A method for on-site fabrication of a false floor in a mine roadway

Abstract

This invention discloses a method for on-site fabrication of a false floor for mine roadways. The false floor separates the top and bottom roadways at the connection point, ensuring that the top roadway meets production needs such as transportation, coal handling, and personnel movement, while also ensuring that the bottom roadway meets ventilation requirements. This results in a complete and reliable production system, significantly shortening the mining cycle and improving mining efficiency. The false floor is constructed with a track framework and reinforced with concrete, resulting in high strength and excellent sealing. Metal mesh is laid on both the upper and lower layers of the intermediate track. During shotcreting, the metal mesh provides support for the grout, preventing excessive grout thickness and potential collapse. Rubber pads are placed at the bottom of the sleepers to effectively reduce vibration during mine car transport. This method is practical and convenient.

Description

Technical Field

[0001] This invention relates to the field of coal mining technology, specifically to a method for on-site fabrication of a false floor for mine roadways. Background Technology

[0002] During coal mining, as mine tunnels are continuously excavated, situations arise where the tops and bottoms of two tunnels become connected. Isolating these tunnels paralyzes the transportation and coal conveying systems. Redesigning the tunnels can lead to resource losses and operational difficulties, impacting mine production. Especially given the current situation where a large amount of high-grade mineral resources cannot be fully developed and utilized, resulting in a sharp decline in mine reserves and grades and significant waste of valuable mineral resources, the sustainable development of mineral resources is of paramount importance.

[0003] To ensure mining safety and convenient product transportation, it is necessary to construct false bottoms in the roadways to separate the vertical sections formed during the tunneling process. Existing technologies generally employ the method of prefabricating false bottoms and then applying them to the roadways. However, this method is not universally applicable to situations where the top and bottom of two roadways intersect during tunneling, necessitating the on-site installation of false bottoms. It has significant limitations. Furthermore, when encountering such situations during tunneling, the working space is particularly confined and irregular. Installing prefabricated false bottoms is challenging when there is an empty roadway below them. Therefore, it is necessary to provide a method for constructing false bottoms in a flexible and convenient manner suitable for the actual working conditions, making it widely applicable to situations where the top and bottom of roadways intersect during tunneling. Summary of the Invention

[0004] This invention provides a method for on-site fabrication of a false bottom for mine roadways, aiming to solve the problem that existing false bottoms are unsuitable and difficult to install when the top and bottom of the roadway are connected during the tunneling process.

[0005] This invention relates to a method for on-site fabrication of a false floor in a mine roadway, comprising the following steps:

[0006] Step 1: Stop excavation at the top tunnel 8-15m away from the tunnel, and lay square timber to build a platform at the bottom tunnel where the tunnel is connected, so as to provide conditions for the continued excavation of the top tunnel;

[0007] Step 2: Continue excavating the top tunnel along the excavation direction at the breakthrough point;

[0008] Step 3: At the junction of the false bottom longitudinal track and the rock mass on both sides of the breakthrough point in the top tunnel, the bottoming height is the sum of the thickness of the false bottom track and the thickness of the top layer of concrete of the track.

[0009] Step 4: Clean up the slag in the tunnel where the top tunnel and the bottom tunnel meet, and then lay a false bottom. The false bottom consists of several layers of abandoned tracks laid in a crisscross pattern. The two ends of the abandoned tracks overlap with the rock mass. The upper and lower surfaces of the middle layer of abandoned tracks are covered with metal mesh, which is fixed to the middle layer of abandoned tracks. The uppermost layer of abandoned tracks is laid at a spacing of 200-300mm.

[0010] Step 5: Cover the top layer of abandoned rails with a flat plate covering the entire cross section, and weigh down the top of the flat plate with a heavy object. Remove the wooden platform from Step 1.

[0011] Step 6: Use a shotcrete machine to spray concrete from bottom to top at the junction of the top and bottom tunnels to create a false roof. After the concrete is fully sprayed without any dead corners, completely seal the gaps on both sides of the abandoned track and the false bottom.

[0012] Step 7: After the concrete in Step 6 has solidified, remove the slab and lay rubber pads and sleepers on top of the top layer of old track in order according to the position of the final running track.

[0013] Step 8: Construct the running track base plate on top of the uppermost layer of discarded tracks;

[0014] Step 9: After the base plate of the running track from Step 8 has completely solidified, lay the running track.

[0015] Preferably, the excavation distance of the top tunnel in step two is 3-6m.

