Tunnel steel arch and steel mesh installation method

Abstract

The application discloses a tunnel steel arch frame and a reinforcing mesh mounting method, which comprises the following steps: S1: excavating; after excavating the tunnel according to the construction sequence, the anchor rod is struck, then the concrete is sprayed to the tunnel wall, after the concrete is solidified to the expected hardness, the steel reinforcing mesh in pieces is placed in turn and side by side according to the construction direction; S2: mounting the steel reinforcing mesh; the adjacent two pieces of steel reinforcing mesh are overlapped together through the steel reinforcing mesh quick overlapping assembly, and the steel reinforcing mesh is connected to the anchor rod; S3: mounting the steel arch frame, the steel arch frame is mounted on the side of the steel reinforcing mesh away from the tunnel wall, meanwhile, the protection device is placed at the lower end joint of the steel arch frame, the protection device is buried by backfilling the sandstone, then the concrete is sprayed again. Not only the adjacent two pieces of steel reinforcing mesh can be overlapped together through the steel reinforcing mesh quick overlapping assembly, so that the waste of the steel reinforcing mesh is reduced, but also the connecting joint of the steel arch frame is protected through the protection device, so that the connection between the two steel arch frames is facilitated.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of initial support of tunnel construction, and particularly relates to a tunnel steel arch and a steel mesh installation method. BACKGROUND

[0002] When the tunnel is excavated, the vault is excavated first, then the side wall, and finally the inverted arch. The steel mesh and the steel arch need to be installed in each area during installation, and the steel arches on the vault, the side wall and the inverted arch are connected together. In the prior art, during the construction of the vault, the side wall and the inverted arch, the steel mesh is first placed between the two steel arches, then the steel arch is installed, and finally the steel mesh is welded between the two steel arches. Since the steel mesh is manufactured in advance, it cannot be guaranteed that the distance between the two steel arches is an integer multiple of the steel mesh, that is, it cannot be guaranteed that one or more pieces of steel mesh can be placed between the two steel arches. Therefore, it is not possible to determine the number of steel meshes placed between the two steel arches. In order to ensure the smooth progress of the construction, more steel meshes are usually placed, which is easy to cause waste of steel meshes. In order to facilitate the connection of the steel arch, the steel arch joint of the previous construction (i.e. during the construction of the vault and the side wall) is excavated. During the excavation process, the steel arch joint is deformed, which is easy to cause the difficulty of splicing of the two steel arches. SUMMARY

[0003] The present application provides a tunnel steel arch and a steel mesh installation method. The two adjacent steel meshes can be spliced together by the steel mesh fast splicing assembly, thereby reducing the waste of steel mesh sheets. The connecting joint of the steel arch can be protected by the protection device, thereby facilitating the connection between the two steel arches.

[0004] To this end, the technical solution adopted by the present application is as follows: a tunnel steel arch and a steel mesh installation method, comprising the following steps:

[0005] S1: Excavation; after excavating the tunnel according to the construction sequence, the anchor rod is struck, and then the tunnel wall is initially sprayed with concrete. After the concrete solidifies to the expected hardness, the steel mesh in pieces is placed in sequence according to the construction direction;

[0006] S2: install the steel mesh; overlap two adjacent steel meshes together through the steel mesh quick overlap assembly, and connect the steel mesh to the anchor rod at the same time; the steel mesh quick overlap assembly comprises a first connecting piece installed at the overlap position of the two steel meshes and having a cross joint position, and a second connecting piece installed at the overlap position of the two steel meshes, the first connecting piece is a long strip-shaped steel sheet, two circular holes matched with the steel bars are provided on the first connecting piece in front and back, and openings extending to the corresponding side circular holes are provided at the front and back ends of the first connecting piece, the second connecting piece is a long strip-shaped steel sheet, two circular holes matched with the steel bars are provided on the second connecting piece in front and back, and an opening in communication with the corresponding side circular hole is provided at any one of the front and back ends of the second connecting piece, and the opening is in communication with the two circular holes on the second connecting piece, and the opening width of the first connecting piece and the second connecting piece is smaller than the radius of the connected circular hole;

[0007] The opening and the circular hole provided on each connecting piece enable the steel bar to be clamped into the circular hole along the opening, and during the specific overlap of the steel mesh, the first connecting piece is clamped into the overlap position of the steel mesh at the cross joint in the rear of construction, and then the steel mesh in the front of construction is clamped into the first connecting piece at a position in front of the first connecting piece, so as to complete the preliminary positioning, and the clamping direction is not limited to horizontal clamping. After the preliminary positioning is completed, the second connecting piece is clamped into the overlap position of the two steel meshes according to the requirement;

[0008] S3: install the steel arch, install the steel arch on the side of the steel mesh away from the tunnel wall, place the protection device at the lower end joint of the steel arch at the same time, backfill the sandstone to bury the protection device, and then spray the concrete again.

