Method for sealing surrounding rock of large-mine-pressure extremely-easily-weathered broken roadway

Abstract

The invention discloses a large-mine-pressure extremely-easily-weathered broken roadway surrounding rock sealing method which comprises the following steps that S1, anchor rods and anchor cables are installed in a roadway, and an anchor net is laid; s2, preparing and spraying roadway surrounding rock; and S3, a polyurethane material for coal mine air blocking is sprayed to replace sprayed concrete to seal roadway surrounding rock, and the spraying thickness is not smaller than 50 mm. The surrounding rock can be closed in time after the coal mine tunnel is constructed, the surrounding rock of the tunnel is prevented from being weathered and broken, and reliability and effectiveness of overall supporting of the tunnel are guaranteed; the spraying layer can generate plastic deformation along with the deformation of the surrounding rock of the roadway under the action of large mine pressure, and does not crack and fall off; compared with the operation of spraying concrete to seal the surrounding rock of the roadway, the device can reduce the potential safety hazard of the top slope caused by cracking and falling of the roadway spraying layer, can greatly reduce the labor intensity, does not generate dust and toxic and harmful gas, purifies the operation environment, and can greatly reduce the occurrence probability of coal mine occupational diseases.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel surrounding rock construction, and in particular relates to a method for sealing tunnel surrounding rocks that are easily weathered and broken due to heavy mining pressure. Background Art

[0002] For some coal mines with complex geological conditions, deep burial depth, high mine pressure, thin coal seams (less than 2.0m) and thick soft rock on the roof and floor, most of the development, preparation and mining tunnels can only be arranged in thick soft rock layers, such as mudstone layers. The main component of mudstone layers is clay, which will swell and deform rapidly when it encounters water. When the tunnel surrounding rock is exposed to the air for a long time, the clay absorbs enough water in the air, and the tunnel surrounding rock will swell, deform and break, which is commonly known as weathering. Therefore, after the construction of coal mine tunnels under such geological conditions, the surrounding rock must be closed in time, otherwise the tunnel surrounding rock will be exposed to the air for a long time, weathering and breaking will occur, causing the suspension beam formed by the anchor net support to fail, causing the overall failure of the tunnel support, forming a safety hazard in the tunnel roof, and also leading to a high tunnel repair rate and a large increase in maintenance costs.

[0003] In the prior art, although the use of traditional shotcrete to seal the tunnel surrounding rock also has an obvious sealing effect, the traditional shotcrete sealing operation has the disadvantages of high labor intensity, slow operation progress, and inability to adapt to the tunnel comprehensive excavation progress. Moreover, for coal mine tunnels with deep coal seams (500-750m) and high mine pressure, after the shotcrete is used to seal the tunnel surrounding rock, the tunnel surrounding rock will be severely deformed under the action of mine pressure. At the same time, the concrete spray layer is a rigid material. After the tunnel is deformed, the concrete spray layer attached to its surrounding rock will produce a large number of cracks and fall off, forming a new roof safety hazard, and the tunnel repair rate is also high. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a method for sealing the surrounding rock of the tunnel that is easily weathered and broken under large mining pressure. The method can realize the timely sealing of the surrounding rock of the coal mine tunnel after construction, prevent the weathering and breaking of the surrounding rock of the tunnel, and ensure the reliable and effective overall support of the tunnel; and the sprayed layer can produce plastic deformation as the surrounding rock of the tunnel is deformed under the action of mining pressure, and will not crack or fall off; compared with the operation of sealing the surrounding rock of the tunnel by spraying concrete, the method can reduce the safety hazard of the top wall caused by the cracking and falling of the sprayed layer of the tunnel, can greatly reduce the labor intensity, improve the work efficiency of excavation construction, do not generate dust and toxic and harmful gases, purify the working environment, and can greatly reduce the incidence of occupational diseases in coal mines.

[0005] The embodiments of the present invention are implemented by the following technical solutions:

[0006] A method for sealing surrounding rocks of a roadway with high pressure and extremely easy weathering and crushing, comprising the following steps:

[0007] S1, install anchor rods and anchor cables in the tunnel, and lay anchor nets;

[0008] S2, preparation and spraying of tunnel surrounding rock;

[0009] S3, spraying polyurethane material for coal mine wind blocking, the spraying layer thickness is not less than 50mm.

