JP3923463B2 - Construction method of underground structure and fixing metal fitting used in the construction method - Google Patents

Description

The present invention relates to a fixing bracket used in the construction method and the construction method of underground structures, as in the case of constructing the underground foundation or basement, etc., with the "Neki" excavating Ground construction takes place, In addition, in the construction of structures that involve work performed by workers entering grooves or holes formed by root cutting (hereinafter collectively referred to as “root cutting grooves”), The present invention relates to a method for constructing a reinforced concrete underground structure that can reduce the amount of overburden and reduce the amount of backfill at the time of backfilling, and a fixing bracket used in the construction method.

  When building an underground structure, such as foundation work or basement construction, rooting was conducted by digging the ground of the part where such a structure was constructed in advance to a predetermined depth, and this was formed by this root cutting. Construction of structures is carried out in the deforestation trench.

  As an example of such an underground structure, a construction example in the case of forming the foundation of a building will be described with reference to FIGS. 11 and 12 as follows.

  First, the above-mentioned root cutting is conducted to dig a predetermined depth of the ground on which the foundation 20 is formed, and a quarry stone is formed in the bottom 13 of the root cutting groove 10 formed by this root cutting, where the foundation is formed, After laying the crushing and carrying out the crushing crushing groundwork, the concrete 14 is disposed on the bottom of the root cutting.

  Then, after the formation position of the foundation 20 is specified on the discarded concrete 14 by inking, reinforcing bars 25 made of deformed reinforcing bars or the like are assembled corresponding to the formation position of the foundation 20, and then, on both sides of the reinforcing bars 25. The concrete molds 31 and 32 are erected.

  Then, after placing concrete as a foundation between the concrete molds 31 and 32 and curing until the concrete is hardened, when the concrete molds 31 and 32 are removed, the reinforced concrete in which the reinforcing bars 25 are embedded is used. The base 20 made is made.

  The foundation 20 formed in this way is back-filled so as to be buried in the deforestation trench 10, thereby completing the foundation work.

  The above-mentioned concrete molds 31 and 32 removed after the base concrete is hardened can be used again at other construction sites by removing the concrete adhering to them. can do.

  In the general foundation method described above, the concrete molds 31 and 32 used for molding the concrete to be the foundation 20 are complicated to remove and recover from the foundation 20 after the concrete is hardened. In addition, in order to use the recovered concrete molds 31 and 32 again, a complicated work for removing the concrete adhering to the concrete molds 31 and 32 is required. There has also been proposed a method of so-called “filling and killing” in which the foundation is refilled in a state where such a formwork is attached without being removed (see Patent Document 1).

  In addition, the work of assembling the reinforcing bars 25 arranged in the foundation 20 at the site, the complexity of performing the assembling work of the concrete molds 31, 32, and the assembling of such reinforcing bars 25 and concrete In order to solve the problem that the progress of construction is easily influenced by the weather etc. by assembling the molds 31 and 32 at the construction site, a unit foundation in which a concrete mold and a reinforcing bar arranged therebetween are combined in advance. There is a basic construction method in which the equipment is assembled in a factory facility, etc., discarded and placed and fixed on the concrete, and concrete is placed between the concrete molds, and after curing, the used concrete molds are buried ( Patent Document 2).

Prior art document information of the present invention includes the following.
Japanese Patent No. 3142519 (page 1-4, FIG. 6) JP 2002-266354 A (page 1-4, FIG. 1)

  In the foundation method as described above, the positioning of the concrete formwork used when placing the concrete is performed before the concrete formwork 31 and 32 is erected, and the assembled reinforcing bar 25 is used as a reference. The concrete placement surfaces of the concrete molds 31 and 32 are brought into contact with the spacers 26 attached to the reinforcement bars 25 in order to secure a predetermined interval between the reinforcement bars 25 and the concrete molds 31 and 32. The concrete molds 31 and 32 facing each other in a state are connected by a connecting member 33 and are attached so as not to be separated from each other by the weight and pressure of the concrete when the concrete is placed. Therefore, the reinforcement bars 25 must be assembled before the concrete molds 31 and 32 are erected.

  Moreover, the connection between the concrete molds 31 and 32 by such a connecting member 33 is, for example, as shown in FIG. 13A, the two concrete molds 31 and 32 opposite to the concrete placement surface. The lateral reinforcement members 36 and 36 made of, for example, reinforcing bars are disposed on the side surfaces of the concrete mold frames 31 and 32, respectively. The concrete mold frames 31 and 32 are disposed between the reinforcement members 36 and 36, respectively. This is performed by bundling with a connecting member 33 which is a wire passed through the metal rod, or as shown in FIGS. 13 (B) to 13 (D), metal bars having male threads cut at both ends 33a and 33b. Both ends 33a, 33b of the connecting member 33 are made to protrude through the one and other concrete molds 31, 32, and an opening 371 is provided in the center at both ends 33a, 33b of the connecting member 33. The formed bracket-shaped fixing bracket 37 (see FIG. 13B) and U-shaped bracket (see FIG. 13C) is inserted, and a reinforcing member 36 such as a reinforcing bar is inserted into the recess of the fixing bracket 37. By fitting and screwing the bolts 35 to both ends 33a and 33b of the connecting member 33, the concrete molds 31 and 32 are laterally reinforced to form a piece of grooved steel 361 having a predetermined length. The both ends 33a and 33b of the connecting member 33 are inserted into the opened hole 362 and the nut 35 is screwed.

  Therefore, the attachment of the connecting member 33 to one concrete mold 31 and the attachment of the connecting member 33 to the other concrete formwork 32 cannot be performed as separate steps, and the two concrete formwork 31 facing each other cannot be performed. , 32 need to be erected at the same time.

  After the two concrete molds 31 and 32 are erected, the work between the concrete molds 31 and 32 cannot be performed. Therefore, the concrete molds 31 and 32 are arranged between the two concrete molds 31 and 32. Assembling of the reinforcing bars 25 has to be performed before both the concrete molds 31 and 32 are erected.

  Therefore, as in the case of constructing a relatively large foundation, all of the assembling of the reinforcing bars 25, the assembling of the concrete molds 31, 32, and the removing work of the concrete molds 31, 32 after curing are all pruned. When an operator needs to enter 10, it is necessary to secure a work space for attaching and detaching the concrete molds 31 and 32 on both sides of the reinforcing bar 25 at the assembly position. In order to secure this work space, it was necessary to excavate (excavate) the ground during root cutting.

