Rapid tunneling method for coal roadway of super-long working face in outburst coal seam

Abstract

The present application relates to a kind of outburst coal seam super-long working face coal roadway rapid excavation method, belong to coal mine coal roadway excavation field.The steps S1, the time-space relationship of drilling, extraction and excavation of determining coal roadway strip n different blocks;S2, in the block N1 in the vicinity of the upper mountain (1) of mining area, design, construction first type roof directional branch long borehole, and sectional hydraulic fracturing is carried out;S3, in the block N2 to N n Design, construction second type roof directional branch long borehole and cut area roof directional branch long borehole in the block N By using coal seam roof directional branch long borehole combined sectional hydraulic fracturing technology, make outburst coal seam super-long working face adjacent block drilling-extraction-excavation coordinate efficient, save roof and floor rock roadway excavation, reduce drilling construction quantity, improve coal seam permeability coefficient, reduce outburst prevention cost, relieve mining and excavation replacement, realize outburst coal seam super-long working face coal roadway continuous rapid excavation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of coal roadway driving in coal mines, and particularly relates to a rapid driving method for coal roadway of outburst coal seam of super-long working face. BACKGROUND

[0002] At present, the coal and gas outburst (referred to as "outburst" for short) disaster is still a worldwide problem, which seriously affects the safety production of coal mines. As known, the coal roadway of outburst coal seam can be driven only after the outburst danger of the coal roadway strip area is eliminated. The existing outburst prevention method for coal roadway strip mainly adopts the through-hole drilling or the bedding drilling to pre-drain the gas in the coal roadway strip area. The through-hole drilling pre-drainage measure needs to drive the roof and floor rock roadway, and the outburst prevention method has large engineering quantity and high cost. The bedding drilling has low hole forming rate and poor drainage effect for soft coal seam.

[0003] With the intensive and efficient production of coal mines, the length of the coal mining working face is gradually lengthened, and the super-long working face with the length of 2-4km appears in some mining areas in China. The traditional outburst prevention method for the super-long working face highlights more deficiencies: the drilling construction time, the roof and floor rock roadway driving time and the coal roadway driving time are further lengthened, and the outburst prevention cost is further increased. In addition, some coal roadway driving does not allow to use the bedding drilling pre-drainage outburst prevention measure, which seriously affects the mining and driving replacement and the safety production of coal mines.

[0004] Therefore, it is urgent to explore a rapid driving method for coal roadway of outburst coal seam of super-long working face to realize the rapid driving of the coal roadway of outburst coal seam of super-long working face, and to relieve the mining and driving replacement and ensure the safety production of coal mines. SUMMARY

[0005] In view of this, the present application aims to provide a rapid driving method for coal roadway of outburst coal seam of super-long working face to solve the problems of high outburst prevention cost, long outburst prevention time and influence on mining and driving replacement of the coal roadway of outburst coal seam of super-long working face.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0007] A rapid driving method for coal roadway of outburst coal seam of super-long working face comprises the following steps: S1, determining the time and space relationship of drilling, drainage and driving of n different blocks of coal roadway strip; S2, designing and constructing the first type of roof directional branch long drill hole in the block N1 near the upper mountain 1 of the mining area, and performing hydraulic fracturing in sections; S3, designing and constructing the second type of roof directional branch long drill hole and the roof directional branch long drill hole of the open-off cut area in the coal roadway blocks N2 to N n and performing hydraulic fracturing in sections;

[0008] The coal roadway comprises a transportation roadway 2 and a return airway 3.

[0009] In step S1, the transportation roadway 2 and the return airway 3 are divided into n blocks of the same length corresponding to each other: n=(Y+Y k )÷Y1; wherein Y is the length of the transportation roadway or the return airway in the direction of the coal seam, in meters; Y k is the control width outside the outline of the cut-and-fill of the coal mining face, in meters; Y1 is the total length of the first block N1, in meters;

[0010] In the direction of the coal seam, the time relationship of seamless connection between the coal roadway excavation and the gas extraction in adjacent blocks should satisfy: T my1 =T dy2 =T zy2 +T cy2 ; wherein T my1 is the time required for the coal roadway excavation of the length Y3 in the block N1, in days; T dy2 is the time required for the gas extraction in the block N2, in days; T zy2 is the time required for the construction of the directional branch long borehole in the roof of the block N2, in days; T cy2 is the extraction time of the block N2;