[0010] In one embodiment of the present invention, the step S2 of preparing the surrounding rock of the tunnel includes: arranging the equipment in the tunnel, flushing the surrounding rock on the top and side of the tunnel, and removing dangerous rocks and loose rocks.

[0011] In one embodiment of the present invention, the method of spraying the polyurethane material for coal mine wind blocking in step S3 is:

[0012] M1, complete the spraying preparation;

[0013] M2, start the machine for test spraying operation and adjust the mixing ratio of raw material A and raw material B;

[0014] M3: When the mixing ratio of raw material A and raw material B reaches the predetermined value, the formal spraying operation is carried out.

[0015] In one embodiment of the present invention, during the formal spraying operation, the coating is sprayed in a Z-shaped pattern from the tunnel vault to the two sides, and the coating is sprayed successively to a preset thickness according to a predetermined number of times.

[0016] The technical solution of the present invention has at least the following advantages and beneficial effects:

[0017] The present invention adopts anchor rods, anchor cables and anchor nets to support the tunnel, and then seals the tunnel surrounding rock by spraying a layer of polyurethane material for blocking wind in coal mines with a thickness of at least 50 mm. Compared with the traditional spraying and condensing operation, the present invention realizes the timely sealing of the surrounding rock of the coal mine tunnel after construction, and ensures the reliable and effective overall support of the tunnel; it can operate simultaneously with the tunnel excavation construction, and improves the construction progress of tunnel excavation under similar conditions in coal mines; it does not generate dust and toxic and harmful substances, improves the environmental sanitation of the workplace, and reduces the probability of occurrence of occupational diseases; the sprayed layer of polyurethane material for blocking wind in coal mines produces plastic deformation as the surrounding rock of the tunnel is deformed, does not crack and fall off, and reduces the safety hazard of the tunnel roof; it greatly reduces the labor intensity, improves the construction efficiency of the tunnels under similar geological conditions in coal mines, reduces a large number of maintenance projects, and saves a large amount of economic investment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 It is a schematic diagram of spraying a polyurethane material spray layer for blocking wind in a coal mine in the present invention, which is extremely easy to be weathered and broken in a large mine pressure tunnel, and sealing the surrounding rock;

[0020] Figure 2 This is the mine pressure observation curve of the tunnel with spraying thickness of 30mm and 50mm.

[0021] Icon: 1-anchor rod, 2-anchor cable, 3-polyurethane spray layer for wind blocking in coal mines. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0025] In the description of the present invention, it should be noted that if the terms "inside" and "outside" appear to indicate an orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings, or are the orientation or positional relationship in which the product of the invention is usually placed when used. This is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0026] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting", "installation", "configuration" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] Example

[0028] Please refer to Figure 1 This embodiment provides a method for sealing surrounding rocks of a roadway with high mine pressure and easy weathering and crushing, which comprises the following steps:

[0029] S1, install anchor rods 1 and anchor cables 2 in the tunnel, and lay anchor nets.

[0030] S2, prepare the surrounding rock of the tunnel, wash the surrounding rock on the top and side of the tunnel, remove the dangerous rock and loose rock, and make up for the unsuitable anchor rod 1 to ensure that the anchor rod 1 and the anchor net support are reliable and effective.

[0031] S3, spraying polyurethane material for coal mine wind blocking, the specific operation method is:

[0032] M1, complete the spraying preparation work, that is, before spraying, first protect the pipes, cables, belt conveyors and other equipment in the tunnel to prevent the spraying materials from being sprayed onto their upper surfaces and affecting the standardization of coal mine safety production, and set thickness marks on the rock surface of the tunnel so that operators can master the spraying thickness standards during spraying; apply the spraying equipment and spraying raw materials to the spraying position, connect the compressed air pipeline to the spraying equipment, and put the suction pipe into the material barrels of raw materials A and raw material B to prepare for spraying. When taking the spraying raw materials, check whether the materials are expired, open the barrel cover to observe whether the color and viscosity of the liquid material are normal and effective, and do not use expired and invalid materials; it should be noted that the coal mine air blocking polyurethane material used in this embodiment is the PT PU (F) type coal mine spraying air blocking polyurethane material commonly used in coal mines for spraying underground closed walls. Those skilled in the art can also use other coal mine air blocking polyurethane materials that are mixed with raw materials A and raw materials B and can achieve the same effect and can be used in coal mines;

