Tunnel waterproof method

Abstract

To provide a tunnel waterproof method capable of installing lining concrete with high quality as releasing workers from hard work.SOLUTION: A tunnel waterproof method of the present invention comprises: an installation process S1 placing an outer peripheral surface of a form body 20 in a generally half-cylindrical shape on a sprayed concrete surface B; an extension process S2 expanding waterproof sheet A on the outer peripheral surface of the form body 20; a covering process S3 partitioning an installation space D between a surface of the form body 20 and the sprayed concrete surface B after covering a gap between the sprayed concrete surface B and the form body 20 at front and rear ends of the form body 20 and both ends thereof; a sucking process S4 sucking air between the sprayed concrete surface C and a rear surface of the waterproof sheet A to attach the waterproof sheet A on the sprayed concrete surface B; and an installation process S5 installing concrete in the installation space D, wherein the waterproof sheet A is sucked and attached sequentially toward both ends from the top end side of the installation space D in the sucking process S4.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a tunnel waterproofing method, and more particularly to a tunnel waterproofing method capable of installing high-quality lining concrete while relieving workers from difficult work. [Background technology]

[0002] In mountain tunnel construction, a sheet waterproofing method is used in which a waterproof sheet is attached to the tunnel's sprayed concrete surface to ensure the tunnel's waterproofing. In recent years, long waterproof sheets of about 10m width have been developed and used for the sheet waterproofing method to improve workability. Since this long waterproof sheet cannot be handled in the unfolded state, it is folded multiple times in the width direction and folded in the length direction into a long strip, and then placed on a sheet cart along the circumferential direction of the tunnel. When attaching the waterproof sheet, the fixing pieces (called "fins", etc.) on the back of the waterproof sheet are nailed to the sprayed concrete surface, then the sheet cart is moved toward the face and the folded waterproof sheet is unrolled, and these processes are repeated until the entire length of the waterproof sheet is attached to the sprayed concrete surface. Patent document 1 discloses a technology in which a waterproof sheet is folded inwards and outwards in the width direction and then folded inwards and outwards in the length direction, placed on the roadbed to the side of a sheet trolley, towed to the other side with a winch and draped over the outer periphery of the sheet trolley, and then unfolded from the front end of the sheet trolley to the rear. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-69862 A Summary of the Invention [Problem to be solved by the invention]

[0004] The conventional technology has the following problems. <1> Construction quality issues The sprayed concrete surface had numerous irregularities caused by excavation and protrusions from the rock bolt caps, and nailing the waterproof sheet would not allow it to conform to the irregularities of the sprayed concrete surface, so there was a risk of gaps appearing between the sprayed concrete surface and the back of the waterproof sheet after the covering concrete was poured. <2> The problem of hard work When fixing the waterproof sheet, multiple workers had to grab the fixing piece (fin) on the back of the folded waterproof sheet, lift the waterproof sheet, press it against the sprayed concrete surface, and nail it in. This required workers to look up and use both hands, making it a physically demanding and difficult task.

[0005] An object of the present invention is to provide a tunnel waterproofing method that solves the problems of the conventional technology as described above. [Means for solving the problem]

[0006] The tunnel waterproofing method of the present invention comprises a placement process in which the outer surface of a substantially semi-cylindrical formwork body is placed close to the sprayed concrete surface; a spreading process in which a waterproof sheet is spread over the outer surface of the formwork body; a shielding process in which the gap between the sprayed concrete surface and the formwork body at the front, rear and both bottom ends of the formwork body is shielded to define a pouring space between the surface of the formwork body and the sprayed concrete surface; a suction process in which air is sucked in between the sprayed concrete surface and the back surface of the waterproof sheet to adsorb the waterproof sheet to the sprayed concrete surface; and a pouring process in which concrete is poured into the pouring space, and is characterized in that in the suction process, the waterproof sheet is sequentially adsorbed from the top side of the pouring space toward both sides.

[0007] In the tunnel waterproofing method of the present invention, in the suction step, a suction pipe may be inserted between the sprayed concrete surface and the back surface of the waterproof sheet in the tunnel axial direction, and air may be sucked through the suction pipe.

