An external-spraying and internal-injecting roadway support structure

Abstract

An outer-spraying and inner-injection roadway supporting structure relates to the technical field of roadway construction, which comprises a roadway main body arranged in the surrounding rock, the side wall of the roadway main body and the lower part of both sides of the arched end are provided with anchor rod assemblies extending into the surrounding rock, the anchor rod assembly comprises an anchor rod main body, the other end of the anchor rod main body is provided with an adjustable anchor rod tray, the pre-tightening force generated by the anchor rod tray and the surrounding rock is adjusted, the inner wall of the roadway main body is paved with a steel mesh, and the steel mesh is welded and fixed with the anchor rod tray, a sprayed concrete layer is arranged on the steel mesh, the side wall of the sprayed concrete layer and the upper part of both sides of the arched end are provided with first grouting pipes extending into the surrounding rock, the top end of the sprayed concrete layer and the middle positions of both side walls are provided with prestressed anchor cable assemblies extending into the surrounding rock, the scheme realizes the reinforced supporting strength, improves the adhesion between the sprayed concrete layer and the surrounding rock, and optimizes the grouting reinforcement effect.

Description

Technical Field

[0001] This utility model relates to the field of tunnel construction technology, specifically to a tunnel support structure with external spraying and internal injection. Background Technology

[0002] The external shotcrete and internal grouting roadway support structure consists of an outer shotcrete layer and an inner grouting reinforcement layer. The shotcrete is sprayed at high speed onto the roadway surface using a shotcrete machine to seal the surrounding rock in a timely manner, resisting weathering and deliquescence and bearing surface loads. At the same time, cement grout or chemical grout is injected into the surrounding rock through boreholes to fill cracks and pores, improving the strength and integrity of the surrounding rock. The two work together to bear the pressure of the surrounding rock and also have a sealing and waterproofing function. It has advantages such as convenient construction, strong adaptability, and excellent support effect.

[0003] For example, the Chinese authorized patent CN219865026U, entitled "A Tunnel Support Structure", includes a tunnel body, a base plate fixed to the inner bottom wall of the tunnel body, an internal support mechanism on the upper surface of the base plate, an external support mechanism on the outer side of the tunnel body, a drainage groove on the upper surface of the base plate, and the internal support mechanism includes a support rod fixed to the upper surface of the base plate. The left side of the support rod is fixedly connected to the left inner wall of the tunnel body. A support plate is fixed to the upper surface of the connecting block, and a fixing block is located on the outer side of the support plate.

[0004] However, the traditional external spraying and internal grouting roadway support structure has poor support strength and adaptability to roadway deformation, and cannot effectively cope with the surrounding rock pressure under complex geological conditions. Moreover, the bonding force between the sprayed concrete layer and the surrounding rock is limited, and it is easy to fall off. The grouting reinforcement effect is not ideal, and it is difficult to achieve all-round reinforcement of the roadway surrounding rock. Therefore, it does not meet the existing needs. In this regard, we propose an external spraying and internal grouting roadway support structure. Utility Model Content

[0005] The purpose of this utility model is to provide an external spraying and internal grouting roadway support structure that can enhance support strength, improve the bonding force between the sprayed concrete layer and the surrounding rock, optimize the grouting reinforcement effect, and achieve efficient and stable support for the surrounding rock of the roadway to meet the needs of roadway construction under different geological conditions.

[0006] To achieve the above objectives, this utility model provides the following technical solution: an external spraying and internal grouting tunnel support structure, comprising a tunnel body disposed within the surrounding rock, wherein the sidewalls of the tunnel body and the lower parts of both sides of the arched end are provided with anchor bolt assemblies extending into the surrounding rock, the anchor bolt assembly comprising an anchor bolt body, one end of which is anchored in the surrounding rock, and the other end of which is provided with an adjustable anchor bolt tray, which is adjusted by the pre-tightening force generated between the anchor bolt tray and the surrounding rock, the inner wall of the tunnel body is laid with a steel mesh, and the steel mesh is welded and fixed to the anchor bolt tray, a sprayed concrete layer is provided on the steel mesh, the sidewalls of the sprayed concrete layer and the upper parts of both sides of the arched end are provided with first grouting pipes extending into the surrounding rock, and the top of the sprayed concrete layer and the middle positions of both sidewalls are provided with prestressed anchor cable assemblies extending into the surrounding rock.

