Construction process for medium-wind-pressure deslagging under geological condition of super-large-burial-depth high-stress soft coal seam

Abstract

The invention relates to the technical field of tunnel construction, in particular to a medium-air-pressure deslagging construction process under the geological condition of a super-large-burial-depth high-stress soft coal seam, which comprises the following steps: S1, establishing a deslagging system which comprises a medium-air-pressure conveying system and a ground deslagging system, and communicating the ground deslagging system with a coal uncovering hole through a deslagging channel, the slag discharging channel and the axis of the coal uncovering hole intersect at an included angle M, and the included angle M is larger than or equal to 30 degrees and smaller than 90 degrees; s2, drilling construction is conducted; s3, installation of an extraction pipe; and S4, regular extraction is conducted, and the extraction concentration is checked. Gas can be diluted through air pressure, gas concentration is reduced, construction safety is guaranteed, meanwhile, coal cinder is conveyed to a ground slag discharging system by independently building a slag discharging channel intersecting with a coal uncovering hole in an acute angle mode, the coal cinder can smoothly enter the slag discharging channel in the axis direction of a drill hole, the coal cinder conveying distance between a drill rod and the ground slag discharging system is prolonged, and construction efficiency is improved. The situation that coal cinder blocks the orifice and sprays the orifice is avoided, the deslagging efficiency can be improved, and the orifice spraying risk is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tunnel construction, in particular to a medium air pressure deslagging construction process under the geological conditions of super-large buried depth high stress soft coal seam. BACKGROUND

[0002] When a coal seam outburst risk is encountered in tunnel excavation, a drill hole is generally drilled in advance, and a hydraulic deslagging method or an air deslagging method is used to slowly release the coal seam outburst energy under controllable conditions to ensure tunnel construction safety.

[0003] The existing hydraulic deslagging method generally reserves a 5m rock pillar as a safety barrier, drills into the outburst coal seam, and uses high-pressure water jet to impact the coal body after coal is found to gradually form several larger diameter holes. The hydraulic deslagging process will discharge a large amount of gas and a certain amount of coal, forming a certain pressure relief and gas discharge safety area in the coal body, destroying the basic conditions for outburst occurrence, and effectively preventing outburst, but due to the swelling properties of coal (rock) when it comes into contact with water and the relative difficulty of deslagging in a downward angle hole, the hydraulic deslagging method is mostly used for flat hole and upward hole construction in coal (rock) layers with a large firmness coefficient.

[0004] The existing air deslagging method uses pressure gas to convert into extremely high-speed airflow in the drill rod central hole, and the drill cuttings and high-speed airflow form gas-solid two-phase flow and are carried out of the drill hole, thereby achieving the effect of deslagging. The released gas and compressed air are mixed, and only gas and solid two-phase flow exists in the hole, which has relatively small scouring and destructive effect on the hole wall, and the possibility of accidents such as drill pipe sticking and drill pipe grabbing is reduced. However, the extremely high-speed airflow provided by air pressure may cause drill cuttings and waste to be ejected at high speed from the drill hole, causing safety hazards, and the air cooling effect is relatively poor. The sandstone layer contained in the formation has a large hardness, and the drill bit consumption is large.

[0005] A certain tunnel excavation encountered a coal seam outburst risk. If a coal uncovering hole is drilled for gas outburst prevention treatment, most of the drill holes are downward angle holes, the coal seam tightness coefficient is <0.8, the coal seam thickness is less than 4m, and the buried depth is >100m, which belongs to super-large buried depth high stress soft coal seam. The coal seam has a small firmness coefficient and is relatively soft. The conventional application of the existing hydraulic deslagging method and air deslagging method cannot directly meet the requirements, and there is a construction safety risk, which affects the construction efficiency. SUMMARY

[0006] The present application aims to overcome the deficiencies in the prior art that the existing super-large buried depth high stress soft coal seam uses the existing hydraulic deslagging method or air deslagging method, which has deficiencies, resulting in construction safety risks and affecting construction efficiency, and provides a medium air pressure deslagging construction process under the geological conditions of super-large buried depth high stress soft coal seam.

