CN115405334B - Construction method for on-site forming of central ditch of highway tunnel - Google Patents

Abstract

The construction method of the central ditch site forming of the highway tunnel, relate to the construction field of the highway tunnel, through pouring, central ditch cover plate template making, installation of the template support assembly, central ditch cover plate reinforcement making and installing, foam board installation, carry on the concrete pouring step to the central ditch cover plate, keep apart and protect and spill water and maintain after pouring, after the central ditch cover plate has intensity, demolish the template support assembly, clear up the debris in the central ditch, deduct the foam board of the seam position after clearing up, can finish the construction by adopting mortar to joint; the comprehensive breakage rate of the central ditch cover plate can be controlled within 3% after the method is used, the service life of the central ditch cover plate is prolonged, the cost expenditure is reduced, and the construction quality and the overall civilized construction environment in a hole are effectively improved.

Description

A construction method for on-site forming of central ditch in highway tunnel

Technical Field

The invention relates to the field of highway tunnel construction, in particular to a construction method for on-site forming of a central water ditch in a highway tunnel.

Background technique

It is well known that the central ditch of a highway tunnel plays an extremely important role as a drainage channel during tunnel construction and operation. The construction process is organized and implemented in the order of invert, filling, ditch side wall, and ditch cover. The ditch cover uses concrete of no less than C30, which is generally prefabricated in a small prefabricated component factory and transported to the construction site for installation by a truck crane. However, the following problems exist during the construction process: (1) The side wall of the central ditch is generally 20 cm thick and is cast separately after the invert filling construction. The flatness of the filling and the top of the ditch side wall is not well controlled, resulting in gaps at the bottom of the ditch cover after laying; (2) The ditch cover prefabricated by the prefabrication factory is not well transported and installed. During the process, it is inevitable that the ditch cover will be damaged by bumps, missing edges, and falling corners; (3) After being crushed by heavy vehicles, the installed ditch cover will suffer large-scale damage at the corners due to the influence of prefabrication errors, installation errors, the top of the ditch side wall and the filling surface elevation. According to statistics, the damage rate of the corners of the installed ditch cover can reach 20%, and the replacement rate is high in the later stage; therefore, it has become a basic demand of technical personnel in this field to propose a construction method for on-site forming of the central ditch of a highway tunnel, which can effectively close the central ditch cover and the ditch side wall and reduce the damage rate of the central ditch cover.

Summary of the invention

In order to overcome the shortcomings of the background technology, the present invention discloses a construction method for on-site forming of a central ditch in a highway tunnel.

In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical scheme:

A construction method for on-site forming of a central ditch in a highway tunnel specifically comprises the following steps:

(1) Casting of the side wall of the central ditch:

After the inverted arch is poured, the contact surface between the side wall of the central ditch and the inverted arch is roughened, the debris after roughening is removed, the contact surface is washed, the template of the side wall of the central ditch is installed, and the concrete of the side wall of the central ditch is poured;

(2) Production of template for central ditch cover:

The bottom mold of the central ditch cover plate adopts a special bridge template with a thickness of 14 to 20 mm. According to the width of the central ditch body, the number of processing in the width direction is planned on the entire bottom mold of the central ditch cover plate to make its width the same as the width of the central ditch body;

(3) Installation of formwork support components:

a. Clean the bottom surface of the central ditch to ensure that the bottom of the central ditch is flat. Install multiple vertical support steel pipes at a longitudinal interval of 1.2m to 1.5m. The bottoms of the vertical support steel pipes are fixed on the channel steel. Horizontal reinforcement supports are installed between two adjacent vertical support steel pipes in the cross-sectional and longitudinal directions of the central ditch. Both ends of the reinforcement supports are circular. Fixed hooks are provided at the upper and lower parts of the vertical support steel pipes. Oblique reinforcement supports are provided between two adjacent vertical support steel pipes in the longitudinal direction. Both ends of the horizontal reinforcement supports and the oblique reinforcement supports are connected by fixed hooks. Each vertical support steel pipe is fixed by reinforcement supports in the cross-sectional and longitudinal directions. Top supports are installed on the tops of the vertical support steel pipes. During the installation process, the height of the top supports is roughly adjusted according to the height of the side walls of the central ditch to ensure that the top of the top supports is basically level with the top of the ditch side walls.

