JP7112923B2 - Tunnel waterproof construction method, water barrier and electromagnetic induction head - Google Patents

Description

TECHNICAL FIELD The present invention relates to a tunnel waterproof construction method and a water barrier used in the method, and more particularly to a waterproof construction method using a watertight construction method in a mountain tunnel.

For example, when constructing a mountain tunnel using the NATM (New Austrian tunneling Method) method, a waterproof sheet is installed directly on the excavated inner wall of the tunnel or through the primary lining to prevent spring water from leaking to the secondary lining side. is doing. Furthermore, in the watertight construction method, a thick waterproof sheet is stretched over the entire circumference of the excavated inner wall of the tunnel, and in places corresponding to the joints of the secondary lining concrete, a belt-shaped water barrier is superimposed on the waterproof sheet. is installed to prevent spring water from flowing into the tunnel (see Patent Document 1, etc.). A pair of longitudinal side edges of the water barrier and the waterproof sheet are sealed by resin welding using, for example, a gun-shaped hot melt device.

Japanese Patent No. 3241344

The hot-melt device incorporates an adhesive mounting portion, a heater for melting the adhesive, and a mechanism for pushing out the melted adhesive, and is heavy. Moreover, it is necessary to periodically replenish the adhesive, which is troublesome. In addition, the construction quality is likely to vary, and there are likely to be areas where the seal is insufficient. Furthermore, since the heater generates high heat, it is easy to damage the surrounding waterproof sheet even if the hand is slightly out of order.
In view of such circumstances, the present invention aims to provide a construction method capable of reliably welding and sealing the longitudinal side edges of a water barrier to a waterproof sheet while avoiding heat damage to the waterproof sheet, etc., in waterproof construction of a tunnel. aim.

In order to solve the above-mentioned problems, a tunnel waterproofing construction method according to the present invention provides a belt-shaped water barrier in which a narrow belt-shaped electromagnetic induction sealing member including a conductive layer and a hot-melt seal layer is provided along the longitudinal edge. prepare a
Arranging the water barrier on the inner peripheral surface of a waterproof sheet stretched along the excavated inner wall of the tunnel,
The sealing layer is welded to the waterproof sheet by heating the electromagnetic induction sealing member by electromagnetic induction while moving an electromagnetic induction head that outputs electromagnetic induction energy along the longitudinal edge.

Preferably, the electromagnetic induction head is moved at a constant speed. The electromagnetic induction energy output remains constant. This results in a constant electromagnetic induction energy delivered per unit length of the water barrier. Therefore, the sealing layer is uniformly heated and melted and uniformly welded to the waterproof sheet at any position in the longitudinal direction of the water barrier.
In other words, the moving speed of the electromagnetic induction head and the electromagnetic induction energy output are set so that each portion of the sealing layer is sufficiently welded to the waterproof sheet. As a result, the longitudinal side edges of the water barrier and the waterproof sheet can be tightly sealed, and it is possible to prevent the sealing from being insufficient depending on the location and the sealing state from varying depending on the operator.
In addition, the electromagnetic induction head itself does not become hot enough to melt the waterproof sheet, and electromagnetic induction heating does not occur in places where there is no conductive layer. No risk of heat damage.

The water barrier is
a strip-shaped water barrier body;
a strip-shaped electromagnetic induction sealing member extending along the longitudinal edge of the back surface of the water barrier body facing the tunnel outer peripheral side,
It is preferable that the electromagnetic induction sealing member includes a conductive layer and a hot-melt sealing layer laminated at least on the tunnel outer peripheral side of the conductive layer.

The electromagnetic induction head includes a head body having an electromagnetic induction circuit that outputs electromagnetic induction energy;
a running body for running the head body along the longitudinal edge of the water barrier;
a speed adjustment unit that adjusts the traveling speed;
is preferably provided.

ADVANTAGE OF THE INVENTION According to this invention, in the waterproofing construction of a tunnel, it is possible to reliably seal the longitudinal side edges of the water barrier with the waterproof sheet, and it is possible to suppress variations in construction quality.

