Novel reinforcing mesh for reducing tunnel rockburst harm and initial support cracking

Abstract

The invention discloses a novel reinforcing mesh for reducing tunnel rockburst harm and initial support cracking, which comprises transverse embossed wave-isolating reinforcing steel bars (11) and longitudinal embossed wave-isolating reinforcing steel bars (12) which are mutually woven, the upper and lower waveform interlacing parts of the transverse embossed wave-isolating reinforcing steel bars (11) and the longitudinal embossed wave-isolating reinforcing steel bars (12) are woven in a cross shape, and the interlacing parts (14) are fixedly connected; the transverse embossed wave-isolating reinforcing steel bars (11) and the longitudinal embossed wave-isolating reinforcing steel bars (12) are vertically arranged to form an embossed wave-isolating dense-grid fine reinforcing steel bar net (1) with one closed side, the reinforcing steel bar net is also provided with grids (1a) with the same size, and the outer end parts of the transverse embossed wave-isolating reinforcing steel bars (11) and the longitudinal embossed wave-isolating reinforcing steel bars (12) are respectively provided with a section of extending reinforcing steel bars (13) with reserved ends. The device has the advantages that energy generated by rockburst, earthquakes, deformation and the like can be effectively absorbed or buffered, and the safety of tunnel construction and operation is enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel steel mesh and support structure, and in particular relates to a new steel mesh for reducing tunnel rock burst hazards and initial support cracking. Background Art

[0002] Infrastructure such as transportation and water conservancy in the west has developed rapidly. Tunnel (hole) projects such as transportation, water conservancy and mining are characterized by deep burial and long length. Deep buried tunnels are in a high-energy geological environment, and dynamic disasters such as rock bursts and large-scale deformations are frequent. Breaking through the technical bottleneck of dynamic disaster pre-control and realizing the transition from post-disaster passive management to pre-disaster active control is not only the inherent demand for the scientific nature of high-quality tunnel construction, but also the core requirement of the people-oriented nature of engineering construction.

[0003] A survey on the design and construction of domestic transportation, water conservancy, and mining tunnels found that the steel mesh currently used for initial support does not take into account and does not have the function of reducing rock bursts and initial support cracking. At the same time, there are also common problems in overlap and laying space interference.

[0004] In the initial support construction of tunnels under complex geological conditions, the overlap of steel mesh seriously affects the construction progress and safety, especially for tunnels with weak and broken surrounding rocks, high ground stress, and high rock bursts that need to be excavated quickly. At present, the steel mesh used for initial support is mainly optimized in terms of steel bar diameter, spacing between steel bars, and steel bar coating, without considering and not having the function of reducing rock burst and initial support cracking. At the same time, there are also common problems in overlap and laying space interference. Therefore, the initial support construction site of the tunnel urgently needs a new steel mesh that can reduce the hazards of tunnel rock burst and initial support cracking. The main features of the new steel mesh are: closed: the edges of the steel mesh are closed, crimping: the longitudinal (transverse) steel bars are located in a "cross-shaped" weaving method above and below the adjacent transverse (longitudinal) steel bars, wave separation: the cross node separates the wave shape of the vertical steel bar, dense grid: small grid size, fine: small steel bar (wire) diameter. Summary of the invention

[0005] The purpose of the present invention is to solve the problems of poor energy absorption and explosion resistance of existing steel meshes, low mesh hanging efficiency and high construction safety risks, and to provide a new steel mesh for reducing the hazards of tunnel rock bursts and initial support cracking, which can effectively avoid the adverse effects of lap length and arch frame installation on the laying and hanging of steel mesh, realize high-efficiency mesh hanging operations in tunnels, effectively absorb the energy generated by rock bursts, earthquakes, deformation pressure, etc., and increase the safety of construction in tunnels.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions: A new type of steel mesh for reducing the risk of rock burst in tunnels and cracking of initial support, comprising mutually coordinated transverse crimped wave-isolating steel bars and longitudinal crimped wave-isolating steel bars, both of which have their own corrugated structures, and the upper and lower corrugated portions of the transverse crimped wave-isolating steel bars and the longitudinal crimped wave-isolating steel bars are arranged in a "cross shape" at the intersection of the two, and the intersection of the two is fixedly connected; The transverse crimped wave-isolating steel bars and the longitudinal crimped wave-isolating steel bars are arranged perpendicularly to each other to form a closed mesh structure of a closed crimped wave-isolating fine steel mesh. The steel mesh is also provided with grids of equal size. The outer ends of the transverse crimped wave-isolating steel bars and the longitudinal crimped wave-isolating steel bars are provided with a section of steel bars reserved for protruding from the end.

