A new type of energy absorbing and releasing anti-impact support for rock burst tunnels

Abstract

The invention discloses a novel energy-absorbing and energy-releasing anti-impact support for impact ground pressure tunnels, wherein two rows of circular holes are prefabricated along the lengths of an external protective steel plate and an internal pressure-bearing support steel plate respectively for installing fixed anchor cables; when the support is installed, the internal pressure-bearing support steel plate and the external pressure-bearing support steel plate form a U-shape corresponding to the tunnel cross-section, and the bottom ends of the internal pressure-bearing support steel plates are respectively fixedly connected with fixed legs, which are inserted into the tunnel bottom plate to fix the internal pressure-bearing support steel plates; the outer ends of the fixed anchor cables sequentially pass through the circular holes on the external protective steel plates and the internal pressure-bearing support steel plates and are fixed by anchors; a continuous yielding anti-impact energy-absorbing device and a high-strength spring are installed at intervals between the internal pressure-bearing support steel plates and the external protection steel plates, and the two ends of the high-strength spring are respectively fixedly connected to the internal pressure-bearing support steel plate and the external protection steel plate, and the bottom end of the continuous yielding anti-impact energy-absorbing device is fixedly connected to the internal pressure-bearing support steel plate, and a distance is left between the top end and the external protection steel plate.

Description

Technical Field

[0001] The invention belongs to the field of coal mine tunnel support and discloses a novel rock burst tunnel energy absorption and release anti-impact support, which is particularly suitable for anti-impact support of rock burst mine tunnels. Background Art

[0002] As the mining depth and mining scope of mines in my country continue to increase, the frequency of rock burst disasters has gradually increased. Statistics show that the vast majority of rock burst accidents occur in tunnels, often causing damage to tunnels and support structures within a range of tens or even hundreds of meters, resulting in heavy casualties and economic losses, seriously affecting mine production and the safe use of tunnels.

[0003] Rock burst is often instantaneous, sudden and extremely destructive, accompanied by a huge release of energy. The maximum impact energy released can reach 10 3 MJ, these energies mainly act in two aspects: (1) acting on the coal rock mass, causing the coal rock mass to break; (2) being transmitted through the coal rock mass to the tunnel surrounding rock and supporting structure, causing the surrounding rock and supporting structure to be damaged. With the increase of mining depth, the elastic strain energy accumulated in the coal rock mass gradually increases, and the more energy is released when rock burst occurs, the greater the degree of damage to the tunnel surrounding rock and supporting structure caused by rock burst.

[0004] At present, anchor support is an important form of tunnel support. Due to the very low elongation of anchor materials, the nearly fixed anchor length cannot adapt to the large deformation of impact ground pressure tunnels and the characteristics of instantaneous release of a large amount of elastic energy, which can easily cause the anchor rod body to break, thereby losing the support effectiveness, and then leading to the collapse of a large range of tunnels. As for other support forms, such as wood support, single hydraulic support, etc., they are all rigid supports that only meet the safety requirements of static tunnel support. Under the impact load, the support material will be instantly destroyed, thereby losing the support capacity and causing the tunnel to become unstable.

[0005] In summary, for rock burst mines, a reasonable tunnel support system should meet the following characteristics: (1) The support system should have sufficient support strength to ensure the support safety of the tunnels in rock burst mines; (2) The support system should have the characteristics of impact resistance and energy absorption. After the rock burst occurs, the support system should be able to absorb part of the impact energy to avoid impact instability and damage to the tunnel surrounding rock; (3) The support system should be able to adapt to the moderate deformation of the tunnel to avoid damage to the support structure. Summary of the invention

[0006] In view of the above-mentioned technical problems and the requirements for a new support system, the present invention proposes a new anti-impact support suitable for rock burst tunnels, which has the characteristics of slowly releasing pressure energy and quickly absorbing impact energy.