b. Place transverse secondary corrugated steel pipes on top of every two vertical supporting steel pipes along the cross-section direction of the central water ditch. The length of the transverse secondary corrugated steel pipes shall not be greater than the width of the central water ditch. Wooden boards are laid in sequence along the cross-section direction of the central water ditch. The length direction of the wooden boards is consistent with the longitudinal direction of the central water ditch. During the laying process, the top support is fine-tuned to ensure that the wooden boards are level after laying;

c. Lay the processed special bridge formwork on top of the laid wooden boards as the bottom formwork of the central ditch cover. After the entire formwork support assembly is installed, it should be consistent with the top elevation of the central ditch side wall;

(4) Fabrication and installation of steel bars for the central ditch cover:

The steel bars of the central ditch cover are made in pieces. Concrete pads are evenly arranged on the bottom form of the laid central ditch cover. The concrete pads are arranged in a plum blossom shape at a spacing of 0.8m*0.8m to ensure that the steel mesh of the cover has sufficient protective layer thickness. At the same time, two "Ω"-shaped hooks are installed along the length direction of the sixth central ditch cover for every 5 central ditch covers.

(5) Installation of foam board:

Install a 10mm thick foam board at every 1.2m in the longitudinal direction. The thickness of the foam board is consistent with the thickness of the central ditch cover. At the same time, install two 10mm thick foam boards along the entire length of the central ditch cover and the filling contact edge. The thickness is consistent with the thickness of the central ditch cover.

(6) Pour concrete on the central ditch cover, and after pouring, isolate and protect it by sprinkling water for maintenance. When the central ditch cover has sufficient strength, remove the formwork support assembly, clean up the debris in the central ditch, remove the foam board at the joint position, and fill the joint with mortar.

In the construction method for on-site forming of the central ditch of a highway tunnel, an inserted vibrating rod is used to evenly vibrate the ditch side wall concrete during pouring, and the vibration should be kept away from the ditch side wall template.

The construction method for on-site forming of the central ditch of a highway tunnel is as follows: the length of the vertical supporting steel pipe = the ditch body height of the central ditch - the exposed length of the top support - the thickness of the wooden board - the thickness of the transverse secondary corrugated steel pipe, wherein the exposed length of the top support is 10 to 15 cm, the thickness of the wooden board is 50 mm, and the diameter of the transverse secondary corrugated steel pipe is Φ42 mm.

In the construction method for on-site forming of the central ditch of a highway tunnel, the bottom stress-bearing surface of the vertical supporting steel pipe is a plane, and the length of the channel steel is 80 mm.

In the construction method for on-site forming of the central ditch of a highway tunnel, the reinforcing support is a Φ16mm round steel, and the fixed hooks at both ends of the horizontal reinforcing support are 70-90mm above the ground.

In the construction method for on-site forming of the central ditch of a highway tunnel, in step (6), when pouring concrete for the central ditch cover, an inserted vibrator is used for micro-vibration. A layer with a thickness of 100 mm is first poured from the middle of the central ditch cover to the surrounding areas, the foam board is strengthened and stabilized by concrete, and then gradually poured full. Finally, the surface is smoothed by plastering the panel to ensure that the height of the central ditch cover is consistent with the height of the invert filling surface.

In the construction method for on-site forming of the central ditch of a highway tunnel, the operation steps of isolating, protecting and watering the ditch in step (6) are as follows: installing a columnar plastic warning column with a height of 80 mm at a position 50 mm away from both sides of the central ditch cover plate, and the column height is 60 cm, to protect the cast central ditch cover plate from rolling, and to perform watering maintenance at the same time.

In the construction method for on-site forming of the central ditch of a highway tunnel, the step of removing the formwork support assembly in step (6) is as follows: after the strength of the central ditch cover plate reaches 50% of the design strength, the reinforcing supports are released one by one from the bottom, and the various parts of the formwork support assembly are removed one by one, and the construction is transferred to the next section.

Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

The construction method for on-site forming of the central ditch of a highway tunnel described in the present invention adopts on-site casting of the central ditch cover plate, which reduces the prefabrication process of the prefabrication plant and reduces the temporary land occupation of the prefabrication plant, saving land resources. The template support assembly is detachably installed, which realizes the on-site casting of the central ditch cover plate, and can effectively ensure that the top elevation of the central ditch cover plate is consistent with the top elevation of the filling surface, ensure that the entire driving surface is at the same elevation, and the central ditch cover plate is effectively closed with the ditch side wall to reduce the gap;

The construction method for on-site forming of the central ditch of a highway tunnel described in the present invention adopts foam boards to divide the central ditch cover plates, and at the same time buries hooks at intervals, which is beneficial to the later maintenance of the central ditch cover plates and the cleaning of debris in the central ditch; after using this method, the comprehensive damage rate of the central ditch cover plates can be controlled within 3%, thereby increasing the service life of the central ditch cover plates, reducing cost expenditure, and effectively improving the construction quality and the overall civilized construction environment in the tunnel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of a cross section of a central ditch structure.