[0007] Furthermore, the grid is a square or a rectangle, and its side length is 75 to 150 mm, and is calculated as an integer multiple of 25 mm or 50 mm.

[0008] Furthermore, the diameter of the transverse corrugated corrugated steel bars and the longitudinal corrugated corrugated steel bars is 3 to 8 mm.

[0009] Furthermore, the intersection is fixed by resistance spot welding or butt welding.

[0010] Furthermore, the crocheting forms of the transverse crocheted corrugated steel bars and the longitudinal crocheted corrugated steel bars are oblique straight or extremely short wave crocheting.

[0011] Furthermore, the wave isolation waveform and wavelength of the transverse crimped wave isolation steel bars and the longitudinal crimped wave isolation steel bars adopt a sine wave or a flat arch wave, and 1 to 3 wave segments are set in one grid.

[0012] Furthermore, the transverse corrugated corrugated steel bars, longitudinal corrugated corrugated steel bars and the reserved protruding steel bars at the ends are all made of low-carbon steel, low-alloy steel and alloy steel, and according to the initial support stress performance, HPB300, HRB400, HRBF400, RRB400, HRB400E, HRB500 and HRBF500 steel bars are selected, and their surfaces are treated with anti-corrosion.

[0013] Furthermore, the length of the steel bars extended out from the ends of the transverse or longitudinal embossed wave-isolating steel mesh is reserved in the range of (twice the steel bar diameter) to 20 mm.

[0014] Furthermore, the transverse embossed wave-isolating steel bars and the longitudinal embossed wave-isolating steel bars in the same row have the same size, and the amplitude and wavelength of the wave isolation of the two are the same.

[0015] The present invention also provides a tunnel support structure, which has sprayed concrete and the above-mentioned closed-end crimped wave-isolated micro-grid fine steel mesh structure. After the closed-end crimped wave-isolated micro-grid fine steel mesh is installed, concrete is sprayed on its outer layer, and the thickness of the concrete spraying is adjusted according to the actual situation of the tunnel.

[0016] Compared with the prior art, the advantages of the technical solution of the present invention are specifically: (1) The present invention utilizes the combination of longitudinal and transverse crimped wave-isolating steel bars / wires, which can absorb or buffer the energy generated by rock bursts, earthquakes, deformation pressure, etc., compared with traditional steel mesh, thereby improving the safety of tunnel construction and operation; (2) The closed crimped wave-isolating fine steel mesh of the present invention is modularly designed, that is, the sizes of the horizontal crimped wave-isolating steel bars and the longitudinal crimped wave-isolating steel bars in the same row are the same, and the amplitude and wavelength of the wave isolation are the same. The factory processing and production realizes batch production and intelligentization, and the component installation can achieve accurate and efficient construction, shortening the construction period; ⑶ In the closed crimped wave-isolating fine steel mesh structure of the present invention, the transverse crimped wave-isolating steel bars and the longitudinal crimped wave-isolating steel bars are woven by staggered overlap in a "cross shape" and fixed by resistance spot welding, ensuring that the connection is tight and reliable, not easy to fall off, and the processing is simple and efficient; (4) The closed-end embossed wave-isolated fine steel mesh of the present invention has reserved protruding steel bars at the end, which increases the effective connection length of the steel mesh, ensures the effective connection of the longitudinal and transverse steel bars at the edge of the steel mesh, and avoids the dislocation and falling of the steel bars during the installation process; ⑸ The closed-end embossed wave-isolating fine grid steel mesh structure of the present invention has reasonable force bearing, uniform force transmission, and convenient installation. It is suitable for a variety of tunnel working environments, can significantly improve the efficiency of laying and hanging mesh for initial tunnel support, and improves the quality of support construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the structure of the closed-end embossing wave-isolated fine steel mesh of the present invention; Figure 2 A top view of the closed embossing wave separation fine steel mesh of the present invention; Figure 3 The present invention is a closed embossing wave separation fine grid steel mesh front view; Figure 4 The closed embossing wave separation micro grid fine steel mesh left view of the present invention; Figure 5 This is a detailed grid structure diagram of the closed-end embossed wave-isolated fine steel mesh of the present invention. DETAILED DESCRIPTION Example 1

[0018] In order to make the present invention more clear, the following is a further description of a new type of steel mesh for reducing the hazards of tunnel rock burst and initial support cracking of the present invention in conjunction with the accompanying drawings. The specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0019] See also Figure 1 and Figure 5A new type of steel mesh for reducing the risk of rock burst in tunnels and cracking of initial support includes transverse crimped wave-isolating steel bars 11, longitudinal crimped wave-isolating steel bars 12 and extended steel bars 13 reserved at the ends.