[0011] When the blocks N1 and N2 are continuously excavated without time gap, the mathematical expression of the coal roadway excavation length of the Y3 region in the block N1 is: Y3=V m ×T my1 =V m ×(T zy2 +T cy2 ); wherein V m is the coal roadway excavation speed, in meters per day;

[0012] The total length Y1 of the block N1 is: Y1=V m ×(T zy2 +T cy2 )+Y c +Y2; wherein Y c is the advance distance required for the coal roadway excavation of the block N1, in meters, which is not less than 20 meters; Y2 is the distance between the roadway drilling field of the second type of directional branch long borehole in the block N1 and the upper slope of the mining area, in meters, and the value range of Y2 is 50-100 meters;

[0013] In step S2, the block near the upper slope 1 of the mining area is the first block N1 in the transportation roadway 2 and the return airway 3, and the first type of directional branch long borehole in the block N1 includes the main borehole 6 and the branch borehole 7; in the vertical direction, the main borehole 6 is spaced apart from the coal seam roof rock layer by h=1-3 meters; in the direction of the coal roadway excavation, the main borehole 6 is located directly above the center line of the coal roadway excavation; the length of the main borehole 6 is the same as the total length Y1 of the block N1; the branch borehole 7 is uniformly and symmetrically arranged on both sides of the main borehole 6;

[0014] The anti-burst control distance of the branch hole 7 in the block N1 on both sides of the main hole 6 is X k + W / 2; in the formula, W is the width of the transportation roadway or the air return roadway, in meters; X k is the horizontal distance between the boundary line of the transportation roadway or the air return roadway in the block N1 and the boundary line of the corresponding block anti-burst control area;

[0015] In step S3, the second type of roof directional branch long hole arranged in the coal roadway in the advancing direction includes a "transportation roadway area roof directional branch long hole" and an "air return roadway area roof directional branch long hole";

[0016] In each block of the transportation roadway 2 and the air return roadway 3, a roadway drilling field 9 is arranged at a Y2 distance from the starting end in each block, starting from the second block N2;

[0017] In the blocks N2 to N n of the transportation roadway 2 and the air return roadway 3, the second type of roof directional branch long hole includes a main hole 12 and a branch hole; the main hole 12 in each block extends from the roadway drilling field 9 in the previous block to the tail end of the current block, and the branch hole is divided into a mining side branch hole 11 and a coal roadway side branch hole 10;

[0018] In the vertical direction, the main hole 12 is spaced apart from the coal seam roof rock layer by 1-3 m; in the coal seam inclination direction, the horizontal distance between the main hole 12 and the corresponding coal roadway advancing center line is D / 2+W / 2; in the formula, D is the width of the roadway drilling field in each block, in meters; the length Y6 of the main hole 12 in each block is Y6=Y1+Y c +Y3;

[0019] In the blocks N2 to N n , the projection length X7 of the mining side branch hole 11 in the horizontal direction is X7=X1-D / 2-W / 2; the projection length X6 of the coal roadway side branch hole 10 in the horizontal direction is X6=X1+D / 2+W / 2; in the formula, X1 is the projection length of the branch hole of the first type of roof directional branch long hole in the horizontal direction in N1, in meters; the anti-burst control distance X3 of the mining side branch hole 11 is X3=X K -D / 2-W / 2; the anti-burst control distance X2 of the coal roadway side branch hole 10 is X2=X K +D / 2+W / 2;

[0020] In the last block N n of the transportation roadway 2 or the air return roadway 3, the construction position of the open-off cut area roof directional branch long hole is determined, which includes a main hole 14 and a branch hole 13;

[0021] The main hole 14 is arranged in the direction of the driving of the mining face cut 4, the horizontal distance between the main hole 14 and the inner contour line of the mining face cut 4 is Y5+c / 2, and the length of the main hole 14 is X3+X5-d / 2; in the formula, Y5 is the total length of the block N n The horizontal distance between the cut area drilling field and the inner contour line of the mining face cut in the construction of the cut area roof directional branch long hole is m; c is the length of the cut area drilling field, m; d is the width of the cut area drilling field, m;

[0022] The branch holes 13 are uniformly arranged on one side in the area outside the control range of the transport roadway and the air return roadway.