[0007] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a new type of impact ground pressure tunnel energy absorption and release anti-impact support, including an external protective steel plate, an inner pressure-bearing support steel plate, a continuous yielding anti-impact energy absorption device, a high-strength spring and a fixed anchor cable; the external protective steel plate and the inner pressure-bearing support steel plate are respectively prefabricated with two rows of regularly arranged circular holes along the length for installing fixed anchor cables; when the support is installed, the inner pressure-bearing support steel plate and the external protective steel plate form a U-shape corresponding to the cross-section of the tunnel, and the bottom ends of the inner pressure-bearing support steel plates are respectively fixedly connected with fixed anchor cables. The fixed legs are inserted into the bottom plate of the tunnel to fix the inner pressure-bearing support steel plate; the outer ends of the fixed anchor cables pass through the circular holes on the outer protection steel plate and the inner pressure-bearing support steel plate in turn and are fixed by anchors; a continuous yielding anti-impact energy-absorbing device and a high-strength spring are installed between the inner pressure-bearing support steel plate and the outer protection steel plate, and the two ends of the high-strength spring are respectively fixedly connected to the inner pressure-bearing support steel plate and the outer protection steel plate, and the bottom end of the continuous yielding anti-impact energy-absorbing device is fixedly connected to the inner pressure-bearing support steel plate, and a distance is left between the top end and the outer protection steel plate.

[0008] Furthermore, the sustainable yielding anti-impact energy absorbing device is a multi-stage conical structure with a hollow interior. When impact ground pressure occurs, the sustainable yielding anti-impact energy absorbing device can quickly collapse step by step under the action of the impact load to absorb part of the released impact energy. At the same time, the contact area between the device and the external protective steel plate gradually increases, which can reduce the concentrated stress applied to the external protective steel plate.

[0009] Furthermore, the length of the fixed leg is 150-200 mm.

[0010] Furthermore, both ends of the high-strength spring are welded to the outer protective steel plate and the inner pressure-bearing support steel plate respectively.

[0011] Furthermore, the end with a larger area of ​​the continuous yielding anti-impact energy absorbing device is fixed to the inner pressure-bearing support steel plate by welding, and a certain distance is left between the other end and the external protection steel plate, and the distance is the pressure yielding space of the bracket.

[0012] Furthermore, the cross-sections of the inner pressure-bearing support steel plate and the outer protection steel plate are both L-shaped, with two rows of parallel circular holes opened on one side; when the inner pressure-bearing support steel plate and the outer protection steel plate are folded into a U shape along the shape of the tunnel, the circular holes on the inner pressure-bearing support steel plate and the outer protection steel plate correspond to each other.

[0013] Furthermore, the inner pressure-bearing support steel plate is welded with a plurality of inner pressure-bearing support steel plate reinforcing wings at equal distances along the length.

[0014] Furthermore, the inner side pressure-bearing support steel plate reinforcement wing is a right-angled triangle structure.

[0015] A circular hole is provided in the middle of the plate body of the inner pressure-bearing support steel plate reinforcement wing.

[0016] Due to the application of the above technical solution, the present invention brings the following positive effects:

[0017] (1) This technical solution installs a high-strength spring between the outer protective steel plate and the inner pressure-bearing support steel plate. After the fixed anchor cable is installed, the anchor cable applies a certain preload force to the inner pressure-bearing support steel plate, and the high-strength spring transfers the preload force to the outer protective steel plate. On the one hand, the inner pressure-bearing support steel plate can fit closely with the surrounding rock of the tunnel, slowing down the initial deformation of the surrounding rock. On the other hand, the bracket has greater retractability and can adapt to the larger initial deformation of the surrounding rock.

[0018] (2) This technical solution can meet the requirements of adapting to the slow deformation of the impact ground pressure tunnel. Its allowable deformation range is determined by the length of the high-strength spring and the distance between the sustainable yielding anti-impact energy absorbing device and the external protective steel plate, which is greatly increased compared with the existing invention. At the same time, while the tunnel is slowly deforming, before the sustainable yielding energy absorbing device takes effect, the support is slowly released by compressing the high-strength spring to improve the support's ability to adapt to the slow deformation of the surrounding rock.

[0019] (3) This technical solution can meet the requirements of absorbing instantaneous energy release in rock burst tunnels. In the case of huge energy release such as instantaneous displacement and ejection of coal rock mass in rock burst, the support achieves the effect of rapid energy absorption through rapid compression of high-strength springs and rapid deformation of the sustainable yielding anti-impact energy absorption device. It is pre-conceived that the hollow structure of the sustainable yielding anti-impact energy absorption device can have a fast response speed and good instantaneous deformation ability when rock burst occurs. In addition, after the sustainable yielding energy absorption device collapses step by step, the contact area between the device and the outer protective steel plate gradually increases, thereby reducing the pressure on the outer protective steel plate and improving the support life of the support structure.

