JP2017031620A - Form for invert - Google Patents

Abstract

The present invention provides an invert form that is less likely to be lifted during concrete placement and that can move smoothly.
An invert form K used when constructing an invert part A of a tunnel, comprising a support frame 1 straddling the central part of the invert part A and a pair of left and right covering the side part of the invert part A. Dam plate portions 2, 2, receiving girder 3, 3,... Extending from each dam plate portion 2 toward the center portion of the inverted portion A, and an anchor 4 connected to the receiving girder 3, The dam plate portions 2 and 2 are supported by the support frame 1 in a state of being opposed to each other with a space therebetween, and the lower end portion of the anchor 4 is embedded in the concrete in the central portion of the invert portion A.
[Selection] Figure 1

Description

  The present invention relates to an invert form.

  When constructing an invert portion having a curved surface (circular arc shape) in a tunnel having a circular cross section, it is common to use a formwork (invert formwork) having a shape that conforms to the inner surface shape of the invert part. . For example, Patent Document 1 discloses an invert mold that covers the entire inner surface of the invert portion.

Since the invert form of Patent Document 1 covers the entire inner surface of the invert part, there is a risk of increasing the weight. If the weight of the invert mold is increased, it takes time to move the invert mold.
Further, when concrete is placed, there is a concern that the invert form will be lifted by the pressure of fresh concrete. If a heavy invert form is used, it is possible to suppress the lifting of the form. However, as described above, if the weight of the invert form is increased, it may take time to move the invert form. There is.
In Patent Document 1, a temporary support is installed between the invert form and the top of the tunnel to prevent the invert form from being lifted. However, if the support is installed, it interferes with the belt conveyor and the like. There is a risk of doing. Moreover, since it is necessary to repeat installation / removal of the support column every time the invert form is moved, there is a possibility that the work becomes complicated.

JP 2005-171549 A

  The present invention realizes an invert form used for constructing an invert part of a tunnel, improves stability of form fixing at a rising portion of a side part, and is used when placing concrete. It is an object of the present invention to provide an invert form that hardly lifts up.

An invert form according to the present invention is an invert form used when constructing an invert part of a tunnel, and covers a support frame straddling a central part of the invert part and a side part of the invert part. A pair of left and right barrier plates, a receiving beam extending from each of the barrier plates to the center of the invert portion, and an anchor connected to the receiving beam.
The both weir plate portions are supported by the support frame in a state of being opposed to each other with a space therebetween, and the lower end portion of the anchor is embedded in the concrete in the central portion of the invert portion.

In the present invention, the dam plate is not disposed in the central portion of the invert portion where the inclination with respect to the horizontal plane becomes gentle, and the dam plate portion is disposed only in the side portion of the invert portion (the rising portion of the side surface portion of the tunnel). is there. According to the present invention, the number of members constituting the invert mold can be reduced as compared with the case where the entire inner surface of the invert portion is covered with the dam plate. That is, according to the present invention, since the weight of the invert form can be reduced, the invert form can be moved smoothly even in a tunnel premises that cannot be equipped with sufficient lifting equipment. Become.
Furthermore, according to the present invention, since the dam plate is not arranged in the central portion of the invert portion, the pressure of the fresh concrete acting on the invert form is compared with the case where the entire inner surface of the invert portion is covered with the dam plate. When the concrete starts to harden around the lower end of the anchor, the effect of restraining the anchor increases and the displacement of the receiving girder is suppressed, so by placing the concrete on the side of the invert part Even if the pressure of fresh concrete acts on the weir plate, it is difficult for the invert form to be lifted.
Note that when concrete is placed on the side of the invert part, the concrete side pressure acts on the dam plate part, but in the present invention, since the dam plate part is supported by the support frame, the inclination generated in the dam plate part. Etc. can be suppressed.
Thus, according to the invert mold according to the present invention, it is possible to improve the stability of mold fixing at the rising portion of the tunnel side surface (the side of the invert portion).

  If the receiving beam is curved along the inner surface of the invert part, it becomes a mark when leveling the surface of the concrete, so that the dimensional accuracy of the invert part can be increased.