[0023] Further, in step S1, the first type of roof directional branch long hole is constructed according to the total length Y1 of the block N1, and gas extraction is performed, so that the block N1 reaches the extraction standard requirement, and then the coal roadway excavation of the block N1 is performed; when the coal roadway excavation of the block N1 reaches the distance Y2, the roadway drilling field 9 in the block N1 is constructed, and then the second type of roof directional branch long hole of the block N2 is constructed in the roadway drilling field 9; the design is sequentially performed according to the design, until the coal roadway excavation of the area segment with the length Y3 in the block N1 is just completed, and the block N2 just reaches the extraction standard; the adjacent blocks N3, N4, …, and the blocks N n The law is cyclically inferred backward.

[0024] Further, in step S2, in the first type of roof directional branch long hole corresponding to the upper slope 1 in the coal seam strike direction, the interval Y4 of the adjacent branch holes 7 is determined according to the hydraulic fracturing radius r.

[0025] In step S3, in the second type of roof directional branch long hole in the transport roadway 2 and the air return roadway 3 in the coal seam strike direction, the interval of the adjacent coal roadway side branch holes 10 and the interval of the mining side branch holes 11 are both Y4, which is determined according to the hydraulic fracturing radius r.

[0026] Further, in step S2, the length Y1 of the main hole 6 of the first type of roof directional branch long hole is 600-1000m.

[0027] Further, in steps S2 and S3, along the coal seam level direction, in the inclined and steeply inclined coal seam roadway, X k ≥20m; in other coal seams, X k ≥15m.

[0028] Further, in step S3, the last block N n The time relationship that the coal roadway excavation and the cut area gas extraction reach the standard should meet: T mq =T dq =T zq +Tcq ; in the formula: T mq is the time required for coal roadway excavation in the block N n , the unit being "day"; T dq is the time required for gas extraction in the cutting area to reach the standard, the unit being "day"; T zq is the time required for the construction of the roof directional branch long borehole in the cutting area, the unit being "day"; T cq is the extraction time in the cutting area, the unit being "day";

[0029] the last block N n in the transport roadway or the air return roadway n , the last block N m in which the coal roadway excavation and the gas extraction in the cutting area reach the seamless connection mq , the calculation formula of the coal roadway excavation length Y5 in the block N m is Y5=V zq ×T cq ; in the formula: V m is the coal roadway excavation speed, the unit being "m / day".

[0030] Further, in the step S3, the main borehole 14 in the roof directional branch long borehole in the cutting area is arranged at a distance of 1-3m from the coal seam roof stratum; the length of the main borehole (14) is X3+X5-d / 2; in the formula, X3 is the outburst control range of the second type roof directional branch long borehole on the extraction side branch hole, the unit being m; X5 is the horizontal distance between the outburst control area boundary line of the block N n in the transport roadway and the outburst control area boundary line of the block N n in the air return roadway, the unit being m; d is the width of the drilling field in the cutting area, the unit being m; the opening interval of the adjacent branch hole 13 is X4, X4 being 30-50m; Y k is not less than 20m.

[0031] Further, in the steps S2 and S3, the construction of the first type roof directional branch long borehole, the second type roof directional branch long borehole and the roof directional branch long borehole in the cutting area all adopt the backward construction method, that is, the main borehole is drilled to the expected depth, and then the branch holes are sequentially constructed in the backward process, and the interval branch holes are segmented for hydraulic fracturing.

[0032] The present application has the following beneficial effects:

[0033] The method utilizes the coal seam roof directional branch long borehole of the mining area uphole to combine the sectional hydraulic fracturing technology, makes the drilling-extraction-mining coordination of the adjacent blocks of the outburst coal seam super-long working face efficient, saves the roof and floor rock roadway mining, reduces the drilling construction amount, improves the permeability coefficient of the coal seam, reduces the outburst prevention cost, reduces the outburst prevention time, relieves the mining replacement, and realizes the continuous and rapid mining of the outburst coal seam super-long working face.

