Sprayed concrete reinforcing structure and construction method

Abstract

The invention discloses a sprayed concrete reinforcing structure and a construction method, and relates to the technical field of auxiliary engineering, the sprayed concrete reinforcing structure comprises a first concrete layer and a second concrete layer which are sequentially constructed, and the first concrete layer adopts quick-hardening concrete constructed on a base layer through a spraying method; a deformation zone and a plurality of fixing plates are longitudinally arranged in the first concrete layer, the surrounding rock is provided with anchor rods, one ends of the anchor rods are fixed on the fixing plates, the fixing plates are fixed in the first concrete layer, and steel bars are arranged after the first concrete layer is constructed to construct the second concrete layer. According to the sprayed concrete reinforcing structure, the first concrete layer can play a good supporting role on the base layer in a short time, the deformation belt is used for overcoming the defect that the deformation capacity of rapid hardening type concrete is poor, and the second concrete layer is constructed above the first concrete layer and used for enhancing the strength of supporting in the later period.

Description

Technical Field

[0001] The invention relates to the technical field of auxiliary engineering, in particular to a shotcrete reinforcement structure and a construction method. Background Art

[0002] Shotcrete is a rapid concrete construction method, often used in conjunction with anchor rods as the primary support for tunnels. The New Austrian Tunneling Method is a method of tunnel construction, which involves blasting and excavating the tunnel construction surface. After the tunnel is excavated, due to the looseness of the rock mass itself and the influence of blasting vibration, if the surrounding rock is not supported in time, it may cause tunnel deformation, instability, collapse and other disasters. Anchor spraying support is generally used in the existing technology, but the early strength growth rate of ordinary silicate shotcrete is slow. In order to increase the solidification rate of shotcrete, fly ash or other substances are added and accelerators are added to form fast-hardening concrete. Although this type of concrete has a fast early strength growth rate, the accelerator, while playing a role in rapid setting, has a significant effect on the later compressive strength and flexural strength of the shotcrete, and is prone to brittle failure. The deformation resistance is also significantly lower than that of ordinary concrete layers. Summary of the invention

[0003] In view of the above shortcomings, the purpose of the present invention is to provide a solution to the problem that ordinary shotcrete has slow early strength growth and quick-hardening concrete has insufficient late strength and is easily brittle failure in support projects. The purpose of the present invention is also to provide a construction method for the above-mentioned structure.

[0004] To this end, a shotcrete reinforcement structure of the present invention comprises a first concrete layer and a second concrete layer which are constructed sequentially, wherein the first concrete layer is a quick-hardening concrete constructed on a base layer by a shotcrete method, a deformation band and a plurality of fixed plates are longitudinally arranged in the first concrete layer, the base layer is provided with an anchor rod, one end of the anchor rod is fixed on the fixed plate, the fixed plate is fixed in the first concrete layer, and after the first concrete layer is constructed, steel bars are arranged to construct the second concrete layer.

[0005] Furthermore, the deformation band is a rubber layer, both sides of the rubber layer are fixed by frames, the frames are fixed on fixed plates, and the fixed plates on both sides of the frame are provided with holes for fixing anchor rods.

[0006] Furthermore, connecting bars are fixed on the fixing plate, and the connecting bars extend upward into the second concrete layer and are fixed to the steel bars in the second concrete layer.

[0007] The present invention also includes a construction method for the above-mentioned shotcrete reinforcement structure, wherein a guide rail parallel to the surface of the base layer is provided, a slider of a frame moves on the guide rail, a baffle is provided on the frame, the baffle is used to block the rebounding concrete, a moving device is provided on the baffle, the moving device can move along the baffle, a concrete spray gun is provided on the moving device and is used to spray concrete onto the base layer; when the first concrete layer is constructed, it starts from the lower part of the base layer, the moving device and the spray gun move along the length direction of the base layer to spray concrete, and after the concrete construction on the lower side is completed, the slider is moved again to drive the frame to move to the upper part of the base layer, and the mobile spray gun is moved along the length direction of the base layer again to spray concrete, and this is repeated until the construction of the first concrete layer in the corresponding area is completed.