[0007] The medium air pressure deslagging construction process under the geological conditions of super-large buried depth high stress soft coal seam comprises the following steps: S1, establish a residue discharge system, the residue discharge system includes a medium pressure conveying system and a ground residue discharge system, the medium pressure conveying system provides pressure wind to the coal uncovering hole in the pitch angle state through the inner hole of the drill rod, the ground residue discharge system is communicated with the coal uncovering hole through a residue discharge channel, the residue discharge channel intersects with the axis of the coal uncovering hole at an included angle, and the included angle M satisfies 30°≤M<90°. S2, drilling construction, drilling into the coal seam by using a casing hole protection process, and residue is discharged to the ground residue discharge system through the residue discharge channel during the drilling process; S3, installation of an extraction pipe, the extraction pipe is placed in the coal uncovering hole and hole sealing construction is performed; S4, regular extraction and inspection of extraction concentration.

[0008] Preferably, the pressure wind is provided by a pressure fan with a rated pressure of 1.2 MPa. It can meet the conventional 0.3-0.6 MPa medium pressure residue discharge construction, and can also meet the 0.6-1.2 MPa higher pressure wind pressure conveying, so as to ensure that the pressure wind with sufficient pressure is provided, and the smooth output of drill cuttings and coal residue in the pitch angle hole is realized.

[0009] Preferably, the coal uncovering hole is drilled to a final hole after penetrating the coal seam floor by at least 0.5 m. This can ensure that the coal uncovering hole penetrates the coal seam, and can extract a wider range of the coal seam.

[0010] Preferably, a wind-water switching mechanism is arranged at the coal uncovering hole, and the wind-water switching mechanism is connected with the medium pressure conveying system and a water feeding mechanism. This can realize the adjustment of the states of air feeding, water feeding, air extraction and the like during the drilling process, adapt to different working conditions, and ensure construction safety.

[0011] Preferably, a dust catching mechanism and / or a water curtain mechanism are arranged at the coal uncovering hole. This can realize dust removal in the tunnel, and ensure the safety of the construction environment in the tunnel.

[0012] Preferably, a monitoring mechanism is arranged in the drill rod, the monitoring mechanism is linked with the medium pressure conveying system, the medium pressure conveying system adjusts the wind direction and / or wind force according to the monitoring data of the monitoring mechanism, and the monitoring mechanism includes a differential pressure sensor and / or a vibration sensor. This can realize the monitoring of the drilling process, ensure that the sticking of the drill rod and the like is found in time, and avoid equipment damage.

[0013] Preferably, a first channel and a second channel are arranged in the drill rod, the first channel penetrates the bottom of the drill rod, the second channel penetrates the sidewall of the drill rod and is directed towards the hole opening direction of the coal uncovering hole, and the penetration position of the second channel on the drill rod is at least 0.5 m higher than the penetration position of the first channel on the drill rod. This can accelerate the output of drill cuttings, coal residue and the like, and improve construction efficiency.

[0014] Preferably, the ground residue discharging system is provided with a particle size detection mechanism for obtaining particle size information, the particle size detection mechanism is linked with the medium air pressure conveying system, and the medium air pressure conveying system adjusts the air direction and / or air pressure according to the particle size information. In this way, the air pressure can be matched with the coal uncovering drilling process.

[0015] Preferably, the coal uncovering hole passes through a broken rock layer section and a pulverous coal layer section, the extraction pipe comprises a cylindrical section arranged corresponding to the broken rock layer section and a screen pipe section arranged corresponding to the pulverous coal layer section, and hole sealing construction is performed on the outer wall of the cylindrical section.

[0016] Preferably, the hole sealing construction comprises end sealing by bagged polyurethane on the outer side of both ends of the cylindrical section and grouting sealing between the two end sealings.

[0017] Compared with the prior art, the present application has the following beneficial effects: 1. The present application provides a medium air pressure residue discharging construction process under the geological condition of super large buried depth and high stress soft coal seam, which is aimed at a downward angle hole coal uncovering hole. The coal residue is conveyed from the drilling hole to the ground residue discharging system by using a medium air pressure conveying system. In this way, the gas can be diluted by air pressure during the residue discharging process, the gas concentration is reduced, and the construction safety is ensured. 2. The present application provides a medium air pressure residue discharging construction process under the geological condition of super large buried depth and high stress soft coal seam. The coal residue is conveyed to the ground residue discharging system by separately establishing a residue discharging channel intersecting the coal uncovering hole at an acute angle. The coal residue can smoothly enter the residue discharging channel along the axis direction of the drilling hole, the coal residue conveying distance between the drilling rod and the ground residue discharging system is extended, which is beneficial to avoid the situation of hole spouting caused by coal residue blockage at the hole position, the residue discharging efficiency is improved, and the hole spouting risk is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a flowchart of the medium air pressure residue discharging construction process under the geological condition of super large buried depth and high stress soft coal seam of embodiment 1.

