Method for fluidized advanced emptying coal body well roadway coal uncovering

Abstract

The present application relates to a kind of fluidized advance emptying coal body well roadway coal uncovering method, belong to well roadway coal uncovering technical field, roadway excavation is before 10m to vertical distance coal seam, advance detection coal seam gas occurrence variation, provide reliable geological parameters for fluidized emptying coal body;Roadway excavation is before 7m to vertical distance coal seam, arrange grouting hole and inject slurry solidification coal uncovering area roadway contour line outside 0-5m range, to form solidification circle, improve surrounding rock strength and block gas source;Solidification circle outside arrangement gas drainage borehole, to reduce the outburst power of gas to solidification circle;In the middle of roadway contour, water jet cutting borehole is arranged, negative pressure pipeline is transported in the bottom of roadway contour and is formed closed loop by water jet cutting and water jet cutting borehole, to realize fluidized advance continuous emptying coal uncovering area coal body.This method effectively solves the problem of long period and high risk in high outburst low permeability soft coal seam uncovering, realizes the safe and efficient fast excavation in high outburst low permeability soft coal seam.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of well and roadway coal uncovering, and relates to a method for well and roadway coal uncovering by fluidization advanced emptying of coal. BACKGROUND

[0002] Among the coal mine related disasters, coal and gas outburst is one of the most important disasters, especially the well and roadway coal uncovering coal and gas outburst. The well and roadway coal uncovering site has good gas sealing and storage conditions and large ground stress, which leads to frequent outburst accidents and large outburst intensity, and is a key point of mine safety production and a bottleneck link of normal mining and excavation replacement.

[0003] For the well and roadway coal uncovering working face of different geological conditions of coalfield, different coal seams and different outburst risks, the coal seam gas control measures mainly include hydraulic punching, hydraulic cutting, drainage borehole, metal framework and loose blasting. The above measures can play a certain outburst prevention role, but the measures such as hydraulic punching and drainage borehole have small influence range and long extraction cycle; the metal framework and grouting solidification only play a passive blocking role and cannot actively release the coal seam ground stress and gas pressure; the traditional hydraulic cutting has limited influence range with small pressure, and has problems such as poor discharge and serious hole collapse; loose blasting has low controllability and is easy to induce disasters. With the technological progress of the coal industry, the Chongqing Research Institute of China Coal Technology and Industry Group has integrated a super-high pressure and large flow water jet generation system equipment with a track type, a water pressure of 100 MPa and a flow of 125 L / min, and the cutting radius can reach about 2.5 m, which is comparable to the size of the roadway profile. Therefore, it is of great significance to construct a composite gas control method based on surrounding rock solidification, gas drainage borehole pressure relief, high-pressure water jet cutting coal body and fluidization transportation of coal slurry advanced emptying of coal body, and to promote safe and rapid coal uncovering of high outburst and low permeability soft coal seams. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a method for well and roadway coal uncovering by fluidization advanced emptying of coal, to realize safe and efficient and rapid tunneling of high outburst and low permeability soft coal seams.

[0005] To achieve the above purpose, the application provides the following technical solutions:

[0006] The application discloses a method for uncovering coal seam by fluidized advanced emptying of coal body in a well or a tunnel, wherein before the tunneling reaches a vertical distance of 10 m from the coal seam, the gas occurrence change of the coal seam is detected in advance to provide reliable geological parameters for fluidized emptying of the coal body; before the tunneling reaches a vertical distance of 7 m from the coal seam, a grouting hole is arranged and grout is injected into a range of 0-5 m outside a profile line of the tunnel in the coal seam uncovering area to form a solidification circle and improve the strength of surrounding rock and block the gas source; a gas drainage borehole is arranged outside the solidification circle to reduce the outburst power of the gas into the solidification circle; a water jet cutting borehole is arranged in the middle of the tunnel profile, and a negative pressure pipeline conveying borehole is arranged at the bottom of the tunnel profile, and the water jet cutting borehole and the negative pressure pipeline conveying borehole form a closed loop by means of water jet cutting to realize fluidized advanced continuous emptying of the coal body in the coal seam uncovering area.