[0034] Other advantages, objects, and features of the application will be in part apparent and in part pointed out hereinafter in the specification, and will be elucidated with reference to the accompanying drawings and claims. The objects and other advantages of the application will be realized and attained by the structure particularly pointed out in the specification as follows. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to make the objects, technical solutions and advantages of the application clearer, the preferred detailed description of the application will be combined with the drawings as follows, in which:

[0036] Figure 1 A plane schematic view of the rapid mining method of the coal roadway of the outburst coal seam super-long working face;

[0037] Figure 2 A sectional view schematic diagram of the first type roof directional branch long borehole in the block N1;

[0038] Figure 3 A sectional view schematic diagram of the second type roof directional branch long borehole in the block N2;

[0039] Figure 4 A sectional view schematic diagram of the second type roof directional branch long borehole in the block N n ;

[0040] Figure 5 A sectional view schematic diagram of the roof directional branch long borehole of the open-off cut area.

[0041] Reference signs:

[0042] 1-mining area uphole;

[0043] 2-transport roadway;

[0044] 3-return airway;

[0045] 4-open-off cut of the mining working face;

[0046] 5-drilling field of the mining area uphole;

[0047] 6-main hole of the first type roof directional branch long borehole;

[0048] 7-branch hole of the first type roof directional branch long borehole;

[0049] 8-Transport lane or return air lane each block outburst control area boundary line;

[0050] 9-Transport lane or return air lane roadway drill site;

[0051] 10-Second type of roof directional branch long borehole coal lane side branch hole;

[0052] 11-Second type of roof directional branch long borehole mining side branch hole;

[0053] 12-Second type of roof directional branch long borehole main hole;

[0054] 13-Open-off cut area roof directional branch long borehole branch hole;

[0055] 14-Open-off cut area roof directional branch long borehole main hole;

[0056] 15-Open-off cut area outburst control area boundary line;

[0057] 16-Gas extraction pipeline;

[0058] 17-Forward packer;

[0059] 18-Backpacker;

[0060] 19-Coal seam;

[0061] 20-Open-off cut area drill site;

[0062] Y is the length of the transport lane or return air lane in the direction of the coal seam;

[0063] Y1 is the total length of the first block N1;

[0064] Y2 is the distance between the roadway drill site and the upper slope in block N1;

[0065] Y3 is the partial area section in block N1;

[0066] Y4 is the interval distance between adjacent branch holes in the first type of roof directional branch long borehole or the second type of roof directional branch long borehole;

[0067] Y5 is the construction position of the open-off cut area drill site;

[0068] Y6 is the main hole length of the second type of roof directional branch long borehole in each block;

[0069] Y k is the control width outside the open-off cut area contour line of the mining working face;

[0070] Y c is the advance distance required by the coal lane excavation in block N1;

[0071] T my1 This represents the time required for tunneling in the Y3 section of block N1.

[0072] T dy2 The time required for gas extraction in block N2 to meet the standards;

[0073] T zy2 The time required to construct the second type of directional branch long borehole in block N2;

[0074] T cy2 The sampling time for block N2;

[0075] T mq For block N n The time required for coal roadway excavation in the Y5 section of medium length;

[0076] T dq The time required for sampling to meet the standards in the incision area;

[0077] T zq The time required for constructing long, directional branch boreholes in the top slab of the cut-eye area;

[0078] T cq The sampling time for the incision area;

[0079] V m This refers to the speed of coal roadway excavation.

[0080] r is the hydraulic fracturing radius;

[0081] h is the distance between each main borehole and the roof strata of the coal seam;

[0082] 'a' represents the length of the drilling site at the top of the mining area.

