JP2023042845A - Lining concrete placing method - Google Patents

Abstract

To provide a lining concrete placing method capable of simply preventing outflow of concrete from a gable side of a form of tunnel lining when the lining concrete is placed between the inner form of the form of tunnel lining and shotcrete.SOLUTION: A form of tunnel lining C comprising an inner form extending in the extension direction of a tunnel and curved in the transverse direction of the tunnel and a flange Cb installed so as to protrude outward in the tunnel transverse direction on a gable side of the inner form, is installed at a position where the shotcrete 12 is placed. Between the inner form Ca and the shotcrete 12 along the flange Cb, at least one layer of extruded polystyrene foam PF, which is a long plate member having a predetermined thickness, is installed. A long air bulk AB is inflated and installed in one layer. A space between the inner form Ca on the gable side and the shotcrete 12 is closed, and the lining concrete is placed in the space 13g formed by the inner form Ca and the shotcrete 12.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD The present invention relates to a method of placing lining concrete, and more particularly to a technique effectively applied to placing lining concrete in the construction of mountain tunnels.

In the construction of mountain tunnels, a blasting method is used in which the tunnel is excavated by placing dynamite in the bedrock and blowing it up. In this construction method, concrete is sprayed on the excavated part and hardened, and rock bolts are installed in the bedrock, and the holding force of the ground itself is used to hold the tunnel. After the rock bolts are installed, a semi-cylindrical form called a center is fitted, and lining concrete is placed (filled) between the sprayed concrete and the center for finishing.

Here, an air bulk is used to prevent the concrete from flowing out from the gable side of the center when filling the center and the shotcrete (placing the lining concrete).

That is, as shown in FIG. 11, which is a cross-sectional view in the tunnel extension direction, and FIG. 12, which is a cross-sectional view along the line ZZ in FIG. It comprises an inner formwork Ca arranged to face the concrete 12, and a flange Cb installed on the gable side of the inner formwork Ca so as to protrude outside of the inner formwork Ca in the tunnel crossing direction. Then, an air bulk AB that is not filled with air is installed on the inner formwork Ca on the flange Cb side, and the air bulk AB is filled with air and expanded to be in close contact with the shotcrete 12, The lining concrete is placed in the space 13g between the formwork Ca and the shotcrete 12 .

If the gap between the gable side of the inner formwork Ca and the shotcrete 12 becomes large, as shown in the figure, a plurality of air bulks AB are used to close the gap.

In FIGS. 11 and 12, the symbol G is the natural ground, the symbol S is the steel shoring, and the symbol 11 is the temporary shotcrete for holding the steel shoring S.

For example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2017-223013) is known as a technique describing tunnel construction using an air bulk.

JP 2017-223013 A

However, the construction method using the air bulk AB described above has the following problems.

That is, when the air bulk AB is inflated, its shape becomes columnar. Then, when the air bulk AB is used in an overlapping manner, the cylindrical air bulk AB is placed on top of the cylindrical air bulk AB. Therefore, when considering the cross section of the air bulk AB, as shown in FIG. It comes to support curved surfaces with curved surfaces. As a result, the contact area between the air bulks AB becomes small, resulting in unstable installation and poor workability.

In addition, the length of the air bulk AB is about 4 m, which is long and heavy (for example, about 6 kg for an air bulk with a diameter of 150 mm and about 8 kg for an air bulk with a diameter of 200 mm). The workability when installing along the direction is extremely poor.

