Construction technology of medium air pressure slag discharge under geological conditions of ultra-large buried depth and high stress soft coal seam

Abstract

The present application relates to the technical field of tunnel construction, in particular to a medium-wind-pressure slag discharge construction process under the geological conditions of super-large buried depth and high stress soft coal seam, comprising the following steps: S1, establishing a slag discharge system, the slag discharge system comprising a medium-wind-pressure conveying system and a ground slag discharge system, the ground slag discharge system being communicated with a coal uncovering hole through a slag discharge channel, the slag discharge channel and the coal uncovering hole axis intersecting at an included angle, the included angle M satisfying 30°≤M<90°; S2, drilling construction; S3, installation of an extraction pipe; S4, regular extraction and checking of extraction concentration. The gas can be diluted by air pressure, the gas concentration is reduced, and the construction safety is ensured. Meanwhile, the slag is conveyed to the ground slag discharge system through the slag discharge channel which is separately established and intersects with the coal uncovering hole at an acute angle, the slag can smoothly enter the slag discharge channel along the drilling axis direction, the slag conveying distance between the drill pipe and the ground slag discharge system is extended, which is conducive to avoiding the situation of hole spouting caused by slag blockage at the hole position, the slag discharge efficiency is improved, and the hole spouting risk is reduced.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, specifically to a medium-pressure slag removal construction process under geological conditions of ultra-deep, high-stress soft coal seams. Background Technology

[0002] When encountering the risk of coal seam outburst during tunnel excavation, the outburst energy is usually released slowly under control by drilling boreholes in advance and using hydraulic or pneumatic slag removal methods to ensure the safety of tunnel construction.

[0003] The existing hydraulic slag removal method generally leaves a 5m rock pillar as a safety barrier. Drilling is carried out into the outburst coal seam. After coal is encountered, high-pressure water jets are used to impact the coal body, gradually forming several large-diameter holes. The hydraulic slag removal process will discharge a large amount of gas and a certain amount of coal, forming a certain safe zone for depressurization and gas discharge in the coal body, destroying the basic conditions for outbursts and playing an effective role in preventing outbursts. However, due to the water-swelling property of coal (rock) and the relative difficulty of slag removal in downward-angled holes, hydraulic slag removal is mostly used for horizontal and upward-angled hole construction in coal (rock) seams with a large strength coefficient.

[0004] The existing pneumatic slag removal method utilizes pressurized gas to be converted into extremely high-speed airflow within the center hole of the drill pipe. Drill cuttings and high-speed airflow form a gas-solid two-phase flow that is carried out of the borehole, thereby achieving the effect of slag removal. The released gas mixes with the compressed air, and only gas and solid two-phase flow occurs within the borehole, resulting in relatively less erosion and damage to the borehole wall and reducing the possibility of accidents such as stuck drill bits or drill bit seizing. However, the extremely high-speed airflow provided by the air pressure may cause drill cuttings and waste to be ejected from the borehole at high speed, creating safety hazards. Furthermore, the air cooling effect is relatively poor, and the thin sandstone layers contained in the formation have high hardness, resulting in a large consumption of drill bits.

[0005] A tunnel excavation encountered a risk of coal seam outburst. If coal seam exposure holes were drilled for gas outburst prevention, most of the holes would be downward angle holes. The coal seam compactness coefficient is <0.8, the coal seam thickness is less than 4m, and the burial depth is >100m. It belongs to an ultra-deep, high-stress soft coal seam with a low coal seam strength coefficient and relatively soft coal seam. The conventional application of existing hydraulic and pneumatic slag removal methods cannot directly meet the requirements, posing construction safety risks and affecting construction efficiency. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing hydraulic or pneumatic slag removal methods for ultra-deep, high-stress soft coal seams, which lead to construction safety risks and affect construction efficiency. This invention provides a medium-pressure slag removal construction process for ultra-deep, high-stress soft coal seams under geological conditions.