[0008] The tunnel waterproofing method of the present invention comprises a waterproof sheet formed by bonding a nonwoven fabric layer and a waterproof layer, and includes a fixing process for fixing the nonwoven fabric layer to the sprayed concrete surface, a positioning process for positioning the outer peripheral surface of a substantially semi-cylindrical formwork body adjacent to the nonwoven fabric layer, a spreading process for spreading the waterproof layer over the outer peripheral surface of the formwork body, a shielding process for shielding the gap between the sprayed concrete surface and the formwork body at the front, rear and both lower ends of the formwork body to define a pouring space between the surface of the formwork body and the sprayed concrete surface, a suction process for sucking air between the nonwoven fabric layer and the back surface of the waterproof layer to adsorb the waterproof layer to the nonwoven fabric layer, and a pouring process for pouring concrete into the pouring space, and is characterized in that in the suction process, the waterproof layer is sequentially adsorbed from the top side of the pouring space toward both sides.

[0009] In the tunnel waterproofing method of the present invention, in the suction step, a suction pipe may be inserted between the nonwoven fabric layer and the back surface of the waterproof layer in the tunnel axial direction, and air may be sucked through the suction pipe. Effect of the Invention

[0010] The tunnel waterproofing method of the present invention has at least one of the following effects. <1> Improving construction quality By sucking in the air between the sprayed concrete surface and the back of the waterproof sheet, the lining concrete can be poured while the waterproof sheet is in close contact with the unevenness of the sprayed concrete surface, preventing the occurrence of voids on the back of the waterproof sheet and allowing the installation of high-quality lining concrete. In addition, by sequentially sucking from the top edge to both bottom edges rather than sucking the entire back of the waterproof sheet at the same time, it is possible to prevent gaps on the back caused by the waterproof sheet being pulled from multiple directions and wrinkles caused by the waterproof sheet bunching up. <2> Free yourself from arduous work The waterproof sheet can be attached to the sprayed concrete surface by the suction means without relying on physical labor by the worker, relieving the worker from the arduous tasks of pressing the waterproof sheet down and hammering nails. [Brief description of the drawings]

[0011] [Figure 1] Flow diagram of the tunnel waterproofing method according to the present invention [Diagram 2] Diagram of the expansion process (1) [Diagram 3] Diagram of the expansion process (2) [Figure 4] Illustration of the shielding process [Diagram 5] Diagram of the suction process (1) [Figure 6] Diagram of the suction process (2) DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The tunnel waterproofing method of the present invention will be described in detail below with reference to the drawings. In the present invention, "front" means the tunnel face side, and "rear" means the tunnel mouth side. The "length" of the waterproof sheet means the dimension corresponding to the tunnel circumferential direction when the waterproof sheet is unfolded, and the "width" means the dimension corresponding to the tunnel axial direction. Furthermore, the "back side" of the waterproof sheet, waterproof layer, and nonwoven fabric layer means the side facing the sprayed concrete surface on the formwork, and the "front side" means the side opposite the back side. EXAMPLES

[0013] [Tunnel waterproofing method] <1> Overall configuration (Figure 1) Tunnel waterproofing method 1 is a method for installing a lining concrete C with a waterproof sheet A on a sprayed concrete surface B in mountain tunnel construction. The tunnel waterproofing method 1 includes at least a placement process S1, a spreading process S2, a shielding process S3, a suction process S4, and a pouring process S5. One feature of the tunnel waterproofing method 1 is that the waterproof sheet A is fixed to the sprayed concrete surface B by sequentially adsorbing it from the top end of the casting space D toward both sides. In the following, we will explain one construction cycle in which new lining concrete C is laid on the face side of the lining concrete C that was laid on the sprayed concrete surface B by the previous construction cycle.

[0014] <1.1> Waterproof sheet In this example, a sheet material in which a nonwoven fabric layer A2 made of a long-fiber nonwoven fabric is laminated to one side of a waterproof layer A1 made of ethylene-vinyl acetate copolymer resin (EVA) is used as the waterproof sheet A. However, the configuration of the waterproof sheet A is not limited to this, and other various known sheet materials may be used as long as they have the required water-proofing performance and strength. The overall width of the waterproof sheet A is selected according to the construction span. The length of the waterproof sheet A corresponds to the inner circumference of the sprayed concrete surface B. In this example, the waterproof sheet A is folded inwards and outwards in the width direction into multiple layers, which are then wound into a roll. Alternatively, the waterproof sheet A may be folded in the width direction and then folded in the length direction.