[0020] See also Figures 2~5 , the upper and lower waveforms of the transverse crimped wave-isolating steel bars 11 and the longitudinal crimped wave-isolating steel bars 12 are intersected in a "cross shape", and the intersection 14 of the two is fixedly connected; The transverse embossed wave-isolating steel bars 11 and the longitudinal embossed wave-isolating steel bars 12 are arranged perpendicularly to each other to form a closed mesh structure of a closed embossed wave-isolating fine steel mesh 1, and the steel mesh is also provided with an equal-sized grid 1a. The outer ends of the transverse embossed wave-isolating steel bars 11 and the longitudinal embossed wave-isolating steel bars 12 are both provided with a section of steel bars 13 reserved for protruding from the end.

[0021] In this embodiment, the closed crimped wave-separated fine steel mesh 1 has the characteristics of closed, crimped, wave-separated, dense, and fine. Crimping refers to the "cross-shaped" staggered weaving method in which the steel bars are first crimped to a set grid size, and then the longitudinal / transverse steel bars are respectively located above and below the adjacent transverse / longitudinal steel bars in sequence; wave-separated refers to the "cross-shaped" staggered weaving method in which the steel bars are first processed into a wave shape with a set grid size, and then the horizontal steel bars are separated by the vertical steel bars according to the wave shape; closed refers to the closure of the edges of the steel mesh, and the longitudinal / transverse steel bars are arranged at a set spacing and at right angles to each other to form a closed mesh as a whole; dense refers to the size of the grid 1a of 75~150mm, which is an integer multiple of 25mm or 50mm; fine steel refers to the small diameter of the steel bar / wire, which is 3~8mm.

[0022] See also Figure 1 and Figure 5 The upper and lower wave intersections 14 of the transverse corrugated corrugated steel bars 11 and the longitudinal corrugated corrugated steel bars 12 are arranged in a "cross shape" and fixed by resistance spot welding or butt welding.

[0023] In this embodiment, the embossing form can be oblique straight or extremely short wave embossing; the wave separation waveform and wavelength can be a sine wave or a flat arch wave, and 1 to 3 wave segments can be set in one grid 1a.

[0024] In this embodiment, the transverse embossed corrugated steel bars 11, the longitudinal embossed corrugated steel bars 12 and the reserved extended steel bars 13 at the ends are all made of HRB400 steel bars, and their surfaces are treated with anti-corrosion.

[0025] In this embodiment, the length of the steel bar 13 extended out from the end is reserved to be twice the diameter of the steel bar.

[0026] See also Figure 1 , Figure 3 and Figure 5The transverse embossed wave-isolating steel bars 11 and the longitudinal embossed wave-isolating steel bars 12 are both modularly designed, that is, the transverse embossed wave-isolating steel bars 11 and the longitudinal embossed wave-isolating steel bars 12 in the same row have the same size, and the amplitude and wavelength of the wave isolation are the same.

[0027] When using the closed crimped wave-isolating fine steel mesh support structure of the present invention, that is, when the initial support steel mesh is laid and hung in the tunnel, firstly, a steel mesh weaving machine is used to weave the transverse crimped wave-isolating steel bars 11 and the longitudinal crimped wave-isolating steel bars 12 into a closed steel mesh structure in a "cross shape" at the intersection of the upper and lower waves, and then it is fixed by resistance spot welding. Secondly, the closed crimped wave-isolating steel mesh 1 is laid and hung at the position where the mesh is required in the tunnel, and it is tied and fixed with steel wire or insulating wire, and finally the steel mesh is covered with sprayed concrete. Example 2

[0028] In this embodiment, a new type of steel mesh is used to reduce the risk of rock burst in tunnels and cracking of initial support. Its structure and use process are basically the same as those in Example 1, except that the materials for making the transverse crimped wave-isolating steel bars 11, the longitudinal crimped wave-isolating steel bars 12, and the steel bars 13 reserved for protruding at the ends are replaced with HRB500 high-strength steel bars. Example 3

[0029] In this embodiment, a new type of steel mesh is used to reduce the risk of rock burst in tunnels and cracking of initial support. Its structure and use process are basically the same as those in Example 1, except that the materials for making the transverse corrugated corrugated steel bars 11, the longitudinal corrugated corrugated steel bars 12, and the steel bars 13 reserved for protruding at the ends are replaced with high-strength steel wires. Example 4

[0030] In this embodiment, a new type of steel mesh is used to reduce the risk of rock burst in tunnels and cracking of initial support. Its structure and use process are basically the same as those in Example 1, except that the length of the steel bars 13 reserved at the end of the steel mesh is changed to 20 mm.