[0019] Figure 2 It is a schematic diagram of the setting of the residue discharging channel in embodiment 1.

[0020] Figure 3 It is a schematic diagram of the structure of the drilling rod in embodiment 1.

[0021] Figure 4 It is a schematic diagram of the drilling construction in embodiment 1.

[0022] Figure 5 It is a schematic diagram of the setting of the extraction pipe in embodiment 1.

[0023] Markings in the figure: 1 - uncovering hole, 2 - drill rod, 21 - first channel, 22 - second channel, 3 - slag discharge channel, 4 - medium-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 DESCRIPTION

[0024] The application will be further described below in connection with specific embodiments. However, it should not be understood that the scope of the above-mentioned subject matter of the application is limited to the following embodiments, and any technology achieved based on the content of the application falls within the scope of the application.

[0025] In the description of the specific embodiments of the application, the orientation or positional relationship terms such as "upper", "lower", "left", "right", "center", "inner", "outer" and the like are expressed based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product / equipment / device of the application is normally used. These orientation or positional relationship terms are only for the convenience of describing the application scheme or simplifying the description in the specific embodiments, for the convenience of the technical personnel to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation or be constructed and operated in a specific positional relationship, and therefore cannot be understood as a limitation on the application.

[0026] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel", "coaxial" and the like appear, it does not mean that the corresponding device / component / element must be absolutely horizontal or vertical or overhanging or parallel or coaxial, but can be slightly inclined or have a deviation, as long as it does not affect the normal function of the related component. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined; "coaxial" means that two components are arranged as coaxially as possible, and are moved in a coaxial or approximately coaxial manner when the relative position changes. Alternatively, it can be simplified to understand that the corresponding device / component / element is arranged in the "horizontal", "vertical", "overhanging", "parallel", "coaxial" direction, and can have an error / offset of ±10% relative to the corresponding direction, more preferably an error / offset of ±8% or less, more preferably an error / offset of ±6% or less, more preferably an error / offset of ±5% or less, and more preferably an error / offset of ±4% or less. 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 / offset range, it can still achieve its role in the application scheme.

[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 catching mechanism and / or a water curtain mechanism are arranged at the opening of the uncovering hole 1. The dust catching mechanism and the water curtain mechanism can be arranged independently of the uncovering hole 1 to carry out dust reduction in the tunnel area where the uncovering hole 1 is located, so as to ensure a safe construction working environment.

[0036] In one or more embodiments, a wind-water switching mechanism 8 is arranged at the opening of the uncovering hole 1, and the wind-water switching mechanism 8 is connected to the medium air pressure conveying system 4 and the water feeding mechanism. The wind-water switching mechanism can realize switching of the working state of each component during the drilling process.

[0037] In an optional embodiment, the wind-water switching mechanism 8 can be a structural assembly for switching the working state between the medium air pressure conveying system 4 and the water feeding mechanism. When encountering a fire situation with smoke in the drilling hole, the air feeding can be stopped in time, and water is introduced to extinguish the fire in the drilling hole, so as to ensure construction safety. The wind-water switching mechanism 8 can be a four-way valve or a four-way pipeline assembly, or other conventional mechanical structures with switching function.

[0038] In an optional embodiment, the wind-water switching mechanism 8 can be a structural assembly for switching the working state of air feeding in the drill rod 2 and air feeding in the uncovering hole 1. When encountering a blockage phenomenon on the outer wall of the drill rod 2, air can be fed to the space between the drill rod 2 and the uncovering hole 1 through the medium air pressure conveying system 4, and air is discharged from the wind-water switching mechanism 8 to the designated position, so as to reverse the hole washing of the uncovering hole 1, and keep the hole unobstructed.

[0039] In an optional embodiment, the wind-water switching mechanism 8 can be a combination structure of a pipeline component and multiple valve structures. By controlling the opening / closing state of different valves, the switching function can be realized.