[0015] <2> Mobile formwork The movable formwork 1 is a formwork (tunnel center) for placing lining concrete C on the inside of the sprayed concrete surface B. The movable formwork 1 comprises at least a base 10 that is movable along the axial direction of the tunnel, a formwork body 20 that is arranged on the base 10 so as to be able to rise and fall freely, a closing body 30, and a suction means 40. The base 10 is made up of multiple gate-shaped platforms connected in the longitudinal direction by beams, and is provided with wheels for movement below the platforms. The formwork body 20 has a roughly semi-cylindrical shape, and its outer peripheral surface corresponds to the curvature of the sprayed concrete surface B.

[0016] <2.1> Obstruction body The closing body 30 is a member that defines a pouring space D between the sprayed concrete surface B and the formwork body 20. The blocking body 30 is disposed linearly at least along the hem (front end edge) of the outer circumferential surface of the formwork body 20 and along both lower end edges of the outer circumferential surface of the formwork body 20 . In this embodiment, a long air bulk that expands when filled with gas is used as the obstruction body 30. Alternatively, an end plate may be combined with the air bulk.

[0017] <2.2> Suction means The suction means 40 is a means for sucking air from within the casting space D. In this example, the suction means 40 includes a long suction tube 41 and a suction device that sucks air through the suction tube 41 . The suction pipe 41 is, for example, a resin tube. The suction pipe 41 is desirably made of a material that has both flexibility for easy handling in a narrow tunnel and rigidity for insertion and removal into the casting space D. In this example, a plurality of ventilation holes are provided near the tip of the suction pipe 41, penetrating the tube body of the suction pipe 41 from inside to outside. The suction device is, for example, an electric suction pump. The electric suction pump is connected to a resin tube (suction pipe 41).

[0018] <3> Placement process The placement step S1 is a step of placing the movable formwork 1 adjacent to the sprayed concrete surface B. Specifically, the placement step S1 is performed, for example, as follows. The movable formwork 1 is moved to the face side end of the lining concrete C that was installed in the previous construction cycle. In detail, the movable formwork 1 is moved toward the face side until the portal side end of the formwork body 20 is located directly below the face side end of the lining concrete C. A stand for installing the waterproof sheet A is placed on the road on the rear side of the movable formwork 1, and a core material is passed through the center of the rolled waterproof sheet A, and it is mounted on the stand so that it can be rotated and pulled out.

[0019] <4> Expanding process The spreading step S2 is a step of spreading the waterproof sheet A over the outer peripheral surface of the formwork body 20. Specifically, the spreading step S2 is performed, for example, as follows. One end of the rolled waterproof sheet A is connected to a wire with a clamping metal fitting, and the wire is passed over the outer peripheral surface of the formwork body 20, stretched across the opposite side of the movable formwork 1, and connected to a winch fixed to the base 10. When the wire is wound up with the winch, the waterproof sheet A is pulled out while rotating on the frame, and is pulled over the outer periphery of the formwork body 20 so that it is hung in a strip-like shape over the formwork body 20 (Figure 2). After placement, the clamping fittings are removed from the waterproof sheet A. Next, the waterproof sheet A on the formwork 20 is pulled out in the width direction and spread out on the formwork 20 (FIG. 3). The front edge of the waterproof sheet A extends forward from the bottom of the formwork body 20. The rear edge of the waterproof sheet A is welded to the front edge of the waterproof sheet A of the previous construction cycle extending from the face side end of the covering concrete C of the previous construction cycle. However, the spreading process S2 is not limited to this, and a method may also be adopted in which, for example, a long roll of waterproof sheet A in an unfolded, unfolded state is wound in the longitudinal direction and stretched around the circumferential direction of the formwork body 20.

[0020] <5> Shielding process The shielding step S3 is a step of defining a pouring space D between the outer peripheral surface of the formwork body 20 and the sprayed concrete surface B. Specifically, the shielding step S3 is performed, for example, as follows. Air is filled into the blocking body 30 at the front edge of the outer periphery of the formwork body 20 to block the bottom of the formwork body 20. The gap between the air bulk and the formwork body 20 is appropriately covered with a rag or the like. At this time, a plurality of suction pipes 41 are inserted in advance in the tunnel axial direction at arbitrary intervals in the tunnel circumferential direction between the blocking body 30 (and the waterproof sheet A placed on the blocking body 30) and the sprayed concrete surface B. At least the tips of the suction pipes 41 are brought close to the sprayed concrete surface B. Air is filled into the closing bodies 30 at both lower edges of the outer periphery of the formwork body 20 to close both lower ends of the formwork body 20. The rear edge of the outer periphery of the formwork body 20 is closed by the front edge of the lining concrete C of the previous construction cycle. As a result, an approximately semi-cylindrical pouring space D is defined by the outer surface of the formwork body 20, the closing bodies 30 at the bottom of the formwork body 20, the closing bodies 30 at both lower edges of the formwork body 20, the covering concrete C of the previous construction cycle, and the sprayed concrete surface B (Figure 4).