[0007] The construction process for medium-pressure slag removal under geological conditions of ultra-deep, high-stress soft coal seams includes the following steps: S1. Establish a slag removal system, which includes a medium-pressure conveying system and a ground slag removal system. The medium-pressure conveying system provides pressurized air to the coal uncovering hole in the downward angle state through the inner hole of the drill rod. The ground slag removal system is connected to the coal uncovering hole through a slag removal channel. The slag removal channel intersects the axis of the coal uncovering hole at an angle M, which satisfies 30°≤M<90°. S2. Drilling construction: The casing protection process is used to drill into the coal seam. During the drilling process, slag is discharged to the surface slag discharge system through the slag discharge channel. S3. Installation of extraction pipe: Insert the extraction pipe into the coal uncovering hole and seal the hole. S4. Regularly sample and check the sampling concentration.

[0008] Preferably, the pressurized air is provided by a blower with a rated pressure of 1.2 MPa. This can meet the requirements of conventional medium-pressure slag removal construction at 0.3-0.6 MPa, and can also meet the requirements of higher pressure air delivery at 0.6-1.2 MPa, ensuring that sufficient pressurized air is provided to achieve smooth output of drill cuttings and slag in the angled borehole.

[0009] Preferably, the coal exposure hole is drilled to a depth of at least 0.5m through the coal seam floor before being terminated. This ensures that the coal exposure hole penetrates the coal seam, enabling extraction over a wider area.

[0010] Preferably, the coal seam opening is equipped with a ventilation-water switching mechanism, which is connected to the medium-pressure air supply system and the water supply mechanism. This allows for adjustments to the ventilation, water supply, and exhaust states during the drilling process, adapting to different working conditions and ensuring construction safety.

[0011] Preferably, the coal seam opening is equipped with a dust collection mechanism and / or a water curtain mechanism to achieve dust removal inside the tunnel and ensure a safe construction environment inside the tunnel.

[0012] Preferably, the drill pipe is equipped with a monitoring mechanism, which is linked to the medium-pressure conveying system. The medium-pressure conveying system adjusts the wind direction and / or wind force based on the monitoring data from the monitoring mechanism. The monitoring mechanism includes a differential pressure sensor and / or a vibration sensor. This enables monitoring of the drilling process, ensuring timely detection of situations such as stuck drill bits, and preventing equipment damage.

[0013] Preferably, a first channel and a second channel are provided inside the drill rod. The first channel penetrates the bottom of the drill rod, and the second channel penetrates the side wall of the drill rod and faces the opening of the coal seam. The penetration position of the second channel on the drill rod is at least 0.5m higher than the penetration position of the first channel on the drill rod. This accelerates the output of drill cuttings, coal slag, etc., and improves construction efficiency.

[0014] Preferably, the ground slag removal system is equipped with a particle size detection mechanism to acquire particle size information. This mechanism is linked to the medium-pressure conveying system, which adjusts the wind direction and / or wind force based on the particle size information to match the wind force with the coal seam drilling process.

[0015] Preferably, the coal exposure hole passes through a fractured rock stratum section and a pulverized coal seam section, and the extraction pipe includes a cylindrical section corresponding to the fractured rock stratum section and a screen pipe section corresponding to the pulverized coal seam section, with the hole being sealed on the outer wall of the cylindrical section.

[0016] Preferably, the sealing construction includes end sealing at both ends of the cylindrical section using bagged polyurethane and grouting between the two end seals.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a medium-pressure slag removal construction process under geological conditions of ultra-deep, high-stress soft coal seams. For coal uncovering holes with downward angles, a medium-pressure conveying system is used to transport coal slag from the borehole to the surface slag removal system. During the slag removal process, gas can be diluted by air pressure to reduce gas concentration and ensure construction safety. 2. This invention provides a medium-pressure slag removal construction process under geological conditions of ultra-deep, high-stress soft coal seams. By establishing a separate slag removal channel that intersects the coal uncovering hole at an acute angle, the slag is transported to the surface slag removal system. The slag can smoothly enter the slag removal channel along the borehole axis, extending the slag transport distance between the drill rod and the surface slag removal system. This helps to avoid slag blockage and blowout at the borehole opening, thereby improving slag removal efficiency and reducing the risk of blowout. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the construction process for medium-pressure slag removal under the geological conditions of ultra-deep, high-stress soft coal seams in Example 1.