As an example, in the example shown in FIG. 12, a root cutting bottom is excavated by about 0.5 m from the bottom 23 of the foundation 20 to be built to the left and right in the figure, and a total of 1.0 m is excavated. In order to have the angle of repose 11 and 12 with respect to the depth H of root cutting, the opening surface of the root cutting groove 10 was extended H / 3 to the left and right in the figure from the root bottom 13, respectively. It has an inverted trapezoidal shape.

  Therefore, the root cutting trench 10 is larger than the foundation 20 to be formed, and the amount of extra excavation increases accordingly, and a large amount of earth and sand needs to be carried out along with the excavation. It will be tremendous.

  In addition, in the case where the root-cutting groove 10 having a sufficient margin with respect to the foundation 20 to be formed is formed in this way, a large amount of earth and sand is also removed when the foundation 20 is backfilled. It is necessary to fill the deforestation groove 10, and the labor spent for backfilling is also great.

In this way, the problem that the root-cutting groove 10 must have a sufficient size with respect to the foundation 20 and, therefore , the problem of an increase in the amount of excavation during root-cutting is reinforced. After the assembling of the streaks 25, the concrete formwork is inevitably produced in the deforestation groove 10, and the concrete mold after use is disclosed as disclosed in Patent Document 1 described above. Even when the frame is removed and buried without being collected, the amount of surplus digging cannot be reduced as long as a work space for attaching the concrete form is required.

  In addition, as disclosed in Patent Document 2, when using a unit foundation device that is pre-assembled in a factory facility or the like, this work method can be omitted, although a part of the work in the deforestation trench can be omitted. When used for the construction of large foundations, the individual unit foundation structures become larger, which incurs costs for transportation, storage, etc., and at the construction site, very large heavy machinery for carrying them into the rooting trench. It is necessary to carry it in, and the cost required for construction increases.

  Therefore, the foundation construction by this method can be applied to relatively small-scale foundation works such as cloth foundations of detached houses as disclosed in Patent Document 2, The method cannot be adopted.

  Therefore, the object of the present invention is made to eliminate the above-mentioned drawbacks of the prior art, such as underground foundations and basements, which are formed even when a relatively large-scale underground structure is constructed. By providing a construction method that can reduce the size of the root cutting trench as much as possible, the root cutting operation can be performed easily and simply, and the amount of earth and sand excavated by the root cutting can be reduced. The construction method of the underground structure which can be reduced, and can reduce the labor even in the backfilling after the construction of the basement or foundation is completed, and the concrete used for such a construction method The purpose is to provide formwork.

In order to achieve the above object, the construction method for an underground structure according to the present invention involves a work performed by an operator entering a groove or hole (rooting groove 10) having a predetermined height formed by root cutting. In the construction method of underground structures,
Fixtures 34 and 34 ′ on which one end 33 a of the connecting member 33 can be attached are placed on the concrete 14 cast on the bottom 23 of the groove or hole (rooting groove 10) formed by root cutting. One concrete mold 31 made of a net such as a lath , which will be described later , attached to the surface is placed on the bottom edge of the wall 11 on the side of the one concrete mold 31 of the groove or hole (rooting groove 10). One concrete formwork 31 is set up close to the bottom edge,
Then, after assembling the reinforcing bars 25 along the one concrete form 31,
The other concrete mold 32, which is a net-like body, is set up against the one concrete mold 31 via the reinforcing bar 25, and the mesh 42 formed on the other concrete mold 32 is interposed therebetween. The connecting member 33 is inserted toward the one concrete mold 31 and the one end 33a of the connecting member 33 is attached to the fixtures 34, 34 'attached to the concrete placement surface of the one concrete mold 31. Further, the other end of the connecting member 33 is fixed to the other concrete formwork 32,
After the concrete was allowed to cure by Da設between the one and the other concrete form 31, wherein the backfilling without removing the one and the other concrete form 31,3 2 (according Item 1).

Further, the one concrete mold 31 and , if necessary , the other concrete mold 32 together with the one concrete mold 31 can be formed by a lath, preferably a rib lath (Claim 2 ).

Of the concrete molds 31 and 32, at least the lower end 31 a of the one concrete mold 31 is fixed in advance on the discarded concrete 14 placed on the bottom surface 13 of the rooting groove 10. angle member 51, wood 52, fixed to the fastener 50, such as a grooved steel 53, it may be configured to be erected to the front punch Kimizo 10 (claim 3).

In the construction method described above, the fixture 34 that can attach the one end 33a of the connecting member 33 that connects between the one concrete mold 31 and the other concrete mold 32 is provided on the one concrete mold 31. Attach to the concrete placement surface of the one concrete form 31 by the time of standing,
When the other concrete formwork 32 is erected, one end 33a of the connecting member 33 may be attached to the fixture 34 and the other end may be fixed to the other concrete formwork 32 (Claim 4 ). ).

Furthermore, in the construction method of the underground structure, the present invention fixes the reinforcing material 36 arranged with the width direction of the concrete mold 31 as the length direction on the outer wall surface of one concrete mold 31 made of the net-like body. The fixing bracket 37 of the
Penetrating the concrete form 31 of the one with the parallel to the concrete form 31 of the one, insert or an external thread 341 provided on the intake with tool 34 can be screwed hole 371 is formed A flat portion 372;
The flat portion 372 rises from both ends of the flat portion 372 in a direction away from the concrete mold 31, then forms a parallel direction with the concrete mold 31, and further tilts the tip toward the concrete mold 31, A fixing portion 373 for sandwiching the reinforcing member 36 between the mold 31 and the mold 31 is provided.

In the conventional construction method of the underground structure, after assembling the reinforcing bars 25 on the discarded concrete 14, the concrete molds 31 and 32 are arranged to face each other with the reinforcing bars 25 interposed therebetween. In addition, the used concrete molds 31 and 32 were removed and recovered after the cast concrete was hardened, whereas in the construction method of the present invention, a fixture was attached to the concrete casting surface. was one of the standing after casting the concrete form 31, performs the assembly of reinforcement 25, further performs the assembly of the other concrete form 32 then pre Symbol kill fills one and the other concrete form 31, 32 And the use of a mesh for the other concrete formwork 32, one of the cores through the mesh 42 of the other concrete formwork 32. One end 33a of the connecting member 33 can be connected to the fixture 34 attached to the concrete form 31, and the work for connecting both the concrete forms 31, 32 is performed only from the other side of the concrete form 32. It becomes possible. As a result, there is no need to provide a work space between one concrete mold 31 and the wall surface 11 on the one concrete mold side .

  Therefore, the bottom edge of one concrete formwork 31 can be set up close to the bottom edge of one wall surface 11 of the root cutting groove 10, and the root cutting groove 10 to be formed along with this can be formed as much as possible. It has become possible to reduce the amount of overburden and backfilling.

