JP2020193475A - Method for assembling arch reinforcement bars - Google Patents

Abstract

To provide a method for assembling arch reinforcement bars that can achieve both high workability and watertightness of tunnels.SOLUTION: A method for assembling arch reinforcement bars of the present invention comprises a first frame work step in which a split arch frame 10a formed by connecting a plurality of temporary main bars 11 arranged in parallel by a plurality of temporary distribution bars 12 is assembled upward from both lower ends of an inner wall of a tunnel, a second frame work step in which two divided arch frames 10a are connected at a top of the tunnel to form an arch frame member 10, an attachment step in which a plurality of bearing members 30 are attached to an outer peripheral side of the arch frame member 10, a connecting step of connecting a plurality of arch frame members 10 arranged in parallel along the tunnel axial direction with a plurality of connecting members 20 to construct a support structure 1, and a reinforcement step of constructing arch reinforcement bars A by reinforcing main reinforcement bars A1 and distribution bars A2 inside the support structure 1. The arch shape of the support structure 1 can be corrected by supporting the inner wall of the tunnel with a plurality of support members 30.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for assembling an arch reinforcing bar for lining a tunnel, and relates to a method for assembling an arch reinforcing bar that can achieve both high workability and watertightness of a tunnel.

In mountain tunnel construction, sheet waterproofing work is often used to lay a tarpaulin on the inner wall of the tunnel after shotcrete construction in order to ensure the watertightness of the tunnel.
Conventional techniques for arranging arched reinforcing bars for lining inside the waterproof sheet include (1) a method of arranging an arch-shaped steel support inside the waterproof sheet to support the arched reinforcing bars, (2). ) There is a method of hanging arch reinforcing bars from sprayed concrete through a waterproof sheet. In addition, the method (2) further includes (2a) an anchor method in which an anchor cast in sprayed concrete is passed through a tarpaulin and the through hole is sandwiched between waterproof rubbers to close the anchor, and (2b) a hanging tool is made of concrete through the tarpaulin. It includes a concrete nail method of fixing with a nail, (2c) a clip method of sandwiching a waterproof sheet with a clip-type hanger and fixing the waterproof sheet.

Japanese Unexamined Patent Publication No. 8-338199 Japanese Unexamined Patent Publication No. 9-4394 Japanese Unexamined Patent Publication No. 2006-291686 Japanese Unexamined Patent Publication No. 2006-176954

Tunnel standard specification and commentary (JSCE Tunnel Engineering Committee: August 2016)

The prior art has the following problems.
<1> The support method using steel support requires a large heavy machine for transporting and installing steel materials, resulting in low workability and high construction cost. In addition, since the installation work by heavy machinery occupies a wide area in the mine, it obstructs the passage of construction vehicles and delays other work such as slipping out.
<2> In the support method using steel support, the side surface of the support obstructs the flow of the lining concrete in the tunnel axial direction, which deteriorates the workability of the lining.
<3> In the anchor method and the concrete nail method, since the anchor and the nail are penetrated through the waterproof sheet, the watertightness may be impaired due to the infiltration of water from the through hole.
<4> In the clip method, the waterproof sheet may be damaged by the clip holding portion. In particular, when placing lining concrete, the weight of the lining concrete may pull it downward, causing the tarpaulin to tear at the corners of the holding portion.
<5> Summarizing the above, while the support method can ensure the watertightness of the tarpaulin, the construction is large and the workability and construction cost are inferior, and the suspension method using anchors etc. can be constructed relatively easily. On the other hand, the watertightness of the waterproof sheet may be impaired. That is, the conventional technique cannot achieve both workability and watertightness of the waterproof sheet.

An object of the present invention is to provide a method for assembling an arch reinforcing bar that can solve the above-mentioned problems of the prior art.

The method for assembling the arch reinforcement of the present invention includes a first frame process for assembling the divided arch frame, a second frame process for connecting the two divided arch frames to form an arch frame member, and supporting the outer peripheral side of the arch frame member. It is provided with an attachment process of attaching a pressure member, a connection process of connecting a plurality of arch frame members to construct a support structure, and a reinforcement arrangement process of constructing an arch reinforcing bar inside the support structure, depending on the pressure member. It is characterized in that the arch shape of the support structure can be corrected.

