JP2019085784A - Construction method of tunnel lining and form for tunnel lining concrete - Google Patents

Abstract

To provide a construction method of a tunnel lining capable of easily carrying out sealing curing or water holding curing continuously after the slide center removal, and a formwork for tunnel lining concrete suitable for the construction method.SOLUTION: A construction method of tunnel lining comprises a formwork assembling step of installing a tunnel lining concrete formwork in a borehole, a placing step of placing concrete C between an inner wall surface of the borehole and the tunnel lining concrete formwork, a formwork removing step for removing tunnel lining concrete formwork, and a curing step of curing concrete C. The tunnel lining concrete formwork has an upper form, a middle form 12 and a lower form 13. In the formwork assembling step, a water permeable formwork 3 is attached to an outer surface of the lower form 13 so as to be flush with the middle form 12, and the water permeable form 3 is left in the formwork removing step.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for constructing a tunnel lining body and a form for tunnel lining concrete.

When constructing a tunnel lining structure in a mountain tunnel such as NATM, it is general to continuously pour concrete along the axial direction of the tunnel by using a slide center. The slide center has a shape corresponding to the cross-sectional shape of the tunnel (the inner surface shape of the tunnel lining structure).
Generally, the tunnel side wall lower than the spring line is inclined to be closer to the center of the tunnel as it goes downward. Therefore, the portion lower than the spring line of the slide center is generally shaped to cover the upper side of the concrete. When the formwork is disposed on concrete, air bubbles are likely to remain under the formwork, and excess water generated when the concrete hardens tends to be accumulated under the formwork.
Therefore, Patent Document 1 discloses a concrete formwork structure in which a water-permeable sheet is stretched to cover the outer surface (surface on the concrete side) of the lower foam disposed at a position lower than the spring line. There is. According to this concrete formwork structure, since excess water and air bubbles discharged when concrete hardens come out through the water-permeable sheet, air bubbles are formed on the lower surface (surface of concrete) of the formwork (lower side foam). And excess water can be suppressed.
In the construction of a tunnel lining construction using a slide center, the slide center may be removed from the mold and moved to the next work area when a predetermined strength is developed in the concrete. In this way, the construction period can be shortened by putting concrete in the subsequent work area while curing in the preceding work area. However, if the slide center is demolded during the curing period, the concrete surface is exposed and comes in contact with the air, which may cause cracking due to rapid cooling and drying.
Therefore, Patent Document 2 discloses a curing method in which a concrete after being demolded is covered with a curing sheet, a water sprinkling means is disposed between the curing sheet and the concrete, and water sprinkling is periodically performed by the water sprinkling means. ing.

JP, 2016-061024, A JP, 2010-168804, A

In the curing method of Patent Document 2, since it is necessary to newly install a curing device after removing the slide center, the construction takes time.
From such a point of view, it is an object of the present invention to propose a method of constructing a tunnel lining body capable of easily performing sealing curing or holding water retention continuously after releasing the slide center, and further, An object of the present invention is to propose a tunnel lining concrete form suitable for the construction method.

In order to solve the above-mentioned subject, the construction method of the tunnel lining body of the present invention comprises a form assembling step of installing a tunnel lining concrete formwork in a borehole, an inner wall surface of the borehole and the tunnel lining. It comprises a placing step of placing concrete between it and a concrete form, a demolding step of removing the tunnel lining concrete form, and a curing step of curing the concrete. The tunnel lining concrete form includes an upper foam, a middle foam having an upper end connected to an end of the upper foam, and a lower foam connected to a lower end of the middle foam. Then, a water permeable frame is attached to the outer surface of the lower foam so as to be flush with the middle foam in the mold assembly process, and the water permeable frame is left in the mold removal process. Do.
According to the construction method of the tunnel lining body, it is possible to discharge the excess water and air bubbles discharged when the concrete hardens through the water permeable frame, and seal by the water permeable frame left at the time of demolding. It can be cured in an environment similar to curing. In addition, surplus water generated at the time of hardening of the concrete and flowing into the water-permeable form is supplied again to the surface of the concrete at the time of curing, so that it is possible to cure in an environment similar to wet curing or water retention curing. Therefore, the tunnel lining construction can be constructed with high quality.
In addition, in the curing step, by supplying the curing water to the water permeable form, it is possible to cure in an environment close to curing in water. Furthermore, in the release step, a curing water supply means for supplying the curing water is provided, and the form support material is interposed between the water permeable form and the curing water supply means. For example, it is possible to support the permeable form during curing without requiring a large-scale support structure.

