A cast-in-place method for a short-distance detour type coal mine air bridge

Abstract

This application provides a method for casting a short-distance bypass type ventilation bridge in a coal mine, comprising the following steps: S1, constructing a first roadway according to the design drawings; S2, determining the intersection area between the completed portion of the first roadway and the unconstructed second roadway according to the design drawings; S3, excavating the intersection area at the bottom of the first roadway to form a foundation pit for casting the ventilation bridge foundation, wherein the width of the foundation pit is greater than the width of the second roadway. The beneficial effect of this invention is that it utilizes the time before the first roadway is completed to complete concrete curing. After curing, the second roadway can be constructed normally. After the first roadway is completed, the conveyor belt can be directly installed without waiting for the ventilation bridge construction and curing, significantly shortening the construction period and improving tunneling efficiency.

Description

Technical Field

[0001] This application belongs to the field of coal mine ventilation bridge construction technology, specifically relating to a short-distance bypass type coal mine ventilation bridge cast-in-place method. Background Technology

[0002] Currently, the construction of ventilation bridges across roadways in coal mines mostly adopts the cast-in-place construction process. However, this process is implemented after the roadway is connected. During construction, multiple procedures need to be carried out simultaneously, such as the installation of conveyor belts, coal and gangue cleaning, and the pouring of concrete for the ventilation bridge. Moreover, the curing period after the ventilation bridge is poured is relatively long, which leads to mutual interference and frequent cross-operations among the various procedures. This not only poses significant safety hazards but also severely restricts the installation progress of conveyor belts, increases the workload of coal and gangue cleaning, and significantly affects the efficiency of underground tunneling.

[0003] Meanwhile, when using prefabricated assembly construction technology, there are high requirements for the processing dimensional accuracy of prefabricated components, the sealing of on-site splicing, and the underground assembly space, which makes construction difficult and still cannot avoid the problems of process conflicts and construction delays that exist in the cast-in-place process. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0005] To address the aforementioned problems, this application provides a method for casting a short-distance bypass type ventilation bridge in coal mines, comprising the following steps: S1. Construct the first tunnel according to the design drawings; S2. Determine the intersection area between the completed section of the first tunnel and the unconstructed section of the second tunnel according to the design drawings; S3. At the bottom of the first tunnel, the intersecting area is excavated to form a foundation pit for pouring the wind bridge foundation, and the width of the foundation pit is greater than the width of the second tunnel. S4. After the excavation work is completed, the bottom of the foundation pit is leveled to form a foundation layer. S5. Lay a first support member and a second support member on the foundation layer along the height direction of the pit. The first support member is laid at intervals on the foundation layer along the width direction of the first tunnel and fixed. The second support member is laid at intervals on the first support member along the length direction of the first tunnel and fixed. S6. Concrete is poured into the foundation pit after the first support and the second support are installed.

[0006] Optionally, after the excavation work is completed, the bottom of the foundation pit is leveled to form a foundation layer, including: After the initial excavation is completed, filling material is spread on the bottom of the pit and its top is leveled to ensure that the flatness deviation of the top of the filling material meets the preset range, thus forming the base layer.

[0007] Optionally, the preset range is 4mm-6mm.

[0008] Optionally, the filling material is loess.

[0009] Optionally, after the excavation work is completed, the bottom of the foundation pit is leveled to form a foundation layer, which further includes: An isolation pad is laid on top of the base layer, and the first support member and the second support member are located on the isolation pad.

[0010] Optionally, the insulating pad is made of bamboo plywood.

[0011] Optionally, a first support member and a second support member are laid on the foundation layer along the height direction of the pit. The first support member is laid at intervals on the foundation layer along the width direction of the first tunnel and fixed. The second support member is laid at intervals on the first support member along the length direction of the first tunnel and fixed. This includes: A fixing net is also laid on the second support member, and anchor rods are tied above the fixing net.

[0012] Optionally, the first support and the second support are hot-rolled I-beams for mining.

[0013] Optionally, the two sides of the second tunnel extend outward by 1.7m to 2.3m respectively to form the two sides of the foundation pit.