FIG. 2 is a schematic structural diagram of the cross section of the central ditch formwork support assembly of the present invention.

FIG3 is a cross-sectional view taken along line A-A in FIG2 .

In the figure: 1. invert filling; 2. center ditch bottom plate; 3. center ditch cover plate; 4. center ditch; 5. center ditch side wall; 6. concrete pad; 7. hook; 8. cover steel mesh; 9. foam board; 10. center ditch cover plate bottom formwork; 11. wooden board; 12. fixed hook; 13. channel steel; 14. reinforced support; 15. vertical support steel pipe; 16. top support; 17. horizontal secondary steel pipe.

Detailed ways

The present invention can be explained in detail by the following examples, and the purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention.

The construction method for on-site forming of the central ditch of a highway tunnel described in conjunction with Figures 1-3 specifically includes the following steps:

(1) Casting of the side wall of the central ditch:

After the inverted arch filling is poured, the contact surface between the central ditch side wall 5 and the inverted arch filling 1 is roughened, the debris after roughening is removed, the contact surface is rinsed, the central ditch side wall formwork is installed, and the central ditch side wall concrete is poured; during the pouring of the ditch side wall concrete, an inserted vibrating rod is used to vibrate evenly, and the vibration should be kept away from the ditch side wall formwork;

(2) Production of template for central ditch cover:

The center ditch cover bottom mold 10 adopts a special bridge template with a thickness of 14 to 20 mm. According to the width of the center ditch 4, the number of processing in the width direction is planned on the entire center ditch cover bottom mold 10 to make its width the same as the center ditch 4.

(3) Installation of formwork support components:

a. Clean the bottom surface of the central ditch 4 to ensure that the bottom of the central ditch 4 is flat, install multiple vertical support steel pipes 15 at a longitudinal interval of 1.2m to 1.5m, and fix the bottoms of the vertical support steel pipes 15 on the channel steel 13. Horizontal reinforcement supports 14 are installed between two adjacent vertical support steel pipes 15 in the cross-sectional direction and the longitudinal direction of the central ditch 4. Both ends of the reinforcement supports 14 are circular, and fixed hooks 12 are provided on the upper and lower parts of the vertical support steel pipes 15, which are arranged between two adjacent vertical support steel pipes 15 in the longitudinal direction. The vertical support steel pipes 15 are provided with oblique reinforcement supports 14, which play a reinforcing role; the horizontal reinforcement supports 14 and the oblique reinforcement supports 14 are connected at both ends by fixing hooks 12, and each vertical support steel pipe 15 is fixed by the reinforcement supports 14 along the cross section and the longitudinal section. A top support 16 is installed on the top of the vertical support steel pipe 15. During the installation process, the height of the top support 16 is roughly adjusted according to the side wall height of the central ditch 4 to ensure that the top of the top support 16 is basically level with the top of the ditch side wall;

The bottom stress-bearing surface of the vertical support steel pipe 15 is a plane, and the length of the channel steel 13 is 80 mm; the length of the vertical support steel pipe 15 = the height of the ditch body of the central ditch 4 - the exposed length of the top support 16 - the thickness of the wooden board 11 - the thickness of the transverse secondary corrugated steel pipe 17, wherein the exposed length of the top support 16 is 10 to 15 cm, the thickness of the wooden board 11 is 50 mm, and the diameter of the transverse secondary corrugated steel pipe 17 is Φ42 mm; the reinforced support 14 is a Φ16 mm round steel, and the fixed hooks 12 at both ends of the horizontal reinforced support 14 are 70 to 90 from the ground. Since the overall volume of the concrete of the central ditch cover is small and the stress-bearing area is limited, the installation method and quantity of the reinforced support can be adjusted according to actual conditions;

b. Place transverse secondary corrugated steel pipes 17 on the top of every two vertical supporting steel pipes 15 along the cross-sectional direction of the central water ditch 4. The length of the transverse secondary corrugated steel pipes 17 shall not be greater than the width of the central water ditch 4. 50mm thick wooden boards 11 are laid in sequence along the cross-sectional direction of the central water ditch 4. The length direction of the wooden boards 11 is consistent with the longitudinal direction of the central water ditch 4. During the laying process, the top support 16 is fine-tuned to ensure that the wooden boards 11 are level after laying;

c. Lay the processed special bridge template on the wooden board 11 as the bottom template 10 of the central ditch cover. After the whole template support assembly is installed, it should be consistent with the top elevation of the central ditch side wall;