[0083] b represents the width of the drilling site at the top of the mining area;

[0084] C is the length of the tunnel drilling site;

[0085] D is the width of the tunnel drilling site;

[0086] c represents the length of the drilling area in the eye region;

[0087] d represents the width of the drilling area in the cut-hole region;

[0088] W is the width of the transport tunnel or return air tunnel;

[0089] X k It is the horizontal distance between the boundary line of the transport lane or return air lane in block N1 and the boundary line of the corresponding block anti-outburst control area;

[0090] X1 is the horizontal projection length of the branch hole of the first type of top plate directional branch long drill hole in block N1;

[0091] X2 is the interval between adjacent branch holes in the long borehole of the second type of roof directional branch in the block N2 to the block N n the control range of outburst prevention of the second type of roof directional branch long borehole in the coal roadway side branch hole;

[0092] X3 is the interval between adjacent branch holes in the long borehole of the second type of roof directional branch in the block N2 to the block N n the control range of outburst prevention of the second type of roof directional branch long borehole in the coal roadway side branch hole;

[0093] X4 is the interval between adjacent branch holes in the long borehole of the second type of roof directional branch in the block N2 to the block N

[0094] X5 is the horizontal distance between the boundary line of the outburst prevention control area in the block N n and the boundary line of the outburst prevention control area in the block N n ;

[0095] X6 is the projection length of the second type of roof directional branch long borehole in the coal roadway side branch hole in the block N2 to the block N n in the horizontal direction;

[0096] X7 is the projection length of the second type of roof directional branch long borehole in the coal roadway side branch hole in the block N2 to the block N n in the horizontal direction. DETAILED DESCRIPTION

[0097] The embodiments of the present application will be described in detail with specific examples, and other advantages and effects of the present application can be easily understood by those skilled in the art from the disclosure. The present application can also be implemented or applied by other different embodiments, and various modifications or changes can be made to the details in the specification based on different views and applications without departing from the spirit of the present application. It should be noted that the drawings provided in the following examples only illustrate the basic concept of the present application in a schematic manner, and the features in the following examples and embodiments can be combined with each other without conflict.

[0098] The drawings are only used for illustrative explanation, and the representation is only a schematic diagram, not a physical diagram, and cannot be understood as a limitation of the present application; in order to better illustrate the embodiments of the present application, some components in the drawings may be omitted, enlarged or reduced, and do not represent the actual size of the product; it can be understood by those skilled in the art that some known structures and their descriptions in the drawings may be omitted.

[0099] 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.

[0100] Please see Figures 1-5 This is a method for rapid tunneling of coal roadways in ultra-long working faces of prominent coal seams, specifically including the following steps:

[0101] Step 1: Determine the spatiotemporal relationship of drilling, extraction and tunneling in different blocks of the coal roadway strip.

[0102] See Figure 1 To achieve rapid excavation of coal roadways in ultra-long working faces of outburst coal seams, continuous excavation of coal roadways in outburst coal seams without time gaps is required. The coal roadways include transport roadway 2 (i.e., "transport roadway of the mining face") and return air roadway 3 (i.e., "return air roadway of the mining face"). This scheme takes transport roadway 2 as an example to explain the detailed steps. The determination steps of return air roadway 3 are the same as those of transport roadway 2, and will not be repeated in this embodiment.

[0103] First, divide transport lane 2 into n blocks of equal length (i.e., N1, N2, N3, ... N in the diagram). n-1 N n Taking blocks N1 and N2 as examples, this paper introduces a rapid coal roadway excavation method: This method first determines the total length Y1 of the transport roadway block N1 by combining the extraction time of block N2 with outburst prevention and construction requirements. Then, it enables continuous excavation of adjacent blocks without time gaps, thereby achieving rapid excavation of coal roadways in ultra-long working faces of outburst-prone coal seams. The specific details are as follows:

[0104] (1) Determine the total length Y1 of transport lane block N1.

[0105] See Figure 1 To achieve rapid excavation of coal roadways, seamless connection between the excavation of adjacent coal roadway blocks and the gas extraction meeting standards is required. Specifically, the time T required for excavation of the Y3-length section of the coal roadway in transport roadway block N1 is [not specified]. my1 The time T required for block N2 extraction to meet the target dy2 Equal. The extraction time for Block N2 includes the construction time T of the second type of roof directional branch long borehole in Block N2. zy2 and sampling time T cy2 That is, the following relationship exists:

[0106] T my1 = T dy2 = T zy2 + T cy2 ;

[0107] In the formula, T my1 is the time required for coal roadway excavation of the length Y3 area section in the (transport roadway) block N1, in units of "days"; T dy2 is the time required for gas extraction to reach the standard in the (transport roadway) block N2, in units of "days"; T zy2 is the time required for construction of the second type of roof directional branch long borehole in the (transport roadway) block N2, in units of "days"; T cy2 is the gas extraction time of the (transport roadway) block N2.