[0019] Figure 2 This is a schematic diagram of the slag discharge channel setup described in Example 1.

[0020] Figure 3 This is a schematic diagram of the drill pipe structure described in Example 1.

[0021] Figure 4 This is a schematic diagram of the drilling operation described in Example 1.

[0022] Figure 5 This is a schematic diagram of the extraction tube setup described in Example 1.

[0023] Marked in the image: 1-Coal exposure hole, 2-Drill rod, 21-First channel, 22-Second channel, 3-Slag discharge channel, 4-Medium air pressure conveying system, 5-Ground slag discharge system, 51-Particle size detection mechanism, 6-Extraction pipe, 61-Cylindrical section, 62-Screen pipe section, 7-Coal seam, 8-Air-water switching mechanism. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0025] Unless otherwise specified, the terms "upper," "lower," "left," "right," "center," "inner," and "outer," etc., used in the description of specific embodiments of the present invention to indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is usually placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, and for enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0026] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," "parallel," and "coaxial" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, parallel, or coaxial. Slight tilt or deviation is permissible, as long as it does not affect the normal function of the relevant component. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," not that the structure must be perfectly horizontal; a slight tilt is acceptable. "Coaxial" means that two components are arranged as coaxially as possible, allowing them to move coaxially or approximately coaxially when their relative positions change. Alternatively, it can be simplified to mean that the corresponding device / component / element, when arranged in "horizontal," "vertical," "suspended," "parallel," or "coaxial" directions, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2-1mm, preferably within 0.2-0.5mm. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the solution of the present invention.

[0027] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0028] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0029] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to connection methods commonly used in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0030] Example 1 like Figures 1-5 As shown, the construction process for medium-pressure slag removal under geological conditions of ultra-deep, high-stress soft coal seams includes the following steps: S1. Establish a slag removal system, which includes a medium-pressure conveying system 4 and a ground slag removal system 5. The medium-pressure conveying system 4 provides pressure air through the coal uncovering hole 1 in the downward angle state of the drill rod 2. The ground slag removal system 5 is connected to the coal uncovering hole 1 through the slag removal channel 3. The slag removal channel 3 intersects the axis of the coal uncovering hole 1 at an angle M, which satisfies 30°≤M<90°.

[0031] S1 is used for construction preparation before drilling to ensure the smooth progress of drilling.

[0032] In an optional embodiment, the slag discharge channel 3 is a transitional connecting section between the ground slag discharge system 5 and the coal uncovering hole 1, so as to guide the drill cuttings and coal slag from the drilling process in a directional manner through the slag discharge channel 3.

[0033] In an optional embodiment, the slag discharge channel 3 can be a circular tube structure, and the side of the slag discharge channel 3 near the drill rod 2 can be set in a funnel shape to achieve better collection and guidance of drill cuttings and coal slag.

[0034] In an optional implementation, the compressed air can be provided by a compressed air compressor with a rated pressure of 1.2 MPa. A compressed air compressor with a rated pressure of 1.2 MPa can provide compressed air with a maximum working pressure of 1.2 MPa, meeting the different air pressure requirements for slag removal, hole cleaning, and hole clearing during the drilling of coal seam 1.

[0035] In one or more embodiments, a dust collection mechanism and / or a water curtain mechanism are provided at the opening of the coal exposure hole 1. The dust collection mechanism and the water curtain mechanism can be set up independently of the coal exposure hole 1 and are used to reduce dust in the tunnel area where the coal exposure hole 1 is located to ensure a safe working environment.

[0036] In one or more embodiments, a ventilation-water switching mechanism 8 is provided at the opening of the coal seam 1, and the ventilation-water switching mechanism 8 is connected to the medium-pressure conveying system 4 and the water supply mechanism. The ventilation-water switching structure can realize the switching of the working state of each component during the drilling process.