[0007] Preferably, a screw is installed in the middle of the anchor tray via a threaded connection, and one end of the screw is connected to the anchor body via a bearing. An adjusting nut is welded and fixed to the outer end of the screw. Locating pins are slidably installed in the through holes at the four corners of the anchor tray, and the locating pins are fixed to the surrounding rock.

[0008] Preferably, a limiting element is provided at one end of the anchor bolt body near the inner surface of the surrounding rock to seal the hole where the anchor bolt body is located.

[0009] Preferably, the mesh size of the steel reinforcement mesh is 100mm*100mm, and the steel reinforcement mesh connects the shotcrete layer and the anchor bolt assembly into a whole.

[0010] Preferably, the prestressed anchor cable assembly consists of an anchor cable tray, a bearing plate, an anchor, steel strands, and a second grouting pipe. The steel strands are arranged in four sets around the perimeter between the anchor cable tray and the bearing plate, with one end of each steel strand penetrating the anchor cable tray. The anchor is fixedly installed at the end of the bearing plate near the surrounding rock. The second grouting pipe is located in the middle between the anchor cable tray and the bearing plate, with one end of the second grouting pipe penetrating the anchor cable tray. The anchor cable tray is supported and fixed to the outer wall of the surrounding rock.

[0011] Preferably, the first grouting pipe and the second grouting pipe are hollow steel pipes with multiple grouting holes on the pipe wall. The diameter of the grouting holes is six millimeters and they are distributed in a spiral shape.

[0012] Preferably, both the first grouting pipe and the second grouting pipe are provided with rubber expansion rings at the ends near the surrounding rock.

[0013] Compared with the prior art, the beneficial effects of this utility model are: 1. The anchor bolt assembly and prestressed anchor cable assembly of this utility model can penetrate deep into the surrounding rock, connecting the roadway surrounding rock with stable rock strata, providing strong anchoring force and support force; the steel mesh and shotcrete layer form a whole, jointly bearing the pressure of the surrounding rock, significantly enhancing the overall strength and stability of the support structure, and effectively resisting the deformation and damage of the roadway surrounding rock.

[0014] 2. The sprayed concrete of this utility model adopts a wet spraying process, which can tightly bond with the steel mesh, anchor body and surrounding rock surface, improving the bonding strength between the sprayed concrete layer and the surrounding rock; the expansion effect of the rubber expansion ring during the grouting process further enhances the sealing and bonding force between the grouting pipe and the sprayed concrete layer, enabling the support structure and the surrounding rock to work together better.

[0015] 3. The support structure of this utility model can flexibly adjust the arrangement density, length, and thickness of the shotcrete layer of anchor bolts and prestressed anchor cables according to different geological conditions and tunnel cross-sectional dimensions, which can adapt to the tunnel construction needs under various complex geological conditions and has broad application prospects. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 For the present utility model Figure 1 Enlarged view of a portion of region A in the middle; Figure 3 This is a perspective view of the anchor bolt assembly of this utility model; Figure 4 This is a perspective view of the reinforcement component of this utility model.