[0021] <5.1> Suction tube arrangement In this example, five suction pipes 41 are arranged in parallel on the closure body 30 along the circumferential direction of the tunnel. In detail, a first suction pipe 41a is arranged at the top end of the formwork body 20, a second suction pipe 41b is arranged at each of the left and right shoulders of the formwork body 20, and a third suction pipe 41c is arranged below the second suction pipe 41b on each of the left and right shoulders of the formwork body 20, for a total of five suction pipes. However, the arrangement of the suction pipes 41 is not limited to this, and any number of suction pipes 41 can be arranged at any intervals along the circumferential direction of the tunnel. The proximal end of each suction tube 41 is connected to a suction device (not shown).

[0022] <6> Suction process The suction step S4 is a step of sucking air between the sprayed concrete surface B and the back surface of the waterproof sheet A. Specifically, the suction step S4 is performed, for example, as follows. The suction device is operated to first suck air from the casting space D through the first suction pipe 41a located at the top end of the formwork body 20. This sucks out the air between the sprayed concrete surface B and the back surface of the waterproof sheet A, and the airtight waterproof sheet A adheres to the sprayed concrete surface B near the first suction pipe 41a (Fig. 5). At this time, negative pressure acts within the nonwoven fabric layer A2 on the back surface of the waterproof sheet A, causing the waterproof sheet A to follow the irregularities of the sprayed concrete surface B and adhere closely. Next, while continuing suction with the first suction pipe 41a, air is sucked from the casting space D through the two second suction pipes 41b arranged in the shoulders of the formwork body 20. As a result, the waterproof sheet A on the shoulders of the formwork body 20 is adsorbed to the sprayed concrete surface B near the second suction pipes 41b. Similarly, while continuing suction with the first suction pipe 41a and the second suction pipe 41b, air is sucked from the casting space D through the two third suction pipes 41c arranged on the shoulders of the formwork body 20 (FIG. 6). As a result, the waterproof sheet A on the shoulders of the formwork body 20 is adsorbed to the sprayed concrete surface B near the third suction pipes 41c.

[0023] <6.1> Stepwise suction One feature of the tunnel waterproofing method of the present invention is that the waterproof sheet A is successively adsorbed from the top end side of the casting space D toward both bottom ends. First, the top end is sucked to position the waterproof sheet A in the circumferential center, and then the waterproof sheet A is successively adsorbed from top to bottom, allowing the waterproof sheet A to be spread out precisely and smoothly around the tunnel. This makes it possible to prevent the waterproof sheet A from being pulled from multiple directions, which could result in gaps on the back of the waterproof sheet A, or the waterproof sheet A coming together in parts to cause wrinkles.

[0024] <7> Concrete pouring process The pouring step S5 is a step of pouring concrete into the pouring space D. Specifically, the pouring step S5 is performed, for example, as follows. While maintaining suction by the suction device, concrete for the lining concrete C is poured into the pouring space D. The concrete is poured, for example, by inserting a concrete pump into the pouring space D through an inspection window of the movable formwork 1. When the concrete has been poured up to the top end, suction by the suction device is stopped and the multiple suction pipes 41 are pulled out from the pouring space D. The subsequent steps are well known and will not be described in detail here. EXAMPLES