  Along with this, it is possible to make the excavating equipment to be used in a small scale, reduce the number of workers, and shorten the construction period.

  In particular, in places where the ground is good and where earth retaining is applied, the rooting groove 10 is slightly attached to the concrete formwork 31 without providing an angle of repose on the wall surface 11 on the one concrete formwork 31 side. Can be formed in parallel with a large gap, and in this case, the root cutting trench to be formed can be made smaller, the amount of overburden during root cutting and the filling during backfilling The amount of return is reduced, reducing the effort for root cutting and backfilling.

  By using a lath as a concrete formwork, it is easy to process the concrete formwork to a desired size, and it is relatively lightweight.

  In particular, when a rib lath is used, the rib included in the lath serves as a reinforcement, and can be prevented from being deformed due to a load or the like when placing concrete.

  In addition, when either lath or rib lath is used as the concrete mold, the back side of the concrete mold can be seen through, which is convenient when performing operations such as connection and reinforcement between the molds.

Moreover, the use of such a class as concrete formwork, by a killing fill this concrete form which is integrally embedded in the pouring been the concrete also acts as a reinforcement, Construction of strong reinforced concrete underground structures becomes possible.

Further, a locking tool 50 such as an angle member 51, a piece of wood 52, a grooved steel 53, or the like is fixed in advance on the discarded concrete 14 placed on the bottoming bottom 13, and at least one concrete mold is fixed to the locking tool 50. By fixing the lower end portion 31 a of the frame 31, it is possible to perform the operation of attaching the lower end portion of the concrete mold 31 only from the center side of the rooting groove 10, and the concrete of one concrete mold 31 Attaching the attachment 34 for attaching the connecting member 33 that enables connection to the other concrete formwork to the placement surface, fixing the pier 36 (rebar) 36 to the wall opposite to the concrete placement surface and this standing on the concrete 14 discarded this fixing bracket 37 (see FIGS. 5 to 7) or the like after attaching to one of the concrete form 31 for Theft is facilitated.

  Furthermore, the fixture 34 which can attach one end 33a of the connection member 33 which connects between the one concrete form 31 and the other concrete form 32 is mounted on the concrete by the time the one concrete form 31 is erected. By attaching to the installation surface, it becomes easy to perform the operation of connecting one concrete mold 31 and the other concrete mold 32 as a separate process from the operation of erecting the concrete mold.

  Next, embodiments of the present invention will be described below with reference to the accompanying drawings.

  In the embodiment shown below, an example of constructing the foundation of a building by the construction method of the present invention will be described as an example, but the construction method of the present invention is an underground structure with root cutting such as a basement building. It can be widely used when constructing objects.

  As shown in FIG. 1, the construction method of the reinforced concrete underground structure of the present invention is formed by first performing the above-mentioned “rooting” by digging the ground on which the foundation 20 is formed to a predetermined depth, and by this root cutting. After carrying out ground work such as laying stones and crushing gravel on the bottom surface 13 of the bottoming groove 10 where the foundation is formed, the discarded concrete 14 is placed.

  After that, after the foundation formation position is specified on the abandoned concrete 14 by inking, one concrete formwork 31 that delimits the outline of the foundation 20 is erected at the formation position of the foundation 20 for inking. Therefore, the reinforcing bars 25 are assembled along one concrete mold 31 on the ink mark, and then the other concrete mold 32 is set up against the one concrete mold 31 via the reinforcing bars 25. Set up.

  The concrete is placed between the concrete molds 31 and 32 erected in this manner, and after curing for a predetermined period until the concrete is hardened, at least one concrete mold 31 of the above-described concrete molds 31 is used. The foundation work is completed by backfilling with the formed foundation 20 without removing and recovering.

  Thus, in the construction method of the present invention, the procedure for assembling the reinforcing bars 25 and the assembling of the concrete molds 31, 32 are different from those of the conventional construction method described above, and between the concrete molds 31, 32. After the concrete that is the foundation placed on the base is hardened, at least one of the concrete molds 31 and 32 (31) is removed and refilled as it is without being recovered, and the conventional construction method is used. It is different.

  Hereinafter, the construction method in the present invention that brings about the above-described action will be described focusing on the differences from the above-described conventional construction method.

[Assembly of one concrete formwork]
In the conventional construction method, after the above inking, the reinforcing bar was first assembled with the deformed reinforcing bar in the formation position of the foundation on the discarded concrete 14, but in the construction method of the present invention, After the inking, the one concrete form 31 is first assembled.

  The one concrete mold 31 is buried without being recovered after the cast concrete is hardened. The right side surface 21 in FIG. 2 and FIG. Defined.

  Thus, since one concrete formwork is to be buried, the material of one concrete formwork 31 has a structure in which it is buried in the concrete to be the foundation 20 and integrated with the foundation. Preferably, in the method of the present invention, a net is used as such a material.

  The lath is preferably used as a lath, and when concrete is placed between the other concrete formwork 32 described later, the placed concrete is placed in the mesh 42 formed in the concrete formwork 31. The concrete mold 31 is configured to be integrated with the foundation 20 as the concrete penetrates and hardens the concrete.

  The lath is not particularly limited in shape and structure as long as it is buried in the concrete placed as described above and integrated with the concrete, and a metal plate with cuts is stretched. Various kinds of existing laths such as a metal lath formed in this manner and a wire lath composed of a metal wire can be used.

  In this embodiment, a rib lath 40 in which ribs are formed at predetermined intervals on a metal lath is used as such a lath. As shown in FIGS. 4 (A) and 4 (B), the rib lath 40 is provided with a portion of the metal lath where no cut is formed at a predetermined interval, and the portion where the cut is not formed is V-shaped. The rib 41 is formed by bending into a shape (V-shaped in the illustrated example), a W-shape, a U-shape, a U-shape, or any other shape that can generate a resistance to bending.

  By using such rib laths 40 as the concrete mold 31, the strength in the height direction of one concrete mold 31 can be improved, thereby preventing deformation of the mold when placing concrete. This can be suitably prevented, and when assembling one of the concrete molds 31, it is not necessary to attach a stiffener or other reinforcing material for reinforcing the concrete form 31 in the vertical direction, and work efficiency can be improved.

  Such a lath is processed into a predetermined size according to the height of the foundation 10 to be formed, and is processed into a predetermined width that is convenient for transportation according to the situation at the site. After assembling the carry-in length, it is installed at a predetermined position and carried into the deforestation groove 10.