[0017] In the diagram: 1. Surrounding rock; 2. Main tunnel body; 3. Anchor bolt assembly; 4. First grouting pipe; 5. Prestressed anchor cable assembly; 6. Shotcrete layer; 7. Anchor bolt body; 8. Limiting component; 9. Screw; 10. Adjusting nut; 11. Anchor bolt tray; 12. Positioning pin; 13. Reinforcing mesh; 14. Anchor cable tray; 15. Bearing plate; 16. Anchor; 17. Steel strand; 18. Second grouting pipe. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0019] Please see Figure 1-4This utility model provides an embodiment of an external spraying and internal grouting tunnel support structure, including a tunnel body 2 set inside the surrounding rock 1. The side walls and the lower parts of both sides of the arched end of the tunnel body 2 are provided with anchor bolt assemblies 3 extending into the surrounding rock 1. The anchor bolt assembly 3 includes an anchor bolt body 7, and one end of the anchor bolt body 7 is anchored in the surrounding rock 1. The other end of the anchor bolt body 7 is provided with an adjustable anchor bolt tray 11, which is adjusted by the pre-tightening force generated between the anchor bolt tray 11 and the surrounding rock 1. The inner wall of the tunnel body 2 is laid with a steel mesh 13, and the steel mesh 13 is welded and fixed to the anchor bolt tray 11. A sprayed concrete layer 6 is provided on the steel mesh 13. The side walls and the upper parts of both sides of the arched end of the sprayed concrete layer 6 are provided with first grouting pipes 4 extending into the surrounding rock 1. The top of the sprayed concrete layer 6 and the middle position of both side walls are provided with prestressed anchor cable assemblies 5 extending into the surrounding rock 1. The anchor bolt assembly 3 penetrates deep into the surrounding rock 1, and uses the anchor bolt body 7 to connect the surrounding rock of the roadway with the deep stable rock layer, providing anchoring force; the adjustable anchor bolt tray 11 generates pre-tightening force, which can effectively compress the surface rock of the surrounding rock 1, limit the loosening and deformation of the surrounding rock 1, enhance the integrity and self-supporting capacity of the surrounding rock 1, improve the resistance of the support structure to the pressure of the surrounding rock 1, and ensure the stability of the roadway during construction and use; After the steel mesh 13 is welded to the anchor tray 11, the anchor assembly 3 is tightly connected to the subsequently sprayed concrete into a whole, which enhances the collaborative working ability of the support structure. When subjected to the pressure of the surrounding rock 1, the steel mesh 13 can disperse the stress, avoid stress concentration that leads to local cracking of the concrete, improve the crack resistance and durability of the support structure, and effectively extend the service life of the roadway support structure. The first grouting pipe 4 can inject grout into the fissures of the surrounding rock 1, fill the fissures, reinforce the surrounding rock 1, improve the density and strength of the surrounding rock 1, and enhance the stability of the surrounding rock 1; the prestressed anchor cable assembly 5 applies prestress to the steel strand 17, so that the anchor cable tray 14 generates a large compressive stress on the surrounding rock 1, which can effectively control the subsidence of the roadway roof and the deformation of the two sides, especially suitable for deep roadways or areas with complex geological conditions, greatly improving the reliability of roadway support.

[0020] Please see Figure 2 and Figure 3A screw rod 9 is installed in the middle of the anchor plate 11 via a threaded connection, and one end of the screw rod 9 is connected to the anchor body 7 via a bearing. An adjusting nut 10 is welded and fixed to the outer end of the screw rod 9. A positioning pin 12 is slidably installed in the through holes at the four corners of the anchor plate 11, and the positioning pin 12 is fixed to the surrounding rock 1. After the anchor body 7 is anchored to the surrounding rock 1, the positioning pin 12 is fixed to the surrounding rock 1, forming a guide and limit on the anchor plate 11 by the positioning pin 12. Then, the adjusting nut 10 is rotated, which drives the screw rod 9 to rotate. Under the friction with the threaded hole in the anchor plate 11, and with the guidance of the positioning pin 12, the anchor plate 11 gradually fits into the surrounding rock 1 while ensuring that its own posture does not change. This causes the anchor plate 11 to generate a pre-tightening force on the surrounding rock, thereby pressing the rock on the surface of the roadway surrounding rock and improving the overall stability of the surrounding rock. This adjustable structure allows construction personnel to precisely adjust the preload of the anchor tray 11 according to the actual surrounding rock conditions, ensuring the consistency of the anchor support effect. The guiding and limiting function of the positioning pin 12 ensures that the anchor tray 11 will not shift or tilt during the adjustment process, improving the accuracy and reliability of the anchor installation and further enhancing the support effect of the anchor on the surrounding rock 1.

[0021] Please see Figure 2 and Figure 3 A limiting element 8 is provided at one end of the anchor bolt body 7 near the inner surface of the surrounding rock 1 to seal the hole where the anchor bolt body 7 is located. The limiting element 8 seals the hole to prevent groundwater, debris and other objects from entering the anchor bolt hole, avoids corrosion of the anchor bolt body 7, and ensures the long-term stability of the anchor bolt. At the same time, it reduces the risk of local loosening or collapse of the surrounding rock 1 caused by the presence of the hole, and improves the safety and reliability of the roadway support.