The present invention has been made in view of the above-mentioned technical background, and is intended to facilitate the outflow of concrete from the gable side of the center when lining concrete is placed between the inner formwork of the center and the shotcrete. It is an object of the present invention to provide a method of placing lining concrete that can prevent the

In order to solve the above-mentioned problems, the method for placing lining concrete according to the present invention described in claim 1 is a method for placing lining concrete in the construction of a mountain tunnel, the method extending in the direction of extension of the tunnel. A center provided with an inner formwork curved in the transverse direction and a flange installed so as to protrude outward in the tunnel transverse direction on the gable side of the inner formwork is installed at a position where the shotcrete is placed, and is attached to the flange. At least one layer of extruded polystyrene foam, which is a long plate-shaped member having a predetermined thickness, is installed between the inner formwork and the shotcrete, and the long air bulk is expanded to 1 A layer is installed, the space between the inner formwork on the gable side and the shotcrete is closed, and lining concrete is placed in the space formed by the inner formwork and the shotcrete. and

According to a second aspect of the present invention, there is provided a method for placing lining concrete according to the first aspect, wherein the extruded polystyrene foam is installed on the inner formwork side, and the air bulk is the shotcrete. It is characterized by being installed on the side.

According to a third aspect of the present invention, there is provided a method for placing lining concrete according to the first aspect, wherein the extruded polystyrene foam is installed on the shotcrete side, and the air bulk is placed on the inner formwork. It is characterized by being installed on the side.

In order to solve the above-mentioned problems, a method for placing lining concrete according to the present invention as set forth in claim 4 is a method for placing lining concrete in the construction of a mountain tunnel. A center provided with an inner formwork curved in the transverse direction and a flange installed so as to protrude outward in the tunnel transverse direction on the gable side of the inner formwork is installed at a position where the shotcrete is placed, and is attached to the flange. At least one layer of extruded polystyrene foam, which is a long plate-shaped member having a predetermined thickness, is placed between the inner formwork and the sprayed concrete along the gable side, and the inner formwork on the gable side and the sprayed concrete are placed. A space between the concrete and the concrete is closed, and lining concrete is placed in the space formed by the inner formwork and the shotcrete.

According to claim 5, there is provided a lining concrete casting method according to any one of claims 1 to 4, wherein one or both sides of the extruded polystyrene foam is provided with a tunnel extension Notches along the direction are formed at predetermined intervals.

The lining concrete casting method of the present invention according to claim 6 is characterized in that, in the invention according to any one of claims 1 to 5, the extruded polystyrene foam is mixed with the hardened lining concrete. It is characterized by being subjected to a peeling treatment for improving peelability.

The method for placing lining concrete according to the present invention described in claim 7 is characterized in that, in the invention described in claim 6, the peeling treatment is performed by using an adhesive tape having a release agent surface on the surface of the extruded polystyrene foam. It is characterized by a process of winding the whole along the width direction, or a process of applying a release agent to the entire extruded polystyrene foam.

According to the present invention, the extruded polystyrene foam has a flat shape in the extending direction of the tunnel. Therefore, when the extruded polystyrene foam and the air bulk are stacked on top of each other, the air bulk is stable and workability is improved. do. Moreover, when only extruded polystyrene foam is used, the work can be reduced.

In addition, the use of extruded polystyrene foam, which is lightweight and easy to handle, improves workability during installation.

As a result, it is possible to easily prevent the outflow of concrete from the gable side of the center when the lining concrete is placed between the inner formwork of the center and the shotcrete.

(a) is a plan view of a continuous belt conveyor system used for constructing a mountain tunnel according to this embodiment, and (b) is a side view of the continuous belt conveyor system of (a). It is a flowchart which shows the outline of construction of a mountain tunnel. 4(a) to 4(d) are explanatory diagrams showing the order of placement of lining concrete in the construction of the mountain tunnel according to the present embodiment. 1 is a cross-sectional view in the direction of extension of a tunnel including an outflow prevention member as an embodiment of the present invention, which is installed when lining concrete is poured in construction of a mountain tunnel; FIG. 5 is a cross-sectional view taken along line WW of FIG. 4; FIG. (a) is a perspective view showing the extruded polystyrene foam used for the outflow prevention member of the present embodiment, (b) is a perspective view showing the extruded polystyrene foam of (a) with a notch formed on one side, ( Figure 3c) is a perspective view of the extruded polystyrene foam of (a) with notches formed on both sides; FIG. 4 is a cross-sectional view in the direction of extension of the tunnel, including an outflow prevention member as another embodiment of the present invention, which is installed when lining concrete is poured in the construction of a mountain tunnel. FIG. 8 is a cross-sectional view taken along line XX of FIG. 7; FIG. 10 is a cross-sectional view in the tunnel extending direction including an outflow prevention member as still another embodiment of the present invention, which is installed when lining concrete is poured in construction of a mountain tunnel. FIG. 10 is a cross-sectional view taken along line YY of FIG. 9; FIG. 2 is a cross-sectional view in the tunnel extension direction including a conventional outflow prevention member installed when lining concrete is placed in the construction of a mountain tunnel. FIG. 12 is a cross-sectional view along line ZZ of FIG. 11;