[0014] Optionally, the foundation pit after the first and second supports have been installed is then filled with concrete, including: After the first and second support components are installed, the foundation pit is poured with concrete in one go, ensuring it is dense and smoothed in time.

[0015] Beneficial effects The embodiment of the present invention provides a method for casting a short-distance bypass coal mine ventilation bridge, which utilizes the time before the first roadway is connected to complete the concrete curing. After the curing is completed, the second roadway can be constructed normally. After the first roadway is connected, the conveyor belt can be installed directly without waiting for the ventilation bridge construction and curing, which greatly shortens the construction period and improves the tunneling efficiency. Attached Figure Description

[0016] Figure 1 This is a flowchart of the method for casting a near-distance bypass coal mine ventilation bridge according to the present invention. Figure 2This is a top sectional view of the cast-in-place method for a near-distance bypass coal mine ventilation bridge according to the present invention. Figure 3 This is a side sectional view of the cast-in-place method for a near-distance bypass coal mine ventilation bridge according to the present invention.

[0017] The reference numerals in the attached figures are as follows: 1. First tunnel; 2. Second tunnel; 3. Excavation pit; 4. First support component; 5. Second support component; 6. Isolation pad; 7. Fixing net; 8. Anchor bolt. Detailed Implementation

[0018] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0019] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0020] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0021] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0022] See also Figure 1-3 As shown, according to an embodiment of this application, a method for casting a short-distance bypass type coal mine ventilation bridge is provided, including the following steps: S1. Construct the first tunnel 1 according to the design drawings.

[0023] In this embodiment, the first tunnel 1 is constructed according to the design drawings. During the construction of the first tunnel 1, the cross-sectional dimensions, slope and support requirements of the design drawings are followed to ensure that the first tunnel 1 is well-formed and reliably supported.

[0024] S2. Determine the intersection area between the completed part of the first tunnel 1 and the unconstructed second tunnel 2 according to the design drawings.

[0025] In this embodiment, the intersection area between the completed part of the first tunnel 1 and the unconstructed second tunnel 2 is determined according to the design drawings. By accurately locating the intersection area, it is convenient to carry out the subsequent construction of the foundation pit.

[0026] S3. At the bottom of the first tunnel 1, the intersecting area is excavated to form a foundation pit 3 for pouring the wind bridge foundation, and the width of the foundation pit 3 is greater than the width of the second tunnel 2.

[0027] In this embodiment, the intersecting area at the bottom of the first tunnel 1 is excavated to form a foundation pit 3 for pouring the wind bridge foundation. The width of the foundation pit 3 is greater than the width of the second tunnel 2, reserving a construction cross-section for the wind bridge structure. The excavation is carried out in layers using an excavation machine and pneumatic picks, strictly controlling the excavation depth and slope to meet design standards. After excavation, the bottom is initially leveled, and sharp rocks and debris are removed to ensure that the foundation pit 3 has a regular outline and uniform depth. By strictly controlling the excavation depth and slope to meet design standards, sufficient space is provided for the pouring of the wind bridge foundation, and it is also ensured that the wind bridge will connect with the second tunnel 2 after completion, while avoiding damage to the wind bridge foundation during the later construction of the second tunnel 2.

[0028] S4. After the excavation work is completed, the bottom of the foundation pit 3 is leveled to form a foundation layer.

[0029] In this embodiment, after the foundation construction is completed, the bottom of the foundation pit 3 is leveled to form a foundation layer. The foundation layer is used to provide a load-bearing foundation for the subsequent laying of the first support member 4 and the second support member 5.

[0030] S5. Lay a first support member 4 and a second support member 5 on the foundation layer along the height direction of the pit 3. The first support member 4 is laid at intervals on the foundation layer along the width direction of the first tunnel 1 and fixed. The second support member 5 is laid at intervals on the first support member 4 along the length direction of the first tunnel 1 and fixed.