[0009] The protection device comprises a top plate, a side plate and a bottom plate, the top plate and the side plate and the side plate and the bottom plate are hinged, the top plate, the side plate and the bottom plate can be enclosed to form a U-shaped structure matched with the joint of the arch, one end of the top plate away from the joint is provided with a rectangular notch matched with the arch, the middle part of the side plate is provided with a rib plate for abutting against the side surface of the joint of the arch, and one end of the bottom plate away from the joint is provided with a pull ring. In use, the top plate, the side plate and the bottom plate can be enclosed to form a U-shaped structure, and then clamped on the joint of the arch.

[0010] As a preferred embodiment of the above scheme, the second connecting piece is arc-shaped at the end away from the opening for easy taking, the two end openings of the first connecting piece are chamfered, the end of the opening on the second connecting piece is chamfered, and the opening connecting the two circular holes on the second connecting piece is chamfered at the circular hole close to the end of the opening.

[0011] Further preferably, the side plate is further hinged with a first wing plate and a second wing plate on the left and right sides respectively, the first wing plate and the second wing plate are arranged to block the corresponding side surface of the joint.

[0012] Further preferably, the rib plate is vertically arranged in the middle of the side plate and the upper and lower ends are arranged as inclined surfaces, and the abutting surface of the rib plate is provided with a circular-arc-shaped protrusion for reducing friction.

[0013] Further preferably, in S1, when the excavated place is a tunnel side wall or an inverted arch, the steel arch joint of the previous construction needs to be dug out when excavating, and the protection device needs to be removed, and then the subsequent process is carried out, and when spraying concrete, the arch joint of the previous construction needs to be avoided.

[0014] Further preferably, in S2, when installing the steel mesh, the overlapping part of the adjacent two steel meshes is between one and two times the distance of each grid of the steel mesh.

[0015] Further preferably, in S3, after the steel arch is installed, the steel mesh overlapping the steel arch is spot welded on the steel arch.

[0016] The beneficial effects of the present application are:

[0017] 1) When excavating, the sprayed concrete can place the steel mesh or the steel arch installation, and the sand and gravel on the tunnel wall falls off.

[0018] 2) When installing the steel mesh, the adjacent two steel meshes are overlapped by the steel mesh quick positioning and overlapping assembly, so that the length of the overlapped steel mesh can be determined, and thus the amount of steel mesh required between the adjacent two I-beams can be determined, thereby reducing the waste of steel mesh.

[0019] 3) The connecting joint of the steel arch is protected by the protection device, so that the connecting joint is less damaged in subsequent construction, thereby facilitating the connection between the two steel arches.

[0020] 4) Because the protection device can enclose a type structure that fits the arch joint, it can replace the traditional concrete cushion block and serve as the foundation of the bottom of the steel arch, thereby reducing the number of concrete cushion blocks used and thereby reducing costs. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is the installation flowchart of the present application.

[0022] Figure 2 is a schematic diagram of the first connecting piece in the present application.

[0023] Figure 3 is a schematic diagram of the second connecting piece in the present application.

[0024] Figure 4 is a schematic diagram of the installation position of the steel mesh quick positioning and overlapping assembly in the present application.

[0025] Figure 5 is a top view of the installation of the steel mesh quick positioning and overlapping assembly in the present application.

[0026] Figure 6 is Figure 5 a sectional view along the section line C-C.

[0027] Figure 7 is an expanded view of the protection device in the present application.

[0028] Figure 8 is a structural schematic view of the protection device in the present application.

[0029] Figure 9 is an expanded view of the protection device in the present application.

[0030] Figure 10 is a structural schematic view of the protection device in the present application.

[0031] Figure 11 is an exploded view of the protection device in the present application (without the rib plate).

[0032] Figure 12 is a structural schematic view of the rib plate in the protection device in the present application.

[0033] Figure 13 is an assembled front view of the protection device in the present application.

[0034] Figure 14 is a schematic view of the use of the protection device in the present application. DETAILED DESCRIPTION

[0035] The present application is further described below by way of examples and with reference to the accompanying drawings:

[0036] As Figures 1-14 shown, a tunnel steel arch and steel mesh installation method mainly includes the following steps:

[0037] First step: Excavation; After excavating the tunnel according to the construction sequence, anchor rods are punched, and then the tunnel wall is initially sprayed with concrete. After the concrete solidifies to the expected hardness, the steel mesh in pieces is placed in sequence according to the construction direction. The construction sequence is to excavate the vault first, then excavate the side wall after the initial support of the vault is completed, then excavate the inverted arch after the initial support of the side wall is completed, and finally complete the initial support of the inverted arch. When spraying concrete, the sprayed concrete thickness is between 30-40mm, which is used to prevent the sand and stone of the excavated tunnel from falling during subsequent construction.