  If the receiving beams adjacent to each other on the left and right are connected to each other, the deformation generated in each receiving beam is reduced, so that it is possible to suppress the deformation of the invert form due to the pressure of the fresh concrete at the time of placing the concrete.

  If the anchor is fixed to a reinforcing bar arranged in the invert part or a reinforcing bar support for supporting the reinforcing bar, the anchor can be suitably restrained as compared with the case where the anchor is installed independently from these. Therefore, it is possible to suppress the displacement / deformation of the invert form due to the pressure of the fresh concrete when placing the concrete.

  According to the present invention, it is difficult for the invert form to be lifted during concrete placement.

It is sectional drawing of the mold for invert which concerns on embodiment of this invention. It is a top view of the mold for invert concerning the embodiment of the present invention. It is the X section enlarged view of FIG. It is the Y section enlarged view of FIG. It is the Z section enlarged view of FIG.

As shown in FIG. 1, the inversion formwork K according to the present embodiment is used when constructing an invert part A of a tunnel.
The invert part A is a part (bottom part) of the secondary lining having a circular cross section, and has a circular arc shape that protrudes downward.
The invert part A of the present embodiment has a reinforced concrete structure, the outer rebar unit A1 disposed on the primary lining B side (the outer periphery side of the secondary lining), and the inner side of the tunnel (the inner periphery of the secondary lining) Side rebar unit A2 arranged on the side). The outer reinforcing bar unit A1 and the inner reinforcing bar unit A2 are a combination of a plurality of reinforcing bars in a lattice shape. Further, on the upper surface of the primary lining B (or a waterproof sheet (not shown) laid on the inner peripheral surface of the primary lining B), a reinforcing bar support A3 that supports the reinforcing bars is installed.

  In the following description, the tunnel transverse direction (left-right direction in FIG. 1) is referred to as “left-right direction”, and the tunnel axis direction (left-right direction in FIG. 2) is referred to as “front-rear direction”.

  The invert mold K includes a support frame 1, a pair of left and right weir plates 2, 2, receiving girders 3, 3, and anchors 4, 4,. At the end of the invert mold K in the tunnel axis direction, a wife mold A4 is disposed as shown in FIG.

  As shown in FIG. 1, the support frame 1 is disposed so as to straddle the central part of the invert part A. The support frame 1 of this embodiment includes side frames 11 and 11 disposed on the left and right sides of the invert portion A, and connecting beams 12 that connect the left and right side frames 11 and 11.

The side frame 11 is a steel frame structure formed on the barrier plate 2 and extends in the front-rear direction (the direction perpendicular to the plane of FIG. 1). The side frame 11 is composed of a vertical structural surface composed of a longitudinal member 1a, a first transverse member 1b and a longitudinal brace 1c, a first transverse member 1b, a second transverse member 1d and a transverse brace 1e shown in FIG. With a horizontal surface. A plurality of vertical planes are parallel to the cross section of the tunnel, and a plurality of vertical planes are arranged side by side in the front-rear direction.
As shown in FIG. 1, the vertical member 1 a is a rod-like member erected at the lower end portion of the barrier plate portion 2, and the first horizontal member 1 b is from the upper end portion of the barrier plate portion 2 to the upper end portion of the vertical member 1 a. It is a rod-shaped member leading to. The vertical brace 1c is a rod-shaped member that extends from the intermediate portion in the height direction of the barrier plate 2 to the intersection of the vertical member 1a and the first horizontal member 1b.
As shown in FIG. 2, the second cross member 1 d is disposed in parallel with the tunnel central axis. The horizontal brace 1e connects the first horizontal members 1b and 1b adjacent to each other in the front-rear direction.