[0031] In this embodiment, a first support member 4 and a second support member 5 are laid on the foundation layer along the height direction of the pit 3. The first support member 4 is laid at intervals on the foundation layer along the width direction of the first tunnel 1 and fixed. The second support member 5 is laid at intervals on the first support member 4 along the length direction of the first tunnel 1 and fixed. This forms a crisscross support structure on the foundation layer. The first support member 4 supports the second support member 5, so that there is sufficient space between the second support member 5 and the foundation layer. This allows concrete to enter the space below the second support member 5 during subsequent pouring, improving the load-bearing capacity of the wind bridge after its formation and during use, enhancing its deformation resistance and bearing strength, and improving its safety during use.

[0032] S6. Concrete is poured into the foundation pit 3 after the first support member 4 and the second support member 5 have been installed.

[0033] In this embodiment, concrete is poured into the foundation pit 3 after the first support member 4 and the second support member 5 are installed. The concrete used must meet the design strength grade and be poured in one continuous pour, without batch pouring. Layered compaction is performed to avoid quality defects such as honeycombing, pitting, and exposed reinforcement. The pouring height meets the design requirements, and the surface is smoothed promptly after pouring. This one-time continuous pouring avoids the formation of construction joints from batch pouring, preventing these joints from becoming the starting point for crack propagation under wind pressure, self-weight, and geological stress. This ensures uniform stress distribution within the concrete and improves the structural integrity and load-bearing capacity of the wind bridge foundation. After pouring, concrete curing is completed before the first tunnel 1 is connected. After curing, the second tunnel 2 can be constructed normally. Once the first tunnel is connected, the conveyor belt can be installed directly without waiting for wind bridge construction and curing, significantly shortening the construction period and improving tunneling efficiency.

[0034] In some embodiments, after the excavation work is completed, the bottom of the foundation pit 3 is leveled to form a foundation layer, including: After the initial excavation is completed, filling material is spread on the bottom of the foundation pit 3 and its top is leveled to ensure that the flatness deviation of the top of the filling material meets the preset range, thus forming the foundation layer.

[0035] The preset range is 4mm-6mm.

[0036] The filling material is loess.

[0037] In this embodiment, after the excavation work is completed, the bottom of the foundation pit 3 is leveled, and sharp rocks and slag are removed, filling material is spread onto the bottom of the foundation pit 3. The preferred filling material is loess, which must be of high quality, free of impurities and lumps, to ensure that its load-bearing capacity meets the standards. During the spreading process, a layered spreading and compaction method is adopted to avoid hollow areas and voids inside the filling material, ensuring that the foundation layer is dense, free of sand and cracks, and that the density meets the load-bearing requirements of the subsequent laying of the first support member 4 and the second support member 5 and the pouring of concrete. After the spreading is completed, the top of the filling material is leveled to strictly control the flatness deviation of the top of the filling material within a preset range of 4mm-6mm. This ensures the flatness of the top support surface of the foundation layer and avoids displacement or tilting of the first support member 4 and the second support member 5 due to insufficient leveling accuracy, thereby indirectly improving the stability and deformation resistance of the overall structure of the wind bridge.

[0038] Understandably, using loess as the filling material is intended to prevent damage to the ventilation bridge during subsequent construction of the second tunnel 2. When construction of the second tunnel 2 proceeds according to the design drawings, and the excavation depth reaches the location of the ventilation bridge and the top is found to be loess, workers will receive a warning indicating that the ventilation bridge has been reached. At this point, the loess will fall downwards to expose the bottom of the ventilation bridge, or workers can manually dig upwards to determine whether the ventilation bridge has been reached, thus reducing the probability of damage to the ventilation bridge during the excavation of the second tunnel 2. Furthermore, the loose nature of loess as a filling material will not hinder the excavation of the second tunnel 2.

[0039] Understandably, the preset range is 5mm to further improve the flatness of the top of the base layer.

[0040] In some embodiments, after the excavation is completed, the bottom of the foundation pit 3 is leveled to form a foundation layer, and the process further includes: An isolation pad 6 is laid on top of the base layer, and the first support 4 and the second support 5 are located on the isolation pad 6.

[0041] The isolation pad 6 is made of bamboo plywood.