[0020] (4) This technical solution enables the new type of support to have the dual characteristics of slow pressure release and rapid impact energy absorption. Different support installation spacing is designed according to the different impact hazard levels of the tunnel, and the exposed area of ​​the surrounding rock is reasonably controlled. This can significantly improve the support status of the rock burst tunnel, avoid tunnel instability due to damage to the support structure when rock burst occurs, and ensure the life safety of people inside the tunnel when rock burst occurs.

[0021] (5) This technical solution transfers the fixed position of the anchor rod to the support structure to avoid the extrusion and damage of the surrounding rock after the anchor rod is subjected to force, maintain the integrity of the surrounding rock, and improve the bearing capacity of the surrounding rock itself.

[0022] The invention has reasonable design, is easy to implement and has good practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0024] Attached Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0025] Attached Figure 2 It is a front view of the sustainable yielding anti-collision energy absorbing device of the present invention.

[0026] Attached Figure 3 It is a top view of the sustainable yielding anti-collision energy absorbing device of the present invention.

[0027] Attached Figure 4 for Figure 2 AA direction cross-sectional view.

[0028] Attached Figure 5 Front view of the inner pressure-bearing support steel plate reinforcement wing.

[0029] Attached Figure 6 Top view of the inner pressure-bearing support steel plate reinforced wing.

[0030] Attached Figure 7 For attachment Figure 1 Middle B is a partially enlarged front view.

[0031] In the figure: 1. Outer protective steel plate; 2. High-strength spring; 3. Fixed anchor cable; 4. Continuous yielding anti-impact energy absorption device; 5. Inner pressure-bearing support steel plate; 6, 6′. Prefabricated anchor cable installation holes; 7. Fixed support legs; 8. Inner pressure-bearing support steel plate reinforcement wing. DETAILED DESCRIPTION

[0032] In order to better explain the present invention, the technical solution of the present invention is further described in detail below through specific implementation methods in conjunction with the accompanying drawings.

[0033] like Figure 1 , 2 As shown, a new type of impact ground pressure tunnel energy absorption and release anti-impact support of the present invention includes an external protective steel plate 1, a high-strength spring 2, a fixed anchor cable 3, a continuous yielding anti-impact energy absorption device 4, an inner pressure-bearing support steel plate 5, prefabricated anchor cable installation holes 6, 6', fixed legs 7, and inner pressure-bearing support steel plate reinforcement wings 8.

[0034] like Figure 1 As shown, the outer protective steel plate 1 is bent into a U shape along the tunnel, wherein two rows of prefabricated anchor cable installation holes 6' arranged in a certain regular pattern are prefabricated on both sides of the axis for passing the fixed anchor cables 3.

[0035] The inner pressure-bearing support steel plate 5 is substantially the same in appearance as the outer protective steel plate 1 , and two rows of prefabricated anchor cable mounting holes 6 arranged in a certain regular pattern are also prefabricated on both sides of the central axis of the inner pressure-bearing support steel plate 5 , which correspond to the prefabricated anchor cable mounting holes 6′ on the outer protective steel plate 1 and are used to install and fix the anchor cables 3 .

[0036] like Figure 5 , 6 As shown, inner pressure-bearing support steel plate reinforcing wings 8 are welded on the inner pressure-bearing support steel plate 5 at a certain pitch. The inner pressure-bearing support steel plate reinforcing wings 8 are a right-angled triangle structure, and a circular hole is provided in the middle of the plate body of the inner pressure-bearing support steel plate reinforcing wings.

[0037] The vertical part of the inner pressure-bearing support steel plate 5 is connected to the fixed leg 7, and the length of the fixed leg 7 is 150~200mm. When the bracket is installed, the fixed leg 7 will be inserted into the tunnel bottom plate to fix the inner pressure-bearing support steel plate 5, thereby enhancing the overall stability of the bracket.

[0038] like Figure 2-4 As shown in Figures 7, the sustainable yielding anti-impact energy absorbing device 4 is a multi-stage conical structure with a hollow interior. When impact ground pressure occurs, the sustainable yielding anti-impact energy absorbing device 4 can collapse rapidly step by step under the action of the impact load to absorb part of the released impact energy. While collapsing, the contact area between the device 4 and the external protective steel plate 1 gradually increases, which can reduce the concentrated stress applied to the external protective steel plate 1.

