Secondary lining structure

Abstract

The utility model provides a secondary lining structure which is supported on the inner side of a primary support of tunnel engineering, the secondary lining structure comprises an inner side steel frame, a plurality of grating steel frames, a plurality of arc-shaped drainage pipes and a concrete unit, and the inner side steel frame and the plurality of grating steel frames provide structural strength for the concrete unit. The influence of surrounding rock creep, underground water erosion, vehicle dynamic load and other factors is reduced, the situation that the structural capacity of the secondary lining is insufficient is avoided, meanwhile, the arc-shaped drainage pipe can drain permeating water, and then the construction process that the arc-shaped drainage pipe is laid firstly and then the concrete unit is poured is conducted. And the damage to the secondary lining structure caused by chiseling away the secondary lining and burying the drainage pipe is avoided, so that the conditions of lining cracking and water leakage in tunnel engineering are avoided.

Description

Technical Field

[0001] This utility model relates to the technical field of tunnel construction, and in particular to a secondary lining structure. Background Technology

[0002] Tunnel engineering faces multiple structural safety challenges during both construction and operation phases. When using mining methods, the composite structure of initial support and secondary lining is prone to insufficient lining thickness in certain areas due to defects such as inadequate compaction, formwork deformation, and shoddy workmanship. Plain concrete structures, lacking steel reinforcement, are subjected to the combined effects of surrounding rock creep, groundwater erosion, and vehicle dynamic loads during operation. Weak areas will deteriorate rapidly along the path of "cavity expansion → seepage channel formation → crack expansion," ultimately leading to through-seepage. Over time, the long-term effects of surrounding rock stress adjustment, groundwater erosion, and external loads will gradually develop these initial defects into seepage channels, causing lining cracking and leakage.

[0003] However, conventional treatment methods have significant limitations in addressing the aforementioned problems: grouting technology has limited effectiveness in filling irregular large voids, and is prone to grout loss or secondary defects; adding a secondary lining requires prolonged traffic closure and increases structural weight, potentially leading to excessive stress in the foundation; burying drainage pipes can only alleviate localized leakage and cannot block the overall seepage network. Insufficient thickness of the plain concrete lining makes it highly susceptible to damage to the secondary lining structure when removing the secondary lining and burying drainage pipes. Furthermore, the removal of grooves and burying of pipes can easily reduce the load-bearing capacity of the lining structure, potentially causing safety accidents. Utility Model Content

[0004] The main purpose of this utility model is to provide a secondary lining structure to solve the problems of lining cracking and water leakage in tunnel engineering.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A secondary lining structure, supported inside the initial support of a tunnel project, the secondary lining structure comprising:

[0007] The inner steel frame has a cross-section that is a downward-opening semi-circular ring, and extends along the extension direction of the initial support. The lower side of the inner steel frame is fixedly installed on the ground of the tunnel.

[0008] Multiple grid steel frames, each grid steel frame being a semi-circular ring, are fixedly installed on the outside of the inner steel frame and adapted to the outside of the inner steel frame, and are equidistantly arranged along the extending direction of the inner steel frame.

[0009] Multiple arc-shaped drainage pipes, each arc-shaped drainage pipe being a semi-circular ring, are fixedly installed on the outer side of the inner steel frame and adapted to the outer side of the inner steel frame. They are equidistantly arranged along the extension direction of the inner steel frame and are staggered with the grid steel frame. The openings of the arc-shaped drainage pipes face the outer side of the inner steel frame and are in contact with the inner side of the initial support.

[0010] The concrete unit is an arc-shaped structure, with the inner steel frame and multiple grid steel frames completely embedded in the concrete unit, and the outer surface of the concrete unit fitting against the inner surface of the initial support.

[0011] As a further improvement of this utility model, the inner steel frame includes at least two layers of steel frame;

[0012] The at least two layers of steel frames are arranged at equal intervals along the radial direction of the semi-circular ring of the inner steel frame.

[0013] As a further improvement of this utility model, the inner steel frame is divided into multiple inner steel frame units along its semi-circular ring.

[0014] The adjacent inner steel frame units are fixedly connected by high-strength bolts or connecting steel bars;

[0015] The two inner steel frame units located at the bottom are fixedly installed on the ground of the tunnel.

[0016] As a further improvement of this utility model, the outer side of the inner steel frame is arranged at intervals with the inner side of the initial support.

[0017] As a further improvement of this utility model, the grating steel frame is divided into multiple grating steel frame units along its semi-circular ring.

[0018] Adjacent grid steel frame units are fixedly connected by high-strength bolts or connecting steel bars;

[0019] The inner side of the grating steel frame unit is fixedly connected to the outer side of the inner steel frame.