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment as an example of the present invention will be described in detail below with reference to the drawings. In the drawings for describing the embodiments, in principle, the same components are denoted by the same reference numerals, and repeated description thereof will be omitted.

The method of placing lining concrete in the present embodiment is particularly applied to placing lining concrete in the construction of mountain tunnels.

In the construction of mountain tunnels, a blasting method is used in which the tunnel is excavated by placing dynamite in the bedrock and blowing it up. This method is called NATM (New Austrian Tunneling Method), in which concrete is sprayed on the excavated part and hardened, rock bolts are installed in the bedrock, and the holding force of the ground itself is used to hold the tunnel.

First, a configuration example of a continuous belt conveyor system used for constructing a mountain tunnel according to the present embodiment will be described with reference to FIG. Here, FIG. 1(a) is a plan view of a continuous belt conveyor system used for construction of a mountain tunnel according to the present embodiment, and FIG. 1(b) is a side view of the continuous belt conveyor system of FIG. 1(a). be.

The illustrated continuous belt conveyor system 1 is a system for transporting debris (excavated material) generated when the face K of the tunnel T is excavated by blasting to the tunnel T mouth. A truck 3 and a belt conveyor 4 are arranged in tandem in order from the face K toward the pit.

The crusher 2 is a self-propelled crusher that crushes the debris generated by blasting into a size that can be carried by the belt conveyor 4 . The tailpiece truck 3 is a self-propelled relay conveying device that conveys the scrap crushed by the crusher 2 to the belt conveyor 4, and is installed at the tip of the belt conveyor 4 (that is, on the face K side of the belt conveyor 4). there is The belt conveyor 4 is a conveying device that carries the sludge carried via the tailpiece carriage 3 toward the mouth of the tunnel T on a long conveying belt 4a. It is installed in a state of being continuously extended from the end to the tunnel T side. Further, the continuous belt conveyor system 1 is provided with a belt storage 5 for storing extra length belts (stretching belts) and applying appropriate tension to the belts 4a.

In addition to the above, the continuous belt conveyor system 1 also includes a belt joint stand (not shown) for adding the belt 4a when the excess belt stored in the belt storage 5 runs out, and a belt 4a circulating drive. A main drive (not shown) which is the main drive for driving, a booster drive (not shown) which drives the belt 4a in the daytime part of the belt conveyor 4, ventilation and electrical equipment (not shown) for controlling each device ) etc. are arranged.

In addition, the continuous belt conveyor system 1 is in a state of being pulled to one side in the width direction of the tunnel T, and the other side in the width direction of the tunnel T is used for spraying concrete against the wall surface of the excavated bedrock. machine (not shown), a face boring machine (not shown) for boring a hole (charge hole) for loading blasting into the face K, and a shovel for loading the crusher 2 with debris generated by the blasting. As a passageway for various heavy equipment such as a self-propelled side dump 7 equipped with 7a, a heavy equipment for loading such as a backhoe, and a breaker (not shown) for performing work such as crushing, excavating, and splitting into small rocks. Enabled. Further, the work site is assigned a material storage area (not shown) for stocking rock bolts, steel shoring, and the like.