[0037] In an optional embodiment, the air-water switching mechanism 8 can be a structural component used for switching the working state between the medium-pressure air delivery system 4 and the water delivery mechanism. When smoke or fire occurs in the borehole, the air supply can be stopped in time and water can be introduced to extinguish the fire in the borehole, ensuring construction safety. The air-water switching mechanism 8 can be a conventional mechanical structure with a passage switching function, such as a four-way valve or a four-way pipeline assembly.

[0038] In an optional embodiment, the air-water switching mechanism 8 can be a structural component for switching the working state of air supply inside the drill rod 2 and air supply inside the coal uncovering hole 1. When encountering blockage on the outer wall of the drill rod 2, air can be supplied to the space between the drill rod 2 and the coal uncovering hole 1 through the medium air pressure conveying system 4, and air can be discharged from the air-water switching mechanism 8 to a designated position to reverse the cleaning of the coal uncovering hole 1, so as to keep the slag discharge in the hole unobstructed.

[0039] In an optional implementation, the feng shui switching mechanism 8 can be a combination of pipe components and multiple valve structures, which can achieve the switching function by controlling the opening / closing state of different valves.

[0040] In one or more embodiments, a monitoring mechanism is provided inside the drill pipe 2. This monitoring mechanism is linked to the medium-pressure conveying system 4. The medium-pressure conveying system 4 adjusts the wind direction and / or wind force based on the monitoring data from the monitoring mechanism. The monitoring mechanism includes a differential pressure sensor and / or a vibration sensor. By installing a monitoring mechanism inside the drill pipe 2, data information during the drilling process can be acquired in real time. This allows operators to adjust their working status accordingly based on the data, ensuring the safety of coal seam drilling, reducing equipment damage rates, lowering construction costs, and improving construction efficiency.

[0041] In one or more embodiments, a first channel 21 and a second channel 22 are provided inside the drill rod 2. The first channel 21 penetrates the bottom of the drill rod 2, and the second channel 22 penetrates the side wall of the drill rod 2 and faces the orifice of the coal exposure hole 1. The penetration position of the second channel 22 on the drill rod 2 is at least 0.5m higher than the penetration position of the first channel 21 on the drill rod 2. By using a double-cavity drill rod 2 for the construction of the angled coal exposure hole 1, appropriate pressure air can be introduced from the bottom of the hole through the first channel 21 to blow up and output the drill cuttings. The relatively lower pressure air introduced from the second channel 22 blows towards the orifice of the coal exposure hole 1, effectively guiding the drill cuttings, improving the drill cuttings output efficiency, and preventing coal slag backflow.

[0042] In one or more embodiments, the ground slag removal system 5 is equipped with a particle size detection mechanism 51. The particle size detection mechanism 51 is used to acquire particle size information. The particle size detection mechanism 51 is linked with the medium-pressure conveying system 4, and the medium-pressure conveying system 4 adjusts the wind direction and / or wind force according to the particle size information. The particle size detection mechanism 51 is used to detect the particle size of the drill cuttings and slag output from the slag removal channel 3, judge the drilling status by the particle size, and adjust the equipment working status in a timely manner to ensure safe drilling and improve construction efficiency.

[0043] In an optional embodiment, the ground slag removal system 5 can be a combination structure of box-type components and pipelines for conventional collection and treatment of drill cuttings, coal slag, etc., such as dust removal and conveying. The particle size detection mechanism 51 can be a multi-stage screen assembly installed in the ground slag removal system 5.

[0044] S2. Drilling construction: A casing-protected borehole is used to drill into the coal seam 7. During the drilling process, slag is discharged to the surface slag discharge system 5 through the slag discharge channel 3 to form the coal seam exposure hole 1.

[0045] In an optional embodiment, the coal seam 1 is drilled to its final position after penetrating at least 0.5m through the bottom plate of the coal seam 7.

[0046] In an optional implementation, the casing protection process involves withdrawing the drill bit midway through drilling, enlarging the hole to the bottom using a reaming drill bit, withdrawing the drill bit again, and then lowering a steel casing into the hole. The casing diameter is slightly smaller than the borehole diameter, and the casing is connected by a spiral thread. The casing is then pushed to the bottom of the hole by the power of the drilling rig to ensure smooth slag removal in the section corresponding to the coal exposure hole 1. Then, a smaller drill bit is used to continue drilling. If drilling becomes difficult again, the drill bit is withdrawn, and a casing of the corresponding size is lowered into the hole for protection. This process is repeated until coal is encountered.