[0016] Preferably, in step four, the overlap length between the two ends of the abandoned track and the rock mass is at least 1.5m.

[0017] Preferably, the metal mesh in step four is a galvanized metal mesh, and each galvanized metal mesh has at least two layers.

[0018] Preferably, in step six, the thickness of each sprayed concrete is ≤150mm, the interval between each spraying is at least 6 hours, and the total thickness of the sprayed concrete is ≥324mm.

[0019] Preferably, the sprayed concrete in step six is ​​a mixture of cement, sand and gravel in a volume ratio of 1:2:2.

[0020] Preferably, an accelerator is added when spraying concrete in step six, and the amount of accelerator added is 4%-6% of the weight of cement.

[0021] Preferably, in step eight, the running track base plate is made of a mixture of cement and mixed sand in a volume ratio of 1:3.

[0022] Preferably, in step eight, the height of the track base plate is greater than two-thirds of the sleeper height and less than the total height of the sleepers.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1. The on-site fabrication method for mine roadway false bottoms provided by this invention, compared with the traditional method of prefabricating and laying false bottoms in advance, solves the problems of narrow and irregular working space when the top and bottom of the roadway are connected during the tunneling process, and the false bottom is difficult to install due to the empty roadway below. This method can be tailored to the actual working conditions of the site to lay the false bottom of the roadway, which is flexible and convenient to operate.

[0025] 2. The on-site fabrication method for a false bottom in mine roadways provided by this invention uses a false bottom to separate the top and bottom roadways at the connection point. This not only ensures that the top roadway meets the production needs for transportation, coal hauling, and personnel movement, but also that the bottom roadway meets ventilation requirements. The production system is complete and reliable, significantly shortening the mining cycle and improving mining efficiency. The false bottom used is constructed with a track as its framework, combined with concrete, resulting in high strength and excellent sealing. Furthermore, metal mesh is laid above and below the intermediate track layer, providing support for the grout and preventing excessive grout thickness from causing it to fall. The metal mesh is made of galvanized metal, which is durable, resilient, and effectively extends the service life of the false bottom, ensuring safety and reliability.

[0026] 3. The on-site fabrication method for the false bottom of mine roadways provided by this invention lays rubber pads at the bottom of the sleepers, which greatly reduces the vibration caused by the transportation of materials by the top mine cars, making the mining process safer. Moreover, the materials used to make the false bottom of the roadway are mostly waste rails and waste rubber pads, which achieves the purpose of repairing and reusing waste, meets the national requirements for energy conservation and environmental protection, and has low production cost.

[0027] 4. The on-site construction method for the false bottom of mine roadways provided by the present invention uses a shotcrete machine to spray concrete from bottom to top, which can completely seal the gaps on both sides of the track and the false bottom to prevent air leakage. After the concrete is integrated with the roadway rock mass, the transportation process is safer. Moreover, spraying concrete in stages can prevent the uncured grout from falling off, making it safe, reliable and highly practical. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the false bottom structure of the mine roadway according to the present invention;

[0029] Figure 2 This is a schematic diagram of the installation of a false bottom in a mine roadway according to the present invention;

[0030] In the diagram: 1-Top tunnel; 2-False bottom; 3-Scrap track; 4-Metal mesh; 5-Rubber pad; 6-Concrete; 7-Bottom tunnel; 8-Running track base plate. Detailed Implementation

[0031] The present invention will be further described below with reference to embodiments:

[0032] Example 1

[0033] This invention relates to a method for fabricating a false floor in the rock section of an intake airway in a coal mine, comprising the following steps:

[0034] Step 1: Stop excavation at the top tunnel 1, 15m away from the tunnel, and lay square timber to build a platform at the bottom tunnel 7 where the tunnel is connected, forming a tight space to ensure that the platform is stable and reliable, so as to provide conditions for the continued excavation of the top tunnel 1.