[0022] Please see Figure 2 The steel mesh 13 has a mesh size of 100mm*100mm. The steel mesh 13 connects the shotcrete layer 6 and the anchor bolt assembly 3 into a whole, which can not only ensure the effective restraint of the shotcrete layer 6 by the steel mesh 13, but also ensure the shotcrete quality and density. By connecting the shotcrete layer 6 and the anchor bolt assembly 3 into a whole, the support structure can share the load when under stress, which improves the overall strength and stability of the support structure and effectively resists the deformation of the surrounding rock 1.

[0023] Please see Figure 1 and Figure 4The prestressed anchor cable assembly 5 consists of an anchor cable tray 14, a bearing plate 15, an anchor 16, steel strands 17, and a second grouting pipe 18. There are four sets of steel strands 17, which are arranged around the anchor cable tray 14 and the bearing plate 15, and one end of the steel strands 17 passes through the anchor cable tray 14. The anchor 16 is fixedly arranged at one end of the bearing plate 15 near the surrounding rock 1. The second grouting pipe 18 is arranged in the middle position between the anchor cable tray 14 and the bearing plate 15, and one end of the second grouting pipe 18 passes through the anchor cable tray 14. The anchor cable tray 14 is supported and fixed on the outer wall of the surrounding rock 1. The prestressed anchor cable assembly 5, with its multiple components working in tandem, provides strong anchoring and support forces. The four sets of steel strands 17 are rationally distributed, which can uniformly transmit prestress and effectively control the deformation of the surrounding rock 1 in the roadway. The second grouting pipe 18 is combined with the anchor cable and grouting is performed after the prestress is applied, which can further strengthen the surrounding rock 1 in the anchoring area of ​​the anchor cable, improve the anchoring effect and stability of the anchor cable, and ensure the long-term safe use of the roadway.

[0024] Please see Figure 1 and Figure 4 The first grouting pipe 4 and the second grouting pipe 18 are hollow steel pipes with multiple grouting holes on the pipe wall. The diameter of the grouting holes is six millimeters and they are arranged in a spiral pattern. Both the first grouting pipe 4 and the second grouting pipe 18 are equipped with rubber expansion rings at the ends near the surrounding rock 1. The hollow steel pipe and the spiral arrangement of the grouting holes facilitate the uniform diffusion of the grout, allowing the grout to fully fill the cracks in the surrounding rock 1 and improve the grouting reinforcement effect. The rubber expansion rings expand under the grouting pressure and fit tightly against the hole wall, effectively preventing grout leakage, ensuring grouting quality, and ensuring that the grouting reinforcement effect is fully exerted, thereby improving the overall strength and stability of the surrounding rock 1.

[0025] Drill holes on the surface of the surrounding rock 1 in the roadway, then insert the threaded steel anchor body 7 into the drill holes. An anchor plate 11 is installed on the other end of the anchor body 7, and the adjustable nut on the anchor is rotated to apply pre-tightening force to the anchor, so that the anchor plate 11 fits tightly against the surface of the surrounding rock 1, thereby pressing the rock on the surface of the surrounding rock 1 in the roadway. The steel mesh 13 is covered on the outside of the anchor plate 11, and the steel mesh 13 is firmly connected to the anchor body 7 by welding, so that the steel mesh 13 connects the shotcrete and the anchor into a whole, enhancing the integrity and crack resistance of the support structure. The shotcrete is applied by wet spraying process to form a shotcrete layer 6, which seals the surface of the surrounding rock 1 in the roadway. Together with the anchor body 7 and the steel mesh 13, it improves the bearing capacity of the support structure. One end of the first grouting pipe 4 passes through the steel mesh 13 and the shotcrete layer 6 and is inserted into the interior of the surrounding rock 1, while the other end protrudes from the surface of the shotcrete layer 6 for connecting the grouting equipment. In the portion of the first grouting pipe 4 located within the shotcrete layer 6, multiple rubber expansion rings with an outer diameter slightly larger than the first grouting pipe 4 are fitted. At key locations on the top and sides of the roadway, prestressed anchor cable assemblies 5, consisting of steel strands 17, anchors 16, and tensioning equipment, are installed. One end of the steel strand 17 is anchored in stable rock strata, and the other end is connected to the anchor cable tray 14 on the roadway surface. Prestress is applied to the steel strand 17 using the tensioning equipment, causing the anchor cable tray 14 to generate significant compressive stress on the surrounding rock 1 of the roadway. The grouting equipment is then connected to the end of the grouting pipe exposed on the surface of the shotcrete layer 6, and the grouting operation is initiated. Under the grouting pressure, the rubber expansion rings expand and tightly adhere to the grouting hole wall of the shotcrete layer 6, achieving a seal and ensuring that the grout is evenly injected into the fissures of the surrounding rock 1, thus achieving comprehensive reinforcement of the surrounding rock 1 of the roadway.