(4) Fabrication and installation of steel bars for the central ditch cover:

The steel bars of the central ditch cover are made in pieces, and the length of the pieces is convenient for the transportation during the later maintenance of the central ditch. The concrete pads 6 are evenly arranged on the laid central ditch cover bottom formwork 10, and the concrete pads are arranged in a plum blossom shape at a spacing of 0.8m*0.8m to ensure that the cover steel mesh 8 has sufficient protective layer thickness. At the same time, two "Ω"-shaped hooks 7 are installed along the length direction of the sixth central ditch cover 3 every 5 central ditch covers 3 to facilitate the cleaning of the central ditch in the later period;

(5) Installation of foam board 9:

A 10mm thick foam board 9 is installed at every 1.2m interval in the longitudinal direction. The thickness of the foam board 9 is consistent with the thickness of the central ditch cover 3. At the same time, a 10mm thick foam board 9 is installed along the entire length of the central ditch cover 3 and the filling contact edge. There are two layers in total, and the thickness is consistent with the thickness of the central ditch cover 3.

(6) Pour concrete on the central ditch cover 3, and after pouring, isolate and protect it by sprinkling water for maintenance. After the central ditch cover 3 has sufficient strength, remove the formwork support assembly, clean up the debris in the central ditch 4, remove the foam board 9 at the joint position, and fill the joint with mortar;

When pouring concrete for the central ditch cover 3, use an inserted vibrator to vibrate slightly. First, pour a layer with a thickness of 100 mm from the middle of the central ditch cover 3 to the surrounding areas. Strengthen the foam board 9 with concrete to firmly position it, then gradually pour it full, and finally finish the surface by plastering the panel to ensure that the height of the central ditch cover 3 is consistent with the height of the invert filling surface.

The operating steps of isolation protection and watering maintenance are as follows: install a columnar plastic warning column with a height of 80 mm at a position 50 mm away from both sides of the central ditch cover 3, and the column height is 60 cm to protect the cast central ditch cover 3 from rolling, and at the same time spray water for maintenance.

The steps of removing the formwork support assembly are as follows: after the strength of the central gutter cover 3 reaches 50% of the design strength, unfasten the reinforcing supports 14 one by one from the bottom, remove the various parts of the formwork support assembly one by one, and transfer to the next section of construction.

Parts of the present invention not described in detail are prior art.

The embodiments selected herein for the purpose of disclosing the invention are currently considered to be suitable, but it should be understood that the invention is intended to include all changes and modifications of the embodiments that fall within the scope of the concept and invention.

Claims (8)