The method for assembling the arch reinforcing bar of the present invention may include an invert rooting step of connecting the inverted reinforcing bars to each other with a rooting bar before the first framework step.

In the method of assembling the arch reinforcing bar of the present invention, the bearing member may have a bearing portion, a rod-shaped portion, and a fixing portion.

In the method of assembling the arch reinforcing bar of the present invention, the extrusion deformation position of the support structure may be specified by frame analysis, and at least a part of the bearing member may be installed at the extrusion deformation position.

From the above configuration, the method for assembling the arch reinforcing bar of the present invention has at least one of the following effects.
<1> Since a support structure that supports the arch reinforcing bars can be constructed simply by assembling the reinforcing bars along the inner wall of the tunnel, the workability is high and the construction cost is low.
<2> Since it is a non-penetrating method that does not make holes in the waterproof sheet, high watertightness can be maintained.
<3> Since the assembly of the support structure itself can be performed manually as long as the scaffolding can be secured, it can be installed in a small work space without the need for a large heavy machine. Therefore, the limited underground space can be effectively used, and the construction can be carried out without stopping the passage of construction vehicles.
<4> Since the support structure is a linear structure made of reinforcing bars, it is difficult to obstruct the flow of lining concrete.
<5> By connecting the two split arch frames at the top of the tunnel, it is possible to assemble the support structure while avoiding temporary equipment such as air ducts. In addition, since the arch frame member does not need to be grounded, the narrow underground space can be effectively used.
<6> As described above, the method for assembling the arch reinforcing bar of the present invention can achieve both high workability and watertightness.

Explanatory drawing of the support structure of this invention. Explanatory drawing (1) of the method of assembling the arch reinforcing bar of this invention. Explanatory drawing (2) of the method of assembling the arch reinforcing bar of this invention. Explanatory drawing (3) of the method of assembling the arch reinforcing bar of this invention. Explanatory drawing (4) of the method of assembling the arch reinforcing bar of this invention. Explanatory drawing (5) of the method of assembling the arch reinforcing bar of this invention. Explanatory drawing (6) of the method of assembling the arch reinforcing bar of this invention. Explanatory drawing (7) of the method of assembling the arch reinforcing bar of this invention. Explanatory drawing of bearing member. Explanatory drawing (1) of correction of an arch shape by a bearing member. Explanatory drawing (2) of correction of an arch shape by a bearing member.

Hereinafter, the method of assembling the arch reinforcing bar of the present invention will be described in detail with reference to the drawings.
In addition, each direction such as "up and down" and "left and right" in the description of the present invention means each direction in the cross-sectional view of the tunnel, that is, each direction in FIG. The "inside" of the tunnel means the central direction in the cross-sectional view of the tunnel, and the "outside" means the opposite direction. The term "sprayed concrete surface" is used to include the waterproof sheet laid on the sprayed concrete surface.

[How to assemble arch rebar]
<1> Overall configuration.
The method for assembling the arch reinforcing bar of the present invention is a construction method for arranging the arch reinforcing bar A for lining inside the sprayed concrete of the tunnel.
Here, the arch reinforcing bar A is formed by connecting a plurality of arch-shaped main reinforcing bars A1 arranged in the tunnel circumferential direction with a plurality of force distribution bars A2 arranged in the tunnel axial direction (FIG. 2G). Since the structure of the arch reinforcing bar A is known, it will not be described in detail here.
The method for assembling the arch reinforcing bar of the present invention has one feature in that an arch-shaped support structure 1 is constructed inside the sprayed concrete, and the arch reinforcing bar A is assembled inside the support structure 1 while being supported by the support structure 1. ..
The method for assembling the arch reinforcing bar of the present invention includes at least a first frame process, a second frame process, an attachment process, a connection process, and a reinforcement arrangement process, and this is regarded as one construction cycle from the tunnel entrance side. Construction will be carried out for each span toward the face side. Further, in this example, an invert rooting step is further provided before the first framework step.