  In the construction method of the present embodiment in which the rib lath 40 as described above is used as the concrete mold 31, the rib 41 is processed at both ends in the width direction of one concrete mold 31. Is preferred.

  Thus, by providing the ribs 41 at both ends in the width direction of the concrete mold 31, when the concrete mold 31 is connected in the width direction, the ribs 41 of the concrete molds 31 adjacent to each other are connected. By superposing the portions, screwing the polymerized ribs 41 to each other, or by binding the polymerized ribs 41 together with a binding wire or the like, the concrete formwork 31 arranged adjacently is firmly connected. be able to.

One concrete mold 31 described above is erected by fixing the lower end portion 31a on the discarded concrete 14 placed on the bottoming bottom 13, but once the concrete mold 31 is placed on the discarded concrete 14. When the frame 31 is erected, it is impossible to secure a space between the one concrete mold 31 and the one wall surface 11 of the deforestation groove 10, so this one concrete mold 31 is placed on the discarded concrete 14. It is preferable to attach a reinforcing bar or the like as a reinforcing material to reinforce it before fixing it to the other, and a mounting tool 34 for attaching a connecting member 33 for connecting to the other concrete formwork 32 is provided on one side. pre-attached to your clause of concrete設面of concrete formwork 31.

  This operation may be performed in the deforestation groove 10, or may be performed before the concrete mold 31 is carried into the deforestation groove 10, and may be performed in any place depending on the situation of the site. .

  As an example, in the embodiment shown in FIG. 5 and FIG. 6, as the above-described connecting member 33, a cylindrical metal rod having male threads cut at both ends (the other end 33 b side is omitted in the figure) is used. In this example, a male screw 341 inserted into a mesh 42 formed on the concrete mold 31 is used as a fixture 34 for attaching one end 33a of the connecting member 33 to one concrete mold 31. At the end opposite to the formed end, a fixture 34 is used in which a screw hole 342 capable of screwing the one end 33a of the connecting member 33 is formed.

In addition, the fixture 34 of the embodiment shown in FIG. 6 is formed in a tapered shape in which the opening edge 343 of the aforementioned screw hole 342 is enlarged as compared with other portions. One end 33 a of the connecting member 33 is guided by the taper shape, and this is easily introduced into the screw hole 342 .

In the embodiment shown in FIG. 5 as well, the opening edge of the screw hole 342 formed in the fixture 34 is processed into a taper shape like the fixture shown in FIG. It is good also as a shape which is easy to guide in the screw hole 342 inside.

In the configuration shown in FIGS. 5 and 6, the attachment 34 is attached to one concrete mold 31 by first forming the male screw 341 provided on the attachment 34 on the concrete form 31 from the concrete placement surface side. By inserting the nut 35, a washer, and other fixing members formed with a female screw to be inserted into the mesh 42 from the front end side of the male screw 341 projecting through the mesh 42. Has been done.

  As a result, the fixture 34 and the fixing member (nut 35 in the illustrated example) are fixed to one concrete mold 31 and the fixture 34 protrudes from the concrete placement surface.

  As the above-described fixing member, in addition to the nut 35 shown in the illustrated example, a metal plate having a screw hole and other various types can be used. When the nut 35 is used, the nut 35 is used. A washer (not shown) may be interposed between the concrete mold 31 and the concrete mold 31, and various configurations can be employed.

One concrete formwork 31 mentioned above is reinforced in order to prevent the concrete formwork 31 from being deformed by the weight or pressure of the concrete placed according to the size of the foundation 20 to be constructed. For example, a reinforcing bar or other reinforcing material 36 can be attached. However, when the foundation 20 to be formed is relatively small, the attachment of the reinforcing material 36 may be omitted depending on the situation.

  In the present embodiment, in order to attach the reinforcing member 36, a fixing bracket 37 for fixing the reinforcing member 36 is further sandwiched between the above-described fixture 34 and the nut 35.

  As the fixing bracket 37, various fixing brackets 37 for attaching the reinforcing member 36 described in the prior art can be used. In addition, instead of attaching the reinforcing member 36 by the fixing bracket 37, FIG. As shown, a reinforcing member made of channel steel 361 may be used, and various configurations can be employed.

  In the present embodiment, as an example, as shown in FIGS. 5 and 6, a flat portion 372 that contacts the concrete mold 31, in which an opening 371 into which the male screw 341 of the fixture 34 is inserted, is formed. A reinforcing material 36 that rises in a direction away from the concrete mold 31 from both ends of the flat portion 372, and then forms a parallel direction with the concrete mold 31 and is further bent slightly toward the concrete mold 31 side. The nut 35 is screwed onto the male screw 341 of the fixture 34 with the reinforcing bar 36 sandwiched between the fixing portion 373 and the concrete mold 31. When tightened together, the reinforcing bar 36 is pressed and fixed to the rib 41 of the concrete mold 31 by the fixing portion 373, and the fixture 34 is fixed to the concrete mold. 31 is fixed to.

As described above, when rib lath is used as one concrete mold 31, the left and right directions in FIG. 5 of the flat portion 372 and the portion disposed in parallel to the concrete mold 31 formed in the fixing portion 373 are used. The misalignment interval is substantially the same as or slightly narrower than the total of the protruding width of the rib 41 and the width of the reinforcing member 36, and the flat portion 372 of the fixing bracket 37 is ribbed ribs by tightening the nut 35. You may comprise so that the non-formation part of 41 may contact.

  The fixing bracket 37 for attaching the reinforcing bar 36 is not limited to the above-described shape, and may be any shape as long as it can fix the reinforcing member 36 having a U-shaped cross section, or other rod shape, for example. It may be.

Moreover, although the example which fixes these with the nut 35 is shown in the above-mentioned example, for example, a female screw is cut in the opening 371 provided in the above-mentioned fixing bracket 37, and the male screw 341 of the fixture 34 is fixed to this. The fixing bracket 37 may be provided with a function as a fixing tool such as the nut 35 described above by screwing into an opening 371 formed in the bracket 37.

  In the above-described embodiment described with reference to FIGS. 5 and 6, male screws are cut at both ends of a metal bar as a connecting tool 33 for connecting between one concrete mold 31 and the other concrete mold 32. Although the example which uses a thing was demonstrated, this connector 33 is not limited to the example of illustration, The thing of various structures can be used.

  As this connection tool 33, for example, the connection member 33 is formed by a wire, or the end portion 33a attached to the above-mentioned attachment tool 34 attached to one concrete mold 31 is formed in an annular shape or a hook shape. In the case of using these connecting tools 33, a wire used as the connecting tool 33 or a lock provided at one end 33a of the connecting tool 33 is used. A fixture 34 'having a structure for locking the part is used.

