixed to the surface of a back cushioning material 12 fixed on a shotcrete surface A.
Specifically, the electromagnetic induction heating element 20 is placed on the back cushioning material 12, and a concrete nail is inserted into the center hole of the electromagnetic induction heating element 20 and nailed to the back cushioning material 12.
The electromagnetic induction heating elements 20 are nailed all around the circumference of the tunnel at predetermined intervals in the tunnel circumferential direction to form a single row, and are fixed in multiple rows at predetermined intervals (in this example, 1 m intervals) in the tunnel axial direction.
The electromagnetic induction heating element 20 is fixed to the entire surface of the back cushioning material 12 while moving the seat truck B as necessary.

<4.1> Electromagnetic induction heating element.
The electromagnetic induction heating element 20 is a member that welds the waterproof sheet 11 by an electromagnetic induction effect caused by a high frequency current generated by an electromagnetic induction device 30 (disk welder).
In this example, as the electromagnetic induction heating element 20, a circular disk body consisting of a combination of a fixed plate 21 made of resin and a welding layer 22 provided on one surface of the fixed plate 21 is adopted.
The welding layer 22 can be constructed by, for example, coating one side of a film body made of a magnetic material such as aluminum with a heat-fusible resin.
However, the structure of the electromagnetic induction heating element 20 is not limited to this, and any structure may be used as long as it can be welded to the waterproof sheet 11 by the electromagnetic induction action of the electromagnetic induction device 30.
The configurations of the electromagnetic induction heating element 20 and the electromagnetic induction device 30 are well known and will not be described in detail here.

<5> Waterproof sheet placement process.
The waterproof sheet arrangement step S3 is performed, for example, in the following steps.
A waterproof sheet 11 which is folded inside and out multiple times in the width direction and folded into a long strip in the longitudinal direction is wound into a roll and temporarily placed on the ground on the side of the sheet truck B.
An electric winch is fixed to the side of the seat truck B opposite to the side where the waterproof sheet 11 is placed, and the wire connected to the electric winch is passed through the seat pedestal on the sheet truck B to the opposite side of the sheet truck B. Pass it to the side.
One end of the rolled waterproof sheet 11 is held between a jig and the jig is connected to the tip of the wire.
When the wire is wound up with an electric winch, the waterproof sheet 11 is pulled in the circumferential direction on the seat pedestal of the seat truck B while unfolding in the longitudinal direction, and is stretched around the outer periphery of the sheet truck B.
After hanging, the jig is removed from the waterproof sheet 11.
Note that the method for arranging the waterproof sheet 11 on the sheet truck B is not limited to the above method, and other methods may be used.

<5.1> Effects of separating the waterproof sheet from the back cushioning material.
The conventional tarpaulin sheet with an integrated back cushioning material is thick and heavy, making it difficult to fold or roll, and is bulky, so it occupies a large amount of space when stored. In addition, since the waterproof sheet with an integrated back cushioning material is heavy, when it is towed by an electric winch, stress is concentrated on the part held by the jig, which may damage the waterproof sheet surface.
In contrast, in the tunnel waterproofing method of the present invention, only the single-layer waterproof sheet 11 is handled in the waterproof sheet arrangement step S3, so various operations such as folding, rolling, and unfolding are easy.
Furthermore, since the waterproof sheet 11 is lightweight, it is less likely to be damaged when being towed by an electric winch.

<6> Starting end fixing step (FIG. 5).
The starting end fixing step S4 is performed, for example, by the following procedure.
The starting end of the waterproof sheet 11 placed on the sheet truck B is pulled up and fixed onto the back cushioning material 12.
Specifically, the fixing piece attached near the starting end of the waterproof sheet 11 is picked up, pressed against the starting end of the back cushioning material 12 on the mine entrance side, and nailed onto the back cushioning material 12 with concrete nails. Similarly, nails are secured all around the tunnel at predetermined intervals in the circumferential direction.
The starting end of the waterproof sheet 11 is left hanging downward, and later it is matched with the rear end on the face side of the waterproof sheet 11 of the previous construction cycle and welded together with an electric heater.

<7> Feeding process (Figure 6).
The feeding step S5 is performed, for example, by the following procedure.
The sheet truck B is moved in the face direction.
Since the starting end of the waterproof sheet 11 on the sheet trolley B is nailed onto the back cushioning material 12 at the starting end on the mine entrance side, the waterproof sheet 11 folded onto the sheet trolley B is moved in the width direction by the movement of the sheet trolley B. It is expanded and brought out.
The width of the waterproof sheet 11 that is fed out per time corresponds to the amount of movement of the sheet truck per time. In this example, the width of the waterproof sheet 11 that is fed out is 4 m/time.