[0108] According to the coal roadway excavation speed V m of the transport roadway block N1 and the coal roadway excavation time T my1 of the transport roadway block N1 (i.e. the sum of the borehole construction time T zy2 and the extraction time T cy2 of the block N2), the coal roadway excavation length of the length Y3 area section in the transport roadway block N1 is determined as:

[0109] Y3 = V m × T my1 = V m × (T zy2 + T cy2 );

[0110] In the formula, V m is the coal roadway excavation speed of the block N1, in units of "meters / day".

[0111] At the same time, according to the requirements for outburst prevention and borehole construction, the coal roadway excavation of the transport roadway block N1 requires a lead distance Y c , and the roadway drill site 9 for construction of the first type of roof directional branch long borehole in the transport roadway block N1 needs to be separated from the mining area raise 1 by a distance Y2, and therefore the total length Y1 of the transport roadway block N1 is:

[0112] Y1 = V m × (T zy2 + T cy2 ) + Y c + Y2;

[0113] In the formula, Y c is the lead distance required for coal roadway excavation of the transport roadway block N1, in units of m, which is generally not less than 20 m; Y2 is the distance between the roadway drill site for construction of the second type of roof directional branch long borehole and the mining area raise in the transport roadway block N1, in units of m, and the value range of Y2 is generally 50-100 m.

[0114] (2)Transportation roadway block division

[0115] Referring to Figure 1 , according to the total length Y of the transportation roadway of the mining face in the direction of the coal seam and the control width Y K outside the outer contour line of the open-off cut of the mining face, the total length of the anti-outburst control of the transportation roadway is calculated, and then divided by the total length Y1 of the transportation roadway block N1, so that the entire transportation roadway is evenly divided into n blocks, and the calculation formula is as follows:

[0116] n = (Y + Y k ) ÷ Y1;

[0117] In the formula, Y is the length of the transportation roadway of the mining face in the direction of the coal seam, in meters; Y k is the control width outside the outer contour line of the open-off cut of the mining face, in meters; and Y1 is the total length of the first block N1 of the transportation roadway, in meters.

[0118] (3) Determining the drilling-extraction-excavation space-time relationship between blocks

[0119] Referring to Figure 1 , according to the total length Y1 of the transportation roadway block N1, the first type of roof directional branch long drill hole in the block is constructed, and gas extraction is performed, so that the transportation roadway block N1 reaches the extraction standard, and then the coal roadway excavation of the transportation roadway block N1 is performed. When the coal roadway excavation of the transportation roadway block N1 reaches Y2, the roadway drilling field 9 in the transportation roadway block N1 is constructed (the roadway drilling field 9 is also the starting end of the second type of roof directional branch long drill hole in the next block N2), and then the second type of roof directional branch long drill hole of the transportation roadway block N2 is constructed in the roadway drilling field 9.

[0120] According to the above design, the coal roadway excavation of the transportation roadway block N1 with a length of Y2 is just completed, the block N2 just reaches the extraction standard, and then the coal roadway excavation of the transportation roadway block N2 is performed. Thus, the continuous excavation of the coal roadway of the block N1 and the block N2 is realized without time gap.

[0121] The adjacent blocks N3, N4, …, N n By analogy, the continuous excavation of the adjacent blocks without time gap can be realized.

[0122] Step 2: Design and construct the first type of roof directional branch long drill hole in the block near the upper slope of the mining area, and perform hydraulic fracturing in sections.

[0123] The block near the upper slope 1 of the mining area is the block N1 in the transportation roadway, and according to the requirements of step 1, the first type of roof directional branch long drill hole is designed and constructed in the transportation roadway block N1, and hydraulic fracturing is performed in sections.

[0124] (1) Design the first type of directional branch long borehole in the roof of transport roadway block N1.