[0035] Step 2: Continue excavating the top tunnel 1 for 6m along the excavation direction from the breakthrough position;

[0036] Step 3: At the overlap position of the false bottom 2 in the top tunnel 1, start the bottom with a thickness of 424mm according to the total thickness of the false bottom;

[0037] Step 4: Clean up the accumulated debris at the junction of the top tunnel 1 and the bottom tunnel 7, and then lay a false bottom 2. The false bottom 2 consists of three layers of abandoned tracks 3 laid in a crisscross pattern. Each layer includes three abandoned tracks 3 with a mass of 24 kg / m. The overlap length between the two ends of the abandoned tracks 3 and the rock mass is 1.5 m. The bottom layer of abandoned tracks 3 is laid along the tunnel excavation direction (longitudinal). After placing one track in the middle, one track is placed on each side 300 mm away from the tunnel wall. The middle layer of abandoned tracks 3 is laid transversely. After placing one track in the middle, one track is placed on each side 500 mm away from the ends of the bottom layer of abandoned tracks 3. The top layer of abandoned tracks 3 is laid longitudinally with a spacing of 200 mm. Metal mesh 4 is laid on the upper surface and the lower surface of the middle layer of abandoned tracks 3. The metal mesh 4 is a 35×35 mm double-layer diamond-shaped galvanized metal mesh. The metal mesh 4 is firmly tied to the abandoned tracks 3 with iron wire.

[0038] Step 5: Cover the top layer of waste track 3 with a flat plate covering the entire cross section, and weigh down the top of the flat plate with a heavy object.

[0039] Step Six: At the junction of the top tunnel 1 and the bottom tunnel 7, use a shotcrete machine to spray concrete 6 in three stages from bottom to top to create a false roof. The thickness of each spray of concrete 6 is 150mm, and the interval between each spray is 6 hours. The total thickness of concrete 6 is 450mm. After the concrete 6 is fully sprayed without any dead corners, completely seal the gaps on both sides of the abandoned track 3 and the false bottom 2. Concrete 6 is a mixture of cement, sand and gravel in a volume ratio of 1:2:2. The cement used in concrete 6 is 42.5 grade ordinary Portland cement. When spraying concrete, an accelerator is added. The accelerator used is CHS-1 type accelerator, and the amount of accelerator added is 6% of the weight of cement added.

[0040] Step 7: After the concrete 6 in Step 6 has solidified, remove the slab and lay the rubber pads 5 and sleepers on the top of the uppermost waste track 3 in sequence according to the position of the final running track.

[0041] Step 8: Construct a 100mm thick running track base plate 8 on top of the uppermost waste track 3. The height of the running track base plate 8 is equal to two-thirds of the height of the sleeper, and the strength is C20. The running track base plate 8 is a mixture of cement and mixed sand with a volume ratio of 1:3. The cement used is 42.5 grade ordinary Portland cement.

[0042] Step 9: Wait 72 hours until the base plate 8 of the running track from Step 8 has completely solidified before laying the running track.

[0043] Example 2

[0044] This invention relates to a method for fabricating a false floor in the rock section of an intake airway in a coal mine, comprising the following steps:

[0045] Step 1: Stop excavation at the top tunnel 1, 12m away from the tunnel, and lay square timber to build a platform at the bottom tunnel 7 where the tunnel is connected, forming a tight space to ensure that the platform is stable and reliable, so as to provide conditions for the continued excavation of the top tunnel 1.

[0046] Step 2: Continue excavating the top tunnel 1 for 5m along the excavation direction from the breakthrough position;

[0047] Step 3: At the overlap position of the false bottom 2 in the top tunnel 1, start the bottom 450mm according to the total thickness of the false bottom;

[0048] Step 4: Clean up the accumulated debris at the junction of the top tunnel 1 and the bottom tunnel 7, and then lay a false bottom 2. The false bottom 2 consists of three layers of abandoned tracks 3 laid in a crisscross pattern. Each layer consists of three abandoned tracks 3 with a mass of 24 kg / m. The overlap length between the two ends of the abandoned tracks 3 and the rock mass is 1.8 m. The bottom layer of abandoned tracks 3 is laid along the tunnel excavation direction (longitudinal). After placing one track in the middle, one track is placed on each side 200 mm away from the tunnel wall. The middle layer of abandoned tracks 3 is laid transversely. After placing one track in the middle, one track is placed on each side 500 mm away from the ends of the bottom layer of abandoned tracks 3. The top layer of abandoned tracks 3 is laid longitudinally with a spacing of 230 mm. Metal mesh 4 is laid on the upper surface and the lower surface of the middle layer of abandoned tracks 3. The metal mesh 4 is a 35×35 mm double-layer diamond-shaped galvanized metal mesh. The metal mesh 4 is locked to the abandoned tracks 3 with anchor bolts.

[0049] Step 5: Cover the top layer of waste track 3 with a flat plate covering the entire cross section, and weigh down the top of the flat plate with a heavy object.