[0047] In an optional implementation, taking into account the difficulty of drilling the coal exposure hole 1 in one go in this embodiment, a two-stage casing protection process can be adopted. The first-stage hole diameter is 133mm, the first-stage casing outer diameter is 120mm, the second-stage hole diameter is 108mm, and the second-stage casing outer diameter is 100mm.

[0048] S3. Installation of extraction pipe 6: Insert extraction pipe 6 into coal exposure hole 1 and seal the hole. This completes the installation of extraction pipe 6.

[0049] In an optional embodiment, the coal exposure hole 1 passes through a fractured rock stratum section and a pulverized coal seam section 7. The extraction pipe 6 includes a cylindrical section 61 corresponding to the fractured rock stratum section and a screen pipe section 62 corresponding to the pulverized coal seam section 7. The outer wall of the cylindrical section 61 is sealed, so that except for the part corresponding to the coal seam 7 which is the screen pipe section 62, the other parts of the extraction pipe 6 are sealed and connected to the coal exposure hole 1, thereby sealing the coal exposure hole 1, preventing gas from leaking from the outer wall of the extraction pipe 6, and ensuring smooth gas extraction.

[0050] In an optional embodiment, the sealing construction includes end sealing of the two ends of the cylindrical section 61 by bagged polyurethane and grouting between the two end seals.

[0051] S4. Regularly extract and check the extraction concentration to ensure the safety of the gas extraction process.

[0052] In an optional implementation, extraction can be carried out 24 hours after borehole sealing, and the first extraction concentration test should be completed within two days. Thereafter, the borehole extraction concentration should be tested at least once a month to form a borehole extraction pipe management log. When the borehole extraction concentration is found to be below 30%, the airtightness of the borehole and extraction pipe 6 should be checked. If there is an airtightness problem, remedial measures should be taken. For example, if the low extraction concentration is caused by the borehole not being sealed tightly, secondary sealing or hole filling measures should be taken to avoid extraction blind spots. The extraction concentration, extraction pressure difference and other parameters of the main pipeline should be tested at least once a week and compared with the monitored extraction parameters. If the error exceeds 5%, the cause should be investigated and dealt with in a timely manner to ensure that the extraction data is true and valid.

[0053] This embodiment describes the medium-pressure slag removal construction technology under the geological conditions of ultra-deep, high-stress soft coal seam 7. Taking the medium-pressure slag removal construction of a down-angle borehole with a coal seam 7 compaction coefficient <0.8, a thickness less than 4m, and a hole depth >100m as an example, the drilling rig can be a ZDY-3200 or ZDY-4000 mining tunnel drilling rig with a borehole diameter of φ94mm and drill rod diameters of φ73mm and φ63mm. It is equipped with an MLGF16 / 7-90G type medium-pressure mobile air compressor to provide compressed air, with a motor power of 90kw and a rated air volume of 16m³. The drilling operation is carried out at a speed of 1.2 MPa and a rated pressure of 1.2 MPa using a casing protection process. During drilling, the gate valve at the water valve shaft of the drilling rig is opened, and compressed air with a pressure of about 1.2 MPa is introduced from the water valve shaft of the drilling rig through the inner hole of the drill rod 2 to the borehole, forming a high-speed airflow. The drill cuttings are mixed with the compressed air and blown towards the borehole opening. They are then transported through the slag discharge channel 3 to the surface slag discharge system 5 for processing. The drill cuttings are finally discharged through the surface slag discharge system 5. After the borehole reaches the designed depth or penetrates at least 0.5 m through the bottom plate of the coal seam 7, the drilling is completed, and then the extraction pipe is installed and the borehole is sealed.