In the embodiment shown in FIG. 7, a male thread 341 ′ inserted into a mesh 42 provided on the concrete formwork 32 on one end side as a fixture 34 ′ used in combination with such a connecting member 33. 5 is similar to the above-described fixture 34 described with reference to FIGS. 5 and 6, but the other end protruding from the concrete placement surface side of the concrete mold 31 has the above-described attachment 34. and needle gold as, cyclic or has a lockable hook-like portion 345 one end of the connecting member 33 formed in a hook shape, in the illustrated embodiment, a substantially C-shaped hook-like It is formed in the part 345. Note that the shape of the hook-shaped portion 345 can be the shape shown in the modified example enclosed by a circle in FIG. 7, or any other shape that can lock one end of the connector 33. It is not limited to the example.

  As described above, the concrete formwork 31 is provided with a fixture 34 that is detachable by screwing or locking one end 33a of the connecting member 33 that connects one concrete formwork 31 and the other concrete formwork 32. By attaching, the upright work of one concrete formwork 31 and the other concrete formwork 32 can be carried out as separate work respectively. As a result, the upright work of one concrete formwork 31 can be performed as a reinforcing bar 25. It is possible to perform it independently prior to assembly.

  In FIG. 5, reference numeral 36 ′ is a reinforcing material for lath connection and / or reinforcing reinforcing bars made of the same reinforcing bars as the reinforcing bars 36 fixed by the fixing bracket 37, and further reinforcing the concrete formwork 31. If necessary, attach it as necessary. In the present embodiment, the reinforcing material 36 ′ is attached to the above-described reinforcing material 36 by, for example, binding with a binding wire.

  In the embodiment of FIGS. 6 and 7 as well, a reinforcing material 36 ′ may be attached as necessary.

  After assembling the concrete formwork 31 assembled in this manner sequentially or in a state where a plurality of pieces are connected as necessary, the lower end 31a is discarded on the concrete 14 at a position to be the outline of the foundation 20 to be formed. Secure and stand vertically.

  As shown in FIGS. 2 and 3, the one concrete mold 31 is attached to the discarded concrete 14 on the bottom edge of the wall 11 on the one concrete mold 31 side of the rooting groove 10. This is done by placing the bottom edge of the lower end 31a of the frame 31 close to each other.

  In this way, by fixing the lower end 31a of one concrete mold 31 on the concrete 14 in a state of being close to the bottom edge of the wall surface 11 of the deforestation groove 10, one concrete form 31 and the deforestation groove No work space is secured between one wall surface 11 and the other concrete formwork 31, but the one concrete form 31 is fixed on the concrete 14 with the reinforcing material 36 attached thereto as described above. It is necessary to secure such work space because it is to be buried as described later, and as a result, in the construction method introduced in the prior art, one concrete mold The working space between one concrete mold 31 and one side wall 11 required for assembling, removing and collecting the frame 31 is reduced by the amount of surplus. And it has a small possible.

  The fixing of the lower end portion 31a of one concrete mold 31 on the discarded concrete 14 can be performed from the center side of the bottoming bottom 13 and can fix the concrete mold 31 in a predetermined position. Any method can be used.

  Once the concrete formwork 31 is disposed at the mounting position on the discarded concrete 14, there is no work space between the concrete formwork 31 and one wall surface 11 of the rooting groove 10, and one of the rooting grooves 10. In the present construction method, first, a locking tool for fixing the lower end portion 31a of the concrete mold 31 on the discarded concrete 14 because the concrete mold 31 cannot be fixed on the wall surface 11 side of the wall. 50, and fixing the lower end portion 31a of the concrete mold 31 to the locking member 50 enables the concrete mold 31 to be fixed only from the center side of the rooting bottom 13. I am doing so.

  In addition, although the above-mentioned latching tool 50 can also be arrange | positioned in the center side of the root cutting bottom 13 with respect to the concrete formwork 31 in the standing state, the lower end part 31a of the concrete formwork 31 is after that Since this is pressed against one wall surface 11 side of the culling groove 10 by the weight or pressure of the concrete placed on the anchoring portion 50, the lower end 31a of the concrete mold 31 is It is preferable that it is attached so that movement to the one wall surface 11 side of the groove 10 can be restricted.

  For example, an angle member 51, a piece of wood 52 having a predetermined thickness, a grooved steel 53, or the like can be used as such a locking tool 50 attached on the discarded concrete 14. Although not shown, a concrete nail may simply be driven onto the discarded concrete 14 and the concrete nail may be used as the locking tool 50.

  The locking member 50 such as the angle member 51, the piece of wood 52, and the grooved steel 53 is discarded with a concrete nail 54 or the like and fixed on the concrete 14.

FIG. 8 (A) is an example in which the lower end 31a of the concrete mold 31 is fixed via the angle member 51 mounted on the discarded concrete 14 among the mounting methods of the concrete mold 31. 14, the lower end 31a of the concrete mold 31 is screwed to an angle member 51 fixed by a concrete nail 54 or the like, and is bound by a binding wire, or a combination of these methods is fixed (in the example shown, the binding wire is (Omitted).

This fixing may be performed, for example, by forming an opening in the rib 41 of the concrete mold 31 and screwing a screw 55 penetrating the rib into a screw hole formed in the angle member 51. The concrete mold 31 may be sandwiched and fixed between the head of the screw 55 and the angle member 51 by tightening 55 (FIG. 8B) . Alternatively, the lower end portion 31a of the concrete mold 31 may be bound directly to the angle member 51 together with the screw 55 without using such a screw 55 with a binding wire (not shown).

9A and 9B show an example in which the lower end portion 31a of the concrete mold 31 is fixed to a piece of wood 52 mounted on the discarded concrete 14, and the concrete nails are disposed on the discarded concrete 14. FIG. The lower end portion 31a of the concrete mold 31 is fixed to the wooden piece 52 fixed by 54 or the like, and the screw 55 penetrating the opening formed in the rib 41 of the concrete mold 31 and other wooden screws and nails are attached to the side of the wooden piece 52. FIG. 10A shows an example of fixing on the discarded concrete 14 by fixing or fixing it together with the screw 55 or the like, or by tying it to the wooden piece 52 with a binding wire (not shown) instead of the screw 55 or the like . The lower end portion 31a of the concrete mold 31 is inserted into the groove of the fixed grooved steel 53, and if necessary, this is fixed with a screw 55, or replaced with this screw 55, or a screw 5 5 is an example of fixing together with a binding wire (not shown).