[0033] M2, start the machine for trial spraying. During the trial spraying process, spray at a low speed first, and adjust the mixing ratio of raw material A and raw material B to 1:1 by adjusting the pumping speed and suction ratio;

[0034] M3, after the mixing ratio of raw material A and raw material B reaches 1:1, the formal spraying operation is carried out, and the spraying is carried out in a Z-shaped sweep from the arch of the tunnel to the two sides. In order to prevent the spraying material from falling due to insufficient condensation, a thin layer of initial spraying is first carried out on the surrounding rock around the tunnel. The initial spraying thickness is based on the spraying layer not dripping, and it can be sprayed to the preset thickness after multiple times. The spraying thickness is not less than 50mm.

[0035] It should be noted that after the construction of coal mine tunnels, under the action of mine pressure, the tunnels will show deformation, bottom bulging, spalling, roof collapse, support damage and other mine pressure manifestations. For tunnels with small deformation, no bottom bulging, spalling, roof collapse, and light support damage, and long tunnel maintenance time, general support can meet the requirements, and basically no maintenance work is required, which is called small mine pressure; for tunnels with large deformation, serious bottom bulging, spalling, roof collapse, support damage, and short tunnel maintenance time, anchor cables, grouting and other reinforcement supports are required, the number of maintenance times is high, and the maintenance work volume is large, which is called large mine pressure. Generally, the greater the burial depth, the greater the mine pressure. The tunnel surrounding rock closure method of the present application is aimed at the surrounding rock closure of soft rock tunnels with large mine pressure and extremely easy weathering and crushing.

[0036] The present invention adopts anchor rod 1 anchor cable 2 + anchor net to support the tunnel, and then seals the tunnel surrounding rock by spraying a coal mine wind-blocking polyurethane material spray layer 3 with a thickness of at least 50 mm, fills the gap between the anchor net and the tunnel surrounding rock, so that the coal mine wind-blocking polyurethane material spray layer 3 and the anchor net form a whole, enhances the tensile strength and toughness of the coal mine wind-blocking polyurethane material spray layer 3, better prevents the coal mine wind-blocking polyurethane material spray layer 3 from being deformed and damaged due to mine pressure, can better isolate the surrounding rock from the air, and prevent the surrounding rock from weathering and breaking, thereby ensuring that the active support of the suspension beam formed by the anchor net and the rock is reliable and effective; the present application adopts PTPU (F) type coal mine spray-coated polyurethane material for wind-blocking to replace traditional shotcrete to seal the tunnel surrounding rock, and uses the PTPU (F) type coal mine spray-coated polyurethane material for wind-blocking that is commonly used in coal mines for spraying underground closed walls in the field of tunnel support, and spray-coated Compared with the traditional shotcrete operation, the tunnel surrounding rock can be sealed in time after the construction of the coal mine tunnel, which can greatly reduce the exposure time of the tunnel surrounding rock in the air, reduce the risk of mudstone weathering of the tunnel surrounding rock, and better ensure the reliability and effectiveness of the overall support of the tunnel; it can operate simultaneously with the tunnel excavation construction, and no longer stop the excavation for shotcrete operation, which improves the construction progress of tunnel excavation under similar conditions in coal mines; it does not produce dust and toxic and harmful substances, improves the environmental sanitation of the workplace, and reduces the incidence of occupational diseases; the sprayed coal mine wind blocking polyurethane material spray layer 3 is light in weight, and can produce plastic deformation with the deformation of the tunnel surrounding rock, without cracking and falling off, reducing the safety hazard of the tunnel roof; it greatly reduces the labor intensity, improves the construction efficiency of tunnels under similar conditions in coal mines, reduces a large number of maintenance projects, and saves a lot of economic investment costs.