[0007] Specifically, the method comprises the following steps:

[0008] S1, before the tunneling reaches a vertical distance of 10 m from the coal seam, the gas occurrence change of the coal seam is detected in advance to determine the thickness of the coal seam in the coal seam uncovering area and the inclination angle of the coal seam, and provide a basis for subsequent arrangement of the gas drainage borehole, the grouting hole, the water jet cutting borehole and the negative pressure pipeline conveying borehole;

[0009] S2, before the tunneling reaches a vertical distance of 7 m from the coal seam, a drilling field is arranged on both sides of the tunnel, a circle of grouting holes is constructed, after the construction of the grouting holes is completed, a grouting pipe is arranged in the grouting holes, the grouting holes are sealed, after the sealing is completed, any grouting hole to be grouted is selected, cement grout is injected into the grouting pipe to solidify the coal body, and it is observed in real time whether grout leaks from other grouting holes, if grout leaks, emergency measures are taken for temporary plugging, the grouting pressure is determined according to the strength of the coal body through on-site test, and the grouting is stopped when the set grouting amount is reached; then, the next grouting hole is grouted until the grouting of all the grouting holes is completed;

[0010] S3, after the grout in the grouting hole is solidified, a circle of gas pre-drainage boreholes are constructed in the coal seam outside the solidification circle, the position of the gas pre-drainage boreholes does not exceed 12 m outside the profile line of the tunnel at the coal seam uncovering position, or 6 m at the bottom or lower side of the steeply inclined coal seam, and the minimum distance to the profile line of the tunnel is not less than 5 m, so as to reduce the outburst power of the gas in the coal seam outside the solidification sealing circle into the coal seam in the solidification sealing circle.

[0011] S4, according to the coal seam detection condition and the position of the tunnel profile line, a negative pressure pipeline conveying borehole is arranged at the bottom of the tunnel profile and penetrates the coal seam, after the construction is completed, the borehole is sealed, the sealing depth is consistent with the rock hole section, and the negative pressure pipeline conveying borehole is used for fluidized output of the water jet cutting coal body;

[0012] S5, after the sealing of the negative pressure pipeline conveying borehole is completed, a water jet cutting borehole is constructed in the middle of the tunnel profile and penetrates the coal seam, and the distance between the terminal hole point of the water jet cutting borehole and the negative pressure pipeline conveying borehole is half of the diameter of the tunnel profile;

[0013] After the water jet cutting borehole construction is completed (S6), the drilling rig rotates slowly without any forward or backward movement. The water jet generator is then activated to cut the coal body, and coal slag is discharged from the water jet cutting borehole. When the radius of the cutting groove reaches the normal distance between the water jet cutting borehole and the negative pressure pipeline conveying borehole, the water jet cutting borehole and the negative pressure pipeline conveying borehole form a closed loop, and coal slag no longer discharges from the water jet cutting borehole. The negative pressure pump is then activated, and when the coal slurry is being output normally from the negative pressure pipeline, the drilling rig drags the drill rod forward or backward. The forward or backward speed of the drilling rig is adjusted according to the viscosity of the coal slag discharged from the negative pressure pipeline conveying borehole to prevent the coal slag from becoming too viscous and clogging the negative pressure pipeline conveying borehole, thus achieving fluidized, advanced, and continuous excavation of the coal body in front of the coal uncovering area.

[0014] Optionally, waterjet cutting drilling can be carried out using integrated drilling and cutting equipment.

[0015] Optionally, the diameter of the borehole delivered by the negative pressure pipeline shall not be less than 94 mm.

[0016] Optionally, the diameter of the waterjet cutting drill is 113 mm.

[0017] Optionally, the water jet generator is a tracked ultra-high pressure water jet generator with a pressure of 100MPa and a flow rate of 125L / min.

[0018] The beneficial effects of this invention are as follows: by strengthening the surrounding rock to block the source of gas, reducing the intensity of gas inrush through pre-drainage boreholes, cutting the coal body with high-pressure water jets, fluidized transport through negative pressure pipelines, and pre-emptive emptying of the coal body, it achieves rapid and safe penetration of coal and gas outburst coal seams, breaking through the bottleneck of mining imbalance.