<8> Welding process (Figure 7).
The welding step S6 is performed, for example, by the following procedure.
An electromagnetic induction device 30 is pressed against the electromagnetic induction heating element 20 through the waterproof sheet 11 from the front side of the waterproof sheet 11 fed out from the sheet truck B, and an electromagnetic field is caused to act on the electromagnetic induction heating element 20 from the electromagnetic induction device 30.
Then, the welding layer 22 of the electromagnetic induction heating element 20 generates heat due to electromagnetic induction, and the heat-fusible resin of the welding layer 22 melts and adheres to the back surface of the waterproof sheet 11.
Here, when the electromagnetic induction device 30 is pressed against the waterproof sheet 11 and the electromagnetic field is cut off, the heat generation of the welding layer 22 stops, and the molten thermofusible resin cools and hardens, making the electromagnetic induction heating element 20 waterproof. It is welded to the back surface of the sheet 11.
A similar operation is performed on all the electromagnetic induction heating elements 20 in the waterproof sheet 11 developed on the back cushioning material 12, and the waterproof sheet 11 is pasted onto the back cushioning material 12 via the electromagnetic induction heating elements 20.

<8.1> Effect of attaching the waterproof sheet from the front side using electromagnetic welding.
In the conventional technology, the waterproof sheet was nailed to the shotcrete surface from the back side, so each time a row of nails in the direction of the tunnel axis was nailed, the sheet cart was moved and the waterproof sheet was fed out to the next fixed piece position. There was a need.
Therefore, for example, if the distance between the fixing pieces in the width direction of the tarpaulin sheet is 1 m, a worker must move up and down the sheet trolley, nail the fixing pieces, and move the sheet trolley for every 1 m width of the tarpaulin. had to be repeated. For this reason, nailing could only be done at one location in the axial direction of the tunnel from the same height on the seat truck, which took time and placed a heavy physical burden on the workers.
In contrast, in the tunnel waterproofing method of the present invention, since the waterproof sheet 11 can be welded from the front side, the waterproof sheet 11 can be welded from the front side. Range welding is possible. Furthermore, a worker can collectively weld multiple rows in the tunnel axis direction from a stage at the same height on the seat truck B.
For example, when the amount of movement of the sheet trolley B is 4 m/time, three rows of waterproof sheets 11 can be welded together at intervals of 1 m in the tunnel axis direction. The time and labor involved in moving can be reduced to several times.

<9> Repeat the process.
The feeding step S5 and the welding step S6 are repeated a predetermined number of times to feed out the entire waterproof sheet 11 and weld the entire width of the waterproof sheet 11 onto the back cushioning material 12.
With the above steps, one construction cycle is completed, and a composite waterproof layer 10 consisting of a waterproof sheet 11 and a back cushioning material 12 is constructed on the shotcrete surface A (FIG. 2).

[Example where a reference line is written on the back cushioning material]
In this example, in the back cushioning material fixing step S1, a reference line 12a parallel to the tunnel axis direction is drawn on the surface of the back cushioning material 12 fixed to the shotcrete surface A.
It is desirable that the reference line 12a be drawn at least at the center of the top of the tunnel.
In this example, in the start end fixing step S4 and the welding step S6, the center position of the waterproof sheet 11 is aligned using the reference line 12a of the back cushioning material 12 as a mark, thereby increasing the construction accuracy and facilitating the construction. It can be done.
The reference line 12a may be drawn in advance before fixing the back cushioning material 12, or may be drawn after the back cushioning material 12 is fixed to the shotcrete surface A based on the survey inside the tunnel.

S1 Back cushioning material fixing process S2 Heating element fixing process S3 Waterproof sheet arrangement process S4 Starting end fixing process S5 Feeding process S6 Welding process 10 Composite waterproof layer 11 Waterproof sheet 12 Back cushioning material 12a Reference line 20 Electromagnetic induction heating element 21 Fixing plate 22 Welding layer 30 Electromagnetic induction device A Shotcrete surface B Sheet truck

Claims (3)

In mountain tunnel construction, a tunnel waterproofing method in which a composite waterproof layer including a back cushioning material and a waterproof sheet is provided on the shotcrete surface,
A back cushioning material fixing step of sequentially laying and fixing a plurality of the back cushioning materials corresponding to the length in the width direction of one waterproof sheet on the shotcrete surface along the tunnel axis direction ;
a heating element fixing step of fixing a plurality of electromagnetic induction heating elements on the back cushioning material in a plurality of rows in the tunnel axial direction ;
a waterproof sheet placement step of placing the waterproof sheet, which has been folded back multiple times in the width direction and folded into a long strip in the longitudinal direction, on a sheet trolley along the circumferential direction of the tunnel;
a start end fixing step of fixing the widthwise start ends of the waterproof sheet onto the back cushioning material at predetermined intervals in the tunnel circumferential direction;
a feeding step of moving the sheet cart in the face direction to pay out the waterproof sheet from above the sheet cart by a width corresponding to a plurality of rows of the electromagnetic induction heating element in the tunnel axis direction ;
An electromagnetic induction device is brought close to the surface of the waterproof sheet fed out from the sheet truck, and the electromagnetic induction heating element on the back cushioning material is heated by electromagnetic induction through the waterproof sheet, so that the waterproof sheet is heated. a welding step of welding the electromagnetic induction heating elements in a plurality of rows in the tunnel axial direction ,
The feeding step and the welding step are repeated a predetermined number of times to bond the waterproof sheet over the entire width onto the back cushioning material.
Tunnel waterproofing method. 2. The tunnel waterproofing method according to claim 1 , wherein a reference line parallel to the tunnel axis is drawn on the surface of the back cushioning material fixed on the shotcrete surface. The tunnel waterproofing method according to claim 1 or 2 , wherein the waterproof sheet has translucency.

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