[0008] Furthermore, the frame is provided with an upper limit portion and a lower limit portion at one end away from the base layer, and the upper limit portion and the lower limit portion include a limit plate protruding from the inner surface of the frame. The upper part of the frame forms the guide rail, and the slider is arranged between the upper limit portion and the lower limit portion.

[0009] Furthermore, the frame includes a bent portion, the bent portion bypasses the connecting rib, the frame includes a cross bar, the cross bar is connected to one end of the bent portion close to the base, and the baffle is provided on the cross bar.

[0010] Furthermore, the baffle is provided with a strip hole, the moving device is connected to both sides of the strip hole and moves along the strip hole, the moving device includes a moving plate, a nozzle is provided on the moving plate, the spray gun is inserted into the nozzle, and the position of the nozzle is opposite to the strip hole so that the concrete sprayed by the spray gun passes through the strip hole.

[0011] Furthermore, a side baffle is also provided on the frame, and the edge position of the side baffle is a predetermined distance away from the base layer or flush with the surface of the first concrete layer. When the frame moves along the guide track, the edge position of the side baffle can scrape the surface of the first concrete layer and make the surface thickness of the first concrete layer consistent.

[0012] Furthermore, the distance between the side baffle and the surrounding rock of the tunnel wall can be adjusted so that a multi-layer spraying construction method is adopted during the construction of the first concrete layer. After spraying a layer of concrete, the height of the side baffle is adjusted, and concrete is sprayed again before the lower layer of concrete solidifies. After repeating several times, the first concrete layer of a predetermined height is reached.

[0013] Furthermore, the second concrete layer is constructed by concrete pouring or concrete spraying, and the second concrete layer is made of concrete formed by mixing ordinary Portland cement, sand, crushed stone, water and admixtures.

[0014] Beneficial technical effects of the present invention: A shotcrete reinforcement structure of the present invention can be used as a primary support for a tunnel or as a support for a slope. Its structure includes two concrete layers. The first concrete layer is formed by spraying quick-hardening concrete on a base layer (slope or tunnel surrounding rock). It has the characteristics of fast strength growth and can provide good support for the base layer in a short time, shortening the construction interval. A deformation band is longitudinally arranged in the first concrete layer to solve the disadvantage of poor deformation capacity of quick-hardening concrete and avoid cracks or even brittle fractures in the first concrete layer due to deformation. The second concrete layer is constructed above the first concrete layer and adopts ordinary concrete to enhance the strength of the support in the later stage. The thickness of the second concrete layer can be several times that of the first concrete layer.

[0015] The present invention also includes a construction method for the above-mentioned shotcrete reinforcement structure, which comprehensively solves the concrete rebound problem by setting a baffle, and the spray gun moves along the baffle to achieve equal distance between the spray gun and the base layer. When the spraying pressure remains unchanged, the density of the shotcrete is consistent. Side baffles are set to limit the thickness of the shotcrete, so as to achieve consistent thickness of the first concrete layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a top view schematic diagram of the deformation band; Figure 2 It is the left view schematic diagram of the deformation band; Figure 3 is a front view schematic diagram of the deformation band; Figure 4 Schematic diagram of the baffle.

[0017] Explanation of the reference numerals: 1. rubber layer; 2. frame; 201. upper limit portion; 202. lower limit portion; 3. fixing plate; 4. anchor rod; 5. connecting rib; 6. bedrock; 7. first concrete layer; 8. slider; 9. frame; 901. bend; 902. cross bar; 903. baffle; 904. side baffle; 905. movable plate; 906. nozzle; 907. strip hole. DETAILED DESCRIPTION