[0054] In this embodiment, the medium-pressure slag removal construction technology under the geological conditions of ultra-deep, high-stress soft coal seams utilizes a medium-pressure conveying system 4 to transport coal slag from the borehole to the surface slag removal system 5 for the coal uncovering borehole 1 at a downward angle. During the slag removal process, the gas concentration can be reduced by diluting the gas with air pressure, ensuring construction safety. At the same time, a separate slag removal channel 3, which intersects the coal uncovering borehole 1 at an acute angle, is established to transport the coal slag to the surface slag removal system 5. The coal slag can smoothly enter the slag removal channel 3 along the borehole axis, extending the coal slag transport distance between the drill rod 2 and the surface slag removal system 5. This helps to avoid the situation of coal slag blockage and blowout at the borehole opening, improves slag removal efficiency, reduces the risk of blowout, prevents waste slag and drill cuttings from flying out and injuring people, and improves construction safety.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A construction technique for medium-pressure slag removal under geological conditions of ultra-deep, high-stress soft coal seams, characterized in that... Includes the following steps: S1. Establish a slag removal system, which includes a medium-pressure conveying system (4) and a ground slag removal system (5). The medium-pressure conveying system (4) provides pressure air to the coal uncovering hole (1) in a downward angle state through the inner hole of the drill rod (2). The ground slag removal system (5) is connected to the coal uncovering hole (1) through a slag removal channel (3). The slag removal channel (3) intersects the axis of the coal uncovering hole (1) at an angle M, which satisfies 30°≤M<90°. S2. Drilling construction: The casing protection process is used to drill into the coal seam (7). During the drilling process, the slag is discharged to the surface slag discharge system (5) through the slag discharge channel (3). S3. Installation of extraction pipe (6): Insert extraction pipe (6) into the coal exposure hole (1) and seal the hole. S4. Regularly sample and check the sampling concentration; The pressurized air is supplied by an air compressor with a rated pressure of 1.2 MPa; The coal uncovering hole (1) is equipped with a ventilation-water switching mechanism (8), which is connected to the medium-pressure conveying system (4) and the water supply mechanism. The drill pipe (2) is equipped with a monitoring mechanism, which is linked to the medium wind pressure transmission system (4). The medium wind pressure transmission system (4) adjusts the wind direction and / or wind force according to the monitoring data of the monitoring mechanism. The monitoring mechanism includes a differential pressure sensor and / or a vibration sensor. The drill rod (2) is provided with a first channel (21) and a second channel (22). The first channel (21) penetrates the bottom of the drill rod (2), and the second channel (22) penetrates the side wall of the drill rod (2) and faces the opening of the coal exposure hole (1). The penetration position of the second channel (22) on the drill rod (2) is at least 0.5m higher than the penetration position of the first channel (21) on the drill rod (2). The ground slag discharge system (5) is equipped with a particle size detection mechanism (51), which is used to obtain particle size information. The particle size detection mechanism (51) is linked with the medium wind pressure conveying system (4), and the medium wind pressure conveying system (4) adjusts the wind direction and / or wind force according to the particle size information.

2. The construction technology for medium-pressure slag removal under geological conditions of ultra-deep, high-stress soft coal seams according to claim 1, characterized in that, The coal exposure hole (1) is drilled to its final position after penetrating at least 0.5m through the bottom plate of the coal seam (7).

3. The construction technology for medium-pressure slag removal under geological conditions of ultra-deep, high-stress soft coal seams according to claim 2, is characterized in that... The coal uncovering hole (1) is equipped with a dust collection mechanism and / or a water curtain mechanism.

4. The construction technology for medium-pressure slag removal under geological conditions of ultra-deep, high-stress soft coal seams according to claim 1, characterized in that, The coal exposure hole (1) passes through the fractured rock strata section and the powdery coal seam (7) section. The extraction pipe (6) includes a cylindrical section (61) corresponding to the fractured rock strata section and a screen pipe section (62) corresponding to the powdery coal seam (7) section. The sealing construction is carried out on the outer wall of the cylindrical section (61).

5. The construction technology for medium-pressure slag removal under geological conditions of ultra-deep, high-stress soft coal seams according to claim 4, characterized in that, The sealing construction includes end sealing with bagged polyurethane on both sides of the cylindrical section (61) and grouting between the two end seals.

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