Further, the tunnel lining concrete form of the present invention comprises an upper foam, a middle foam having an upper end connected to an end of the upper foam, and a lower foam connected to a lower end of the middle foam. . In this tunnel lining concrete formwork, the lower foam is joined to the middle foam, and can be fixed at a position where the outer surface of the lower foam is retracted to the inner hollow side with respect to the outer foam of the middle foam It is characterized by
According to the tunnel lining concrete formwork, for example, the water permeable formwork can be installed to be flush with the middle form by retracting the lower form with respect to the middle form. If a water-permeable form is installed on the outer surface of the lower foam, excess water and air bubbles discharged when the concrete hardens is discharged through the water-permeable form, so it is possible to construct lining concrete with high quality. . In addition, by leaving the water-permeable frame at the time of demolding, sealed curing or water holding and curing can be carried out continuously without using a curing device separately. In addition, you may arrange a decorative mold frame on the outer surface of a lower foam | form.

  According to the construction method of the tunnel lining structure of the present invention, it is possible to simply carry out the sealing curing or the water holding curing continuously after the slide center is released. Moreover, according to the tunnel lining concrete formwork of this invention, the permeable form used for the construction method of the tunnel lining body of this invention can be installed simply.

It is a front view showing a tunnel lining concrete form according to an embodiment of the present invention. It is a front view which shows the installation condition of a permeable form. (A) is a perspective view which shows the upper end part of lower foam | form, (b) is a perspective view which shows the other form of (a). It is an expanded sectional view showing a permeable form. It is sectional drawing which shows the temporarily fixed condition of a permeable form. It is a front view showing a curing situation.

  In the present embodiment, in the case of constructing a tunnel lining body continuous in the tunnel axial direction using a slide center, the construction period can be shortened as compared with the conventional one, and a tunnel lining body which enables high quality construction. The construction method and the tunnel lining concrete formwork used for this will be described. In the present embodiment, the construction period can be shortened by starting concrete placing work in the adjacent subsequent work area in parallel with curing of the concrete in the preceding work area. Moreover, according to the tunnel lining concrete formwork of this embodiment, while removing the excess water and air bubbles which are discharged | emitted when concrete hardens, the said concrete can be cured in the environment near water curing.

The construction method of the tunnel lining body according to the present embodiment includes a mold assembly process, a placing process, a mold removal process, and a curing process.
In the formwork assembly process, as shown in FIG. 1, a tunnel lining concrete formwork 1 is installed in the drilling hole 2. The tunnel lining concrete form 1 is movable along the axial direction of the tunnel, and makes it possible to continuously cast tunnel lining concrete (concrete C). In the present embodiment, the blasted concrete 21 is sprayed on the hole wall (inner surface) of the drilling hole 2. The tunnel lining concrete form 1 is installed in a state where a predetermined distance (a thickness necessary for the tunnel lining body) is secured from the surface of the hole wall of the drilling hole 2 (in the present embodiment, shot concrete 21). The shotcrete 21 may be omitted according to the ground condition.
The tunnel lining concrete form 1 of the present embodiment is a so-called slide center, and has an upper foam 11, a middle foam 12 and a lower foam 13. The upper foam 11 is disposed at the top end of the tunnel. The middle foam 12 of the present embodiment is disposed above the spring line SL of the tunnel side wall. The upper end of the middle foam 12 is connected to the end of the upper foam 11. The lower foam 13 is connected to the lower end of the middle foam 12 and disposed at the leg of the tunnel side wall (lower part than the spring line SL). That is, in the present embodiment, the middle foam 12 and the lower foam 13 are joined at the position of the spring line SL. The boundary position between the middle foam 12 and the lower foam 13 is not limited, and may be, for example, a position lower than the spring line SL.