[0040] In one or more embodiments, a monitoring mechanism is arranged in the drill rod 2, and the monitoring mechanism is linked with the medium air pressure conveying system 4. The medium air pressure conveying 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. By arranging the monitoring mechanism in the drill rod 2, data information during the drilling process can be obtained in real time, so that the working personnel can adjust the corresponding working state according to the data information, so as to ensure the safety of the uncovering drilling hole, and it is also beneficial to reduce the equipment damage rate, reduce the construction cost, and improve the construction efficiency.

[0041] In one or more embodiments, the first channel 21 is arranged through the bottom of the drill rod 2, and the second channel 22 is arranged through the sidewall of the drill rod 2 and towards the opening direction of the coal uncovering hole 1, and the through position of the second channel 22 on the drill rod 2 is at least 0.5 m higher than the through position of the first channel 21 on the drill rod 2. By using the double-cavity drill rod 2 to construct the coal uncovering hole 1 in the form of a downward angle, pressure wind with a suitable wind pressure can be introduced from the bottom of the hole through the first channel 21 to blow up and output the drill cuttings, and pressure wind with a relatively smaller pressure introduced from the second channel 22 is blown towards the opening side of the coal uncovering hole 1 to effectively guide the drill cuttings, improve the output efficiency of the drill cuttings, and prevent the backflow of coal residue.

[0042] In one or more embodiments, the ground residue discharge system 5 is provided with a particle size detection mechanism 51 for obtaining particle size information, and 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 power according to the particle size information. The particle size detection mechanism 51 is used to detect the particle size of the drill cuttings and coal residue output from the residue discharge channel 3, to determine the drilling state through the particle size, to timely adjust the working state of the equipment, to ensure safe drilling, and to improve the construction efficiency.

[0043] In an optional embodiment, the ground residue discharge system 5 can be a combined structure of a box-type assembly and a pipeline for dust removal, conveying, and other conventional collection and treatment of drill cuttings, coal residue, and the like, and the particle size detection mechanism 51 can be a multi-stage screen assembly arranged in the ground residue discharge system 5.

[0044] S2, drilling construction, the drill rod 2 is drilled into the coal seam 7 by using the casing hole protection technology, and the residue is discharged to the ground residue discharge system 5 through the residue discharge channel 3 during the drilling process to form the coal uncovering hole 1.

[0045] In an optional embodiment, the coal uncovering hole 1 is drilled to a depth of at least 0.5 m through the coal seam 7.

[0046] In an optional embodiment, the casing hole protection technology is that the drill rod is withdrawn during drilling, a reaming bit is used to ream to the bottom of the hole, the drill rod is withdrawn, a steel casing is lowered into the hole, the diameter of the casing is slightly smaller than the diameter of the hole, the casing is connected by a spiral thread, and is pushed to the bottom of the hole by the power of the drilling machine to ensure that the casing smoothly discharges the residue corresponding to the section of the coal uncovering hole 1, then a smaller drill bit is used to continue drilling, the drill rod is withdrawn again when drilling is difficult, a casing with a corresponding size is lowered into the hole again for hole protection, and so on until coal is found.

[0047] In an optional embodiment, in combination with the characteristics of the coal uncovering hole 1 of the present embodiment that it is difficult to drill a hole at one time, a two-stage casing hole protection technology can be used, the first hole diameter is 133 mm, the outer diameter of the first casing is 120 mm, the second hole diameter is 108 mm, and the outer diameter of the second casing is 100 mm.

[0048] S3, install the extraction pipe 6, put the extraction pipe 6 into the coal uncovering hole 1 and seal the hole to achieve the installation of the extraction pipe 6.

[0049] In an optional embodiment, the coal uncovering hole 1 passes through a broken rock section and a pulverized coal seam 7 section, the extraction pipe 6 includes a cylindrical section 61 arranged corresponding to the broken rock section and a screen pipe section 62 arranged corresponding to the pulverized coal seam 7 section, and the hole sealing construction is performed on the outer wall of the cylindrical section 61, so that the extraction pipe 6 is connected to the coal uncovering hole 1 except for the screen pipe section 62 corresponding to the coal seam 7, the coal uncovering hole 1 is sealed, gas leakage from the outer wall of the extraction pipe 6 is avoided, and smooth gas extraction is ensured.