A plurality of the connecting beams 12 are arranged in parallel at intervals in the front-rear direction (tunnel axis direction). As shown also in FIG. 1, the connection beam 12 of this embodiment is a steel solid truss structure pushed over the center part of the invert part A, and a tunnel crossing direction (left-right direction of FIG. 1). It extends to. The connecting beam 12 connects the left and right side frames 11 and 11 above a region where the barrier plate 2 is not disposed (region where the reinforcing bar is exposed).
The connecting beam 12 includes a pair of front and rear vertical construction composed of an upper chord member 1f, a lower chord member 1g, a diagonal member 1h and a vertical member 1i, a pair of front and rear upper chord members 1f and 1f, a diagonal member 1j shown in FIG. It has an upper horizontal surface composed of a material 1k, and a pair of front and rear lower chord members 1g, 1g, a lower horizontal surface composed of a diagonal material and a vertical material (not shown).
Note that the configuration of the connecting beam 12 may be changed. For example, instead of the connecting beam 12 having a truss structure, a connecting beam 12 made of H-shaped steel or I-shaped steel may be used.

  At an appropriate position on the upper surface of the support frame 1, a bracket 13 capable of locking a hook of a suspension material (wire or chain) 6 is fixed. The bracket 13 is used when the invert mold K is moved.

The dam plate portion 2 is disposed so as to cover the side portion of the invert portion A. The left and right weir plate portions 2 and 2 are opposed to each other in an inverted C shape with the central portion of the invert portion A (region in which the weir plate is not disposed) interposed therebetween.
As shown in FIG. 2, a plurality of through holes 2 a, 2 a,. The through-hole 2a has a hole diameter large enough to insert a vibrator for concrete. Although illustration is omitted, around the through hole 2a, a holding portion capable of holding a lid member that closes the through hole 2a is disposed.

As shown in FIG. 3, the dam plate portion 2 of the present embodiment includes a steel plate 2b that is curved along the inner surface shape of the side portion of the invert portion A, a reinforcing rib 2c that is joined to the upper surface of the steel plate 2b, and a steel plate. 2b or a sheet pile receiving member 2d provided at the upper end of the reinforcing rib 2c.
The reinforcing rib 2c is made of a steel material such as angle steel. The lower end of the side frame 11 is joined to the reinforcing rib 2c. In addition, although illustration is abbreviate | omitted, the some reinforcement rib 2c, 2c, ... is arrange | positioned at the upper surface of the steel plate 2b at the grid | lattice form.
As shown in FIG. 4, the sheet pile receiving members 2 d and 2 d are portions that hold a sheet pile A <b> 5 that is disposed at the upper end of the invert portion A, and are arranged side by side at intervals. The sheet pile receiving members 2d and 2d are connected via a connecting member 2e. A sheet pile A5 is inserted between the sheet pile receiving members 2d and 2d. The sheet pile A5 is a wife frame for molding the upper end surface of the invert part A, and is fixed by driving a camber A6 between the sheet pile A5 and one sheet pile receiving member 2d. In addition, the sheet pile A5 is arrange | positioned so that it may become perpendicular | vertical with respect to the internal peripheral surface of a tunnel.

As shown in FIG. 1, the receiving beam 3 extends from the dam plate portion 2 toward the central portion of the invert portion A. The receiving beam 3 is curved along the inner surface of the invert part A. The upper end portion of the receiving beam 3 is positioned at the upper end portion of the barrier plate portion 2, and the lower end portion of the receiving beam 3 is positioned at the bottom portion of the invert portion A.
A portion of the receiving girder 3 along the dam plate portion 2 is fixed to the upper surface of the dam plate portion 2 by a vise, a bolt, a nut, or the like.

  As shown in FIG. 2, the receiving girder 3 of the present embodiment includes two steel materials 3 a and 3 a that are arranged side by side at an interval in the front and rear, and a connection plate (not shown) that connects the steel materials 3 a and 3 a. Yes. The steel material 3a is made of channel steel. In this embodiment, the slits are formed in the receiving beam 3 by making the webs of the steel materials 3a and 3a face each other with a gap therebetween.

The anchor 4 is connected to the receiving beam 3 as shown in FIG. The lower end of the anchor 4 is embedded in the concrete at the center of the invert part A.
The anchor 4 of the present embodiment includes a bar 41 fixed to the reinforcing bar support A3, a presser plate 43 attached to the bar 41, and a nut screwed to the male screw portion 42 at the upper end of the bar 41. 44.
The bar 41 is made of a steel member, and protrudes from the upper surface of the receiving beam 3 through a slit (between the steel materials 3a and 3a shown in FIG. 2) of the receiving beam 3. A female screw is formed at the lower end of the bar 41.
The presser plate 43 is fixed to the upper surface of the receiving beam 3 by a nut 44.