In the continuous belt conveyor system 1, at the time of blasting, the tip of the crusher 2 located at the head is arranged at a position where the shear scattered from the face K does not reach. As a result, it is possible to prevent the crusher 2, the tailpiece carriage 3, and the belt conveyor 4 from being damaged due to the shear scattered from the face K during blasting. When transporting the blasted debris, the side dump 7 moves toward the face K, and the excavated debris is dumped into the crusher 2 by the shovel 7a.

In FIG. 1(b), the dotted line extending to the left and right indicates the area of the shotcrete in the longitudinal direction of the tunnel T, and the symbol B indicates the rock bolt installed in the concrete. Also, the shotcrete and the rock bolt B will be described later.

Next, the outline of construction of a mountain tunnel will be described using the flow chart of FIG.

First, as described above, a charge hole is drilled in the face (step St01), an explosive is loaded (step St02), and blast excavation is performed (step St03). Then, the muck is carried out (step St04).

Next, it is determined whether or not to install the steel shoring S (Figs. 4, 6, 9) based on the condition of the rock (step St05). St06), erecting the steel shoring S (step St07). If the steel shoring S is erected in step St07, it is placed on the surface of the concrete that has been temporarily sprayed, or if the steel shoring S is not installed in step St05, it is directly ground G (Fig. 4 , 5, 7 to 10) are sprayed with concrete (step St08), and rock bolts B (FIGS. 4, 6, 9) are installed (step St09).

In the present application, the concrete that is sprayed when installing the steel shoring S is referred to as temporary shotcrete 11 (Figs. 4, 5, 7 to 10), and the temporary shotcrete 11 or steel shoring S is installed. The concrete that is sprayed onto the surface of the natural ground G is simply called the shotcrete 12 (Figs. 4, 5, 7-10). Further, in the present application, it is assumed that the shotcrete 12 is sprayed onto the temporary shotcrete 11 on the premise that the steel shoring S is erected. However, it is not excluded to directly spray the shotcrete 12 onto the natural ground G without erecting the steel shoring S.

Now, once the rock bolt B has been installed in step St09, finally, to prevent water leakage into the tunnel, a waterproof sheet is affixed as necessary, the center is fitted, and the spraying that was performed in step St08 is performed. Lining concrete is placed between the concrete 12 and the center, and finishing work is performed (step St10). The lining concrete is placed, for example, every other day. Then, it is determined whether or not the series of work is completed (step St11), and if completed, the construction of the tunnel is finished. If the work is not completed in step St11, the process returns to step St01 and the subsequent steps are repeated.

Here, the placement of the lining concrete 13 will be described with reference to FIG. As shown, the center C is a semi-cylindrical formwork that can be moved on steel rails (not shown) to cast the lining 13 in the shotcrete 12 portion of the tunnel T. It has become. As shown in the figure, the center C consists of an inner formwork Ca that extends in the extension direction of the tunnel T and is curved in the transverse direction of the tunnel T, and a flange Cb that is installed on the gable side of the center C so as to protrude outward in the tunnel transverse direction. and Then, while moving the center C, the lining concrete 13 is placed in the space 13 g between the center C and the shotcrete 12 .

That is, as shown in FIG. 3(a), when the inner formwork Ca of the center C is moved and installed at the position where the lining concrete is placed (that is, the position where the shotcrete 12 is placed), As shown in FIG. 3(b), a flange Cb is attached to the gable side of the inner formwork Ca. Subsequently, in order to prevent the placed concrete from flowing out from the gable side of the center C, as shown in FIG. An outflow prevention member 14 (details will be described later) is installed to close the space between the inner formwork Ca on the gable side and the shotcrete 12 . Then, as shown in FIG. 3(d), the lining concrete 13 is placed in the space 13g formed by the inner formwork Ca and the shotcrete 12. Then, as shown in FIG.