[0125] See Figure 1 , Figure 2 The first type of directional branch long borehole in the roof of transport roadway block N1 includes main borehole 6 and branch borehole 7, and its construction parameters are designed as follows:

[0126] 1) Design main hole 6

[0127] Given the relatively poor porosity of coal seams (especially soft coal seams), in order to ensure the construction length of the main borehole 6, in the vertical direction, the main borehole 6 is generally arranged above the roof strata of the coal seam, and the vertical distance h between the two is 1 to 3 m; in the coal roadway excavation direction, the main borehole 6 is arranged directly above the center line of the coal roadway excavation, that is, the projection of the main borehole 6 coincides with the center line of the coal roadway excavation; the length of the main borehole 6 is the total length Y1 of the transport roadway block N1, which is generally 600 to 1000 m.

[0128] 2) Design branch holes

[0129] Branch holes 7 are evenly and symmetrically arranged on both sides of the main hole 6, and the branch holes 7 on both sides are spaced Y4 on the horizontal plane according to the hydraulic fracturing radius r.

[0130] Assuming the width of transport tunnel 2 is W, then with the center of main tunnel 6 as the starting point, the anti-outburst control distance of branch tunnel 7 on both sides of main tunnel 6 is X. k +W / 2; where W is the width of transport lane 2, in meters; X k It is the horizontal distance between the boundary line of the transport lane (i.e., the lane outline) in block N1 and the boundary line 8 of the corresponding block anti-outburst control area.

[0131] It should be noted that: along the coal seam direction, in inclined and steeply inclined coal seam roadways, X k The value of X is at least 20m (all distances are along the coal seam bedding plane, the same below); in other coal seams, X k The value of is at least 15m.

[0132] (2) Drill long directional branch boreholes in the first type of roof of construction block N1 and carry out hydraulic fracturing in sections.

[0133] Construction was carried out according to the above design parameters. This construction adopted a backward construction method, that is, after the main hole 6 was drilled to the expected depth, the branch holes 7 were constructed in sequence during the backward process, and hydraulic fracturing was carried out in sections of several branch holes 7 at intervals. That is, the front packer 17 and the rear packer 18 were moved towards the hole opening in sequence according to the drilling length.

[0134] Step 3: In coal roadway blocks N2 to N nThe second type of roof directional branch long borehole in different blocks and the roof directional branch long borehole in the open-off cut area are designed and constructed, and hydraulic fracturing is performed in sections.

[0135] In addition to the transportation roadway 2 and the air return roadway 3, the coal seam in different blocks in the coal roadway strip area also includes the open-off cut area. The second type of roof directional branch long borehole in each block in the transportation roadway 2 is recorded as "roof directional branch long borehole in the transportation roadway area", the second type of roof directional branch long borehole in each block in the air return roadway 3 is recorded as "roof directional branch long borehole in the air return roadway area", and the roof directional branch long borehole in the open-off cut area is recorded as "roof directional branch long borehole in the open-off cut area". The following details are described for the transportation roadway area (the same as the air return roadway 3 area) and the open-off cut area respectively.

[0136] (1) Transportation roadway area

[0137] Referring to Figure 3 On the basis of step 2, when the coal roadway in the transportation roadway block N1 is excavated to the Y2 position, a roadway drilling field 9 of the block N2 is designed and constructed according to the length C and the width D, then the construction parameters of the second type of roof directional branch long borehole in the block N2 are designed, and the construction and sectional hydraulic fracturing are performed in the roadway drilling field 9 (in the block N2).

[0138] Block N3, block N4, … block N n By analogy, one roadway drilling field (9) is set at the Y2 distance from the starting end of each block.

[0139] The second type of roof directional branch long borehole in the transportation roadway block N2 includes the main borehole 12 and the branch borehole, and the construction parameter design method is as follows:

[0140] 1) Design the main borehole 12

[0141] Referring to Figure 1 In the transportation roadway block N2, the main borehole 12 of the second type of roof directional branch long borehole is the same as the block N1 in the vertical direction, and is generally arranged at 1-3 m of the coal seam roof stratum. In the coal seam inclination direction, the main borehole 12 is arranged at half of the width of the roadway drilling field 9, that is, the horizontal distance between the projection of the main borehole 12 and the corresponding coal roadway excavation center line is D / 2+W / 2; in the formula: D is the width of the roadway drilling field in the block N2, and the unit is m.