[0039] like Figure 1 As shown, the high-strength spring 2 is fixed between the outer protective steel plate 1 and the inner pressure-bearing support steel plate 5 .

[0040] The fixed anchor cable 3 is a high-strength prestressed anchor cable, which is used to fix the entire anti-collision support.

[0041] As a further improvement of the present invention, a high-strength spring 2 and a continuous yielding anti-impact energy absorption device 4 are installed between the external protective steel plate 1 and the inner pressure-bearing support steel plate 5, and the two ends of the high-strength spring 2 are respectively welded to the external protective steel plate 1 and the inner pressure-bearing support steel plate 5.

[0042] As a further improvement of the present invention, the end of the sustainable yielding anti-impact energy absorbing device 4 with a larger area is fixed to the inner pressure-bearing support steel plate 5 by welding, and a certain distance is left between the other end and the outer protection steel plate 1, as shown in the attached Figure 7 As shown, this distance is the pressure relief space of the bracket.

Claims

1. A new type of energy absorbing and releasing anti-impact support for rock burst tunnels, characterized in that: It includes an external protective steel plate, an inner pressure-bearing support steel plate, a continuous yielding anti-impact energy absorption device, a high-strength spring and a fixed anchor cable; the outer protective steel plate and the inner pressure-bearing support steel plate are respectively prefabricated with two rows of regularly arranged circular holes along the length for installing the fixed anchor cable; when the bracket is installed, the inner pressure-bearing support steel plate and the outer protective steel plate form a U-shape corresponding to the cross-section of the tunnel, and the bottom end of the inner pressure-bearing support steel plate is respectively fixedly connected with a fixed leg, which is inserted into the bottom plate of the tunnel to fix the inner pressure-bearing support steel plate. Side pressure-bearing support steel plate; the outer ends of the fixed anchor cables pass through the circular holes on the outer protection steel plate and the inner pressure-bearing support steel plate in turn and are fixed by anchors; a continuous yielding anti-impact energy-absorbing device and a high-strength spring are installed between the inner pressure-bearing support steel plate and the outer protection steel plate, the two ends of the high-strength spring are respectively fixedly connected to the inner pressure-bearing support steel plate and the outer protection steel plate, the bottom end of the continuous yielding anti-impact energy-absorbing device is fixedly connected to the inner pressure-bearing support steel plate, and a distance is left between the top end and the outer protection steel plate; The sustainable yielding anti-impact energy absorbing device is a multi-stage cone-shaped structure with a hollow interior. When impact ground pressure occurs, the sustainable yielding anti-impact energy absorbing device can collapse rapidly step by step under the action of the impact load to absorb part of the released impact energy. While collapsing, the contact area between the device and the external protective steel plate gradually increases, which can reduce the concentrated stress applied to the external protective steel plate. The end with a larger area of ​​the sustainable yielding anti-impact energy absorbing device is fixed to the inner pressure-bearing support steel plate by welding, and a certain distance is left between the other end and the outer protection steel plate, and the distance is the pressure yielding space of the bracket.

2. According to claim 1, a new type of energy absorbing and releasing anti-impact support for rock burst tunnels is characterized in that: The length of the fixed leg is 150-200 mm.

3. The novel energy absorbing and releasing anti-impact support for rock burst tunnel according to claim 1 is characterized in that: The two ends of the high-strength spring are respectively welded to the outer protective steel plate and the inner pressure-bearing support steel plate.

4. The novel energy absorbing and releasing anti-impact support for rock burst tunnel according to claim 1 is characterized in that: The cross-sections of the inner pressure-bearing support steel plate and the outer protection steel plate are both L-shaped, with two rows of parallel circular holes on one side; when the inner pressure-bearing support steel plate and the outer protection steel plate are folded into a U shape along the shape of the tunnel, the circular holes on the inner pressure-bearing support steel plate and the outer protection steel plate correspond to each other.

5. The novel energy absorbing and releasing anti-impact support for rock burst tunnel according to claim 1 is characterized in that: The inner side pressure-bearing support steel plate is welded with a plurality of inner side pressure-bearing support steel plate reinforcing wings at equal distances along the length.

6. The novel energy absorbing and releasing anti-impact support for rock burst tunnel according to claim 5 is characterized in that: The inner side pressure-bearing support steel plate reinforcement wing is a right-angled triangle structure, and a circular hole is provided in the middle of the plate body of the inner side pressure-bearing support steel plate reinforcement wing.

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