A support member 14 is disposed on the inner side (the center side of the tunnel) of the upper foam 11, the middle foam 12 and the lower foam 13. The support member 14 is a member for supporting the upper foam 11, the middle foam 12 and the lower foam 13, and is a framework structure formed in a portal shape by appropriately combining shape steels and the like. The support member 14 has wheels 15 at its lower end, and travels on rails laid along the axial direction of the tunnel. That is, the tunnel lining concrete form 1 is movable to a predetermined place. The traveling means of the support member 14 is not limited.
The support member 14 supports the upper foam 11, the middle foam 12 and the lower foam 13 so as to be able to advance and retract in the tunnel radial direction or to be rotatable around a rotation axis parallel to the tunnel axial direction. That is, the tunnel lining concrete form 1 can be reduced in diameter at the time of demolding (moving). The support member 14 also comprises a working scaffold 16. The work scaffolding 16 functions as a temporary storage for workmen's scaffolding and material equipment at the time of placing concrete. In addition, arrangement | positioning of the work scaffold 16 etc. are not limited. The configuration of the tunnel lining concrete form 1 is not limited.

The lower end of the lower foam 13 is located closer to the tunnel center line than the upper end of the lower foam 13. That is, as shown in FIG. 2, the lower foam 13 is inclined so as to approach the center side of the tunnel as it goes downward. The lower foam 13 is bolted to the middle foam 12 so that it can be set back (retracted) with respect to the middle foam 12. That is, the outer surface of the lower foam 13 can be disposed flush with the outer surface of the middle foam 12 and can be retracted to the inner air side with respect to the outer surface of the middle foam 12. The lower foam 13 of the present embodiment includes a first member 17 and a second member 18. The second member 18 is rotatable around a rotation axis parallel to the tunnel axial direction, and is pivotally supported by the lower end portion of the first member 17. The lower foam 13 does not necessarily have to be divided into the first member 17 and the second member 18.
The first member 17 is bolted to the lower end of the middle foam 12. As shown in FIG. 3 (a), since a long hole is formed as a bolt hole 17a on the upper end surface (the joint portion with the middle form 12) of the first member 17 of the present embodiment, the first The member 17 can be advanced and retracted in the tunnel radial direction with respect to the middle foam 12. The bolt holes 17a of the first member 17 (lower foam 13) do not necessarily have to be long holes. For example, as shown in FIG. 3B, a large number of bolt holes 17a are formed in the joint portion of the first member 17 (lower form 13), and the bolt holes 17a through which the bolts are inserted are shifted to form the middle form 12 The lower foam 13 may be fixed in a retracted state. Further, the thickness of the water-permeable mold frame may be shifted and integrated without fixing the bolt.

Since the outer surface (surface on the hole wall side) of the lower foam 13 of this embodiment is positioned closer to the center of the tunnel than the outer surface of the middle foam 12, a step is formed between the middle foam 12 and the lower foam 13. It is formed.
In the present embodiment, the water permeable frame 3 is installed on the step portion (the outer surface of the lower foam 13) between the middle foam 12 and the lower foam 13. That is, the water permeable form 3 is provided so as to be attached to the surface of the concrete C in a state of being supported by the tunnel lining concrete form 1. The outer surface (surface on the ground side) of the water permeable form 3 is flush with the outer surface of the middle foam 12.