[0018] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0019] Reference Figures 1 to 4As shown, a shotcrete reinforcement structure of the present invention comprises a first concrete layer 7 and a second concrete layer which are constructed in sequence. The first concrete layer 7 is a quick-hardening concrete constructed on a base layer by a shotcrete method. A deformation band and a plurality of fixing plates 3 are longitudinally arranged in the first concrete layer 7. The surrounding rock is provided with an anchor rod 4. One end of the anchor rod 4 is fixed on the fixing plate 3. The fixing plate 3 is fixed in the first concrete layer 7. After the construction of the first concrete layer 7, steel bars are arranged to construct the second concrete layer. This embodiment takes tunnel construction as an example, and uses anchor rods 4 and the panel of the first concrete layer 7 constructed by shotcrete to form an anchor-sprayed support. The anchor rods 4 are first fixed on the fixing plate 3, and then concrete is sprayed to form the first concrete layer 7. The anchor-sprayed support plays a role in supporting and reinforcing the surrounding rock and limiting the free development of surrounding rock deformation. The first concrete layer uses fast-hardening concrete. Both fast-hardening concrete and ordinary shotcrete are existing technologies. Fast-hardening concrete is mixed by adding fly ash, more accelerators, and can be mixed with sulphoaluminate cement, crushed stone, sand, etc. Ordinary shotcrete generally uses silicate cement and a certain amount of accelerators and water reducers and other admixtures, of course, also including crushed stone, sand, etc. Fast-hardening concrete has the characteristics of short initial setting time and fast strength growth. The deformation band can use a rubber layer. The second concrete layer can use ordinary shotcrete. It is constructed after the first concrete layer 7 solidifies. The second concrete layer is used to improve the overall strength of the primary support and make up for the problem of insufficient strength of the first concrete layer 7. The thickness of the second concrete layer should be greater than the thickness of the first concrete layer 7, such as 3 to 5 times. The thickness of the first concrete layer 7 can be 50 mm.

[0020] In the above embodiment, referring to Figure 1 , Figure 2 and Figure 3 As shown, the two sides of the rubber layer 1 are fixed by a frame 2, and the frame 2 is fixed or integrated with the fixing plate 3 at the bottom. The fixing plate 3 includes a plurality of fixing ears arranged on both sides, and a hole is arranged in the middle of the fixing ears. The anchor rods 4 pass through the fixing ears and are fixed on the fixing plate 3. The anchor rods 4 in this embodiment are staggered on both sides of the fixing plate 3. The fixing plate 3 can be used to fix the anchor rods 4. Similarly, the anchor rods 4 also play a role in fixing the fixing plate 3. The frame 2 is set on the fixing plate 3, and the rubber layer 1 is fixed to the frame 2 by steel wire or other means, so that the first concrete layer 7 can be connected to the rubber layer, which plays a role in increasing deformation, and the frame 2 can limit the rubber layer 1 to prevent it from shifting during the concrete spraying process.

[0021] In the above embodiment, referring to Figure 3 As shown, the connecting ribs 5 can be fixed above the anchor rods 4 by threads or welding, and the connecting ribs 5 extend upward into the second concrete layer and are fixed to the steel bars in the second concrete layer, or the fixing plate 3 can be extended to both sides for a section, and the connecting ribs 5 are arranged on the extended section and extend into the second concrete layer.