1 is a cross-sectional view of a tunnel including a waterproof structure according to one embodiment of the present invention; FIG. FIG. 2 is a cross-sectional view along line II-II of FIG. 1 showing the tunnel before the construction of the secondary lining. 3 is an enlarged cross-sectional view of circle portion III of FIG. 1. FIG. FIG. 4 is a cross-sectional view showing an example of a water barrier in the waterproof structure. FIG. 5(a) is a front view of the water barrier seen from the inner peripheral side of the tunnel. FIG. 5(b) is a rear view of the water barrier as seen from the outer circumference of the tunnel. FIG. 5(c) is a back view showing a modified form of the temporary fixing member of the water barrier. FIG. 6 is an enlarged cross-sectional view of circular portion VI of FIG. FIG. 7 is a perspective view of an electromagnetic induction head used for installing the water barrier. FIG. 8 is a circuit diagram of the electromagnetic induction head. FIG. 9 is an explanatory diagram showing how the water barrier is installed. FIG. 10 is a view of the water barrier at the time of installation as seen from the inner circumference side of the tunnel along line XX in FIG. FIG. 11 is an explanatory front view showing a modified state of use of the electromagnetic induction head. FIG. 12 is a cross-sectional view showing a modification of the water barrier. FIG. 13(a) is a front view of the water barrier according to the modification as viewed from the inner peripheral side of the tunnel. FIG. 13(b) is a rear view of the water barrier according to the modified example as seen from the tunnel outer peripheral side.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.
1 and 2 show a tunnel 1 of the watertight type (non-drainage type). A waterproof sheet 4 is stretched over the entire circumference of an excavated inner wall 2a of the natural ground 2 with a primary lining 3 interposed therebetween. As shown in FIG. 3, the waterproof sheet 4 includes a back cushioning material 4b and an impermeable sheet 4a arranged on the inner surface side of the tunnel. The back cushioning material 4 b is made of nonwoven fabric and faces the primary lining 3 . An impermeable sheet 4a is arranged on the tunnel inner surface side of the back cushioning material 4b. The water-impermeable sheet 4a is made of a water-impermeable resin such as EVA. The thickness of the impermeable sheet 4a is thicker than that used in a normal drainage type, and is, for example, several mm.
As shown in FIG. 1, a secondary lining 5 is constructed on the inner peripheral side of the waterproof sheet 4 in the tunnel.

As shown in FIG. 2, water barriers 10 (10A, 10B) are installed at key points of the waterproof sheet 4. As shown in FIG. The water barrier 10A extends annularly along the tunnel circumferential direction. The water barrier 10B extends linearly along the tunnel axis direction. The installation location of the water barrier 10 (10A, 10B) is preferably a location corresponding to the joint of the secondary lining concrete 5a, but may be a location other than the joint.

As shown in FIG. 4 , the water barrier 10 includes a strip-shaped water barrier body 11 , a temporary fixing member 20 and an electromagnetic induction sealing member 30 .
The water barrier body 11 includes a base portion 12 and a plurality of large and small protrusions 13 and 14 . The base portion 12 is formed in a flat strip shape. Protrusions 13 and 14 protrude from the front surface of the base portion 12 (the surface facing the inner circumference of the tunnel). As shown in FIG. 5( a ), the ridges 13 and 14 are arranged side by side in the width direction of the water barrier 10 and extend parallel to the longitudinal direction of the water barrier 10 .

Specifically, three large ridges 13 and two small ridges 14 are alternately arranged on both sides of the water barrier 10 in the width direction. The small ridges 14 are arranged to be biased to the large ridges 13 on both sides of the three large ridges 13 . The water barrier 10 as a whole is provided with six ridges 13 .
A portion of the base portion 12 outside the portion where the ridges 13 and 14 are arranged constitutes a fin portion 15 in the width direction. A pair of fins 15 are formed on both lateral sides of the base portion 12 .

As shown in FIG. 5(b), a temporary fixing member 20 and an electromagnetic induction sealing member 30 are provided on the back surface of the base portion 12 of the water barrier body 11 (the surface facing the outer circumference of the tunnel). The temporary fixing member 20 is formed in a band-like shape extending along the longitudinal direction of the water barrier 10 and arranged at the widthwise central portion of the back surface of the base portion 21 .
In addition, as shown in FIG. 5C, the temporary fixing member is not limited to a strip shape, and may be circular (or spot-shaped), for example. A plurality of circular temporary fixing members 20B may be spaced apart in the longitudinal direction of the water barrier 10 .

As shown in FIG. 4, the temporary fixing member 20 includes a conductive layer 21 such as aluminum, hot-melt layers 22 and 23, and an adhesive layer 24. As shown in FIG. Hot-melt layers 22 and 23 are laminated on both sides of the conductive layer 21, respectively. The hot-melt layer 22 on the base portion 12 side is adhered to the base portion 12 via the adhesive layer 24 .
As shown in FIG. 4, the hot-melt layer 23 on the back side of the conductive layer 21 is welded to the waterproof sheet 4 by electromagnetic induction heating. As a result, the water barrier 10 is temporarily fixed to the waterproof sheet 4 via the temporary fixing members 20 .