[0042] In this technical solution, an isolation pad 6 is laid on top of the foundation layer. The isolation pad 6 improves the flatness of the foundation layer and isolates the poured concrete from it. The isolation pad 6 is made of bamboo plywood, which uses high-quality bamboo such as moso bamboo as its base material. It undergoes high-temperature and high-pressure treatment to form a dense structure. The core structure consists of two layers of bamboo mats or bamboo curtains bonded together with high-performance adhesives such as phenolic resin. This not only enhances the interlayer bonding strength of the boards but also optimizes the stress direction through the natural texture of the bamboo, effectively dispersing the load transmitted by subsequent support components. During installation, it is ensured that the bamboo plywood adheres tightly to the foundation layer, is laid flat, and has no warping or hollow areas. This isolates fine scum and impurities from the surface of the foundation layer, improves the uniform stress distribution after the first support component 4 and the second support component 5 are laid, and prevents cement slurry from seeping into the foundation layer during concrete pouring, thus ensuring the structural integrity of the wind bridge foundation.

[0043] It is understandable that by setting up the isolation pad 6, a flat plane structure is formed at the bottom of the wind bridge after maintenance, which improves the overall structural strength of the wind bridge. After the construction of the second tunnel 2, the isolation pad 6 can be removed.

[0044] In some embodiments, a first support member 4 and a second support member 5 are laid on the base layer along the height direction of the pit 3. The first support member 4 is laid at intervals on the base layer along the width direction of the first tunnel 1 and fixed. The second support member 5 is laid at intervals on the first support member 4 along the length direction of the first tunnel 1 and fixed. A fixing net 7 is also laid on the second support member 5, and an anchor rod 8 is tied above the fixing net 7.

[0045] The first support member 4 and the second support member 5 are mining hot-rolled I-beams No. 11.

[0046] In this technical solution, a first support member 4 and a second support member 5 are laid on the foundation layer along the height direction of the pit 3. Both the first support member 4 and the second support member 5 are made of mining hot-rolled I-beam No. 11, and the material is selected as 20MnK or Q235 mining steel, which has good strength and toughness. The I-beam structure can effectively distribute the load, resist bending and geological stress, and effectively prevent the wind bridge foundation from cracking and collapsing in the complex underground environment, ensuring long-term operational stability. During laying, the first support member 4 is laid at intervals on the isolation pad 6 along the width direction of the first roadway 1 and fixed, and the second support member 5 is laid at intervals on the first support member 4 along the length direction of the first roadway 1 and fixed, forming a crisscrossing double-layer support structure. The first support member 4 is 5.4m long, and the second support member 5 is 9m long, with a spacing of 300mm between them. During the laying process, the horizontal and vertical alignment of the first support component 4 and the second support component 5 need to be adjusted. Spacers are used for secure fixing to prevent displacement or tilting during concrete pouring and to ensure uniform stress distribution on the support structure. After the first support component 4 and the second support component 5 are laid and fixed, a fixing net 7 is laid on the second support component 5. During laying, it is ensured that the fixing net 7 fits snugly against the second support component 5. The fixing nets 7 are bound together with #14 double-strand iron wire to prevent loosening or displacement. The fixing net 7 effectively disperses the stress during concrete pouring, preventing structural defects caused by localized stress concentration. After the fixing net 7 is laid, anchor rods 8 are tied above it. The anchor rods 8 are made of φ20×2100mm threaded steel. During the tying process, it is ensured that the anchor rods 8 are vertically arranged and evenly spaced. This not only enhances the resistance of the wind bridge foundation and prevents floating and cracking during later use, but also further disperses the load and improves the wind bridge foundation's resistance to underground geological stress.

[0047] It is understandable that the fixed mesh 7 is a welded steel mesh.

[0048] In some embodiments, the two sides of the second tunnel 2 extend outward by 1.7m to 2.3m respectively to form the two sides of the foundation pit 3.

[0049] In this technical solution, the foundation pit 3 is formed by extending 1.7m to 2.3m outward from both sides of the second tunnel 2, reserving a complete construction section for the wind bridge foundation. This ensures that the wind bridge, once formed, can fully cover the span of the second tunnel 2, avoiding problems such as insufficient width and load-bearing area caused by excessive extension. During the excavation, the design centerline of the second tunnel 2 is used as a reference to control the extension dimensions on both sides, ensuring symmetry on both sides of the foundation pit 3. Combined with the excavation depth and slope requirements, this not only provides sufficient working space for the wind bridge foundation pouring but also ensures a stable connection between the wind bridge foundation and the first tunnel 1 and the second tunnel 2. This disperses the wind pressure and geological stress borne by the wind bridge, preventing cracking and damage at the edges of the wind bridge due to concentrated stress.