[0031] The novel steel mesh of the present invention utilizes the combination of longitudinal and transverse crimped wave-isolating steel bars to absorb or buffer the energy generated by rock bursts, earthquakes, deformation pressure, etc., thereby enhancing the safety of tunnel construction and operation; the dense grid structure realizes the uniform and high-density arrangement of the tunnel initial support steel mesh, reduces the number and degree of cracking of the initial support concrete, and reduces the rebound of the shotcrete; the closed structure can avoid the spatial interference caused by excessive extension of steel bars compared to the traditional steel mesh, saves time, manpower and cost for laying the steel mesh, avoids the increase and unevenness of the shotcrete caused by the warping of the protruding steel bars, and reduces the overlap workload of laying the steel mesh.

[0032] In addition to the above embodiments, the present invention may also have other implementations. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. A new type of steel mesh for reducing the risk of rock burst in tunnels and cracking of initial support, characterized in that : It includes a transverse crimped corrugated steel bar (11) and a longitudinal crimped corrugated steel bar (12) that cooperate with each other, both of which have a corrugated structure, and the upper and lower corrugated intersections of the transverse crimped corrugated steel bar (11) and the longitudinal crimped corrugated steel bar (12) are arranged in a "cross shape", and the intersections (14) of the two are fixedly connected; The transverse embossed wave-isolating steel bars (11) and the longitudinal embossed wave-isolating steel bars (12) are arranged perpendicularly to each other to form a closed mesh structure of a closed embossed wave-isolating fine steel mesh (1), and the steel mesh is also provided with a grid (1a) of equal size. The outer ends of the transverse embossed wave-isolating steel bars (11) and the longitudinal embossed wave-isolating steel bars (12) are each provided with a section of steel bars (13) reserved for protruding from the end.

2. The new steel mesh for reducing tunnel rock burst hazards and initial support cracking according to claim 1 is characterized in that : The grid (1a) is a square or a rectangle, and its side length is 75 to 150 mm and is calculated as an integer multiple of 25 mm or 50 mm.

3. The new steel mesh for reducing tunnel rock burst hazards and initial support cracking according to claim 1 or 2 is characterized in that : The diameter of the transverse embossed corrugated steel bars (11) and the longitudinal embossed corrugated steel bars (12) is 3 to 8 mm.

4. The novel steel mesh for reducing rock burst hazards and initial support cracking in tunnels according to claim 1 or 2 is characterized in that : The intersecting portion (14) is fixed by resistance spot welding or butt welding.

5. The new steel mesh for reducing tunnel rock burst hazards and initial support cracking according to claim 1 or 2 is characterized in that : The embossing forms of the transverse embossed wave-isolating steel bars (11) and the longitudinal embossed wave-isolating steel bars (12) are oblique straight or extremely short wave embossing.

6. The new steel mesh for reducing tunnel rock burst hazards and initial support cracking according to claim 1 or 2, characterized in that : The wave isolation waveform and wavelength of the transversely embossed wave isolation steel bars (11) and the longitudinally embossed wave isolation steel bars (12) are sinusoidal waves or flat arch waves, and 1 to 3 wave segments are set in one grid (1a).

7. The new steel mesh for reducing tunnel rock burst hazards and initial support cracking according to claim 1 or 2 is characterized in that : The transverse crimped wave-isolating steel bars (11), the longitudinal crimped wave-isolating steel bars (12) and the reserved protruding steel bars (13) at the ends are all made of low-carbon steel, low-alloy steel or alloy steel. According to the initial support bearing performance, the steel bars are HPB300, HRB400, HRBF400, RRB400, HRB400E, HRB500 or HRBF500 steel bars, and their surfaces are treated with anti-corrosion.

8. The new steel mesh for reducing rock burst hazards and initial support cracking in tunnels according to claim 1 or 2, characterized in that : The length of the steel bars (13) reserved at the ends of the transverse or longitudinal embossed wave-isolating steel mesh is in the range of (twice the steel bar diameter) to 20 mm.

9. The new steel mesh for reducing tunnel rock burst hazards and initial support cracking according to claim 1 or 2, characterized in that : The transverse embossed wave-isolating steel bars (11) and the longitudinal embossed wave-isolating steel bars (12) in the same row have the same size, and the amplitude and wavelength of the wave isolation of the two are the same.

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