[0022] The present invention also includes a construction method for the above-mentioned shotcrete reinforcement structure, which includes setting a guide rail. In order to reduce the construction steps, a combination structure of two fixed plates and a frame 2 at a predetermined distance can be selected to be improved as the guide rail, specifically, referring to Figure 3 As shown, the frame 2 is provided with an upper limit portion 201 and a lower limit portion 202 at one end away from the base layer. The upper limit portion 201 and the lower limit portion 202 include limit plates protruding from the inner surface of the frame 2. The upper limit portion 201 and the lower limit portion 202 at the upper part of the frame 2 form a guide rail. The slider 8 is provided between the upper limit portion 201 and the lower limit portion. Wheels or ball bearings may be provided on the slider 8. The upper part of the frame 2 is higher than the height of the first concrete layer 7. During the construction of the first concrete layer 7 of the tunnel, the construction is carried out from bottom to top. A hole is provided below the guide rail for the slider 8 to enter between the upper limit portion 201 and the lower limit portion 202. The slider 8 is provided on a frame 9. The frame 9 includes a bend 901 and a cross bar 902. The bend 901 bypasses the connecting rib 5, or the cross bar 902 is higher than the connecting rib 5. The cross bar 902 is connected to the end of the bend 901 close to the surrounding rock. A baffle 903 is provided on the cross bar 902. Refer to Figure 4 As shown, a moving device is provided on the baffle 903, and a track and a strip hole 907 parallel to the track are also provided on the baffle 903. The moving device is connected to both sides of the strip hole 907 and moves along the strip hole 907. The moving device includes a moving plate 905, and a nozzle 906 is provided on the moving plate 905. The spray gun is inserted into the nozzle 906. The position of the nozzle 906 is directly opposite to the strip hole 907 so that the concrete sprayed by the spray gun passes through the strip hole. The moving device can move along the track on the baffle 903. The above-mentioned crossbar 902 and the moving device can be driven by a hydraulic system or a pneumatic system (not shown in the figure) to move accordingly. When the first concrete layer 7 is constructed, it starts from the lower part of the tunnel wall, and the moving device and the spray gun move along the length direction of the tunnel to spray concrete. After the concrete construction on the lower side is completed, the crossbar 902 is moved to drive the frame 9 to move to the upper part of the tunnel, and the spray gun is moved again along the length direction of the tunnel to spray concrete. Repeat until the first concrete layer 7 of the corresponding area is completed. During the construction process, a concrete spraying machine is used. A hydraulic or pneumatic system can be set on the concrete spraying machine to connect with the frame 9. Of course, the frame 9 can also be set on a wheeled conveyor alone, and the spray gun of the concrete spraying machine is inserted into the nozzle 906 of the baffle. The baffle 903 is not only used to block the rebounding concrete, but also enables the spray gun to move along the baffle 903, so that the distance between the gun head and the tunnel wall is equal, the pressure of the sprayed concrete is the same, and it has a more consistent density. On both sides of the guide rail, the places that cannot be sprayed directly can be manually sprayed or constructed by adjusting the spray gun angle, such as tilting. After the spraying of concrete is completed, the frame 9 can also be moved alone to drive the side baffle to scrape the surface of the first concrete layer 7 back and forth.

[0023] In the above embodiment, referring to Figure 3 As shown, the frame 9 is also provided with a side baffle 904, and the edge of the side baffle 904 is flush with the surface of the first concrete layer 7. When the frame 9 moves along the guide rail, the edge of the side baffle 904 can scrape the surface of the first concrete layer 7 and make the thickness of the first concrete layer 7 uniform. In fact, multiple groups of anchor rods 4 and fixing plates 3 are also provided on the bedrock 6 between the two combined structures (fixing plate 3 and frame 2) of the guide rail. Connecting ribs 5 can also be provided on these fixing plates 3, and grooves that match the connecting ribs 5 can be provided on the side baffle 904 for the connecting ribs 5 to pass through.

[0024] In the above embodiment, the tunnel is generally constructed in sections, each section is more than ten meters long, and the deformation joint can generally be set at each section. The initial setting time of the quick-hardening concrete is generally 1 hour or less, so the construction time can be reduced by dividing each section into two or more sections. In another embodiment, the distance between the side baffle 904 and the surrounding rock of the tunnel wall is set to be adjustable. This adjustable method is a prior art, such as through a pneumatic or hydraulic system. At this time, a multi-layer re-spraying construction method can be adopted. After spraying a layer of concrete, the height of the side baffle 904 is adjusted, and concrete is sprayed again before the initial setting of the lower layer of concrete. After repeating several times, the first concrete layer 7 reaches a predetermined height. This construction method has better integrity and compactness.