[0050] In some embodiments, the foundation pit 3 after the first support member 4 and the second support member 5 have been installed is concrete-poured, including: After the first support member 4 and the second support member 5 are installed, the foundation pit 3 is poured with concrete in one go, and the concrete is poured densely and smoothed in time.

[0051] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A method for casting a short-distance bypass type ventilation bridge in a coal mine, characterized in that, Includes the following steps: S1. Construct the first tunnel (1) according to the design drawings; S2. Determine the intersection area between the completed part of the first tunnel (1) and the unconstructed second tunnel (2) according to the design drawings; S3. At the bottom of the first tunnel (1), the intersecting area is excavated to form a foundation pit (3) for pouring the wind bridge foundation, and the width of the foundation pit (3) is greater than the width of the second tunnel (2). S4. After the excavation work is completed, the bottom of the foundation pit (3) is leveled to form a foundation layer; S5. Lay a first support member (4) and a second support member (5) on the foundation layer along the height direction of the pit (3). The first support member (4) is laid at intervals on the foundation layer along the width direction of the first tunnel (1) and fixed. The second support member (5) is laid at intervals on the first support member (4) along the length direction of the first tunnel (1) and fixed. S6. Concrete is poured into the foundation pit (3) after the first support member (4) and the second support member (5) are installed.

2. The method for casting a near-distance bypass type coal mine ventilation bridge according to claim 1, characterized in that, After the excavation work is completed, the bottom of the foundation pit (3) is leveled to form a foundation layer, including: After the foundation construction is completed, fill material is spread on the bottom of the foundation pit (3) and the top of it is leveled so that the flatness deviation of the top of the fill material meets the preset range, forming a foundation layer.

3. The method for casting a near-distance bypass type coal mine ventilation bridge according to claim 2, characterized in that, The preset range is 4mm-6mm.

4. The method for casting a near-distance bypass type coal mine ventilation bridge according to claim 2, characterized in that, The filling material is loess.

5. The method for casting a near-distance bypass type coal mine ventilation bridge according to claim 2, characterized in that, After the excavation work is completed, the bottom of the foundation pit (3) is leveled to form a foundation layer, which also includes: An isolation pad (6) is laid on top of the base layer, and the first support (4) and the second support (5) are located on the isolation pad (6).

6. The method for casting a near-distance bypass type coal mine ventilation bridge according to claim 5, characterized in that, The isolation pad (6) is made of bamboo plywood.

7. The method for casting a near-distance bypass type coal mine ventilation bridge according to claim 1, characterized in that, A first support member (4) and a second support member (5) are laid on the foundation layer along the height direction of the pit (3). The first support member (4) is laid at intervals on the foundation layer along the width direction of the first tunnel (1) and fixed. The second support member (5) is laid at intervals on the first support member (4) along the length direction of the first tunnel (1) and fixed. The structure includes: A fixing net (7) is also laid on the second support member (5), and anchor rods (8) are tied above the fixing net (7).

8. The method for casting a near-distance bypass type coal mine ventilation bridge according to claim 7, characterized in that, The first support member (4) and the second support member (5) are mining hot-rolled I-beams No.

11.

9. The method for casting a near-distance bypass type coal mine ventilation bridge according to claim 1, characterized in that, The two sides of the second tunnel (2) extend outward by 1.7m to 2.3m respectively to form the two sides of the foundation pit (3).

10. The method for casting a near-distance bypass type coal mine ventilation bridge according to claim 1, characterized in that, The foundation pit (3) after the first support member (4) and the second support member (5) have been installed is then filled with concrete, including: The foundation pit (3) after the first support member (4) and the second support member (5) are installed is poured with concrete in one go, and the concrete is poured densely and smoothed in time.

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