The reinforcing bar support A3 includes a plurality of concrete spacers 51, 51,... Interspersed on the primary lining B (or a waterproof sheet laid on the inner peripheral surface of the primary lining B), the spacer 51, .. Are provided, a grid-like pedestal 52, a screw rod 53 rising from the grid-like pedestal 52, and a pair of upper and lower reinforcing bar holding portions 54, 55 attached to the screw rod 53.
The lattice-shaped pedestal 52 is made of a plurality of steel materials combined in a lattice shape. The vertical and horizontal steel materials intersect on the spacer 51.
The lower end portion of the screw rod 53 passes through the lattice-like pedestal 52 and is screwed to the spacer 51. The bar 41 of the anchor 4 is screwed to the upper end portion of the screw bar 53.
The reinforcing bar of the outer reinforcing bar unit A1 is fixed to the lower reinforcing bar holding part 54, and the reinforcing bar of the inner reinforcing bar unit A2 is fixed to the upper reinforcing bar holding part 55.

Next, a method for constructing the invert portion A using the invert mold K will be described.
The invert construction method according to the present embodiment includes a reinforcing bar assembly process, a formwork installation process, a concrete placing process, and a demolding process.

  In the reinforcing bar assembly process, the reinforcing bar support A3 is installed on the primary lining B (or the waterproof sheet laid on the inner peripheral surface of the primary lining B) in the area where the invert part A is constructed. This is a process of using the outer reinforcing bar unit A1 and installing the inner reinforcing bar unit A2 that is good.

The mold installation process is a process of installing the invert mold K and the wife mold A4 (see FIG. 2) in the area where the invert part A is constructed. The mold installation process is performed after the reinforcing bar assembly process. When the invert form K is carried in, a terha crane (not shown) provided at the top of the tunnel is used.
In addition, although illustration is abbreviate | omitted, the Telha crane is provided with the rail hung on the steel supporter, and the hoist which drive | works a rail. The suspension member 6 connected to the hoist is hooked on the bracket 13 of the support frame 1.
When the invert mold K is positioned above the inner reinforcing bar unit A2, the invert mold K is lowered. The invert formwork K is mounted on the existing invert part and the wife formwork A4, and then fixed to the anchor bolt or insert previously embedded in the existing invert part, and also fixed to the end formwork A4. To do.
In the central part of the invert part A, the bar 41 which is a constituent element of the anchor 4 is connected to the reinforcing bar receiving base A3, and the presser plate 43 of the anchor 4 is received and brought into contact with the upper surface of the beam 3. Note that the bar 41 may be erected on the reinforcing bar receiving base A3 before the invert form K is installed. In this case, the invert form K is installed while inserting the bar 41 into the slit of the beam 3 (between the steel members 3a and 3a shown in FIG. 2). Alternatively, the bar 41 may be erected on the reinforcing bar receiving base A3 after the invert form K is installed.
When the inversion form K is installed, the sheet pile A5 is held by the sheet pile receiving portions 2d and 2d (see FIG. 4) of the dam plate portion 2.

  The concrete placing step is a step of placing concrete on the invert part A. In the concrete placing step, concrete is placed at the center of the invert part A, and then concrete is placed on the side of the invert part A. When concrete is placed in the center of the invert part A, the bar 41 of the anchor 4 is embedded in the concrete.

If the concrete placement starts from the center of the invert portion A, the concrete starts to harden at the center of the invert portion A (around the anchor 4) when the concrete is placed on the side of the invert portion A. . When the concrete starts to harden, the anchor 4 is integrated with the concrete with the reinforcing bar support A3. As a result, the degree of restraint of the anchor 4 is increased and the displacement of the receiving beam 3 is suppressed. Even if the pressure of fresh concrete acts on the dam plate portion 2 due to the concrete placement on the portion, it is difficult for the invert form K to be lifted.
In addition, after placing concrete in the center part of the invert part A, once the placement work is interrupted and the concrete is hardened, the concrete may be placed on the side part of the invert part A.