[0026] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A roadway support structure with external jetting and internal injection, comprising a roadway body (2) disposed within the surrounding rock (1), characterized in that: The sidewalls of the main tunnel (2) and the lower parts of both sides of the arched end are provided with anchor bolt assemblies (3) extending into the surrounding rock (1). The anchor bolt assembly (3) includes an anchor bolt body (7), and one end of the anchor bolt body (7) is anchored in the surrounding rock (1). The other end of the anchor bolt body (7) is provided with an adjustable anchor bolt tray (11), which is adjusted by the pre-tightening force generated by the anchor bolt tray (11) and the surrounding rock (1). The inner wall of the main tunnel (2) is laid with a steel mesh (13), and the steel mesh (13) is welded and fixed to the anchor bolt tray (11). A shotcrete layer (6) is provided on the steel mesh (13). The sidewalls of the shotcrete layer (6) and the upper parts of both sides of the arched end are provided with first grouting pipes (4) extending into the surrounding rock (1). The top of the shotcrete layer (6) and the middle position of both sidewalls are provided with prestressed anchor cable assemblies (5) extending into the surrounding rock (1).

2. The external spraying and internal injection tunnel support structure according to claim 1, characterized in that: A screw (9) is installed in the middle of the anchor tray (11) by threaded connection, and one end of the screw (9) is connected to the anchor body (7) by bearing. An adjusting nut (10) is welded and fixed to the outer end of the screw (9). A positioning pin (12) is slidably installed in the through hole at each of the four corners of the anchor tray (11), and the positioning pin (12) is fixed to the surrounding rock (1).

3. The external spraying and internal injection tunnel support structure according to claim 2, characterized in that: The anchor body (7) is provided with a limiting element (8) at one end near the inner surface of the surrounding rock (1) to seal the hole where the anchor body (7) is located.

4. The external spraying and internal injection tunnel support structure according to claim 1, characterized in that: The mesh size of the steel mesh (13) is 100mm*100mm. The steel mesh (13) connects the shotcrete layer (6) and the anchor bolt assembly (3) into a whole.

5. The external spraying and internal injection tunnel support structure according to claim 1, characterized in that: The prestressed anchor cable assembly (5) consists of an anchor cable tray (14), a bearing plate (15), an anchor (16), steel strands (17), and a second grouting pipe (18). There are four sets of steel strands (17), which are arranged around the anchor cable tray (14) and the bearing plate (15), and one end of the steel strands (17) passes through the anchor cable tray (14). The anchor (16) is fixedly arranged at one end of the bearing plate (15) near the surrounding rock (1). The second grouting pipe (18) is arranged at the middle position between the anchor cable tray (14) and the bearing plate (15), and one end of the second grouting pipe (18) passes through the anchor cable tray (14). The anchor cable tray (14) is supported and fixed on the outer wall of the surrounding rock (1).

6. The external spraying and internal injection tunnel support structure according to claim 5, characterized in that: The first grouting pipe (4) and the second grouting pipe (18) are hollow steel pipes with multiple grouting holes on the pipe wall. The diameter of the grouting holes is six millimeters and they are distributed in a spiral shape.

7. The external spraying and internal injection tunnel support structure according to claim 5, characterized in that: Both the first grouting pipe (4) and the second grouting pipe (18) are equipped with rubber expansion rings at the ends of the pipes closest to the surrounding rock (1).

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