[0020] As a further improvement of this utility model, a semi-circular placement groove is provided on the inner side of the initial support.

[0021] The grating frame is accommodated within the placement groove, and the grating frame is spaced apart from the bottom wall and side wall of the placement groove.

[0022] As a further improvement of this utility model, a semi-circular drainage groove is provided on the inner side of the initial support.

[0023] The drain pipe is embedded in the drain trough, and the opening of the drain pipe is in contact with the bottom wall of the drain trough.

[0024] As a further improvement of this utility model, water channels are arranged at both ends of the arc-shaped drainage pipe;

[0025] The drainage channel extends along the extension direction of the initial support and is located on the ground of the tunnel.

[0026] The upper opening of the water trough is connected to the lower opening of the arc-shaped drain pipe.

[0027] As a further improvement of this utility model, an anchor rod extends out from the inner side of the initial support;

[0028] The protruding part of the anchor rod supports the inner steel frame or the grid steel frame.

[0029] This utility model provides a secondary lining structure for support within the initial support of a tunnel project. The secondary lining structure includes: an inner steel frame with a downward-opening semi-circular cross-section extending along the direction of the initial support, and its lower side fixedly installed on the tunnel floor; multiple grid steel frames, each semi-circular in shape, fixedly installed on the outer side of the inner steel frame and adapted to its outer side, and equidistantly arranged along the extension direction of the inner steel frame; and multiple arc-shaped drainage pipes. The arc-shaped drainage pipe is a semi-circular ring, fixedly installed on the outside of the inner steel frame and adapted to the outside of the inner steel frame. It is equidistantly arranged along the extension direction of the inner steel frame and staggered with the grid steel frame. The opening of the arc-shaped drainage pipe faces the outside of the inner steel frame and contacts the inner side of the initial support. The concrete unit is an arc-shaped structure, with the inner steel frame and multiple grid steel frames completely embedded within it. The outer surface of the concrete unit is in contact with the inner surface of the initial support. The device provided by this invention provides structural strength to the concrete unit through the inner steel frame and multiple grid steel frames, reducing the impact of factors such as surrounding rock creep, groundwater erosion, and vehicle dynamic loads. This avoids insufficient structural capacity of the secondary lining. Simultaneously, the arc-shaped drainage pipe can drain seeping water. Furthermore, the construction process of first laying the arc-shaped drainage pipe and then pouring the concrete unit avoids damage to the secondary lining structure caused by chiseling away the secondary lining to embed the drainage pipe, thereby preventing lining cracking and leakage in tunnel engineering. Attached Figure Description

[0030] Figure 1 A schematic diagram of the overall structure of a secondary lining structure provided by this utility model;

[0031] Figure 2 A schematic diagram of the assembled inner steel frame, grating steel frame, and arc-shaped drainage pipe of a secondary lining structure provided by this utility model;

[0032] Figure 3 for Figure 2 Enlarged view of part A;

[0033] Figure 4 A front view structural schematic diagram of the inner steel frame, grating steel frame and arc drainage pipe of a secondary lining structure provided by this utility model;

[0034] Figure 5 for Figure 4 Schematic diagram of the BB cross-sectional structure;

[0035] Figure 6 A schematic diagram of the inner steel frame of a secondary lining structure provided by this utility model;

[0036] Figure 7 A schematic diagram of a grating steel frame for a secondary lining structure provided by this utility model;

[0037] Figure 8 A schematic diagram of the structure of an arc-shaped drainage pipe with a secondary lining structure provided by this utility model;

[0038] Labeling Explanation: 1. Inner steel frame; 2. Grating steel frame; 3. Arc-shaped drainage pipe; 4. Concrete unit; 5. Placement groove; 6. Drainage channel; 7. Flow channel; 8. Anchor bolt; 9. Mountain; 10. Initial support. Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0040] A secondary lining structure is provided for support within the initial support 10 of the tunnel engineering, such as... Figure 1 and Figure 2 As shown, the secondary lining structure includes: an inner steel frame 1, as... Figure 6 As shown, the inner steel frame 1 has a downward-opening semi-circular cross-section and extends along the direction of the initial support 10. The lower side of the inner steel frame 1 is fixedly installed on the tunnel floor; multiple grid steel frames 2, such as Figure 7 As shown, the grating steel frame 2 is a semi-circular ring, fixedly installed on the outside of the inner steel frame 1, and adapted to the outside of the inner steel frame 1, and equidistantly arranged along the extending direction of the inner steel frame 1; multiple arc-shaped drainage pipes 3, such as Figure 8As shown, the arc-shaped drainage pipe 3 is a semi-circular ring, fixedly installed on the outside of the inner steel frame 1, and adapted to the outside of the inner steel frame 1. It is equidistantly arranged along the extension direction of the inner steel frame 1, and staggered with the grid steel frame 2. The opening of the arc-shaped drainage pipe 3 faces the outside of the inner steel frame 1 and contacts the inner side of the initial support 10. The concrete unit 4 is an arc-shaped structure. The inner steel frame 1 and multiple grid steel frames 2 are completely embedded in the concrete unit 4, and the outer surface of the concrete unit 4 is in contact with the inner surface of the initial support 10. In this embodiment, the concrete unit 4 is a structure made of concrete used in tunnel engineering.