As shown in FIG. 4, an electromagnetic induction sealing member 30 is provided on each of the back surfaces of the pair of fins 15 of the water barrier body 11 facing the outer circumference of the tunnel (upper surface in FIG. 4). As shown in FIG. 5( b ), the electromagnetic induction sealing member 30 is formed in a strip shape with a narrower width than the water barrier body 11 and extends along the longitudinal edges of the water barrier body 11 . The width of the electromagnetic induction sealing member 30 (three layers 31 to 33 to be described later) is slightly smaller than the width of the fin portion 15 (preferably 5 mm or more, more preferably about 10 mm).

As shown in FIG. 6, the electromagnetic induction sealing member 30 includes a conductive layer 31 and sealing layers 32,33. The conductive layer 31 is made of metal such as aluminum. The thickness of the conductive layer 31 is preferably about 6 μm to 100 μm.

Seal layers 32 and 33 are laminated on both sides of the conductive layer 31, respectively. The seal layer 33 on the outer peripheral side of the tunnel (upper side in FIG. 6) is made of a hot-melt film and has hot-melt properties. The thickness of the seal layer 33 is preferably about 30 μm to 100 μm.
The seal layer 32 on the base portion 12 side (lower side in FIG. 6) is made of a thermoplastic resin such as linear low-density polyethylene (LLDPE), and has hot-melt properties. The thickness of the sealing layer 32 is preferably about 30 μm to 200 μm, more preferably about 100 μm.

A seal layer 32 is adhered to the back surface (upper surface in FIG. 6) of the base portion 12 via an adhesive layer 34 . As a result, the electromagnetic induction sealing member 30 is joined to the water barrier body 11 .
The width of the adhesive layer 34 is slightly smaller (for example, 5 mm or more) than the widths of the conductive layer 31 and the sealing layers 32 and 33 . The material of the adhesive layer 34 is, for example, an acrylic adhesive. The thickness of the adhesive layer 34 is preferably about 30 μm to 100 μm, more preferably about 50 μm.

As shown in FIG. 3, the sealing layer 33 of the electromagnetic induction sealing member 30 is welded to the waterproof sheet 4 over the entire length of the water barrier 10 by electromagnetic induction heating. The welded seal layer 33 seals (stops water) between the waterproof sheet 4 and the conductive layer 31 . In addition, the portion of the seal layer 32 that protrudes from the adhesive layer 34 (see FIG. 6) is welded over the entire length to the water barrier body 11 by electromagnetic induction heating. The welded seal layer 32 seals (stops water) between the conductive layer 31 and the water barrier body 11 . Consequently, the electromagnetic induction sealing member 30 seals (stops water) the entire length of the water barrier 10 between the pair of longitudinal edges of the water barrier 10 and the waterproof sheet 4 .

<Tunnel construction method>
The method of constructing the tunnel 1 will be described with a focus on the waterproofing construction, especially the installation construction of the water barrier 10 .
The natural ground 2 is excavated, and the shotcrete 3a is placed on the inner wall 2a of the excavation to construct the primary lining 3.
A waterproof sheet 4 is stretched over the inner peripheral surface of the primary lining 3 .

Further, water barriers 10 are installed at key points on the inner peripheral surface of the waterproof sheet 4 (for example, places where the secondary lining concrete 5a is laid).
Specifically, the water barrier 10 is stretched along the inner circumferential surface of the waterproof sheet 4 in the tunnel circumferential direction. By electromagnetically welding the temporary fixing member 20 to the waterproof sheet 4, the central part in the width direction of the water barrier 10 is temporarily fixed to the waterproof sheet 4. - 特許庁A general known electromagnetic induction head can be used for the electromagnetic welding.
An electromagnetic induction head 40, which will be described later, may be used as a temporary fixing welding means for the temporary fixing member 20. FIG.

After the temporary fixing, the pair of longitudinal edges of the water barrier 10 are joined to the waterproof sheet 4 .
<Electromagnetic induction head 40>
Here, as shown in FIG. 7, an electromagnetic induction head 40 is prepared. The electromagnetic induction head 40 has a head body 41 and a traveling body 42 . The head body 41 has, for example, a rectangular parallelepiped box shape elongated in the front-rear direction. Note that the shape of the head body 41 is not limited to a box shape, and can be modified as appropriate, and may be, for example, a disk shape. A handle 41 b is provided on the upper surface of the head body 41 .

A running body 42 is provided at the bottom of the head body 41 . This allows the electromagnetic induction head 40 to be self-propelled. The traveling body 42 is composed of circular wheels. The running bodies 42 are provided on both the left and right sides of the head main body 41 in the front and rear in the running direction. The running bodies 42 may be provided only on the left and right sides of the front portion of the head body 41 in the running direction, and may not be provided on the rear portion. The traveling body 42 may be a crawler instead of a wheel.