As shown in FIG. 2, the permeable form 3 includes a weir 4, a water retaining layer 5 laminated on the concrete C side of the weir 4, and a permeable sheet 6 laminated on the concrete C side of the water retaining layer 5. Have. In the water permeable form 3 of this embodiment, the upper end of the water permeable form 3 is cut off so that the water permeable form 3 is not pushed down by the middle foam 12 when the tunnel interior concrete form 1 is demolded. There is. The corner cut portion of the upper end portion of the water-permeable form 3 is along the locus when the middle foam 12 is released. In addition, the structure of the water permeable form 3 is not limited.
The weir 4 is formed of a wooden plate. The weir 4 disperses the force when supporting the water permeable form 3. In addition, the material which comprises the weir 4 is not limited to a wood. Moreover, what is necessary is just to provide the weir 4 as needed, and when the water holding layer 5 has sufficient proof stress, you may abbreviate | omit.

The water retention layer 5 is formed of a plate material configured to be capable of retaining water. The water retention layer 5 of this embodiment is provided with the core material 51 and the surface materials 52 and 52 laminated | stacked on both surfaces of this core material 51, respectively, as shown in FIG. In addition, the material which comprises the water holding layer 5 will not be limited if it is a plate-shaped member which can be holding water.
The core member 51 is formed by heat-sealing two thermoplastic resin sheets 54, 54 having a plurality of hollow convex portions 53, 53, ... formed in a state where the hollow convex portions 53 are abutted against each other. There is.
The hollow convex portions 53, 53, ... of the thermoplastic resin sheets 54, 54 are in the shape of truncated cones and have the same dimensions. The plurality of hollow convex portions 53, 53,... Are arranged regularly and in a staggered manner on one surface of the thermoplastic resin sheet 54, and a continuous internal space 55 is formed inside the core material 51. It is formed. The shape of the hollow convex portion 53 is not limited to the truncated cone shape, and may be, for example, a truncated pyramid shape or a cylindrical shape. Further, the size and the arrangement of the hollow convex portion 53 are not limited. Further, the material constituting the thermoplastic resin sheet 54 is not limited, but polypropylene-based resins such as homopolypropylene, random polypropylene and block-like polypropylene are suitable for productivity, cost, physical properties, low temperature resistance and heat resistance. It is preferable from the viewpoint of balance with the characteristics of

  The facing materials 52, 52 laminated on both sides of the core material 51 are made of a plate or sheet (thermoplastic resin sheet) made of a thermoplastic resin. Although the material of the surface material 52 is not limited, it is compatible with the core material 51 and can be heat-fused, and the balance with the characteristics such as cost, physical properties, low temperature resistance, heat resistance, etc. From the viewpoint of superiority etc., for example, polypropylene-based resins such as homopolypropylene, random polypropylene and block-like polypropylene are preferable.

  A plurality of through holes (leaching means) 56, 56,... Are formed on the surface (outside surface) of the water retaining layer 5 on the water supply layer side, so that water (such as curing water or breathing water) can flow in and out. It is done. The through holes 56 are formed in the face material 52 and the core material 51, and some of the through holes 56 reach the internal space 55. Therefore, when water is supplied to the internal space 55 of the water retaining layer 5, the water flows out from the through holes 56 and is supplied to the surface of the concrete C via the water permeable sheet 6. Although the size of the through hole 56 is not limited, it is preferable to set the diameter to 1 mm or more so as not to be clogged by a mortar portion, a fine aggregate or the like. Further, the arrangement of the through holes 56 is not limited either, but in the present embodiment, the distance between the through holes 56 (the distance between the adjacent through holes 56) is 10 mm or more.

As shown in FIG. 2, the water-permeable sheet 6 is disposed on the contact surface with the concrete C, and absorbs excess water (including breathing water) generated after the placement of the concrete C, and Water (curing water) is supplied to the surface of concrete C during curing.
The water-permeable sheet 6 of the present embodiment is a non-woven fabric. In addition, the material which comprises the water-permeable sheet 6 will not be limited if it is a sheet material which had water permeability, for example, may be a woven fabric, and is a vinyl sheet in which many holes were formed. May be

In the placing step, concrete C is placed between the inner wall surface (blasted concrete 21) of the drilling hole 2 and the tunnel lining concrete form 1.
Excess water including breathing water generated after the placement of the concrete C (when the concrete C hardens) flows out from the through holes 56, 56, ... into the internal space 55 of the water permeable form 3 via the water permeable sheet 6. . The excess water that has flowed into the internal space 55 may be drained as appropriate, or may be stored in the internal space 55. In addition, what is necessary is just to drain excess water, for example from the drainage port (not shown) previously formed in the water permeable form frame 3. As shown in FIG. When the concrete C has a predetermined strength, the tunnel lining concrete form 1 is removed from the mold and moved. At this time, the permeable form 3 is left on the surface of the concrete C.