<2> Support structure (Fig. 1).
Prior to the explanation of the assembly direction of the arch reinforcing bar, the structure of the support structure 1 for supporting the arch reinforcing bar A will be described.
The support structure 1 is an arch-shaped support structure formed by assembling reinforcing bars.
The support structure 1 includes a plurality of arch frame members 10, a plurality of connecting members 20 for connecting the plurality of arch frame members 10 in the tunnel axial direction, and a plurality of connecting members 20 arranged between the arch frame member 10 and the sprayed concrete surface. It is composed of a bearing member 30 and.
In this example, there are a plurality of invert reinforcing bars 40 projecting upward from the inside of the invert concrete and a rooting bar 50 connecting the invert reinforcing bars 40 to each other, and the lower end of the arch frame member 10 is provided with the invert bar. Connect with 40.
When the lining concrete is placed, the support structure 1 is left in the formwork with the arch reinforcing bar A supported, and is integrally embedded in the lining.

<2.1> Arch frame member.
The arch frame member 10 is an arch-shaped component that supports the load of the arch reinforcing bar A.
The arch frame member 10 is formed by connecting ladder-shaped divided arch frames 10a raised from both sides of the tunnel at the top of the tunnel, and has a plurality of setup main bars 11 and a plurality of setup distribution force bars 12 as an overall structure. , And a plurality of connecting tools 13.
The setup main bar 11 is composed of gently curved reinforcing bars, and by connecting a plurality of setup main bars 11 in the longitudinal direction, an arch structure having a curvature corresponding to the sprayed concrete surface as a whole is formed.
The setup distribution force bar 12 is composed of a linear reinforcing bar extending in the tunnel axial direction, and is hung in parallel between two parallel setup main bars 11.
The connecting tool 13 is a member that connects the setup main bar 11 and the setup distribution force bar 12 in an orthogonal state. In addition, it is also used for connecting the setup main bar 11 and the invert insertion bar 40, connecting the setup main bar 11 and the connecting force distribution bar 21 described later, and the like.
The connector 13 includes, for example, a combination of two plates and bolts having orthogonal grooves (orthogonal type), a combination of a U-shaped bolt and a fixing plate (lap joint type), a coupler, and the like.

<2.2> Connecting member (Fig. 3).
The connecting member 20 is a component for connecting a plurality of arch frame members 10 to each other and fixing the arch reinforcing bar A.
The connecting member 20 has a connecting force distribution bar 21 extending in the tunnel axial direction and a main bar attachment bar 22 extending in parallel with the connecting force distribution bar 21.
In this example, the connecting force distribution bar 21 is connected by the connecting tool 13 in a state orthogonal to the setup main bar 11, and the main bar attaching bar 22 is connected to the rod-shaped portion 32 of the bearing member 30 described later.

<2.3> Supporting member (Fig. 3).
The bearing member 30 is a component that has both a function of correcting the bending of the arch frame member 10 to maintain the shape and a spacer function of defining the mounting position of the arch reinforcing bar A.
The bearing member 30 is attached to an appropriate place between the sprayed concrete surface and the setup main bar 11.
The bearing member 30 has a planar bearing portion 31, a rod-shaped portion 32 protruding from the back surface of the bearing portion 31, and a fixing portion 33 attached to the rod-shaped portion 32.
The fixing portion 33 is a member for fixing the setup main bar 11 and the like at an arbitrary position on the rod-shaped portion 32. By adjusting the fixed position of the fixing portion 33, the distance between the sprayed concrete surface and the setup main bar 11 and the like can be arbitrarily set.
In this example, a rectangular steel plate with a nut welded to the back surface as the bearing portion 31, a screw steel rod screwed to the nut of the bearing portion 31 as the rod-shaped portion 32, and a fixing bolt screwed as the fixing portion 33. Fixing metal fittings that can be fixed at an arbitrary height on the rod-shaped portion 32 are adopted. However, the configuration of the bearing member 30 is not limited to this, and for example, the bearing portion 31 may be a circular plate.
Further, the main bar attaching bar 22 is fixed to the tip of the rod-shaped portion 32 by the connecting means 34. In this example, a reinforcing bar binding wire is adopted as the connecting means 34.

