Roadway section structure suitable for loose rock mass

Abstract

The utility model relates to the technical field of mining roadways, in particular to a roadway section structure suitable for loose rock masses, the section structure comprises a top plate, two side walls and a bottom plate, the connecting positions of the top plate and the two side walls and the connecting positions of the bottom plate and the two side walls are arc-arch-shaped transition angles, and the hanging top distance b of the top plate meets Slt; blt; l and S are the minimum width required by transportation of equipment in the roadway, and L is the primary caving step pitch of the immediate roof. The shape of the section of the roadway is changed, the arc-arch-shaped transition angles are designed at the four corners of the roadway, the roadway is integrally designed to be provided with the double-arch-shaped roadway sections on the two sides, the arch structures are main pressure-bearing structures, stress concentration is not prone to being generated under the pressure effect of loose rock mass around the roadway, and the roadway is not prone to deformation. The bearing capacity and the supporting effect of the roadway are improved. The shape of the roadway can effectively improve the supporting capacity of the loose rock mass roadway, reduce the supporting cost of the roadway, save the construction time of the roadway and improve the tunneling efficiency of the roadway.

Description

Technical Field

[0001] The utility model relates to the technical field of mining tunnels, in particular to a tunnel cross-section structure suitable for loose rock masses. Background Art

[0002] In traditional mining operations, especially in loose rock environments, tunnel stability and safety are critical issues. Loose rock typically has low strength, high permeability, and uneven physical and mechanical properties, making tunnel support challenging. Traditional rectangular or circular cross-section designs often fail to effectively adapt to these geological conditions, easily causing collapse and surrounding rock instability. Furthermore, these designs often require large amounts of support materials, increasing costs and reducing efficiency.

[0003] Under the existing tunnel support conditions, the deformation and failure of the surrounding rock usually have the following characteristics: (1) The tunnel deformation is large, and there is no stable period under the support of the I-steel shed, showing obvious soft rock tunnel characteristics. (2) The tunnel first begins to deform from the bottom plate, resulting in bottom bulging, which then causes the support legs to become unstable and finally causes the roof to sink. (3) The tunnel deformation is asymmetrical, showing the mutual displacement deformation characteristics of "bottom plate bulging and roof plate sinking". (4) The top beam of the shed does not show obvious bending, while the legs show serious bending, twisting and bottom drilling. (5) In some sections of the tunnel, the surrounding rock shows mud expansion due to the influence of water, which aggravates the deformation of the tunnel.

[0004] Often, mining roadways can be severely deformed and damaged during excavation. In some areas, the roof and floor plates can move closer than 1 meter, leaving the coal and rock masses on both sides loose and fragmented. This often requires multiple repairs to maintain the roadway's basic stability, which is expensive. Furthermore, as the roadway later serves the subsequent coal mining face, it will be subject to further mining activity, making it even more difficult to maintain stability and severely impacting normal production. Therefore, it is crucial to address the issue of mining roadway support to ensure that the roadway remains stable and serves future mining operations.

[0005] In addition, thick loose layers are difficult to anchor. Due to the large thickness of the loose surrounding rock, after the tunnel is excavated, the tunnel surrounding rock is difficult to form a stable structure under the influence of excavation disturbance. When anchor rods and anchor cables are used for support, it is very easy for the support of unspecified layers in the thick loose and difficult-to-anchor coal rock to fail, thereby causing the roof to collapse and the two sides to deform, resulting in poor or even ineffective surrounding rock support when anchor rods and anchor cables are used for support of the loose and difficult-to-anchor coal rock.

[0006] Currently, arched cross-section designs are widely considered to provide better support in weak strata. However, existing arched designs often fail to fully consider the specific mechanical behavior of loose rock masses, such as particle loss and stress redistribution, which limits their effectiveness in practical applications.

[0007] Therefore, how to change the traditional tunnel cross-sectional structure in thick layers of loose and difficult-to-anchor surrounding rock to an effective support method supplemented by anchor rods and anchor cables is an important problem that needs to be solved urgently in the industry. Utility Model Content

[0008] In response to the technical problems that existing tunnel supports are prone to deformation and instability in loose rock environments, the utility model provides a tunnel cross-section structure suitable for loose rock masses, which can improve the bearing capacity and stability of tunnels in loose rock masses, reduce support costs and difficulty, and solve the technical problem that existing tunnel forms cannot meet the requirements of tunnel support under loose rock conditions.

[0009] The utility model provides a tunnel cross-section structure suitable for loose rock mass, comprising a top plate, two side walls and a bottom plate, wherein the connection between the top plate and the two side walls and the connection between the bottom plate and the two side walls are both arc-shaped transition angles, and the top plate has a cantilever distance of 1 / 4" and a bottom plate. b satisfy S <b<L , S The minimum width required for transporting equipment in the tunnel. L It is the step distance of the first collapse of the direct top, and the unit is m.

[0010] Furthermore, the radius of the circle where the transition angle is located r The calculation formula is, , h is the arch height of the transition angle, a is the chord length of the transition angle arc, and the unit is m. The radius of the circle where the transition angle is located can be directly calculated based on the chord length and arch height data in the actual tunnel design. r , which is beneficial to designing the shape and size of the tunnel and carrying out tunnel excavation.

[0011] Furthermore, the roof is provided with a plurality of first reinforcement anchor rods inserted into the loose rock mass above the roof, which is beneficial for auxiliary fixing of the roof and enhancing the stability of the tunnel roof.

[0012] Furthermore, a plurality of second reinforcement anchor rods are provided on both side walls and inserted horizontally into the loose rock mass, which is beneficial for auxiliary fixing of the two side walls and strengthening the stability of the tunnel side walls.