As shown in the aforementioned FIG. 10 (A), when using a groove-type steel 53 the lower end portion 31a of the concrete form 31 is inserted to a fixed concrete form 31, the bottom of the groove of the groove-type steel 53 The bolts and concrete nails that pass through may be discarded and driven onto the concrete 14, whereby the grooved steel 53 may be discarded and fixed onto the concrete 14. However, it is relatively difficult to drive a nail or the like into the groove bottom surface of the grooved steel 53. from, for example, with an incision at predetermined intervals on one side than the bottom surface of the groove-type steel 53 as shown in FIG. 10 (B), expand the steel piece 531 between the cuts in the extending direction of the bottom surface, the steel strip 531 For example, the grooved steel 53 may be fixed on the concrete 14 by driving the concrete nails 54 penetrating into the concrete 14.

  In order to prevent the concrete formwork 31 assembled as described above from being inclined, the upper end of the concrete formwork 31 is locked to the opening edge of the rooting groove 10 by a locking bar (not shown), for example. May be.

[Rebar assembly]
After the assembly of one concrete mold 31 is completed as described above, the reinforcing bars 25 such as deformed reinforcing bars embedded in the foundation 20 along the concrete mold 31 are assembled. The reinforcement bars 25 can be assembled by various known methods.

  At this time, the reinforcing bar 25 is attached with a spacer 26 for maintaining a predetermined interval between the reinforcing bars 25 and the concrete molds 31 and 32 in the same manner as described in the prior art. , 32 prevents the reinforcing bar 25 from being exposed to the surface and positions the reinforcing bar 25 and the concrete molds 31, 32.

  In the illustrated embodiment, the spacers are attached to the reinforcing bars 25 arranged at the height direction in the longitudinal direction at predetermined intervals, so that a predetermined distance is provided between the reinforcing bars 25 and the concrete molds 31 and 32. The interval is secured.

[Assembly of concrete formwork (the other)]
When the assembling of the reinforcing bars 25 is completed as described above, the other concrete formwork 32 is then confronted with the concrete formwork 31 erected as described above via the reinforcing bars 25. Assemble.

The concrete form 32 used here, that use similarly lath and Riburasu and one concrete form 31 described above.

The use of class as the other concrete form 32 of this, after the concrete has been pouring has hardened, it is removed, it is possible to killing fill without recovery, the assembly of the concrete form 32 At this time, since it is easy to grasp the situation on the back side through the mesh, it is relatively easy to screw or lock the connecting member 33 to the fixture 34 attached to one concrete mold 31. There is an advantage of being.

In the present embodiment, after the lath that has been processed to a Jo Tokoro size loaded into the root Kimizo 10 as concrete form 32, which stand along the reinforcement 25 that is assembled in the manner described above The other concrete mold 32 is connected to the one concrete mold 31 by a connecting member 33, and the reinforcing material 36 such as a reinforcing bar is also attached to the other concrete mold 32 as necessary. Install.

  The attachment of the other end 33 b of the connecting member 33 to the other concrete formwork 32 can be performed by the same method as the attachment to the one concrete formwork 31.

In the case where the connecting member 33 used in this embodiment is in the shape of a metal rod and both ends 33a and 33b are male threaded, or one end is annular or hook-shaped and the other end is male threaded After the rib lath 40 to be the other concrete mold 32 is erected along the reinforcing bar 25, one end 33a of the connecting member 33 is connected to one concrete mold through the mesh 42 formed on the other concrete mold 32. While inserting it toward the frame 31, one end of the connecting member 33 is screwed or locked to a fixture 34 attached to the concrete placing surface of one concrete mold 31.

  Thereafter, for example, a bolt 35 ′ is screwed into the other end (not shown) of the connecting member 33 protruding from the side opposite to the concrete placement surface of the other concrete formwork 32, so that the other The connection between the concrete mold 32 and the connecting member 33 is completed.

  When the reinforcing material 36 such as a reinforcing bar is attached to the side surface of the other concrete formwork 32 opposite to the concrete placement surface, the other concrete formwork 32 has a side opposite to the concrete placement surface. Before the nut 35 or the like is screwed onto the other end of the connecting member 33 protruding from the side surface, a fixture that can be attached to the reinforcing member 36, for example, a fixing bracket 37 similar to that attached to one concrete mold 31 is provided. After the mounting, the nut 35 is screwed to the other end 33b, so that the reinforcing material is the same as in the case of mounting the reinforcing material 36 on the one concrete mold 31 except that the mounting tool 34 is not used. 36 can be attached.

  Further, when a known concrete mold made of plywood or the like is used as the other concrete mold 32, for example, the concrete mold 32 is connected to the other concrete mold 32 and the other end of the connecting member 33. Before screwing the aforementioned nut or the like into the other end of the connecting member 33 projecting through, a disk-like support shown in, for example, Japanese Patent Application Laid-Open No. 11-190127 is attached, or this support The concrete formwork 32 can also be fixed by the configuration described in Japanese Patent Application Laid-Open No. 11-190127, such as sandwiching a plywood or the like cut to a predetermined size between the concrete formwork 32.

When a wire or the like is used as the connecting member 33 instead of the above-described metal rod, for example, the folded end portion of the wire folded in half is used as one end 33a of the connecting member 33 and the mesh of the other concrete mold 32 is used. 42 is inserted toward one concrete mold 31, and the folded end of the inserted connecting member 33 is attached to one concrete mold 31 , for example, a hook-shaped portion of a fixture 34 ′ shown in FIG. 7. Lock to 345.

Then, both ends of the wire protruding from the mesh 42 of the other concrete mold 32 are connected, and a reinforcing bar 36 or the like is inserted into the loop of the wire generated by this connection, and then the end of this wire is attached. When Yuku shortens the overall length of the loop formed by the wire or the like to twisting, with between concrete form 31, 32 is fixed by the connecting, concrete設面both concrete form 31, 32 reinforcement 25 The spacer is positioned in contact with the spacer.

  In addition, it is preferable that the other concrete formwork 32 standing upright in this way is discarded and fixed to the concrete top 14 similarly to the case of the above-mentioned one concrete formwork. This fixing method is similar to the one concrete mold 31 described above, and is disposed in advance on the concrete 14, and the above-mentioned angle member, pier, concrete nail, groove for locking the lower end of the concrete mold 32 on the concrete 14 is used. A locking tool such as mold steel may be attached, and the concrete mold 32 may be erected at the mounting position of the locking tool and the lower end thereof may be fixed. Alternatively, the concrete mold 32 may be placed at a predetermined position. After standing up, the above-mentioned locking tool is discarded and fixed on the concrete 14, and the lower end of the concrete formwork 32 may be fixed to this locking tool. The procedure is not limited.