<2.4> Invert insertion muscle, root consolidation muscle.
The invert bar 40 is a component that connects the lower end of the arch frame member 10 to the invert concrete.
A plurality of invert bar bars 40 are arranged in the invert concrete, and the tip thereof is projected upward from the upper surface of the invert concrete. The invert insertion bars 40 are arranged in parallel along the tunnel axial direction in accordance with the distance between the setup main bars 11.
The root compaction muscle 50 is a component that connects the invert insertion muscles 40 to each other.
The rooting bar 50 is composed of a linear reinforcing bar extending in the direction of the tunnel axis, and is bridged between a plurality of parallel invert bar bars 40.

<3> Invert root consolidation process.
The invert root consolidation step is a step of rooting the split arch frame 10a.
A rooting bar 50 is hung in the direction of the tunnel axis between a plurality of invert bar 40s parallel to both sides of the invert concrete, and the intersection of the two is rigidly connected by the connecting tool 13.
In the method for assembling the arch reinforcing bar of the present invention, the split arch frame 10a is assembled in a cantilevered state toward the center of the tunnel in the subsequent first frame step, so that the split arch frame 10a is tilted or shaken due to its own weight. There is a risk. Therefore, by connecting the invert insertion bars 40 to each other and firmly rooting them in advance, it is possible to reduce the inclination and blurring and reduce the work load.

<4> First framework process.
The first framework step is a step of constructing the split arch frames 10a on both sides of the tunnel.
In the first frame process, the setup main bar 11 is first connected to the upper part of the invert insertion bar 40 to construct the lower split arch frame 10a, and then the setup main bar 11 is added above the lower split arch frame 10a. By going, the upper split arch frame 10a is assembled.

<4.1> Connection of setup main bar and invert insertion bar (Fig. 2A).
The lower part of the two setup main bars 11 is connected to the upper part of the two adjacent invert insertion bars 40 by the connecting tool 13.
The weight of the split arch frame 10a is concentrated on the connecting portion between the setup main bar 11 and the invert insertion bar 40. Therefore, it is desirable that the setup main bar 11 and the invert insertion bar 40 are firmly connected by using a bolt type connecting tool 13 or the like. In this example, a metal fitting that combines a U-shaped bolt and a plate is adopted as the connecting tool 13, and the setup main bar 11 and the invert insertion bar 40 are rigidly connected at two upper and lower positions in a state of being overlapped in parallel.
Subsequently, a plurality of setup distribution force bars 12 are hung between the two parallel setup main bars 11 and connected in a ladder shape by the plurality of connecting tools 13.
In the above, the ladder structure was constructed after first connecting the setup main bar 11 and the invert insertion bar 40. However, after the ladder structure has been grounded in advance, the procedure for connecting the setup main bar 11 and the invert insertion bar 40 is as follows. There may be.

<4.2> Assembly of the split arch frame (Fig. 2B).
The upper setup main bar 11 is added and connected to the tip of the lower setup main bar 11.
Specifically, the curved direction of the upper setup main bar 11 is aligned with the tunnel center direction, and the upper end portion of the lower setup main bar 11 and the lower end portion of the upper setup main bar 11 are overlapped in parallel to both. Is rigidly connected with the connector 13.
After the two setup main bars 11 are added, a plurality of setup distribution force bars 12 are hung between the setup main bars 11 and connected in a ladder shape by the connecting tool 13. In addition, the procedure may be a procedure of connecting the lower setup main bar 11 and the upper setup main bar 11 after the ladder structure has been grounded in advance.
The above steps are repeated according to the number of divisions of the setup main bar 11, and two division arch frames 10a are constructed on both sides of the tunnel.
The split arch frame 10a may be inclined toward the center of the tunnel due to its own weight. In this case, it may be temporarily supported from below by a support pipe or the like.

<5> Second framework process (Fig. 2C).
The second frame step is a step of connecting the two divided arch frames 10a at the top of the tunnel to construct the arch frame member 10.
The setup main bar 11 is hung between the two divided arch frames 10a facing each other, and the two are connected via the connecting tool 13. The setup distribution force bars 12 are arranged between the setup main bars 11 at appropriate intervals.
In tunnel construction where natural ventilation becomes insufficient, forced ventilation using a blower is required by law (Article 602 of the Occupational Safety and Health Regulations). For this reason, temporary equipment such as a ventilation duct W is arranged near the center of the top of the tunnel.
Therefore, if the arch frame member 10 is grounded in an arch shape in advance, the arch frame member 10 cannot be erected because it interferes with the temporary equipment. In addition, since it occupies a large area of the road surface when laying the ground, it obstructs the passage of construction vehicles and hinders other processes.
In order to solve the above inconvenience, the method of assembling the arch reinforcing bar of the present invention includes a first frame step of assembling the arch frame member 10 upward from both lower ends of the tunnel and two divided arch frames 10a. It is performed in two steps with the second frame process of connecting the divided arch frames 10a at the top.
As a result, it is possible to prevent the arch frame member 10 from interfering with the temporary equipment and to eliminate the need for the groundwork of the arch frame member 10 to effectively utilize the narrow underground space and secure the passage of construction vehicles. It will be possible.