[0050] Step Six: At the junction of the top tunnel 1 and the bottom tunnel 7, use a shotcrete machine to spray concrete 6 in three stages from bottom to top to create a false roof. The thickness of each sprayed concrete 6 is 120mm, with an interval of 6 hours between each spraying. The total thickness of the concrete 6 is 360mm. After the concrete 6 is fully sprayed without any blind spots, completely seal the gaps on both sides of the abandoned track 3 and the false bottom 2. The shotcrete 6 is a mixture of cement, sand, and gravel in a volume ratio of 1:2:2. The cement used in the concrete 6 is 42.5 grade ordinary Portland cement. An accelerator is added during the shotcrete spraying. The accelerator used is CHS-1 type accelerator, and the amount of accelerator added is 4% of the weight of the cement added.

[0051] Step 7: After the concrete 6 in Step 6 has solidified, remove the slab and lay the rubber pads 5 and sleepers on the top of the uppermost waste track 3 in sequence according to the position of the final running track.

[0052] Step 8: Construct a 100mm thick running track base plate 8 on top of the uppermost waste track 3. The height of the running track base plate 8 is equal to two-thirds of the height of the sleeper, and the strength is C20. The running track base plate 8 is a mixture of cement and mixed sand with a volume ratio of 1:3. The cement used is 42.5 grade ordinary Portland cement.

[0053] Step 9: Wait 72 hours until the base plate 8 of the running track from Step 8 has completely solidified before laying the running track.

[0054] Example 3

[0055] This invention relates to a method for fabricating a false floor in the rock section of an intake airway in a coal mine, comprising the following steps:

[0056] Step 1: Stop excavation at the top tunnel 1, 8m away from the through tunnel, and lay square timber to build a platform at the bottom tunnel 7 where the tunnel is connected, forming a tight space to ensure that the platform is stable and reliable, providing conditions for the continued excavation of the top tunnel 1.

[0057] Step 2: Continue excavating the top tunnel 1 for 4m along the excavation direction from the breakthrough position;

[0058] Step 3: At the overlap position of the false bottom 2 in the top tunnel 1, start the bottom 440mm according to the total thickness of the false bottom;

[0059] Step 4: Clean up the accumulated debris at the junction of the top tunnel 1 and the bottom tunnel 7, and then lay a false bottom 2. The false bottom 2 consists of three layers of abandoned tracks 3 laid in a crisscross pattern. Each layer consists of three abandoned tracks 3 with a mass of 24 kg / m. The overlap length between the two ends of the abandoned tracks 3 and the rock mass is 1.6 m. The bottom layer of abandoned tracks 3 is laid along the tunnel excavation direction (longitudinal). After placing one track in the middle, one track is placed on each side 200 mm away from the tunnel wall. The middle layer of abandoned tracks 3 is laid transversely. After placing one track in the middle, one track is placed on each side 500 mm away from the ends of the bottom layer of abandoned tracks 3. The top layer of abandoned tracks 3 is laid longitudinally with a spacing of 200 mm. Metal mesh 4 is laid on the upper surface and the lower surface of the middle layer of abandoned tracks 3. The metal mesh 4 is a 35×35 mm double-layer diamond-shaped galvanized metal mesh. The metal mesh 4 is firmly tied to the abandoned tracks 3 with iron wire.

[0060] Step 5: Cover the top layer of waste track 3 with a flat plate covering the entire cross section, and weigh down the top of the flat plate with a heavy object.

[0061] Step Six: At the junction of the top tunnel 1 and the bottom tunnel 7, use a shotcrete machine to spray concrete 6 in three stages from bottom to top to create a false roof. Each spray of concrete 6 is 100mm thick, with a 6-hour interval between each spray. The total thickness of concrete 6 is 300mm. After the concrete 6 is fully sprayed without any blind spots, completely seal the gaps on both sides of the abandoned track 3 and the false bottom 2. Concrete 6 is a mixture of cement, sand, and gravel in a volume ratio of 1:2:2. The cement used in concrete 6 is 42.5 grade ordinary Portland cement. An accelerator is added during the spraying of concrete. The accelerator used is CHS-1 type accelerator, and the amount of accelerator added is 4% of the weight of cement added.

[0062] Step 7: After the concrete 6 in Step 6 has solidified, remove the slab and lay the rubber pads 5 and sleepers on the top of the uppermost waste track 3 in sequence according to the position of the final running track.