[0041] Tunnel engineering often involves construction within the mountain body 9. This embodiment uses the construction of a tunnel within the mountain body 9 as an example for illustration. Furthermore, the inner steel frame 1 and the grating steel frame 2 can be constructed using either reinforcing steel bars or steel plates; this embodiment uses reinforcing steel bars as an example.

[0042] To increase the structural stiffness and support capacity of concrete unit 4, such as Figure 4 As shown, the inner steel frame 1 includes at least two layers of steel frames. These at least two layers are arranged at equal intervals along the radial direction of the semi-circular inner steel frame 1. The specific number of layers is determined by the material, parameters, and support capacity requirements of the steel frame itself. In this embodiment, the inner steel frame 1 includes two side steel frames. Each layer of the steel frame is an arc-shaped mesh of reinforcing bars, with adjacent reinforcing bars arranged perpendicularly and staggered, and fixedly connected by binding or welding. Reinforcing bars or steel plates are fixedly installed between the two layers of steel frames, with both ends of the reinforcing bars or steel plates fixedly connected to the two layers of steel frames by binding or welding. The inner steel frame 1 uses a Φ6-8mm reinforcing mesh, with an internal mesh spacing of 200mm.

[0043] To facilitate the installation of the inner steel frame 1, the inner steel frame 1 is divided into multiple inner steel frame units along its semi-circular shape. Adjacent inner steel frame units are fixedly connected by high-strength bolts or connecting steel bars. The two inner steel frame units at the bottom are fixedly installed on the tunnel surface. In this embodiment, the inner steel frame unit includes two layers of steel frame units, which are assembled in a splicing manner during installation to prevent transportation inconvenience caused by transporting the inner steel frame 1 as a whole. Adjacent inner steel frame units can be fixedly connected by locking anchor bolts 8. The inner steel frame unit at the bottom is installed on the tunnel surface using type II welded joints and expansion bolts, or it can be installed on the tunnel surface using U-shaped bases and expansion bolts.

[0044] In order to facilitate the complete embedding of the inner steel frame 1 into the concrete unit 4 and enable the inner steel frame 1 to play the role of structural support, the outer side of the inner steel frame 1 and the inner side of the initial support 10 are arranged at intervals to provide pouring space for the concrete unit 4, while also enabling the concrete unit 4 to fit perfectly with the inner side of the initial support 10.

[0045] To facilitate the installation of the grating frame 2, the grating frame 2 is divided into multiple grating frame units along its semi-circular shape; adjacent grating frame units are fixedly connected by high-strength bolts or connecting steel bars; the inner side of the grating frame unit is fixedly connected to the outer side of the inner steel frame 1. Multiple grating frame units are fixedly connected by anchor bolts 8 to form an arc-shaped grating frame 2, and the inner side of the grating frame unit is also fixedly connected to the outer side of the inner steel frame 1 by anchor bolts 8.

[0046] In order to make the steel grid frame 2 completely embedded within the concrete unit 4, and to allow the steel grid frame 2 to serve as a structural support, such as... Figure 5 As shown, a semi-circular placement groove 5 is provided on the inner side of the initial support 10; the grid steel frame 2 is accommodated in the placement groove 5, and there is a gap between the grid steel frame and the bottom wall and side wall of the placement groove 5. The concrete unit 4 is poured into the placement groove 5, so that the grid steel frame 2 is completely embedded in the concrete unit 4. At the same time, after the concrete unit 4 solidifies, the concrete unit 4 is fixed in the placement groove 5, which improves the structural strength of the support structure.

[0047] To increase the stiffness and load-bearing capacity of the secondary lining structure, the grating steel frame 2 can be replaced with I-beams.