In the demolding process, the tunnel lining concrete form 1 is removed. At this time, the permeable form 3 is left on the surface of the concrete C (see FIG. 6). The form 1 for tunnel lining concrete that has been demolded is moved to the next work area.
When the tunnel lining concrete form 1 is removed from the mold, as shown in FIG. 5, first, the second member 18 of the lower foam 13 is scooped up, and a water permeable form by the temporary supporting member 71 such as a support jack. Temporarily fix 3 Subsequently, with the water permeable form 3 temporarily fixed, the remaining part of the tunnel lining concrete form 1 is removed (demolded). In addition, the temporary fixing method of the permeable form frame 3 is not limited. In addition, temporary fixing of the water-permeable form 3 may be performed as needed.
When the tunnel lining concrete form 1 is moved (removed), as shown in FIG. 6, the curing water supply means 8 is disposed, and the form support material 7 is made of the water permeable form 3 and the curing water supply means. Interlock with 8 and intervene. The curing water supply means 8 of the present embodiment includes a water storage tank 81 for storing curing water, and a water tank frame 82 on which the water storage tank 81 is mounted. The water tank mount 82 is erected on the roadbed, and the water storage tank 81 is installed on the water tank mount 82. In the present embodiment, the frame support 7 is interposed between the water permeable mold 3 and the water tank mount 82 in cooperation with each other. In the case where the water tank frame 82 is not provided (that is, when the water storage tank 81 is directly installed on the roadbed), the form support material 7 is interposed between the water permeable form 3 and the water storage tank 81. Just do it.
The frame support 7 of this embodiment is configured to be extensible by combining a so-called single pipe and a jack. In addition, the material which comprises the formwork support 7 is not limited as long as it can support the permeable form frame 3 at the time of curing.
Moreover, the water tank stand 82 of the present embodiment is formed of a frame scaffolding. The configuration of the water tank pedestal 82 is not limited as long as it can support the water reservoir 81, and may be formed, for example, by combining single-pipe pipes.

In the curing step, concrete C after demolding is cured.
In the present embodiment, curing water is supplied to the left-over water permeable form 3. The permeable form 3 is pressed against the surface of the concrete C by the form supporting member 7 which takes a reaction force to the curing water supply means 8. The curing water is supplied from the curing water supply means 8 (water storage tank 81) to the water holding layer 5 via the water supply pipe 83. Since the water storage tank 81 is disposed at a position higher than the water retaining layer 5, the curing water can be supplied to the water retaining layer 5 by letting it flow naturally. In addition, the supply method of curing water is not limited, For example, you may pressure-feed by a pump etc. In addition, the curing water may be supplied as needed. As the curing water, for example, water (tap water, river water, etc.) collected from outside the tunnel may be used, or underground water generated along with the excavation of the tunnel may be used.
The curing water supplied to the water permeable form 3 (water holding layer 5) penetrates the water permeable sheet 6 through the through holes 56 and is supplied to the surface of the concrete C. Therefore, concrete C is cured in an environment close to underwater curing (water retention curing). In the case where surplus water generated at the time of hardening of the concrete C is stored in the water retaining layer 5, the surplus water is also supplied to the surface of the concrete C.
When curing of the concrete C is completed, the permeable form 3 is removed from the surface of the concrete C, and the curing water supply means 8 is removed or moved.