[0063] Step 8: Construct a 100mm thick running track base plate 8 on top of the uppermost waste track 3. The height of the running track base plate 8 is equal to two-thirds of the height of the sleeper, and the strength is C20. The running track base plate 8 is a mixture of cement and mixed sand with a volume ratio of 1:3. The cement used is 42.5 grade ordinary Portland cement.

[0064] Step 9: Wait 72 hours until the base plate 8 of the running track from Step 8 has completely solidified before laying the running track.

[0065] After the completion of the project shown in the above embodiments, it was jointly inspected and accepted by various production departments, and put into use after passing the inspection. During the mining period, no false bottom fractures or slurry spalling occurred, and no harmful gases such as methane were released, meeting the safety production standards.

Claims

1. A method for on-site fabrication of a false floor for a mine roadway, characterized in that, Includes the following steps: Step 1: Stop excavation at the top tunnel (1) 8-15m away from the tunnel, and lay square timber to build a platform at the bottom tunnel (7) at the breakthrough point to provide conditions for the continued excavation of the top tunnel (1); Step 2: Continue excavating the top tunnel (1) along the excavation direction at the breakthrough position; Step 3: At the junction of the false bottom longitudinal track and the rock mass on both sides of the connection point in the top tunnel (1), the bottoming height is the sum of the thickness of the false bottom track (2) and the thickness of the top layer of concrete. Step 4: Clean up the slag in the tunnel where the top tunnel (1) and the bottom tunnel (7) meet, and then lay a false bottom (2); the false bottom (2) includes several layers of abandoned tracks (3) laid in a crisscross pattern. The two ends of the abandoned tracks (3) are connected to the rock mass. The upper surface and the bottom surface of the middle layer of abandoned tracks (3) are covered with metal mesh (4). The metal mesh (4) is fixed to the middle layer of abandoned tracks (3). The uppermost layer of abandoned tracks (3) is laid at a spacing of 200-300mm. Step 5: Fully cover the top layer of waste track (3) with a flat plate, and weigh down the top of the flat plate with heavy objects. Remove the wooden platform from Step 1. Step 6: At the junction of the top tunnel (1) and the bottom tunnel (7), use a shotcrete machine to spray concrete (6) from bottom to top in several stages to create a false roof. After the concrete (6) is fully sprayed without any dead angles, completely seal the gaps on both sides of the abandoned track (3) and the false bottom (2). Step 7: After the concrete (6) in Step 6 has solidified, remove the slab and lay rubber pads (5) and sleepers on the top of the uppermost waste track (3) in sequence according to the position of the final running track. Step 8: Construct the running track base plate (8) on top of the uppermost waste track (3); Step 9: After the base plate (8) of the running track in Step 8 has completely solidified, lay the running track.

2. The method for on-site fabrication of a false floor in a mine roadway as described in claim 1, characterized in that: In step two, the excavation distance of the top tunnel (1) is 3-6m.

3. The method for on-site fabrication of a false floor in a mine roadway as described in claim 1, characterized in that: In step four, the overlap length between the two ends of the abandoned track (3) and the rock mass should be at least 1.5m.

4. The method for on-site fabrication of a false floor in a mine roadway as described in claim 1, characterized in that: In step four, the metal mesh (4) is a galvanized metal mesh, and each galvanized metal mesh has at least two layers.

5. The method for on-site fabrication of a false floor in a mine roadway as described in claim 1, characterized in that: In step six, the thickness of each sprayed concrete (6) is ≤150mm, the interval between each spraying is at least 6 hours, and the total thickness of the sprayed concrete (6) is ≥324mm.

6. The method for on-site fabrication of a false floor in a mine roadway as described in claim 5, characterized in that: In step six, the sprayed concrete (6) is a mixture of cement, sand and gravel in a volume ratio of 1:2:

2.

7. The method for on-site fabrication of a false floor in a mine roadway as described in claim 6, characterized in that: In step six, when spraying concrete (6), an accelerator is added. The amount of accelerator added is 4%-6% of the weight of cement.

8. The method for on-site fabrication of a false floor in a mine roadway as described in claim 1, characterized in that: In step eight, the running track base plate (8) is made of a mixture of cement and mixed sand in a volume ratio of 1:

3.

9. A method for on-site fabrication of a false floor in a mine roadway as described in claim 1, characterized in that: In step eight, the height of the running track base plate (8) is greater than two-thirds of the height of the sleeper and less than the total height of the sleeper.

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