[0048] To facilitate the installation of drainage pipes and drainage, a semi-circular drainage groove 6 is provided on the inner side of the initial support 10. The drainage pipe is embedded in the drainage groove 6, with its opening in contact with the bottom wall of the drainage groove 6. When groundwater infiltrates to the secondary lining side, the internal space of the drainage groove 6 provides flow space for the groundwater. Furthermore, due to the circular structure of the drainage groove 6, the groundwater flows downwards under its own weight after entering the drainage groove 6. In this embodiment, the arc-shaped drainage pipe 3 is a semi-circular φ50mm PVC pipe. The spacing between adjacent arc-shaped drainage pipes 3 is required to be greater than 2m. The arc-shaped drainage pipe 3 is fixed in the drainage groove 6 using thin iron wire and nails, and the gap between the arc-shaped drainage pipe 3 and the drainage groove 6 is sealed with epoxy resin or micro-expansion cement, thus ensuring that water flows strictly along the arc-shaped drainage pipe 3. The drainage groove 6 can be a dovetail groove or a rectangular groove. Workers can also use rebar anchoring to fix the position of the arc-shaped drainage pipe 3 in the drainage groove 6, preventing it from moving arbitrarily and ensuring the effectiveness and reliability of the drainage system.

[0049] To increase the structural strength of the arc-shaped drainage pipe 3, an arc-shaped support strip is provided on the inner arc side of the arc-shaped drainage pipe 3. In this embodiment, it is constructed by splicing arc-shaped plates and is connected by welding during operation. An arc-shaped groove is provided on the lower side of the arc-shaped drainage pipe 3, and the outer arc-shaped peripheral side of the arc-shaped plate is fitted into the arc-shaped groove. During the assembly of the inner steel frame 1, the inner peripheral side of the arc-shaped plate abuts against the outer side of the inner steel frame 1, thereby further providing structural support for the arc-shaped drainage pipe 3. In this embodiment, the arc-shaped drainage pipe 3 and the arc-shaped support plate are integrally formed.

[0050] To facilitate the drainage of water from the drainage trough 6, both ends of the arc-shaped drainage pipe 3 are equipped with water channels 7. The water channels 7 extend along the extension direction of the initial support 10 and are located on the tunnel floor. The upper opening of the water channel 7 is connected to the lower opening of the arc-shaped drainage pipe 3. In this embodiment, the upper opening of the water channel 7 is connected to the lower opening of the drainage pipe, and the water in the drainage pipe flows out through the lower opening and into the drainage trough 6 through the upper opening. The two openings of the water channel 7 are respectively connected to external channels, which can discharge the water out of the tunnel.

[0051] To increase the ease of erecting the steel frame and improve structural strength, such as Figure 3 As shown, anchor rods 8 extend from the inner side of the initial support 10; the extended portion of the anchor rods 8 is supported under the reinforcing bars of the inner steel frame 1 or the reinforcing bars of the grid steel frame 2. The specific number and location of the anchor rods 8 are determined according to construction requirements, and this embodiment does not impose specific limitations. In this embodiment, one end of the anchor rod 8 is inserted into the initial support 10, and the other end is supported under the reinforcing bars of the inner steel frame 1 or the grid steel frame 2, providing support for the inner steel frame 1 and the grid steel frame 2. Simultaneously, to prevent the inner steel frame 1 and the grid steel frame 2 from detaching from the anchor rods 8 during installation, the end of the anchor rod 8 is hook-shaped, hooking under the reinforcing bars of the inner steel frame 1 or the grid steel frame 2, also providing tension for the inner steel frame 1 and the grid steel frame 2, reducing the burden on workers. The installation steps for anchor bolt 8 are as follows: Determine the anchor bolt 8 hole position and drill the hole, strictly control the hole depth (50-100mm shorter than the length of anchor bolt 8) and angle deviation (≤15°), and clean the hole with high-pressure air or water after drilling; then install the resin anchoring agent and insert the anchor bolt 8, and use the drilling machine to stir to make the anchoring agent fully mixed, ensuring that the exposed length is 30-50mm and pre-tightening to the design torque.

[0052] The structure provided in this embodiment has the following technical effects:

[0053] 1. Improved structural stability

[0054] Insufficient thickness of plain concrete lining can lead to insufficient lining strength when grooved. The installation of inner steel frame 1 and grating steel frame 2 can significantly improve the strength of plain concrete lining.

[0055] Anchor bolt 8 can tightly connect the initial support 10 with the secondary lining structure, improving the self-stabilizing ability of the support structure.

[0056] 2. Improved waterproofing and drainage

[0057] Laying water pipes can promptly drain water from leaking areas in the tunnel, reduce the pressure of groundwater on the tunnel lining, and minimize lining damage caused by water erosion.