[Concrete placement]
As described above, when the assembly of one concrete mold 31, the reinforcement bars 25, and the other concrete mold 32 are completed, concrete is placed between the concrete molds 31 and 32. . The placed concrete becomes reinforced concrete with reinforcing bars embedded therein by hardening the concrete placed by curing for a predetermined period.

As described above, in the method of the present invention, the mesh-like body as a concrete formwork, because in the present embodiment is to use class, some of pouring the concrete in the network Although it permeates, it does not completely flow out due to the viscosity of the concrete, and at this time, the excess water in the concrete is removed by the mesh shape of the lath, increasing the concrete strength, and most of the concrete is a concrete formwork. Stay in the space between.

  In addition, the concrete that has passed through the mesh is cured in this way, so that the formed foundation and the concrete formwork are integrated.

〔backfilling〕
In this way, after the concrete was pouring is cured, concrete formwork 31, 32, and rebar and used as a reinforcing material 36 in the concrete form 31 of this one, the fixed bracket for anchoring 37 When the bolts 35 are attached, they are not removed and collected, and the state in which they are attached is regarded as a structure, and the backfilling is performed.

It should be noted that a reinforcing bar 36 attached to the other concrete formwork 32 as a reinforcing material 36, a fixing bracket 37 for attaching the reinforcing bar 36, an angle material 51 for discarding the lower end of the other concrete formwork 32 and fixing it on the concrete 14, and a grooved steel. The locking tool 50 such as 53 may be backfilled after being removed and collected as necessary, and any of these may be backfilled without being removed or collected, or buried.

[Action]
As described above, the concrete molds 31 and 32 and the reinforcing bars 25 are assembled in the order of assembling one concrete mold 31, assembling the reinforcing bars 25, and assembling the other concrete mold 32. By using a net-like body which is a part of the foundation 20 constructed integrally with the placed concrete as the one concrete formwork 31 assembled as described above, the amount of surplus digging at the time of root cutting is reduced. It has become something that can be.

That is, in the known construction methods that Oite described prior art, the shape of the root Kimizo 10, in order to secure a working space for assembling the one concrete form 31, 12 in longitudinal section are formed in the shape of figure symmetrical basic 20 formed therein around as shown, the bottom surface 13 of root Kimizo 10 is Oite formed on construction methods of the present invention, FIG. 2 As shown, the side surface 21 side of the foundation formed can be rooted as a shape without a working space.

  Therefore, in the case of the construction method of the present invention, excavation of the hatched portion in FIG. 2 is unnecessary for the rooting trench 10 formed in the prior art construction method shown in FIG. The amount of excavation has been reduced.

  In the embodiment shown in FIG. 2, the wall surfaces 11 and 12 of the rooting groove 10 formed on the left and right in FIG. 2 are both inclined at a predetermined angle of repose α. Thus, it is not necessary to provide such a repose angle α for the wall surface 11 on the side of the concrete formwork 31 of the deforestation groove 10, and this is one side surface of the foundation 20 formed as shown in FIG. 21 may be formed in parallel.

  By forming the cross-sectional shape of the pruning groove 10 in this way, in the embodiment shown in FIG. 3, the hatched portion in FIG. Therefore, the amount of surplus can be further reduced as compared with the embodiment shown in FIG.

  In addition, since the cross-sectional shape of the deforestation groove 10 can be made smaller as compared with the conventional construction method in this way, the amount of earth and sand necessary for backfilling and the labor required for backfilling can be reduced. It is possible to do.

  In the formation of the underground foundation constructed by the method of the present invention and the construction method of the underground structure by the conventional construction method, the reduction rate of the excavation amount and the reduction amount of the backfill amount at the time of root cutting are shown as an example as follows: It is.

[Conventional method 1]
The cross-sectional shape of the deforestation groove 10 when forming an underground foundation having a height H and a width A in the cross section is as shown in FIG.

  In this root-cutting groove 10, the root-cutting bottom 13 is 0.5 m on one side and a total of about 1.0 m are excavated to secure a working space with respect to the bottom surface 23 of the foundation 20. In order to provide an angle of repose α, H / 3 is further excavated with respect to the foundation on which H / 3 is further added to 0.5 m on one side and a total of 2H / 3 on the left and right sides.

Therefore, the total cross-sectional area of the pruning groove by this method is
(H / 3) × H + 0.5H × 2 + AH = (H2 / 3) + H + AH
In addition, the root cutting section excluding the basic part is
(H2 / 3) + H
It is.

  In the above formula, the thickness of the discarded concrete (generally about 0.1 m) is ignored.

[Application method 1]
In the construction method 1 of the present application, the cross-sectional shape of the pruning groove in the case of forming an underground foundation of the same size as the conventional construction method is as shown in FIG. In addition, in FIG. 2, the space of width 0.1m provided on one side of the underground foundation is the thickness (0.05m) of one concrete formwork to be buried and the margin (0.05m) for the root cutting position. ).

  In this construction method, as compared with the conventional construction method 1, it is possible to reduce the root cutting of 0.4 × H = 0.4H indicated by oblique lines.

Therefore, assuming a case where a foundation having a height (H) of 1.8 m is formed as an example, a cross section of a reduced portion of the root cutting groove formed in Example 1 and a root cutting groove formed by the conventional method 1 The cross-sectional ratio is 0.4H / [(H2 / 3) + H] excluding the foundation forming part.
= 0.72 / 2.88 ≒ 0.25 ... 25%
Therefore, it is possible to reduce the surplus amount and the backfill amount by about 25% in the cross-sectional ratio.

As an example, assuming that a foundation having a height (H) of 3.0 m is formed, a cross-section of a reduced portion of the rooting groove formed in Example 1 and a rooting groove formed by the conventional method 1 The cross-sectional ratio of the material excluding the formation part of the foundation = 1.2 / 6 = 0.20 ... 20%
Therefore, in the cross-sectional ratio, it is possible to reduce the amount of overburden and backfill by about 20%.

[Example 2]
In the construction method 2 of the present application, the cross-sectional shape of the pruning groove in the case of forming an underground foundation of the same size as the conventional construction method is as shown in FIG. In FIG. 3, the space of 0.1 m width provided on one side of the underground foundation is the thickness (0.05 m) of one concrete formwork 31 to be buried and the margin (0. 05m).

In this construction method, compared to the conventional construction method 1, the area indicated by the oblique lines,
0.4H + (H2 / 6)
Can be reduced.