[0037] In order to better illustrate the effective effect of spraying polyurethane materials for blocking wind in coal mines to seal the surrounding rock of the tunnel, the construction of spraying polyurethane materials for blocking wind in coal mines to seal the surrounding rock in the 1151 working face transportation tunnel of a coal mine is taken as an example. The 1151 working face transportation tunnel is a semi-coal rock tunnel with a large burial depth (500-750m) and high mine pressure. The thickness of the coal seam is 1.7m. Since the bottom plate of the coal seam is a layer of siltstone with a thickness of about 1m, it is difficult for the comprehensive excavator to cut. Therefore, the tunnel is excavated by breaking the coal seam roof to retain the bottom plate of the coal seam. The cross section of the tunnel is a straight wall semicircular arch. The main lithology of the top plate of the coal seam in the tunnel is mudstone, with clay minerals and quartz as the main components. The clay minerals contain a large amount of illite and illite-montmorillonite mixed minerals, have obvious hydrophilic disintegration characteristics, and have obvious expansion. It is a soft rock with a large burial depth, easy weathering, easy disintegration when encountering water, and obvious water absorption and expansion. After the construction of this type of soft rock tunnel, the tunnel surrounding rock deforms quickly and greatly under the action of mine pressure. In 7-10 days, the top and bottom plates move closer to each other by more than 150mm. The mudstone on the top plate is very easy to weather and break, so the surrounding rock must be closed in time. By comparing the anchor net tunnel support tunnel and the anchor net spraying tunnel support tunnel, it is found that the anchor net spraying tunnel has sprayed concrete to seal the surrounding rock, so the top rock of the tunnel will not be weathered and broken, and the deformation and damage of the tunnel are significantly lower than those of the anchor net support tunnel. However, under the action of mine pressure, as the top, bottom and two sides of the tunnel move closer to each other, the concrete spraying layer also cracks and falls off over a large area. At the same time, because the sprayed concrete produces more rebound objects and a large amount of dust, the material consumption is large and the transportation line is long. The labor intensity of the sprayed concrete operation is high, and there are many workers, no less than 6 people per shift, and the material consumption is large, there are many links and a large amount of compressed air consumption. The excavation face cannot be operated at the same time. In order to close the surrounding rock of the tunnel in time, one shift must be stopped every day for shotcrete operation, which reduces the excavation operation time and greatly reduces the progress of tunnel excavation. The tunnel with anchor net + anchor cable + shotcrete closed support has a monthly comprehensive excavation construction progress of no more than 100m / month.

[0038] In order to ensure that the surrounding rock of the coal mine tunnel can be closed in time after construction, and to ensure the reliability and effectiveness of the overall support of the tunnel. In the 30-50m section of the 1151 transport tunnel, a test of spraying polyurethane materials for coal mine wind blocking was carried out. The spraying only required 2 people to operate, and one shift completed the spraying of the 20-meter tunnel in 8 hours. After a month of continuous observation, the surrounding rock of the tunnel did not weather and break, and played a sealing role. Although the top and bottom walls of the tunnel also deformed under the action of mine pressure, the top and bottom and the two sides moved closer by 120-300mm, and the steel mesh also showed bending deformation, but there was no crack in the spray layer, and the top rock did not weather and break. After that, during the construction of the 1151 working face transport tunnel and the 1151 working face wind tunnel, the whole length of the experiment was sprayed with polyurethane materials for coal mine wind blocking to close the tunnel surrounding rock, and the tunnel support technical parameters were observed and collected for 6 months. After the tunnel was sprayed with polyurethane materials for coal mine wind blocking, its effects were shown in the following aspects: First, under the action of mine pressure, the sprayed layer of polyurethane materials for coal mine wind blocking can produce a certain amount of plastic deformation, but there is no cracking or shedding of the sprayed layer; second, the spraying operation and tunnel comprehensive excavation construction were carried out simultaneously, and the tunnel excavation construction progress was increased from 100m / month to 140-170m / month; third, a large number of tunnel maintenance projects were reduced. Due to the large mine pressure in the tunnel and the serious bottom drum of the tunnel, the roof will still produce a lot of deformation, causing the track and belt conveyor to be skewed, and local maintenance is required to adjust the track and belt conveyor. However, there is basically no tunnel roof and two-side maintenance project, and the tunnel roof support is reliably and effectively guaranteed. Compared with the traditional shotcrete closed tunnel surrounding rock, the maintenance work volume has been halved, saving a lot of economic costs; fourthly, the environmental sanitation of the closed support tunnel surrounding rock operation has been greatly improved. No rebound or dust is generated during the spraying operation, and no toxic and harmful substances such as CO and ammonia are monitored. The working environment is clean and hygienic, without odor.