[0025] [Example of applying a waterproof sheet separately] In the first embodiment, a single waterproof sheet A was adsorbed, but in this embodiment, the waterproof layer A1 and the nonwoven fabric layer A2 are attached separately. In this example, a fixing step S0 of fixing the nonwoven fabric layer A2 to the sprayed concrete surface B is provided prior to the placing step S1. In the fixing step S0, the nonwoven fabric layer A2 is transported to the top end of the tunnel using a sheet cart or the like, and fixed to the sprayed concrete surface B. In detail, on the sheet cart, the longitudinal center of the nonwoven fabric layer A2 is aligned with the circumferential center of the sprayed concrete surface B and fixed with concrete nails. Next, the entire length of the nonwoven fabric layer A2 is nailed to the sprayed concrete surface B at a specified interval from the center to both sides. In the spreading step S2, only the waterproof layer A1 is spread on the formwork 20. In the suction step S4, the suction pipe 41 is inserted between the waterproof layer A1 and the nonwoven fabric layer A2 and suction is performed. The waterproof layer A1 is adsorbed to the surface of the nonwoven fabric layer A2 by suction. In addition, the number of nonwoven fabric layers A2 is not limited to one, and multiple nonwoven fabric layers A2 may be combined with one waterproof layer A1, and multiple nonwoven fabric layers A2 may be laid out on the sprayed concrete surface B, with one waterproof layer A1 being adsorbed to the multiple nonwoven fabric layers A2. EXAMPLES

[0026] [Other Examples of Suction Means] In the first embodiment, a combination of a plurality of suction tubes 41 and a suction device is used as the suction means 40, but the present invention is not limited to this. For example, the waterproof sheet A may be provided with a suction valve that communicates with both sides, and the valve and the suction device may be connected with a suction hose to perform suction. Alternatively, the suction pipe 41 may be arranged from below the formwork body 20 along the circumferential direction of the formwork body 20. In short, it is sufficient that the waterproof sheet A is configured so that it can be adsorbed sequentially from the top end of the casting space D toward both bottom ends. [Explanation of symbols]

[0027] 1. Mobile formwork 10 Foundations 20 Formwork 30 Obstruction body 40 Suction means 41 Suction tube 41a 1st suction tube 41b 2nd suction tube 41c 3rd suction tube A. Waterproof sheet A1 waterproof layer A2 non-woven layer B. Sprayed concrete surface C Lining concrete D Casting space S0 Fixed process S1 placement process S2 Expansion process S3 shielding process S4 Suction process S5 Casting process

Claims

1. In mountain tunnel construction, a waterproofing method is used in which a waterproof sheet is laid on the surface of sprayed concrete and lining concrete is installed on the inner surface of the waterproof sheet. A placement step of placing an outer peripheral surface of a substantially semi-cylindrical formwork body adjacent to the sprayed concrete surface; A spreading process of spreading the waterproof sheet on the outer peripheral surface of the formwork body; A shielding process for shielding the gap between the sprayed concrete surface and the formwork body at the front and rear ends and both lower ends of the formwork body to define a casting space between the surface of the formwork body and the sprayed concrete surface; A suction process for sucking air between the sprayed concrete surface and the back surface of the waterproof sheet to adsorb the waterproof sheet to the sprayed concrete surface; A pouring step of pouring concrete into the pouring space, In the suction step, the waterproof sheet is sequentially sucked from the top end side of the casting space toward both sides. Tunnel waterproofing method.

2. In the suction step, A suction pipe is inserted between the sprayed concrete surface and the back surface of the waterproof sheet in the tunnel axial direction, and air is sucked through the suction pipe. A tunnel waterproofing method according to claim 1.

3. In mountain tunnel construction, a waterproofing method is used in which a waterproof sheet is laid on the surface of sprayed concrete and lining concrete is installed on the inner surface of the waterproof sheet. The waterproof sheet is formed by bonding a nonwoven fabric layer and a waterproof layer, a fixing step of fixing the nonwoven fabric layer to the sprayed concrete surface; a positioning step of positioning an outer peripheral surface of a substantially semi-cylindrical frame body adjacent to the nonwoven fabric layer; A spreading process of spreading the waterproof layer on the outer peripheral surface of the formwork body; A shielding process for shielding the gap between the sprayed concrete surface and the formwork body at the front and rear ends and both lower ends of the formwork body to define a casting space between the surface of the formwork body and the sprayed concrete surface; A suction step of suctioning air between the nonwoven fabric layer and the back surface of the waterproof layer to adsorb the waterproof layer to the nonwoven fabric layer; A pouring step of pouring concrete into the pouring space, In the suction step, the waterproof layer is sequentially sucked from the top end side of the casting space toward both sides. Tunnel waterproofing method.

4. In the suction step, A suction pipe is inserted between the nonwoven fabric layer and the back surface of the waterproof layer in the tunnel axial direction, and air is sucked through the suction pipe. A tunnel waterproofing method according to claim 3.

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