<6> Attachment process (Fig. 2D).
The attachment step is a step of attaching the bearing member 30 to the arch frame member 10.
A bearing member 30 is arranged between the setup main bar 11 and the sprayed concrete surface, and the bearing portion 31 is brought into contact with the sprayed concrete surface.
The fixing portion 33 is brought into contact with the outside of the setup main bar 11, and the fixing bolt of the fixing portion 33 is screwed while the setup main bar 11 is pressed inward in the arch direction to fix the fixing portion 33 on the rod-shaped portion 32. (Fig. 3).
The same operation is repeated, and all the bearing members 30 are attached to the setup main bar 11.
The attachment location of the bearing member 30 can be arbitrarily set, but it is desirable to attach the bearing member 30 to at least the top, shoulders, and sides of the setup main bar 11.
By attaching the bearing member 30 to the outer periphery of the arch frame member 10, the arch frame member 10 is supported in a state of being supported in the arch inner direction by the plurality of bearing members 30.

<7> Repeating the process (Fig. 2E).
By repeating the steps <4> to <6> described above, a predetermined number of arch frame members 10 per span are constructed along the tunnel axial direction.

<8> Connecting step (Fig. 2F).
The connecting step is a step of connecting a plurality of arch frame members 10 with the connecting member 20.
The connecting force distribution bars 21 are hung inside the setup main bars 11 of the arch frame members 10 arranged in parallel in the tunnel axial direction, and are integrally connected by the connecting tool 13.
In this example, the connecting force distribution bar 21 is arranged in a direction orthogonal to the setup main bar 11 near the intersection of the setup main bar 11 and the bearing member 30, and is connected to the setup main bar 11 via the connecting tool 13 ( Figure 3).
Similarly, the setup main bars 11 of all the arch frame members 10 are connected at appropriate intervals along the tunnel circumferential direction.
From the viewpoint of structural integrity, it is desirable that all arch frame members 10 parallel in the tunnel axial direction are continuously connected by one connecting force distribution bar 21 at each position in the tunnel circumferential direction. However, the present invention is not limited to this, and a plurality of connecting force distribution bars 21 may be added in a straight line or in a staggered manner in the tunnel axial direction and connected.
Subsequently, the main bar attachment bar 22 is attached parallel to the inside of the connecting force distribution bar 21. Specifically, the main bar attachment bar 22 is fixed to the tip end side of the rod-shaped portion 32 of the bearing member 30 by the binding wire of the connecting means 34 (FIG. 3).
The fixed position of the main bar attachment bar 22 on the rod-shaped portion 32 is set in consideration of the design bar arrangement position of the main bar A1. Desirably, the fixed position of the main bar attaching bar 22 is marked in advance on the rod-shaped portion 32. As a result, the bearing member 30 functions as a spacer for positioning the main bar A1.
With the above, the support structure 1 is completed.

<9> Correction of arch shape.
Since the support structure 1 has an arch structure formed by combining reinforcing bars, the arch shape bends flat due to its own weight.
Specifically, the center top of the arch frame member 10 sinks inward due to the weight of the reinforcing bar, and the shoulder portion (extruded deformation position P) is pushed outward by the reaction, and the arch shape swells in the tunnel width direction (FIG. 4A). ).
When the arch shape is bent, the bearing portion 31 of the bearing member 30 at the central top is lifted from the sprayed concrete surface, so that the top of the arch reinforcing bar A cannot secure an appropriate covering thickness at the time of lining.
Therefore, by pushing up the fixing portion 33 of the bearing member 30 at the extruded deformation position P toward the tip end side of the rod-shaped portion 32 and widening the distance between the setup main bar 11 and the sprayed concrete surface, the setup main bar 11 at the extruded deformation position P is It is compressed inward, and this reaction pushes up the central top of the setup main bar 11 upward (FIG. 4B).
By the above work, the bending of the arch frame member 10 can be corrected.
The arch shape may be corrected for each arch frame member 10 before the <8> connecting step.