[0058] The specific implementation method is as follows:

[0059] After the initial support 10 is completed and the structural strength of the initial support 10 meets the requirements of the secondary lining structure, firstly, grooves 5 and drainage channels 6 are opened on the inner side of the initial support 10, and anchor bolts 8 are buried in the preset positions.

[0060] Then, the arc-shaped drainage pipe 3 is installed in the drainage trough 6, and the grid steel frame 2 is assembled. At this time, some of the steel bars of the grid steel frame 2 are located on the upper side of the anchor rod 8 and are in contact with the anchor rod 8. Then, the inner steel frame 1 is assembled, and the connection between the grid steel frame 2 and the inner steel frame 1 is completed. Alternatively, as the assembly height of the inner steel frame 1 changes, the grid steel frame 2 and the arc-shaped drainage pipe 3 are also assembled simultaneously, so as to adjust the positional relationship of the three under the same height conditions.

[0061] Then, concrete is poured into concrete unit 4 using a secondary lining trolley to complete the secondary lining structure.

[0062] The specific embodiments of the utility model have been described in detail above, but they are only examples, and the utility model is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications or substitutions to the utility model are also within the scope of the utility model. Therefore, all equivalent transformations, modifications, and improvements made without departing from the spirit and principles of the utility model should be covered within the scope of the utility model.

Claims

1. A secondary lining structure, supported inside the initial support (10) of a tunnel engineering project, characterized in that, The secondary lining structure includes: The inner steel frame (1) has a cross-section that is a downward-opening semi-circular ring and extends along the extension direction of the initial support (10). The lower side of the inner steel frame (1) is fixedly installed on the ground of the tunnel. Multiple grid steel frames (2), the grid steel frames (2) are semi-circular rings, fixedly installed on the outside of the inner steel frame (1), and adapted to the outside of the inner steel frame (1), and are equidistantly arranged along the extension direction of the inner steel frame (1). Multiple arc-shaped drainage pipes (3) are semi-circular rings, fixedly installed on the outside of the inner steel frame (1) and adapted to the outside of the inner steel frame (1), and are equidistantly arranged along the extension direction of the inner steel frame (1), and are staggered with the grid steel frame (2). The opening of the arc-shaped drainage pipe (3) faces the outside of the inner steel frame (1) and contacts the inside of the initial support (10). The concrete unit (4) is an arc-shaped structure. The inner steel frame (1) and multiple grid steel frames (2) are completely embedded in the concrete unit (4), and the outer side of the concrete unit (4) is in contact with the inner side of the initial support (10).

2. The secondary lining structure according to claim 1, characterized in that, The inner steel frame (1) includes at least two layers of steel frame; The at least two layers of steel frames are arranged at equal intervals along the radial direction of the semi-circular ring of the inner steel frame (1).

3. The secondary lining structure according to claim 1, characterized in that, The inner steel frame (1) is divided into multiple inner steel frame units along its semi-circular ring. The adjacent inner steel frame units are fixedly connected by high-strength bolts or connecting steel bars; The two inner steel frame units located at the bottom are fixedly installed on the ground of the tunnel.

4. The secondary lining structure according to claim 1, characterized in that, The outer side of the inner steel frame (1) is spaced apart from the inner side of the initial support (10).

5. A secondary lining structure according to claim 1, characterized in that, The grid steel frame (2) is divided into multiple grid steel frame units along its semi-circular ring; Adjacent grid steel frame units are fixedly connected by high-strength bolts or connecting steel bars; The inner side of the grating steel frame unit is fixedly connected to the outer side of the inner steel frame (1).

6. A secondary lining structure according to claim 1, characterized in that, The initial support (10) has a semi-circular placement groove (5) on its inner side; The grating steel frame (2) is accommodated in the placement groove (5), and the grating steel frame (2) is spaced from the bottom wall and side wall of the placement groove (5).

7. A secondary lining structure according to claim 1, characterized in that, The initial support (10) has a semi-circular drainage groove (6) on its inner side; The drain pipe is embedded in the drain trough (6), and the opening of the arc-shaped drain pipe (3) is in contact with the bottom wall of the drain trough (6).

8. A secondary lining structure according to claim 1, characterized in that, Both ends of the arc-shaped drainage pipe (3) are provided with water channels (7); The water channel (7) extends along the extension direction of the initial support (10) and is located on the ground of the tunnel; The upper opening of the water trough (7) is connected to the lower opening of the arc-shaped drain pipe (3).

9. A secondary lining structure according to claim 1, characterized in that, An anchor rod (8) extends from the inner side of the initial support (10); The protruding part of the anchor rod (8) supports the inner steel frame (1) or the grid steel frame (2).

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