[0019] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0021] Fig. 1 A schematic diagram of the roadway layout and coal seam occurrence profile of the coal uncovering face;

[0022] Fig. 2 Schematic diagram of borehole layout for coal seam exposure roadway cross section;

[0023] Fig. 3 A schematic diagram of water jet cutting and negative pressure pipeline transportation for fluidized advanced hollowing of coal seams.

[0024] Attached reference numerals: 1. Roadway; 2. Water jet cutting borehole; 3. Negative pressure pipeline conveying borehole; 4. Grouting hole; 5. Gas drainage borehole; 6. Coal seam floor; 7. Solidification ring; 8. Coal seam; 9. Coal slurry output pipeline; 10. Negative pressure coal slurry output pump; 11. Drilling rig; 12. Water jet generator; 13. Detailed Implementation

[0025] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0026] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0027] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0028] See Figs. 1-3A method for coal seam exposure in a fluidized bed pre-excavation coal seam is mainly targeted at soft coal seams with high outburst and low permeability. The method includes: before tunnel 1 reaches a vertical distance of 10m from the coal seam, accurately detecting changes in coal seam gas occurrence to provide reliable geological parameters for fluidized bed pre-excavation; before tunnel 1 reaches a vertical distance of 7m from the coal seam, grouting holes 4 are arranged to inject grout to solidify the area 0-5m outside the tunnel outline of the coal seam exposure zone, forming a solidification zone 7 to increase the strength of the surrounding rock and block the gas source; gas drainage boreholes 5 are arranged outside the solidification zone 7 to reduce the force of gas surging into the solidification zone 7; subsequently, water jet cutting boreholes 2 are arranged in the middle of the tunnel outline, and negative pressure pipeline conveying boreholes 3 are arranged at the bottom of the tunnel outline, relying on water jet cutting to form a closed loop. The specific steps include:

[0029] a. Before tunnel 1 is excavated to a vertical distance of 10m from the coal seam, the changes in coal seam gas occurrence should be accurately detected in advance to determine the coal seam thickness and dip angle in the pre-exposed coal area. This will provide a basis for the subsequent layout of gas drainage borehole 5, grouting borehole 4, water jet cutting borehole 2, and negative pressure pipeline conveying borehole 3.

[0030] b. Before tunnel 1 is excavated to a vertical distance of 8m from the coal seam, drilling sites are set up on both sides of tunnel 1 to construct a ring of grouting holes 4. After the grouting holes 4 are constructed, grouting pipes are installed in the grouting holes 4 to seal them. After the sealing is completed, any grouting hole 4 to be grouted is selected, and cement grout is injected through the grouting pipe. After solidification, the coal body is solidified. Other grouting holes 4 are constantly monitored for grout leakage. If grout flows out, emergency measures should be taken to temporarily seal it. The grouting pressure should be determined by on-site testing based on the strength of the coal body. Grouting is stopped when the set grouting volume is reached.

[0031] c. Repeat step b until grouting of all grouting holes 4 is completed to form a solidified ring 7, located between the coal seam floor 6 and the coal seam roof 9, within a range of 0–5 m outside the borehole control roadway outline. Fig. 1 , 2 As shown.

[0032] d. After the slurry has solidified, construct a ring of gas pre-drainage boreholes inside the coal seam 8 outside the solidification ring 7 to control the gas flow from the roadway outline at the coal exposure point to 12m (6m at the bottom or lower side of the steeply inclined coal seam). At the same time, ensure that the minimum distance from the outer edge of the control range to the roadway outline (including the outline of the expected coal exposure section roadway) is not less than 5m, thereby reducing the gas flow from the coal seam outside the solidification sealing ring into the coal seam 8 inside the solidification sealing ring.

[0033] e. Based on the coal seam 8 detection and the roadway outline location, precisely arrange negative pressure pipelines to deliver borehole 3 below the roadway outline. The borehole diameter should not be less than 94mm, and the depth should penetrate to the coal seam 8. After construction, use seamless steel pipes to seal the boreholes, with the sealing depth consistent with the rock borehole section. This is used for the fluidized output of water jet cutting of the coal body. Fig. 2 As shown.