[0013] Furthermore, the roof and both side walls are installed with tightly fitting anchor nets, which are installed by installing the roof anchor net on the head of the first reinforcement anchor rod and the side wall anchor nets on the head of the second reinforcement anchor rod. The anchor net support further improves the stability of the tunnel.

[0014] The beneficial effect of the present invention is that: the present invention changes the cross-sectional shape of the tunnel and designs arc-shaped transition angles at the four corners of the tunnel, so that the tunnel as a whole is designed to have a "double-arch" tunnel cross-section on both sides. The arch structure is the main pressure-bearing structure, and it is not easy to produce stress concentration under the pressure of the loose rock mass around the tunnel, thereby increasing the bearing capacity and support effect of the tunnel.

[0015] The tunnel shape of this utility model can effectively improve the support capacity of loose rock tunnels, reduce tunnel support costs, save tunnel construction time, and improve tunnel excavation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Figure 1 This is a structural diagram of Example 1 of the specific implementation method of the present utility model.

[0018] Figure 2 This is a schematic diagram of solving the transition angle radius in a specific implementation manner of the present utility model.

[0019] Figure 3 This is a structural diagram of Example 2 of the specific implementation method of the present utility model.

[0020] In the figure, 1-second reinforcement anchor rod, 2-first reinforcement anchor rod, 3-top plate, 4-transition angle, 5-side wall, 6-bottom plate. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the following will be combined with the drawings of the embodiments of the present invention to clearly and completely describe the technical solutions of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0022] Example 1

[0023] Combine Figure 1 The utility model provides a tunnel cross-section structure suitable for loose rock mass, including a top plate 3, a bottom plate 6 and two side walls 5. The connection between the top plate 3 and the two side walls 5 and the connection between the bottom plate 6 and the two side walls 5 are both arc-shaped transition angles 4.

[0024] The tunnel construction is as follows:

[0025] According to the material transportation and ventilation requirements during the production of the working face, the cross-sectional area of ​​the tunnel is calculated to obtain the tunnel width and height; according to the tunnel cross-sectional area requirements, combined with the mechanical parameters of the tunnel roof, the tunnel cantilever distance b = 3.5m is obtained. The range of the working face tunnel cantilever distance b mainly meets two conditions. First, it meets the material transportation needs of the working face production. The tunnel must be able to transport large equipment and materials. At present, the larger equipment transported in the tunnel is unit brackets and trackless rubber-wheeled vehicles. The transportation of unit brackets is more difficult and requires more space. The minimum tunnel width S = 1.5m is required to transport the equipment. Therefore, the cantilever distance b of the tunnel roof is greater than S; the significance of the tunnel cross-sectional design is to reduce the tunnel cantilever distance to ensure that the tunnel roof does not break during the construction process, which increases the difficulty of tunnel support. In the actual working face production process, the maximum cantilever distance fracture width of the tunnel is consistent with the initial collapse step distance of the direct roof of the working face. Both are manifested as the maximum collapse step distance of the direct roof. The initial collapse step distance of the direct roof is L = 5m. Therefore, the cantilever distance of the tunnel roof is greater than S. b Less than L ; The utility model is suspended from the top b satisfy S <b<L conditions.

[0026] Combine Figure 2 According to the designed transition angle chord length a = 2.5m, the arch height h = 0.4m, the radius of the transition angle 4 of the four arc arch shapes is calculated as follows: r , =2.2m.

[0027] According to the rock type and the shape and size of the tunnel cross-section structure designed above, excavation is carried out to obtain the tunnel.

[0028] Example 2

[0029] Combine Figure 3 Example 2 differs from Example 1 in that Example 2 includes a plurality of first reinforcement anchor rods 2 on the roof 3, inserted into the loose rock mass above the roof 3. A plurality of second reinforcement anchor rods 1 are horizontally inserted into the loose rock mass on the side walls 5. Tightly fitting anchor nets are installed on both the roof and side walls. These anchor nets are installed by installing the roof anchor nets at the heads of the first reinforcement anchor rods 2 and the side wall anchor nets at the heads of the second reinforcement anchor rods 1. This provides auxiliary reinforcement of the roof 3 and side walls 5 through anchor rod support and anchor net support, further enhancing the stability of the roadway.

[0030] Although the present invention has been described in detail with reference to the accompanying drawings and in conjunction with preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, persons of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall fall within the scope of the present invention. Any changes or substitutions that can be easily conceived by persons skilled in the art within the technical scope disclosed in the present invention shall fall within the scope of protection of the present invention.

Claims

1. A tunnel cross-section structure suitable for loose rock mass, the cross-section structure includes a top plate, two side walls and a bottom plate, characterized in that: The connection between the top plate and the two side walls, and the connection between the bottom plate and the two side walls are all arc-shaped transition angles. b satisfy S <b<L , S The minimum width required for transporting equipment in the tunnel. L It is the step distance of the first collapse of the direct top, and the unit is m.

2. The tunnel cross-section structure suitable for loose rock mass according to claim 1, characterized in that: The radius of the circle where the transition angle is located r The calculation formula is, , h is the arch height of the transition angle, a is the chord length of the transition angle arc, and the unit is m.

3. The tunnel cross-section structure suitable for loose rock mass according to claim 1, characterized in that: The top plate is provided with a plurality of first reinforcement anchor rods inserted into the loose rock mass on the upper portion of the top plate.

4. The tunnel cross-section structure suitable for loose rock mass according to claim 3, characterized in that: A plurality of second reinforcement anchor rods are arranged on both side walls and are horizontally inserted into the loose rock mass.

5. The tunnel cross-section structure suitable for loose rock mass according to claim 4, characterized in that: The top plate and both side walls are installed with tightly fitting anchor nets.

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