Here, even if the outflow prevention member 14 is pushed by the lining concrete 13 when the lining concrete 13 is placed and filled, the side surface of the outflow prevention member 14 is pressed by the flange Cb and the movement is prevented. , the outflow preventing member 14 does not drop from the gable side of the center C. Thus, the flange Cb has a function of supporting the outflow prevention member 14 so that it does not fall from the gable side of the center C when the lining concrete 13 is placed.

When placing the lining concrete 13, as shown in FIG. 3(d), the concrete is poured in order from the bottom, and finally the concrete is blown up and poured into the ceiling. Further, in the present embodiment, the length of the lining concrete 13 poured at one time is, for example, about 10 to 15 m, and the thickness of the lining concrete 13 is, for example, 30 cm or more. However, the numerical values of the lining concrete 13 in the present invention are not limited to these.

Moreover, although the flange Cb is attached to the inner formwork Ca in the present embodiment, the inner formwork Ca and the flange Cb may be integrated so that the attachment of the flange Cb can be omitted.

Next, the outflow prevention member 14 installed when the lining concrete 13 is placed will be described with reference to FIGS. 4 to 10. FIG.

FIG. 4 is a cross-sectional view in the tunnel extension direction including an outflow prevention member as one embodiment of the present invention installed when lining concrete is placed in the construction of a mountain tunnel, and FIG. 5 is the WW line of FIG. FIG. 6 is a perspective view showing extruded polystyrene foam used for the outflow prevention member.

As shown in FIGS. 4 and 5, the outflow prevention member 14 is provided by installing an extruded polystyrene foam PF, which is a long plate-shaped member having a predetermined thickness, and expanding a long air bulk AB. It is. Also, an extruded polystyrene foam PF is installed on the inner formwork Ca side, and an air bulk AB is installed on the shotcrete 12 side.

Here, the extruded polystyrene foam PF is a plate-like member obtained by dissolving polystyrene and mixing it with a foaming agent, a flame retardant, etc. and extruding it into a plate shape (see FIG. 6(a)). This extruded polystyrene foam PF not only can be processed to the desired size at the manufacturing stage, but can also be easily cut at the work site. Furthermore, it has high heat insulation performance, is resistant to water and moisture, and is lightweight. easy to handle. The extruded polystyrene foam PF has a length of 910 mm, a width of 225 mm, and a thickness of 50 mm, but the dimensions are not particularly limited.

In the present embodiment, such extruded polystyrene foam PF is arranged along the inner mold Ca (that is, so that the longitudinal direction of the extruded polystyrene foam PF is the circumferential direction of the tunnel T). Then, by placing one layer of air-free air bulk AB on it (that is, on the shotcrete 12 side) and expanding it, the air bulk AB and the extruded polystyrene foam PF are combined by using the expansion of the air bulk AB The gap between the inner formwork Ca on the gable side and the shotcrete 12 is blocked by the above.

In addition, three layers of the extruded polystyrene foam PF are installed including FIG. 7 and FIG. 8 described below, but it is not necessary to have three layers. That is, the number of extruded polystyrene foams PF to be installed depends on the thickness of one extruded polystyrene foam PF, the diameter of the air bulk AB when expanded, and the distance between the inner formwork Ca on the gable side and the shotcrete 12. Therefore, it is not always necessary to have three layers, and at least one layer may be installed. However, for the air bulk AB, only one layer is arranged.

Depending on the length of the inner formwork Ca in the transverse direction of the tunnel and the length of the extruded polystyrene foam PF, one extruded polystyrene foam PF may be sufficient for arranging one layer of the extruded polystyrene foam PF. Yes, and you may need more than one. Similarly, for the air bulk AB, one sheet may be sufficient for arranging one layer, and a plurality of sheets may be required.