[0034] f. After the sealing of the negative pressure pipeline conveying borehole 3 is completed, construct the water jet cutting borehole 2 in the middle of the roadway outline. The borehole diameter is 113mm and the depth is 8mm to penetrate the coal seam. The normal distance between the end point of the water jet cutting borehole 2 and the negative pressure pipeline conveying borehole 3 should be half the diameter of the roadway outline.

[0035] g. Water jet cutting borehole 2 is constructed using integrated drilling and cutting equipment. After construction, the drilling rig 12 rotates slowly without forward or backward movement. The water jet generator 13 is activated to cut the coal body. Initially, coal slag is discharged from the high-pressure water jet cutting borehole 2. When the radius of the cutting groove reaches the normal distance between the water jet cutting borehole 2 and the negative pressure pipeline conveying borehole 3, the water jet cutting borehole 2 and the negative pressure pipeline conveying borehole 3 form a closed loop, and coal slag no longer flows out of the water jet cutting borehole 2. The negative pressure pump is activated. When the coal slurry is output normally from the negative pressure pipeline, the forward (or backward) key of the drilling rig 12 is turned on, and the drill rod is slowly dragged forward (or backward). The forward (or backward) speed of the drilling rig 12 is adjusted according to the viscosity of the coal slag discharged from the negative pressure pipeline conveying borehole 3 to prevent the coal slag from becoming too viscous and clogging the negative pressure pipeline conveying borehole 3. This achieves fluidized, advanced, and continuous excavation of the coal body in front of the coal uncovering area. Fig. 2 , 3 As shown.

[0036] In this invention, the solidification of the slurry forms a sealed solidification ring 7, which on the one hand prevents the coal seam gas outside the solidification ring 7 from flowing into the coal seam inside the solidification ring 7 in large quantities, and on the other hand, the solidification ring 7 provides strong support for the coal and gas outburst outside the solidification ring; the arrangement of pre-drainage boreholes outside the solidification ring 7 can effectively reduce the intensity of gas inflow at the bottom of the well.

[0037] The present invention uses a water jet generator 13 to provide power for coal cutting and structural changes in the coal exposure area, and a negative pressure coal slurry output pump 11 to provide power for the fluidized output of coal slurry. The fluidized coal in the coal exposure area is output through the coal slurry output pipeline 10.

[0038] The water jet generating device 13 in this invention can be a tracked ultra-high pressure water jet generating device with a pressure of 100MPa and a flow rate of 125L / min. Using this device to cut the coal body can create a space of similar size to the roadway cross-section, which is convenient for advanced fluidized emptying of the coal body. The output negative pressure pump provides power for fluidized coal slag transportation, effectively solving the problem of difficult coal slurry discharge in downward-sloping boreholes. It can be used for remote operation at a vertical distance of 7m from the coal seam, and the rock pillar provides a safety barrier for the operators, improving the safety of the workers.

[0039] This invention addresses the challenges of high outburst risk, high outburst intensity, and long outburst suppression time in mine tunnels exposed to soft, low-permeability coal seams. It proposes a solution that achieves rapid and safe penetration of coal and gas outburst-prone seams by strengthening the surrounding rock to block gas sources, reducing gas inrush intensity through pre-drainage boreholes, using high-pressure water jets to cut the coal body, employing negative-pressure pipeline fluidized transport, and pre-emptively hollowing out the coal body. This breakthrough overcomes the bottleneck of mining imbalance.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for coal uncovering in a coal seam tunnel using fluidized bed pre-excavation, characterized in that: Before the roadway reaches a vertical distance of 10m from the coal seam, advance detection of changes in coal seam gas occurrence is conducted to provide reliable geological parameters for fluidized coal body excavation. Before the roadway reaches a vertical distance of 7m from the coal seam, grouting holes are arranged and grout is injected to solidify the area 0-5m outside the roadway outline of the coal exposure area, forming a solidification zone to increase the strength of the surrounding rock and block the gas source. Gas drainage boreholes are arranged outside the solidification zone to reduce the gas outflow force into the solidification zone. Water jet cutting boreholes are arranged in the middle of the roadway outline, and negative pressure pipeline conveying boreholes are arranged at the bottom of the roadway outline. The water jet cutting boreholes and negative pressure pipeline conveying boreholes rely on water jet cutting to form a closed loop to achieve fluidized advance continuous excavation of the coal body in the coal exposure area.