  The demolding step is a step of demolding the invert mold K. When removing the inversion form K, first, the nut 44 of the anchor 4 is loosened, and the presser plate 43 is removed. Thereafter, the invert form K is lifted up using a Telha crane (not shown) and moved forward or backward. When the invert mold K is moved, the bar 41 of the anchor 4 is removed from the screw bar 53 in the vicinity of the upper surface of the invert part A. The hole remaining after removing the bar 41 is repaired with mortar.

As described above, according to the invert mold K of this embodiment, the number of members constituting the invert mold K can be reduced as compared with the case where the entire inner surface of the invert portion A is covered with the barrier plate. . In other words, since the weight of the invert form K can be reduced, the invert form K can be moved smoothly even in a tunnel yard that cannot be equipped with sufficient lifting equipment.
Furthermore, according to the invert form K, since the barrier plate is not arranged in the central portion of the invert portion A, the invert die is used at the time of placing concrete compared to the case where the entire inner surface of the invert portion A is covered with the barrier plate. When the pressure of the fresh concrete acting on the frame K decreases and the concrete starts to harden around the anchor 4, the degree of restraint of the anchor 4 increases and the displacement of the receiving beam 3 is suppressed. Even if the pressure of fresh concrete acts on the dam plate 2 due to the concrete placement on the side of A, the invert form K is unlikely to be lifted. In other words, the invert form K is light but hardly lifts.
Moreover, in the present embodiment, since the anchor 4 is fixed to the reinforcing bar support A3, the anchor 4 can be suitably restrained.
Note that when concrete is placed on the side of the invert portion A, the concrete side pressure acts on the dam plate portion 2, but in this embodiment, the dam plate portion 2 is supported by the support frame 1, so the dam plate The inclination etc. which generate | occur | produce in the part 2 can be suppressed.
Thus, according to the invert formwork K, it is possible to improve the stability of the formwork fixing at the rising part of the tunnel side face part (side part of the invert part).

  Further, according to the invert form K, the receiving beam 3 is curved along the inner surface of the invert portion A, so that it becomes a mark for leveling the concrete surface. Therefore, the dimensional accuracy of the inverted part A can be increased.

The configuration exemplified in the above embodiment is merely an example.
For example, although illustration is omitted, the lower ends of the receiving beams 3 and 3 adjacent to the left and right may be connected to each other. If the receiving beams 3 and 3 adjacent to each other on the left and right are connected to each other, the deformation generated in each receiving beam 3 is reduced, so that the deformation of the invert form K due to the pressure of fresh concrete when placing concrete is suppressed. Can do.
In the above embodiment, the anchor 4 is fixed to the reinforcing bar support A3. However, the anchor 4 may be fixed to the reinforcing bar arranged in the invert portion A, or the anchor 4 may be fixed to the reinforcing bar or the reinforcing bar support A3. It may be installed independently.

  Moreover, when increasing the area | region covered with the dam plate part 2, what is necessary is just to construct a steel plate in the receiving beam 3 and 3 adjacent front and back.

K form for invert 1 support stand 2 weir plate 3 receiving girder 4 anchor A invert A3 rebar support stand

Claims (4)

An invert form used when constructing an invert part of a tunnel,
A support frame straddling the center of the invert part;
A pair of left and right weir plates covering the sides of the invert part;
Receiving girders extending from the respective weir plates toward the central portion of the invert portion;
An anchor connected to the receiving beam,
The both weir plate parts are supported by the support frame in a state of facing each other with a gap between them,
The invert mold is characterized in that a lower end portion of the anchor is embedded in concrete at a central portion of the invert portion.   2. The invert form according to claim 1, wherein the receiving beam is curved along an inner surface of the invert portion.   The invert form according to claim 1 or 2, wherein the receiving beams adjacent on the left and right are connected to each other.   4. The invert form according to claim 1, wherein the anchor is fixed to a reinforcing bar arranged in an invert portion or a reinforcing bar support for supporting the reinforcing bar. 5. .

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