According to the construction method of the tunnel lining body of the present embodiment and the tunnel lining concrete form 1, the permeable form installed on the outer surface of the lower foam 13 by retracting the lower foam 13 with respect to the middle foam 12 The frame 3 can be flush with the middle foam 12. If the water permeable form 3 is installed, excess water and air bubbles which are discharged when the concrete C hardens can be discharged through the water permeable form 3, and as a result, air bubbles and the like remain on the surface of the concrete C. In addition, it can be constructed with high quality. In addition, no level difference occurs in the side wall portion.
By leaving the water-permeable form 3 at the time of demolding of the tunnel lining concrete form 1, while performing sealing curing or water holding curing continuously before demolding, concrete pouring in the next work area during the curing period is carried out. The installation work can be started. Therefore, shortening of a construction period can be achieved.
In addition, by leaving the water permeable form 3 at the time of demolding, it is possible to continuously carry out sealed curing or water holding curing before demolding without using a curing device separately. Moreover, since the surplus water which generate | occur | produced at the time of concrete hardening and flowed in in the water permeable form 3 is supplied to the surface of concrete C at the time of curing, it becomes possible to cure in the environment similar to wet curing or water retention curing. Furthermore, by supplying the curing water to the permeable form 3, it is possible to cure in an environment similar to underwater curing. Therefore, the tunnel lining construction can be constructed with high quality.
In addition, in the demolding process, the curing water supply means 8 for supplying the curing water is disposed, and the form support material 7 is interposed in cooperation with the water permeable form 3 and the curing water supply means 8. And can support the permeable form 3 during curing without requiring a large-scale support structure.

As mentioned above, although embodiment of this invention was described, this invention is not limited to above-mentioned embodiment, About each said component, it can change suitably in the range which does not deviate from the meaning of this invention.
For example, the method of fixing the water-permeable form 3 after removing the form for the tunnel lining concrete is not limited, and the support structure may be separately constructed when the curing water is not supplied.
Although the case where the water permeable frame 3 is installed on the outer surface of the lower foam 13 has been described in the embodiment, a cosmetic mold frame may be disposed on the outer surface of the lower foam 13.
Further, since the lower foam 13 can be advanced to and retracted from the middle foam 12, the lower foam 13 is flush with the outer face of the middle foam 12 in a section where the water permeable frame 3 is unnecessary. Fix 13 only.
The lower foam 13 may be slidably attached to the middle foam 12.

Reference Signs List 1 tunnel lining concrete formwork 11 upper form 12 middle form 13 lower form 2 drilled hole 3 water permeable form 4 basement 5 water holding layer 6 water permeable sheet 7 formwork support material 8 curing water supply means 81 water tank 82 water tank stand

Claims (5)

A formwork assembly process for installing a tunnel lining concrete formwork in a borehole;
A placing step of placing concrete between the inner wall surface of the wellbore and the tunnel lining concrete formwork;
A demolding step of removing the tunnel lining concrete formwork;
And a curing process for curing the concrete.
The tunnel lining concrete formwork has an upper foam, a middle foam having an upper end connected to an end of the upper foam, and a lower foam connected to a lower end of the middle foam;
In the mold assembly process, a water permeable frame is attached to the outer surface of the lower foam so as to be flush with the middle foam,
In the said demolding process, the construction method of the tunnel lining body characterized by leaving the said permeable form remaining.   The method for constructing a tunnel lining structure according to claim 1, wherein the curing water is supplied to the remaining water permeable form frame in the curing step.   In the demolding process, a curing water supply means for supplying the curing water is disposed, and a form support material is provided by interlinking the water permeable form frame and the curing water supply means. The construction method of the tunnel lining body according to claim 2. Upper form,
A middle foam having an upper end connected to an end of the upper foam;
And a lower foam connected to the lower end of the middle foam, for a tunnel lining concrete formwork,
The lower foam is joined to the middle foam, and the outer surface of the lower foam is fixable at a position receding to the inner air with respect to the outer surface of the middle foam. frame. A permeable form is installed on the outer surface of the lower foam,
5. The tunnel lining concrete form as set forth in claim 4, wherein the outer surface of the water permeable form is flush with the outer surface of the middle foam.

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