As shown in FIG. 8, the head main body 41 is equipped with a power supply circuit 43, an electromagnetic induction circuit 46, a controller 44 (control section), an operation panel 45, a motor drive circuit 47, and a motor 48. .
The power circuit 43 converts power supplied from an external power source into power for each power drive element of the electromagnetic induction head 40 . Instead of the external power source, the head body 41 may incorporate an internal power source (battery).
The electromagnetic induction circuit 46 includes an output coil 46a for electromagnetic induction energy (induced magnetic flux).

Although detailed illustration is omitted, the operation panel 45 includes, for example, an electromagnetic induction energy output ON/OFF unit, an electromagnetic induction energy output amount setting unit, a travel start/stop operation unit, a travel speed setting unit, and the like. ing. By operating the operation panel 45, the operator A turns on/off the electromagnetic induction energy output, increases or decreases the electromagnetic induction energy output, starts or stops traveling, or changes the traveling speed. can be changed. Operation information of the operation panel 45 is input to the controller 44 .

The controller 44 controls the output of the electromagnetic induction energy, the traveling speed, etc., based on the operation information.
A motor drive circuit 47 drives a motor 48 .
A motor 48 is connected to the traveling body 42 so as to be able to transmit torque.

The controller 44 , the operation panel 45 , the motor drive circuit 47 and the motor 48 constitute a speed adjustment section 49 that adjusts the running speed of the electromagnetic induction head 40 .
The controller 44 and thus the speed control unit 49 may calculate the travel speed at which the seal layer 33 can be welded from the output of electromagnetic induction energy or the like, and automatically set the travel speed. A person other than a specific manager may be prevented from arbitrarily increasing or decreasing the electromagnetic induction energy output or changing the running speed.

<Seal of Water Barrier 10>
As shown in FIGS. 9 and 10, the electromagnetic induction head 40 is applied to the fin portion 15 (longitudinal edge portion) of the water barrier 10, and the electromagnetic induction circuit 46 and motor 48 are operated. By operating the electromagnetic induction circuit 46, electromagnetic induction energy is output from the coil 46a. The electromagnetic induction energy heats the conductive layer 31 of the electromagnetic induction sealing member 30 by electromagnetic induction. At the same time, the running body 42 is rotationally driven by the operation of the motor 48, so that the electromagnetic induction head 40 moves along the longitudinal edge of the water barrier 10 at a predetermined speed, as indicated by the white arrow in FIG. It is automatically driven (moved).

Thereby, a constant amount of electromagnetic induction energy per unit length is supplied to the electromagnetic induction sealing member 30 . As a result, the sealing layers 32 and 33 are uniformly heated and melted and welded to the water barrier body 11 and the waterproof sheet 4 at any position in the longitudinal direction of the electromagnetic induction sealing member 30 .
In other words, the traveling speed (moving speed) and electromagnetic induction energy output of the electromagnetic induction head 40 are set so that each portion of the seal layers 32 and 33 is sufficiently welded.
As a result, the longitudinal side edge of the water barrier 10 and the waterproof sheet 4 can be tightly sealed, and it is possible to prevent the sealing from being insufficient depending on the location and the sealing state from varying depending on the operator. As a result, variations in construction quality can be prevented or suppressed.
Both longitudinal side edges of the water barrier 10 are welded and sealed to the tarpaulin 4 in a similar manner.

As shown in FIG. 9, during the welding and sealing operation, the operator A manually supports the electromagnetic induction head 40 by, for example, gripping the handle 41b.
The worker A only needs to support or hold the electromagnetic induction head 40 so that it does not drop due to gravity. Movement along the longitudinal edges of the water barrier 10 is left to the self-running of the electromagnetic induction head 40 . It is preferable that the operator A does not push the electromagnetic induction head 40 forward in the propelling direction or apply the brake.
Since the electromagnetic induction head 40 itself does not become extremely hot, and electromagnetic induction heating does not occur in areas where there is no conductive layer, the surrounding waterproof sheet 4 is likely to be thermally damaged even if the hands are out of order. None.

By bringing the electromagnetic induction head 40 into contact with the protruding portion 13 in the vicinity of the fin portion 15, the electromagnetic induction head 40 may be caused to travel using the protruding portion 13 in the vicinity as a guide. The electromagnetic induction head 40 may be provided with a slide engaging portion (not shown) that is slidably engaged with the proximate ridge portion 13 .
As shown in FIG. 11 , a guide rail 6 may be installed along the water barrier 10 in the tunnel, and the electromagnetic induction head 40 may be self-propelled along the guide rail 6 .