<10> Reinforcing step (Fig. 2G).
The bar arrangement step is a step of arranging the arch reinforcing bar A inside the support structure 1.
The outside of the arched main bar A1 is brought into contact with the inside of the main bar attachment bar 22 and fixed with a binding wire.
Since the main bar mounting bar 22 is fixed at a predetermined position on the rod-shaped portion 32 of the bearing member 30, the distance between the main bar A1 and the sprayed concrete surface becomes constant by pressing the supporting member 30 against the sprayed concrete surface. It is fixed and thus the main bar A1 is placed in an appropriate covering position within the lining.
Similarly, the main bar A1 is fixed at a predetermined interval along the tunnel axial direction.
A plurality of main bars A1 are connected by a plurality of force distribution bars A2 in the tunnel axial direction to construct an arch reinforcing bar A.
Due to the arrangement of the arch reinforcing bars A, the load on the support structure 1 may increase and the arch shape may be deformed. In this case, the arch shapes of the support structure 1 and the arch reinforcing bar A are corrected by repeating the work of <9> again.
In this example, the arch reinforcing bar A is modeled in advance, the extrusion deformation position P is specified by frame analysis, and the bearing member 30 is arranged at least at a position corresponding to the extrusion deformation position P on the arch frame member 10. ..

<11> Subsequent process.
A movable formwork is arranged inside the arch reinforcing bar A, and lining concrete is placed between the movable formwork and the sprayed concrete surface. These subsequent steps are known and will not be described in detail here.

1 Support structure 10 Arch frame member 10a Divided arch frame 11 Setup main bar 12 Setup distribution force bar 13 Connecting tool 20 Connecting member 21 Connecting force distribution bar 22 Main bar mounting bar 30 Supporting member 31 Supporting part 32 Rod-shaped part 33 Fixed Part 34 Connecting means 40 Invert insertion bar 50 Rooting bar A Arch rebar A1 Main bar A2 Force distribution bar P Extruded deformation position W Air pipe

Claims (4)

It is a method of assembling arch reinforcing bars related to tunnel lining.
The first frame process, in which a split arch frame formed by connecting multiple setup main bars arranged in parallel with multiple setup distribution force bars is assembled upward from both lower ends of the tunnel inner wall,
A second frame process in which the two divided arch frames are connected at the top of the tunnel to form an arch frame member, and
An attachment process in which a plurality of pressure bearing members are attached to the outer peripheral side of the arch frame member, and
A connecting step of connecting a plurality of the arch frame members arranged in parallel along the tunnel axial direction with a plurality of connecting members to construct a support structure.
It is provided with a reinforcement step of arranging main reinforcement and force distribution reinforcement inside the support structure to construct an arch reinforcement.
It is characterized in that the arch shape of the support structure can be corrected by supporting the inner wall of the tunnel with the plurality of support members.
How to assemble arch rebar. It has a plurality of invert reinforcing bars protruding upward from both sides of the invert concrete, and is provided with an invert rooting step of connecting the plurality of invert reinforcing bars to each other by a rooting bar prior to the first framework step. The method for assembling an arch reinforcing bar according to claim 1, wherein in the first framework step, the lower portion of the setup main bar is connected to the invert bar. The bearing member can fix a planar bearing portion, a rod-shaped portion protruding from the back surface of the bearing portion, and the setup main bar or the setup distribution force bar at an arbitrary position on the rod-shaped portion. The method for assembling an arch reinforcing bar according to claim 1 or 2, wherein the arch reinforcing bar is provided with a fixing portion. Claims 1 to 1, wherein the extrusion deformation position of the support structure on the sprayed concrete surface is specified by frame analysis, and at least a part of the plurality of bearing members is installed at the extrusion deformation position. The method for assembling an arch reinforcing bar according to any one of 3.