1. A construction method for on-site forming of a central ditch in a highway tunnel, characterized in that it specifically comprises the following steps: (1) Casting of the side wall of the central ditch: After the inverted arch is poured, the contact surface between the side wall of the central ditch and the inverted arch is roughened, the debris after roughening is removed, the contact surface is washed, the template of the side wall of the central ditch is installed, and the concrete of the side wall of the central ditch is poured; (2) Production of template for central ditch cover: The bottom mold of the central ditch cover plate adopts a special bridge template with a thickness of 14 to 20 mm. According to the width of the central ditch body, the number of processing in the width direction is planned on the entire bottom mold of the central ditch cover plate to make its width the same as the width of the central ditch body; (3) Installation of formwork support components: a. Clean the bottom surface of the central ditch to ensure that the bottom of the central ditch is flat. Install multiple vertical support steel pipes at a longitudinal interval of 1.2m to 1.5m. The bottoms of the vertical support steel pipes are fixed on the channel steel. Horizontal reinforcement supports are installed between two adjacent vertical support steel pipes in the cross-sectional and longitudinal directions of the central ditch. Both ends of the reinforcement supports are circular. Fixed hooks are provided at the upper and lower parts of the vertical support steel pipes. Oblique reinforcement supports are provided between two adjacent vertical support steel pipes in the longitudinal direction. Both ends of the horizontal reinforcement supports and the oblique reinforcement supports are connected by fixed hooks. Each vertical support steel pipe is fixed by reinforcement supports in the cross-sectional and longitudinal directions. Top supports are installed on the tops of the vertical support steel pipes. During the installation process, the height of the top supports is roughly adjusted according to the height of the side walls of the central ditch to ensure that the top of the top supports is basically level with the top of the ditch side walls. b. Place transverse secondary corrugated steel pipes on top of every two vertical supporting steel pipes along the cross-section direction of the central water ditch. The length of the transverse secondary corrugated steel pipes shall not be greater than the width of the central water ditch. Wooden boards are laid in sequence along the cross-section direction of the central water ditch. The length direction of the wooden boards is consistent with the longitudinal direction of the central water ditch. During the laying process, the top support is fine-tuned to ensure that the wooden boards are level after laying; c. Lay the processed special bridge formwork on top of the laid wooden boards as the bottom formwork of the central ditch cover. After the entire formwork support assembly is installed, it should be consistent with the top elevation of the central ditch side wall; (4) Fabrication and installation of steel bars for the central ditch cover: The steel bars of the central ditch cover are made in pieces. Concrete pads are evenly arranged on the bottom form of the laid central ditch cover. The concrete pads are arranged in a plum blossom shape at a spacing of 0.8m*0.8m to ensure that the steel mesh of the cover has sufficient protective layer thickness. At the same time, two "Ω"-shaped hooks are installed along the length direction of the sixth central ditch cover for every 5 central ditch covers. (5) Installation of foam board: Install a 10mm thick foam board at every 1.2m in the longitudinal direction. The thickness of the foam board is consistent with the thickness of the central ditch cover. At the same time, install two 10mm thick foam boards along the entire length of the central ditch cover and the filling contact edge. The thickness is consistent with the thickness of the central ditch cover. (6) Pour concrete on the central ditch cover, and after pouring, isolate and protect it by sprinkling water for maintenance. When the central ditch cover has sufficient strength, remove the formwork support assembly, clean up the debris in the central ditch, remove the foam board at the joint position, and fill the joint with mortar. 2. The construction method for on-site forming of the central ditch of a highway tunnel according to claim 1 is characterized in that during the pouring of concrete on the ditch side walls, an inserted vibrating rod is used to vibrate evenly, and the vibration should be kept away from the ditch side wall template. 3. The construction method for on-site forming of the central ditch of a highway tunnel according to claim 1 is characterized in that: the length of the vertical support steel pipe = the ditch body height of the central ditch - the exposed length of the top support - the thickness of the wooden board - the thickness of the transverse secondary corrugated steel pipe, wherein the exposed length of the top support is 10 to 15 cm, the thickness of the wooden board is 50 mm, and the diameter of the transverse secondary corrugated steel pipe is Φ42 mm. 4. The construction method for on-site forming of the central ditch of a highway tunnel according to claim 1 is characterized in that the bottom stress-bearing surface of the vertical supporting steel pipe is a plane and the length of the channel steel is 80 mm. 5. The construction method for on-site forming of the central ditch of a highway tunnel according to claim 1 is characterized in that: the reinforcing support is a round steel of Φ16 mm, and the fixed hooks at both ends of the horizontal reinforcing support are 70 to 90 mm above the ground. 6. The construction method for on-site forming of the central ditch of a highway tunnel according to claim 1 is characterized in that: in step (6), when pouring concrete for the central ditch cover plate, an inserted vibrator is used for micro-vibration, and a layer with a thickness of 100 mm is poured first, from the middle of the central ditch cover plate to the surrounding area, the foam plate is strengthened and firmly positioned by concrete, and then gradually filled, and finally the surface is smoothed by plastering the panel to ensure that the height of the central ditch cover plate is consistent with the height of the invert filling surface. 7. The construction method for on-site forming of the central ditch of a highway tunnel according to claim 1 is characterized in that: the operation steps of isolation protection and watering maintenance in step (6) are: a columnar plastic warning column with a height of 80 mm is installed at a position 50 mm away from both sides of the central ditch cover plate, and the column height is 60 cm to protect the cast central ditch cover plate from rolling and watering maintenance at the same time. 8. The construction method for on-site forming of the central ditch of a highway tunnel according to claim 1 is characterized in that: the step of removing the formwork support assembly in step (6) is: after the strength of the central ditch cover reaches 50% of the design strength, the reinforcing supports are released one by one from the bottom, and the various parts of the formwork support assembly are removed one by one, and the construction is transferred to the next section.