[0025] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A shotcrete reinforcement structure, characterized in that: The method comprises a first concrete layer and a second concrete layer which are constructed in sequence. The first concrete layer is a quick-hardening concrete constructed on a base layer by a spraying method. A deformation band and a plurality of fixing plates are longitudinally arranged in the first concrete layer. The base layer is provided with an anchor rod, one end of the anchor rod is fixed on the fixing plate, and the fixing plate is fixed in the first concrete layer. After the first concrete layer is constructed, steel bars are arranged to construct the second concrete layer.

2. A shotcrete reinforcement structure according to claim 1, characterized in that: The deformation belt is a rubber layer, and the two sides of the rubber layer are fixed by frames, and the frames are fixed on the fixing plates. The fixing plates on the two sides of the frame are provided with holes for fixing anchor rods.

3. A shotcrete reinforcement structure according to claim 2, characterized in that: The fixing plate is fixed with connecting bars, which extend upward into the second concrete layer and are fixed to the steel bars in the second concrete layer.

4. A construction method for a shotcrete reinforcement structure according to claim 3, characterized in that: A guide rail parallel to the surface of the base layer is provided, and a slider of the frame moves on the guide rail. A baffle is provided on the frame, and the baffle is used to block the rebounding concrete. A moving device is provided on the baffle, and the moving device can move along the baffle. A concrete spray gun is provided on the moving device and is used to spray concrete onto the base layer. When the first concrete layer is constructed, it starts from the lower part of the base layer first, and the moving device and the spray gun move along the length direction of the base layer to spray concrete. After the concrete construction on the lower side is completed, the slider is moved again to drive the frame to move to the upper part of the base layer, and the mobile spray gun is moved along the length direction of the base layer again to spray concrete, and this is repeated until the first concrete layer construction of the corresponding area is completed.

5. A construction method for sprayed concrete reinforcement structure according to claim 4, characterized in that: The frame is provided with an upper limit portion and a lower limit portion at one end away from the base layer. The upper limit portion and the lower limit portion include a limit plate protruding from the inner surface of the frame. The upper part of the frame forms the guide rail, and the slider is arranged between the upper limit portion and the lower limit portion.

6. A construction method for a shotcrete reinforcement structure according to claim 5, characterized in that: The frame comprises a bent portion, the bent portion bypasses the connecting ribs, the frame comprises a cross bar, the cross bar is connected to one end of the bent portion close to the base layer, and the baffle is arranged on the cross bar.

7. A construction method for a shotcrete reinforcement structure according to claim 4, 5 or 6, characterized in that: The baffle is provided with a strip hole, the moving device is connected to both sides of the strip hole and moves along the strip hole, the moving device includes a moving plate, a nozzle is provided on the moving plate, the spray gun is inserted into the nozzle, and the nozzle is located opposite to the strip hole so that the concrete sprayed by the spray gun passes through the strip hole.

8. The construction method of a shotcrete reinforcement structure according to claim 7, characterized in that: The frame is also provided with a side baffle, the edge of which is at a predetermined distance from the base layer or flush with the surface of the first concrete layer. When the frame moves along the guide track, the edge of the side baffle can scrape the surface of the first concrete layer and make the surface thickness of the first concrete layer uniform.

9. A construction method for a shotcrete reinforcement structure according to claim 8, characterized in that: The distance between the side baffle and the surrounding rock of the tunnel wall can be adjusted so that a multi-layer spraying construction method is adopted during the construction of the first concrete layer. After spraying a layer of concrete, the height of the side baffle is adjusted, and concrete is sprayed again before the lower layer of concrete solidifies. After repeating several times, the first concrete layer of a predetermined height is reached.

10. The construction method of a shotcrete reinforcement structure according to claim 4, characterized in that: The second concrete layer is constructed by concrete pouring or concrete spraying, and the second concrete layer is made of concrete formed by mixing ordinary Portland cement, sand, crushed stone, water and admixture.

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