According to this embodiment, since the extruded polystyrene foam PF has a flat shape with respect to the extending direction of the tunnel T, by stacking the extruded polystyrene foam PF and the air bulk AB, a circular shape can be obtained. Since there is no need to support a curved surface with a curved surface (see FIG. 11) as in the case where a columnar air bulk AB is placed on top of a columnar air bulk AB, the air bulk AB is stabilized and workability is improved.

In addition, by using the extruded polystyrene foam PF, which is lightweight and easy to handle, the use of the heavy air bulk AB can be minimized, thereby improving the workability at the time of installation.

This makes it possible to easily prevent concrete from flowing out from the gable side of the center C when the lining concrete 13 is placed between the inner formwork Ca of the center C and the shotcrete 12 .

4 and 5, the extruded polystyrene foam PF is installed on the inner formwork Ca side, and the air bulk AB is installed on the shotcrete 12 side. The conformability to unevenness is improved, and the space between the inner formwork Ca on the gable side and the shotcrete 12 can be closed more firmly.

As shown in FIG. 6(a), the extruded polystyrene foam PF can be used as it is. However, as shown in FIG. 6(b), including FIGS. On one side of the foam PF, or on both sides of the extruded polystyrene foam PF as shown in FIG. As an example, in the case of the dimensions of the extruded polystyrene foam PF of the present embodiment described above (length 910 mm, width 225 mm, thickness 50 mm), cutouts PFc having a depth of 10 mm are formed at intervals of 30 mm. Moreover, when forming on both sides, the cutouts PFc are arranged alternately on both sides.

By forming the notch PFc in this way, the extruded polystyrene foam PF is blown into the shape of the inner mold Ca (the shape of the tunnel T), or as shown in FIGS. When installed on the side of the shotcrete 12, it becomes easy to follow the shape of the shotcrete 12, and the gap between the inner formwork Ca on the gable side and the shotcrete 12 can be more firmly blocked. be possible.

In the present embodiment, the cross-sectional shape of the notch PFc along the longitudinal direction of the extruded polystyrene foam PF is triangular, but may be other shapes such as quadrilateral.

Here, extruded polystyrene foam PF, including FIGS. 7 to 10 described below, is desirably subjected to a peeling treatment for improving the peelability from the hardened lining concrete 13 . Specific examples of the release treatment include a process of wrapping the entire extruded polystyrene foam PF with an adhesive tape having a release agent surface, or a process of applying a release agent to the entire extruded polystyrene foam PF. .

In this way, it is possible to prevent the lining concrete 13 after hardening from adhering to the extruded polystyrene foam PF and tearing off the ends of the extruded polystyrene foam PF, and workability at the time of demolding. The durability can be improved by improving and reusing multiple times. In addition, since the extruded polystyrene foam PF is generally cheaper than the air bulk AB, the cost can be reduced.

When the extruded polystyrene foam PF is wound with an adhesive tape, it is wound along the lateral direction of the extruded polystyrene foam PF. By winding along the lateral direction, the extruded polystyrene foam PF is not difficult to bend in the longitudinal direction (that is, it is not difficult to bend along the inner mold frame Ca), and the strength of the extruded polystyrene foam PF is improved. .

Here, in the case shown in FIGS. 4 and 5, the extruded polystyrene foam PF is installed on the inner formwork Ca side, and the air bulk AB is installed on the shotcrete 12 side. As shown, the installation positions of both may be reversed so that the air bulk AB is installed on the inner formwork Ca side and the extruded polystyrene foam PF is installed on the shotcrete 12 side.

In this way, the heavy air bulk AB can be placed on the inner formwork Ca, so the operator does not need to lift the air bulk AB to a high position (that is, the upper surface of the extruded polystyrene foam PF). can be reduced.

Alternatively, as shown in FIGS. 9 and 10, the gap between the gable-side inner formwork Ca and the shotcrete 12 may be closed only by the extruded polystyrene foam PF without using the air bulk AB. In addition, although three layers of the extruded polystyrene foam PF are installed in the drawing, it is not necessary to have three layers. In other words, the number of extruded polystyrene foams PF installed is determined according to the thickness of one extruded polystyrene foam PF and the distance between the gable-side inner formwork Ca and the shotcrete 12. It suffices that at least one layer is installed instead of three layers.