[0039] It should be noted that the present application uses a spray layer of polyurethane material for coal mine wind blocking instead of traditional shotcrete to close the tunnel surrounding rock, which greatly reduces labor intensity and improves work efficiency. When carrying out comprehensive excavation tunnel construction in tunnels with large mine pressure and extremely easy to weather and break soft rock, it is necessary to keep up with the progress of comprehensive excavation to spray the closed tunnel surrounding rock, which is generally about 5.6-7.2m. The amount of spraying material is calculated to be 280-360kg, and only 2 people are needed to complete it in 3 hours. For traditional shotcrete operations, it takes 8 hours to stop a shift and at least 6 workers to complete 3-5m.

[0040] The present application sprays the coal mine wind-blocking polyurethane material on the tunnel surrounding rock with a spray layer thickness of at least 50 mm, which can strictly isolate the contact between rock and air, effectively prevent the weathering and crushing of the soft rock tunnel surrounding rock that is easily weathered and crushed by large mine pressure, and ensure that the overall support of the tunnel is reliable and effective.

[0041] According to the analysis of tunnel mine pressure results, when the spraying thickness reaches 50mm, the sealing effect can meet the tunnel support requirements, such as Figure 2 As shown in the figure, Changneng Coal Mine of Yunnan Tianli Coal Chemical Co., Ltd. sprayed polyurethane materials for coal mine wind blocking in the 1151 working face transport lane to seal the surrounding rock. Two sections of lanes with spraying thickness of 30mm and 50mm were selected for testing, and the mine pressure was observed and the mine pressure observation curve was drawn. The mine pressure of the lane is expressed by the amount of deformation of the lane roof sinking. In the lane with a spraying thickness of 50mm, the sinking deformation of the lane roof is small, but there is no tearing of the spray layer and anchor net. It shows that after the spraying thickness is 50mm and the gap between the anchor net and the surrounding rock is fully filled, the spray layer can form a whole with the anchor net, which enhances the tensile strength and toughness of the spray layer. Under the action of mine pressure, the anchor net and the spray layer can be kept intact, which can better protect the surrounding rock of the lane from weathering and crushing, thereby better ensuring the overall support of the lane is effective.

[0042] When excavating soft tunnels with mine pressure and extremely easy weathering and crushing, the operation of spraying polyurethane materials for coal mine wind blocking can be coordinated with the tunnel comprehensive excavation process and operated at the same time. Improve the progress of comprehensive excavation and maximize the efficiency of comprehensive excavation. In addition, since the spraying of polyurethane materials for coal mine wind blocking requires less labor, less material, less compressed air, fewer links, simple machine operation, and fast operation speed, the operation process basically does not affect the various process operations such as cutting, support and transportation in tunnel comprehensive excavation construction.

[0043] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for sealing surrounding rocks of highly weathered and broken tunnels with high mine pressure, characterized by The following steps, S1, install anchor rods and anchor cables in the tunnel, and lay anchor nets; S2, preparation and spraying of tunnel surrounding rock; S3, spraying polyurethane material for coal mine wind blocking, the spraying thickness is not less than 50mm.

2. The method for sealing surrounding rocks of tunnels with high mining pressure and extremely easy weathering and breaking according to claim 1 is characterized in that: The step S2 of preparing and spraying the tunnel surrounding rock includes: arranging and protecting the equipment and pipelines in the tunnel, washing the dust of the tunnel top and wall surrounding rock, and removing dangerous rocks and loose stones.

3. The method for sealing surrounding rocks of a roadway with high mine pressure and easily weathered and broken according to claim 1 is characterized in that: The method of spraying the polyurethane material for coal mine air blocking in step S3 is: M1, complete the spraying preparation; M2, start the machine for test spraying operation and adjust the mixing ratio of raw material A and raw material B; M3: When the mixing ratio of raw material A and raw material B reaches the predetermined value, the formal spraying operation is carried out.

4. The method for sealing surrounding rocks of a roadway with high mine pressure and easily weathered and broken according to claim 3 is characterized in that: During the formal spraying operation, the spray is carried out in a Z-shaped sweep from the tunnel arch to the two sides, and the spray is applied successively to the preset thickness according to the predetermined number of times.

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