[0038] When the excavated place is the tunnel side wall or the inverted arch, the steel arch joint of the previous construction needs to be excavated out at the time of excavation, and the protection device is then removed, and then the subsequent process is performed. When spraying concrete, the arch joint of the previous construction needs to be avoided.

[0039] Second step: install the steel mesh; through the steel mesh fast lap assembly, the adjacent two steel meshes are lapped together, and meanwhile the steel meshes are connected to the anchor rod. When lapping, the overlapping part of the adjacent two steel meshes is between one time and two times of the distance of each grid of the steel mesh. The connection of the steel mesh and the anchor rod adopts the prior art.

[0040] The steel mesh fast positioning lap assembly mainly consists of the first connecting piece 1 installed at the lap position of the two steel meshes with the cross joint and the second connecting piece 2 installed at the lap position of the two steel meshes. During installation, the first connecting piece is clamped at the first connecting piece installation position A of the overlapping of the two steel meshes for preliminary positioning, and the clamping direction is not limited to horizontal clamping. After the preliminary positioning is completed, the second connecting piece is clamped at the second connecting piece installation position B and in a different direction from the first connecting piece for further positioning of the two steel meshes.

[0041] In order to clamp the connecting piece and the two steel meshes, the first connecting piece 1 is a long strip-shaped steel sheet, two round holes matched with the steel bars are arranged side by side on the first connecting piece 1, and openings extending to the corresponding side round holes are arranged at the front and rear ends of the first connecting piece 1. Similarly, the second connecting piece 2 is a long strip-shaped steel sheet, two round holes matched with the steel bars are arranged side by side on the second connecting piece 2, and an opening communicating with the corresponding side round hole is arranged at any one of the front and rear ends of the second connecting piece 2, and the opening communicates the two round holes on the second connecting piece 2.

[0042] During the installation of the first connecting piece 1, one end of the first connecting piece is clamped on the steel bar at the corresponding position of one of the steel meshes, and then the steel bar on the other steel mesh is clamped correspondingly, at this time, the two steel meshes are preliminarily positioned, and the length of the two steel meshes after lapping is also determined. The end far away from the opening of the second connecting piece 2 is preferably arc-shaped for easy taking. After the installation of the first connecting piece is completed, the arc-shaped end of the second connecting piece 2 is taken, and the second connecting piece 2 is clamped on the parallel steel bars of the two steel meshes in a direction different from the first connecting piece 1, so that the two steel meshes are further positioned, and the relative displacement between the two steel meshes is prevented.

[0043] The opening width of the first connecting piece 1 and the second connecting piece 2 is smaller than the radius of the connected round hole, so that the connecting piece will not easily slip off after being clamped on the steel mesh, and the connection is stable.

[0044] Preferably, the first connecting piece 1 is a long strip-shaped rectangular steel sheet.

[0045] In order to facilitate the smooth clamping of the steel bars into the corresponding round holes of the connecting piece, the opening at the two ends of the first connecting piece 1 is chamfered; the end of the opening of the second connecting piece 2 is chamfered; and the opening connecting the two round holes of the second connecting piece 2 is chamfered at the round hole close to the end of the opening.

[0046] Third step: install steel arch, install steel arch on the side of the steel mesh away from the tunnel wall, at the same time put the protection device at the lower end joint of the steel arch, and backfill sandstone to bury the protection device, and then spray concrete. After the installation of the steel arch, the steel mesh overlapping the steel arch can be spot welded on the steel arch to increase the overall connectivity, and longitudinal reinforcement extending along the tunnel is welded separately between the two steel frames.

[0047] The protection device is mainly composed of a top plate 3, a side plate 4 and a bottom plate 5. The top plate 3 and the side plate 4, and the side plate 4 and the bottom plate 5 are both hinged, and a rotatable shaft can be used.

[0048] The top plate 3, the side plate 4 and the bottom plate 5 can be enclosed to form a U-shaped structure that fits the arch joint. The end of the top plate 3 away from the joint is provided with a rectangular notch 3a that cooperates with the arch. In use, the arch is clamped into the rectangular notch of the top plate 3, and the side plate 4 and the bottom plate 5 are sequentially fitted with the arch joint, and sand is filled outside the formed U-shaped structure protection device, and concrete is sprayed to isolate the concrete.

[0049] The rectangular notch of the top plate 3 cooperates with the arch to abut tightly, and the middle of the side plate 4 is provided with a rib plate 6 for abutting with the side surface of the arch joint to limit the position and enhance the strength of the overall structure.

[0050] The end of the bottom plate 5 away from the joint is provided with a pull ring 5a. The pull ring 5a can be a hole provided on the bottom plate 5, or a circular ring installed on the bottom surface of the bottom plate 5. When the arch joint is exposed by blasting after the excavation of the lower part of the tunnel is completed, the protection device can be quickly disassembled through the pull ring 5a.