2. The method for coal uncovering in a fluidized bed pre-excavation coal seam tunnel according to claim 1, characterized in that: Includes the following steps: Before the tunnel is excavated to a vertical distance of 10m from the coal seam, S1 will conduct advance detection of the changes in coal seam gas occurrence, determine the coal seam thickness and dip angle in the pre-exposed coal area, and provide a basis for the subsequent layout of gas drainage boreholes, grouting holes, water jet cutting boreholes, and negative pressure pipeline transportation boreholes. Before the S2 roadway reaches a vertical distance of 7m from the coal seam, drilling sites are set up on both sides of the roadway to construct a ring of grouting holes. After the grouting holes are constructed, grouting pipes are installed inside the holes to seal them. After sealing, any grouting hole to be grouted is selected, and cement grout is injected through the grouting pipe. After solidification, the coal body is solidified, and other grouting holes are monitored in real time for any grout leakage. If grout leaks out, emergency measures are taken to temporarily seal it. The grouting pressure should be determined by on-site testing based on the coal body strength. Grouting is stopped when the set grouting volume is reached. Then, the next grouting hole is grouted until all grouting holes are grouted. After the grout in the injection hole S3 has solidified, a ring of gas pre-drainage boreholes is constructed in the coal seam outside the solidification ring. The location of the gas pre-drainage boreholes should not exceed 12m outside the roadway outline at the coal exposure point, or 6m at the bottom or lower side of the steeply inclined coal seam, and the minimum distance to the roadway outline should not be less than 5m, so as to reduce the power of gas from the coal seam outside the solidification sealing ring to the coal seam inside the solidification sealing ring. Based on the coal seam detection and the location of the roadway outline, S4 arranges a negative pressure pipeline to deliver the borehole at the bottom of the roadway outline, and the depth is to penetrate the coal seam. After the construction is completed, the borehole is sealed, and the sealing depth is consistent with the rock borehole section, which is used for the fluidized output of water jet cutting of coal. After the S5 negative pressure pipeline conveying borehole is sealed, a water jet cutting borehole is constructed in the middle of the roadway outline, penetrating the coal seam to the depth. The normal distance between the end point of the water jet cutting borehole and the negative pressure pipeline conveying borehole is half the diameter of the roadway outline. After the water jet cutting borehole construction is completed (S6), the drilling rig rotates slowly without any forward or backward movement. The water jet generator is then activated to cut the coal body, and coal slag is discharged from the water jet cutting borehole. When the radius of the cutting groove reaches the normal distance between the water jet cutting borehole and the negative pressure pipeline conveying borehole, the water jet cutting borehole and the negative pressure pipeline conveying borehole form a closed loop, and coal slag no longer discharges from the water jet cutting borehole. The negative pressure pump is then activated, and when the coal slurry is being output normally from the negative pressure pipeline, the drilling rig drags the drill rod forward or backward. The forward or backward speed of the drilling rig is adjusted according to the viscosity of the coal slag discharged from the negative pressure pipeline conveying borehole to prevent the coal slag from becoming too viscous and clogging the negative pressure pipeline conveying borehole, thus achieving fluidized, advanced, and continuous excavation of the coal body in front of the coal uncovering area.

3. The method for coal uncovering in a fluidized bed pre-excavation coal seam tunnel according to claim 1, characterized in that: Waterjet cutting drilling is carried out using integrated drilling and cutting equipment.

4. The method for coal uncovering in a fluidized bed pre-excavation coal seam tunnel according to claim 1, characterized in that: The diameter of the borehole for negative pressure pipeline delivery shall not be less than 94mm.

5. The method for coal uncovering in a fluidized bed pre-excavation coal seam tunnel according to claim 1, characterized in that: The diameter of the hole drilled by water jet cutting is 113 mm.

6. The method for coal uncovering in a fluidized bed pre-excavation coal seam tunnel according to claim 2, characterized in that: The water jet generator is a tracked ultra-high pressure water jet generator with a pressure of 100MPa and a flow rate of 125L / min.

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