Therefore, assuming a case where a foundation having a height of 1.8 m is formed as an example, the cross-sectional ratio of the deforestation groove formed by the present construction method 2 and the cross-section ratio of the deforestation groove formed by the conventional construction method 1 is [0.4H + (H2 / 6)] / [(H2 / 3) + H] excluding the formation part of the foundation
= 1.260 / 2.88 ≒ 0.44 ... 44%
Accordingly, it is possible to reduce the amount of overburden and backfill by about 44% in the cross-sectional ratio.

As an example, assuming a case where a foundation with a height of 3 m is formed, the cross-sectional ratio of the deforestation groove formed by the method 2 of this application and the cross-section ratio of the pruning groove formed by the conventional method 1 is the foundation. [0.4H + (H2 / 6)] / [(H2 / 3) + H]
= 2.7 / 6 = 0.45 ... 45%
Therefore, it is possible to reduce the amount of overburden and backfill by 45% in the cross-sectional ratio.

  The construction method of the reinforced concrete underground structure of the present invention described above is used when constructing a reinforced concrete underground structure that involves work in a deforestation ditch, such as when constructing a basement or constructing a relatively large foundation. In addition, it can be used as an alternative to various conventional methods.

The flow which shows the work process in the construction method of this invention. Explanatory drawing which shows the relationship between the structure (foundation) constructed | assembled by the construction method of this invention, and root cutting. Explanatory drawing which shows the relationship between the structure (foundation) constructed | assembled by the construction method of this invention, and root cutting. The front view of explanatory drawing of the rib lath used as a concrete formwork. Sectional drawing of the BB line of FIG. 4 (A) of the explanatory drawing of the rib lath used as a concrete formwork. The schematic sectional drawing which shows the attachment state of the separator with respect to a concrete formwork. The schematic sectional drawing which shows the attachment state of the separator with respect to a concrete formwork. The schematic sectional drawing which shows the attachment state of the separator with respect to a concrete formwork. The side view which shows the attachment state (angle use) of the concrete formwork lower end with respect to abandoned concrete. The top view which shows the attachment state (angle use) of the concrete formwork lower end with respect to abandoned concrete. The side view which shows the attachment state (using pier) of the concrete formwork lower end with respect to abandoned concrete. The top view which shows the attachment state (use of a pier) of the concrete formwork lower end with respect to abandoned concrete. The side view which shows the attachment state (use of groove type steel) of the concrete formwork lower end with respect to abandoned concrete. The top view which shows the attachment state (use of groove type steel) of the concrete formwork lower end with respect to abandoned concrete. The flow which shows the work process in the construction method of this invention. Explanatory drawing which shows the relationship between the structure (foundation) constructed | assembled by the conventional construction method, and pruning. It is a schematic explanatory drawing which shows the attachment state of the connection member which connects between concrete molds in the conventional construction method, and the example attached by binding a reinforcing material with a wire. It is a schematic explanatory drawing which shows the attachment state of the connection member which connects between concrete formwork in the conventional construction method, and the example which attached the fixing bracket which fixes a reinforcing material to the both ends of the connection member which consists of metal bars. It is a schematic explanatory drawing which shows the attachment state of the connection member which connects between concrete formwork in the conventional construction method, and the example which attached the fixing bracket which fixes a reinforcing material to the both ends of the connection member which consists of metal bars. It is a schematic explanatory drawing which shows the attachment state of the connection member which connects between concrete formwork in the conventional construction method, The example which attached the reinforcing material to grooved steel, and was attached to the metal rod-shaped connection member.

Explanation of symbols

10 Root-cutting groove 11, 12 Wall surface
13 Root cutting bottom (bottom of the pit)
14 Abandoned concrete 20 Foundation 21 and 22 Side (of foundation)
23 Bottom (foundation)
25 Reinforcing bar 26 Spacer 31 One concrete form 31a Lower end (of one concrete form)
32 The other concrete formwork 33 Connecting member 33a One end (of connecting member )
34, 34 'fitting 341 male screw 342 screw hole 343 opening edge 345 bowl 35 nut (fixing tool)
36 Reinforcing material (rebar)
361 Reinforcement (Groove-type steel)
37 brackets (for mounting reinforcements)
371 Opening 372 Flat part 373 Fixing part 40 Rib lath 41 Rib 42 Mesh 50 Locking tool 51 Angle material 52 Wood piece 53 Grooved steel 531 Steel piece 54 Concrete nail

Claims (5)

In the construction method of an underground structure involving work performed by an operator entering a groove or hole of a predetermined height formed by root cutting ,
One concrete formwork which consists of a net-like body in which a fixture for attaching one end of a connecting member is attached to a concrete placement surface on abandoned concrete placed on the bottom of a groove or hole formed by root cutting , With the bottom edge of the one concrete mold close to the bottom edge of the wall surface on the one concrete mold side of the groove or hole,
Then, after assembling the reinforcing bars along the one concrete formwork,
The other concrete mold, which is a net-like body, is erected against the one concrete mold via the reinforcing bar, and the connecting member is arranged via a mesh formed on the other concrete mold. One end of the connecting member is attached to the fixture attached to the concrete placement surface of the one concrete formwork, and the other end of the connecting member is further connected to the one concrete formwork. Fixed to the other concrete formwork,
After the concrete cured by Da設a between the one and the other concrete form, construction method of underground structures, wherein the backfilling without removing the one and the other of the concrete formwork.   2. The construction method for an underground structure according to claim 1, wherein at least one of the concrete molds is formed by lath.   A locking tool is fixed in advance on the discarded concrete placed on the bottom surface of the groove or hole, and at least a lower end portion of the one concrete mold is fixed to the locking tool. The construction method of the underground structure of 1 or 2. An attachment that can attach one end of a connecting member that connects between the one concrete formwork and the other concrete formwork is mounted on the one concrete formwork before the one concrete formwork is erected. Attach to the concrete casting surface,
The one end of the connecting member is attached to the fixture when the other concrete mold is erected, and the other end is fixed to the other concrete mold. The construction method of the underground structure described. 5. The construction method for an underground structure according to claim 1, wherein the width direction of the concrete form is long on the side opposite to the concrete placement surface of the one concrete form made of the net-like body. A fixing bracket for fixing a reinforcing material arranged as a direction,
And the flat portion is inserted to the external thread of the fixture which can be screwed hole is formed through said one of the concrete form with the arranged parallel to the one of the concrete form,
Rise from both ends of the flat part in a direction away from the concrete mold, and then parallel to the concrete mold, and further tilted toward the concrete mold side with the one concrete mold. A fixing bracket comprising a fixing portion for sandwiching the reinforcing member therebetween.

Images