[0051] In order to make the device fit the arch, the top plate 3, the side plate 4 and the bottom plate 5 are rectangular steel plates, and the length and width of the top plate 3 and the bottom plate 5 match the length and width of the arch joint, and the height of the side plate 4 is higher than the thickness of the arch joint. After the protection is installed, the space for connecting the arch joint with the next joint can be left.

[0052] According to the needs, the left and right sides of the side plate 4 can be respectively hinged with a first wing plate 7 and a second wing plate 8 that block the corresponding side surfaces of the joint, to protect the side surfaces of the joint.

[0053] Preferably, the rib plate 6 is vertically arranged in the middle of the side plate 4 and both upper and lower ends are provided with inclined surfaces, facilitating the covering of the top plate 3 and the side plate 4. At the same time, the abutting surface of the rib plate 6 is provided with a circular arc protrusion for reducing friction, avoiding causing additional damage to the abutting surface of the joint, and also facilitating the quick removal of the protection device.

Claims

1. A method for installing a tunnel steel arch frame and reinforcing mesh, characterized in that, Includes the following steps: S1: Excavation; After excavating the tunnel in the construction sequence, anchor bolts are installed, and then initial concrete is sprayed onto the tunnel wall. After the concrete has hardened to the expected hardness, large sections of steel mesh are placed side by side in the construction direction. S2: Install steel mesh; use a quick steel mesh lap assembly to lap two adjacent steel mesh pieces together, and also connect the steel mesh to the anchor rod; the quick steel mesh lap assembly includes a first connector (1) installed at the lap position of the two steel mesh pieces with cross joints and a second connector (2) installed at the lap position of the two steel mesh pieces. The first connector (1) is a long strip of steel sheet. The first connector (1) has two round holes that match the steel bars, and both ends of the first connector (1) have openings that extend to the corresponding side round holes. The second connector (2) is a long strip of steel sheet. The second connector (2) has two round holes that match the steel bars, and either end of the second connector (2) has an opening that communicates with the corresponding side round hole. The opening connects the two round holes on the second connector (2). The width of the openings on the first connector (1) and the second connector (2) is smaller than the radius of their connected round holes. S3: Install the steel arch frame. Install the steel arch frame on the side of the steel mesh away from the tunnel wall. At the same time, place a protective device at the lower end joint of the steel arch frame, backfill with sand and gravel to bury the protective device, and then spray concrete again. The protective device includes a top plate (3), a side plate (4), and a bottom plate (5). The top plate (3) and the side plate (4), and the side plate (4) and the bottom plate (5) are hinged. The top plate (3), the side plate (4), and the bottom plate (5) can be closed to form a U-shaped structure that fits with the arch frame joint. The top plate (3) has a rectangular notch (3a) at one end away from the connection point to cooperate with the arch frame. The side plate (4) has a rib plate (6) in the middle to abut against the side of the arch frame joint. The bottom plate (5) has a pull ring (5a) at one end away from the connection point.

2. The method for installing tunnel steel arch frames and reinforcing mesh according to claim 1, characterized in that: The second connector (2) has an arc shape at the end away from the opening for easy handling. The first connector (1) has chamfers at both ends of the opening. The second connector (2) has chamfers at the end of the opening. The opening of the second connector (2) that connects two round holes has chamfers at the end of the round hole near the opening.

3. The method for installing tunnel steel arch frames and reinforcing mesh according to claim 1, characterized in that: The side plate (4) is also hinged to the left and right sides respectively with a first wing plate (7) and a second wing plate (8) that block the corresponding sides of the joint.

4. The method for installing tunnel steel arch frames and reinforcing mesh according to claim 1, characterized in that: The rib (6) is vertically arranged in the middle of the side plate (4) and both the upper and lower ends are set as inclined surfaces. The abutting surface of the rib (6) is provided with an arc-shaped protrusion for reducing friction.

5. The method for installing tunnel steel arch frames and reinforcing mesh according to claim 1, characterized in that: In S1, when the excavation site is the tunnel sidewall or invert, the steel arch joints from the previous construction need to be dug out during excavation, and the protective devices need to be removed before proceeding with subsequent procedures. When spraying concrete, the arch joints from the previous construction must be avoided.

6. The method for installing tunnel steel arch frames and reinforcing mesh according to claim 1, characterized in that: In S2, when installing the reinforcing mesh, the overlapping portion of two adjacent reinforcing meshes is between one and two times the distance between each grid on the reinforcing mesh.

7. The method for installing tunnel steel arch frames and reinforcing mesh according to claim 1, characterized in that: After the steel arch frame is installed in S3, the steel mesh that overlaps with the steel arch frame is spot welded to the steel arch frame.

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