As shown in FIG. 1, after the water barrier 10 is welded, the secondary lining concrete 5a is poured to construct the secondary lining 5. As shown in FIG. Thus, a watertight tunnel 1 is constructed.
By surely sealing between the water barrier 10 and the waterproof sheet 4, it is possible to surely prevent spring water from leaking to the secondary lining 5 side.

The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the invention.
For example, as the sealing layer of the electromagnetic induction sealing member 30, at least the sealing layer 33 on the outer peripheral side of the tunnel, which is welded to the waterproof sheet 4 and seals between the conductive layer 31 and the waterproof sheet 4, is sufficient. The conductive layer 31 and the water barrier body 11 may be liquid-tightly joined by sealing means and joining means different from the electromagnetic induction heating welding method.

The cross-sectional shape of the water barrier is not limited to that of the embodiment (FIG. 4). As shown in FIGS. 12 and 13(a), a narrow water barrier 10C may be used. The water barrier 10C has three large protrusions 13 arranged in the center and both sides in the width direction. Small ridges 14 are arranged between adjacent large ridges 13 . The small ridges 14 are arranged to be biased toward the large ridges 13 on both sides.
As shown in FIG. 13(b), the temporary fixing member 20 is unnecessary in the narrow water barrier 10C.
The wide water barrier 10 of the embodiment (FIG. 4) and the narrow water barrier 10C of FIGS. can be used separately.
The moving speed and output of the electromagnetic induction head 40 may be changed according to environmental conditions such as temperature.

INDUSTRIAL APPLICABILITY The present invention can be applied, for example, to waterproof construction in mountain tunnels by the watertight construction method.

1 Tunnel 2 Natural ground 2a Excavation inner wall 3 Primary lining 4 Waterproof sheet 5 Secondary lining 10, 10B Water barrier 11 Water barrier main body 15 Fin (longitudinal edge)
30 Electromagnetic induction seal member 31 Conductive layer 32 Seal layer 33 on water barrier main body side Seal layer 34 on tunnel outer peripheral side Adhesive layer 40 Electromagnetic induction head 41 Head main body 42 Running body 43 Power supply circuit 44 Controller (control unit)
45 Operation panel 46 Electromagnetic induction circuit 46a Coil 47 Motor drive circuit 48 Motor 49 Speed controller

Claims (3)

A strip-shaped electromagnetic induction sealing member comprising a conductive layer and hot-melt seal layers laminated on both sides of the conductive layer is attached to a strip-shaped water barrier body via an adhesive layer narrower than the electromagnetic induction sealing member. Prepare strip-shaped water barriers along the longitudinal edges,
Arranging the water barrier on the inner peripheral surface of a waterproof sheet stretched along the excavated inner wall of the tunnel,
While an electromagnetic induction head that outputs electromagnetic induction energy is moved along the longitudinal edge, the electromagnetic induction sealing member is heated by electromagnetic induction, and the conductive layer of the sealing layers on both sides is sandwiched between the electromagnetic induction sealing member and the water barrier main body. welds the seal layer on the opposite side to the waterproof sheet, and welds the portions of the sealing layers on both sides protruding from the adhesive layers on both sides in the width direction of the seal layer on the water barrier main body side to the water barrier main body. A tunnel waterproofing construction method characterized by: A water barrier used for tunnel waterproofing according to claim 1,
a strip-shaped water barrier body;
a strip-shaped electromagnetic induction sealing member extending along the longitudinal edge of the back surface of the water barrier body facing the tunnel outer peripheral side,
The electromagnetic induction sealing member includes a conductive layer and hot-melt sealing layers laminated on both sides of the conductive layer, and the electromagnetic induction sealing member has an adhesive layer narrower than the electromagnetic induction sealing member. A water barrier for waterproofing tunnels , wherein both side portions of the electromagnetic induction sealing member in the width direction protrude from the adhesive layer . An electromagnetic induction head used for tunnel waterproofing construction according to claim 1,
a box-shaped or disk-shaped head body;
a handle provided on the upper surface of the head body;
an electromagnetic induction circuit mounted on the head body and outputting electromagnetic induction energy ;
a running body provided at the bottom of the head body for running the head body along the longitudinal edge of the water barrier;
The amount of electromagnetic induction energy supplied to the sealing layers on both sides of the electromagnetic induction sealing member mounted on the head main body and provided on the water barrier is constant per unit length of the water barrier. a speed control unit that controls the speed;
An electromagnetic induction head for tunnel waterproofing construction, comprising:

Images