[0050] In an optional embodiment, the hole sealing construction includes end sealing by bagged polyurethane on the outer side of both ends of the cylindrical section 61 and grouting sealing between the two end sealings.

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

[0052] In an optional embodiment, the extraction can be performed after the hole sealing construction for 24 hours, the first extraction concentration of the drilling hole is detected within two days, the extraction concentration of the drilling hole is detected at least once a month thereafter, a drilling extraction pipe 6 management account is formed, when the drilling extraction concentration is found to be lower than 30%, the air tightness of the drilling hole and the extraction pipe 6 is checked, if there is a problem with the air tightness, treatment measures are taken, such as secondary sealing or reaming measures to handle the low extraction concentration caused by the sealing of the drilling hole, to avoid the occurrence of extraction blind area, the main pipeline extraction concentration, extraction pressure difference and other parameters are detected at least once a week and compared with the monitored extraction parameters, if the error exceeds 5%, the cause should be found out and handled in time to ensure the authenticity and effectiveness of the extraction data.

[0053] The construction process of the medium air pressure residue discharge under the geological condition of the super large buried depth high stress soft coal seam 7 in the embodiment is described by taking the medium air pressure residue discharge construction in the coal uncovering of the downhole with the fastening coefficient of the coal seam 7 less than 0.8, the thickness of the coal seam 7 less than 4 m, and the hole depth greater than 100 m as an example. The drill rig can be selected from ZDY-3200 and ZDY-4000 mine tunnel drill rigs. The drilling diameter is φ94 mm. The drill rod 2 has a diameter of φ73 mm and φ63 mm. The matched MLGF16 / 7-90G type medium air pressure mobile air compressor provides the compressed air with the motor power of 90 kw, the rated air volume of 16 m³ / min, and the rated pressure of 1.2 MPa. The hole is drilled by using the casing hole protection process. The gate valve at the water jet shaft of the drill rig is opened in the hole. The compressed air with the air pressure of about 1.2 MPa is sent to the drill rod 2 inner hole from the water jet shaft of the drill rig, reaches the high-speed airflow formed in the hole, and is blown to the hole mouth after being mixed with the drill cuttings. The drill cuttings are transported into the ground residue discharge system 5 for treatment. The drill cuttings are finally transported and discharged by the ground residue discharge system 5. After the hole reaches the designed depth or the hole penetrates the coal seam 7 bottom plate by at least 0.5 m, the hole is terminated. Then, the pipe installation and hole sealing are performed.

[0054] The construction process of the medium air pressure residue discharge under the geological condition of the super large buried depth high stress soft coal seam in the embodiment is used for the coal uncovering hole 1. The medium air pressure conveying system 4 is used to convey the coal residue from the hole to the ground residue discharge system 5. The gas can be diluted by the air pressure in the residue discharge process to reduce the gas concentration and ensure the construction safety. Meanwhile, the residue discharge channel 3 intersecting with the coal uncovering hole 1 at an acute angle is separately established to convey the coal residue to the ground residue discharge system 5. The coal residue can smoothly enter the residue discharge channel 3 along the axial direction of the hole, the residue conveying distance between the drill rod 2 and the ground residue discharge system 5 is extended, the coal residue blockage at the hole mouth is avoided, the residue discharge efficiency is improved, the hole spouting risk is reduced, the waste residue and drill cuttings are prevented from flying out to hurt people, and the construction safety is improved.

[0055] The above only describes the preferred embodiments of the present application and should not be used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

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.

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 pressurized air is supplied by an air compressor with a rated pressure of 1.2 MPa.

3. 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).

4. The construction technology for medium-pressure slag removal under geological conditions of ultra-deep, high-stress soft coal seams according to claim 3, is characterized in that... The coal uncovering hole (1) is equipped with a ventilation and water switching mechanism (8), which is connected to the medium-pressure conveying system (4) and the water supply mechanism.

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

6. The construction technology for medium-pressure slag removal under geological conditions of ultra-deep, high-stress soft coal seams according to any one of claims 1-5, characterized in that, 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.

7. The construction technology for medium-pressure slag removal under geological conditions of ultra-deep, high-stress soft coal seams according to claim 6, is characterized in that... 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 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).

8. 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 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.

9. 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).

10. The construction technology for medium-pressure slag removal under geological conditions of ultra-deep, high-stress soft coal seams according to claim 9, 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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