In this way, the heavy air bulk AB becomes unnecessary, and the space between the gable-side inner formwork Ca and the shotcrete 12 can be closed only by the relatively lightweight extruded polystyrene foam PF. Work can be reduced.

Although the invention made by the present inventor has been specifically described based on the embodiments, the embodiments disclosed in this specification are illustrative in all respects and are limited to the disclosed technology. isn't it. That is, the technical scope of the present invention should not be construed in a restrictive manner based on the description of the above embodiments, but should be construed according to the description of the scope of claims. All modifications are included as long as they do not deviate from the description technology and equivalent technology and the gist of the claims.

In the above explanation, the case where the present invention is applied to blockage between the inner formwork on the gable side of the center and the shotcrete when the lining concrete is poured is shown. It can also be applied to a lining method (FILM (Flat Insulated Lining Method)). The smooth-back tunnel lining method is a construction method in which the gap between the uneven parts of the shotcrete and the waterproof sheet installed on the inner formwork is filled with a back-filling material such as mortar, and the waterproof sheet is adhered to the entire surface. , it is possible to apply the present invention to the closure between the gable side inner formwork and the shotcrete.

11 Temporary shotcrete 12 Shotcrete 13 Lining concrete 13g Space 14 Outflow prevention member AB Air bulk B Rock bolt C Center Ca Inner formwork Cb Flange G Ground PF Extruded polystyrene foam PFc Notch S Steel support T Tunnel

Claims (7)

A method for placing lining concrete in the construction of a mountain tunnel, comprising:
Shotcrete is poured into a center provided with an inner formwork extending in the extension direction of the tunnel and curved in the transverse direction of the tunnel and a flange installed so as to protrude outward in the tunnel transverse direction on the gable side of the inner formwork. position and
At least one layer of extruded polystyrene foam, which is a long plate-shaped member having a predetermined thickness, is installed between the inner formwork and the shotcrete along the flange, and a long air bulk is inflated. and install one layer, closing the space between the inner formwork on the gable side and the shotcrete,
placing lining concrete in the space formed by the inner formwork and the shotcrete;
A method of placing lining concrete characterized by: wherein the extruded polystyrene foam is installed on the inner formwork side and the air bulk is installed on the shotcrete side;
The method for placing lining concrete according to claim 1, characterized in that: wherein the extruded polystyrene foam is installed on the shotcrete side and the air bulk is installed on the inner formwork side;
The method for placing lining concrete according to claim 1, characterized in that: A method for placing lining concrete in the construction of a mountain tunnel, comprising:
Shotcrete is poured into a center provided with an inner formwork extending in the extension direction of the tunnel and curved in the transverse direction of the tunnel and a flange installed on the gable side of the inner formwork so as to protrude outward in the tunnel transverse direction. position and
At least one layer of extruded polystyrene foam, which is a long plate-shaped member having a predetermined thickness, is placed between the inner formwork and the shotcrete along the flange, and the inner formwork on the gable side is provided. Blocking the gap with the shotcrete,
placing lining concrete in the space formed by the inner formwork and the shotcrete;
A method of placing lining concrete characterized by: On one or both sides of the extruded polystyrene foam, notches are formed at predetermined intervals along the extending direction of the tunnel.
The method for placing lining concrete according to any one of claims 1 to 4, characterized in that: The extruded polystyrene foam is subjected to a release treatment to improve release from the hardened lining concrete.
The method for placing lining concrete according to any one of claims 1 to 5, characterized in that: The peeling treatment is
A process of wrapping the entire extruded polystyrene foam along the width direction with an adhesive tape having a release agent surface,
Or a process of applying a release agent to the entire extruded polystyrene foam,
The method for placing lining concrete according to claim 6, characterized in that:

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