[0142] The main hole 12 in each block extends from the roadway drilling site 9 in the previous block to the end of the block, i.e. the starting end of the main hole 12 (of the second type of roof directional branch long borehole) in the block N2 is the roadway drilling site 9 arranged in the block N1, and the main hole 12 extends to the end of the block N2. Similarly, the starting end of the main hole 12 in the block N3 is the roadway drilling site 9 arranged in the block N2, and the main hole 12 extends to the end of the block N3; and so on and so forth to the block N n. The above-mentioned arrangement mode makes the main hole 12 and the roadway drilling site 9 in each block intersect in the plane; the main holes 12 in the adjacent two blocks intersect after the block N2; thus the branch hole can be used to solve the outburst prevention problem of the next block in each cycle after the block N2. It is emphasized that the main hole 12 after the block N2 is different from the main hole 6 in the block N1, and the branch hole also becomes asymmetric.

[0143] The length between the roadway drilling sites in the two adjacent blocks is Y2+Y c +Y3; the length Y6 of the main hole 12 in each block is Y6=Y1+Y c +Y3; i.e. the length of the interval from the roadway drilling site 9 in the block N1 to the end of the block N2 is Y6. In the formula, Y6 is the length of the main hole 12 of the second type of roof directional branch long borehole in each block, and the unit is m; Y2 is the distance between the roadway drilling site for the construction of the second type of roof directional branch long borehole and the upgate in the block N1, and the unit is m; Y c is the advance distance required to be left for the coal roadway excavation in the block N1, and the unit is m; and Y3 is the length of the partial area section in the block N1, and the unit is m.

[0144] For each block after the N2 block of the coal roadway, the total length of the main hole 12 in each block is Y6.

[0145] 2) Design of branch hole

[0146] The branch hole of the second type of roof directional branch long borehole is divided into the mining side branch hole 11 and the coal roadway side branch hole 10, and the projection length X7 of the mining side branch hole 11 in the horizontal direction is X7=X1-D / 2-W / 2, and the projection length X6 of the coal roadway side branch hole 10 in the horizontal direction is X6=X1+D / 2+W / 2; in the formula, X1 is the projection length of the branch hole of the first type of roof directional branch long borehole in the horizontal direction in the block N1, and the unit is m. The outburst prevention control distance X3 of the mining side branch hole 11 is X3=X K -D / 2-W / 2; and the outburst prevention control distance X2 of the coal roadway side branch hole 10 is X2=X K +D / 2+W / 2.

[0147] The branch hole 11 on the side of the recovery and the branch hole 10 on the side of the coal roadway are designed according to the hydraulic fracturing radius r and are spaced Y4 on the horizontal plane. Similarly, in the inclined and steeply inclined coal seam roadway, the value of X k is at least 20 m (all are distances along the seam level direction, the same below); in other coal seams, the value of X k is at least 15 m.

[0148] 3) Construction of the main hole 12 and the branch hole 11 on the side of the recovery and the branch hole 10 on the side of the coal roadway, and segmented hydraulic fracturing

[0149] According to the above design parameters, the construction is carried out. This construction adopts a retreating construction method, that is, after the main hole 12 is drilled to the expected depth, the branch hole 11 on the side of the recovery and the branch hole 10 on the side of the coal roadway are sequentially constructed in the retreating process, and segmented hydraulic fracturing is carried out on the interval of several branch holes.

[0150] Block N3, block N4, … block N n By analogy, until the design of the entire roadway is completed, it should be noted that the outburst control range of the last block n is the area outside the width Y k of the cut hole outer contour line.

[0151] (2) Cut hole area

[0152] Referring to Figure 3 , Figure 4 , first, the construction position Y5 of the cut hole area drill field 20 of the cut hole area directional branch long hole of the roof of the cut hole area in the last block N n of the transport roadway 2 (the block corresponds to the cut hole area) is determined (that is, the distance from the cut hole 4 of the recovery working face is Y5), then the cut hole area drill field 20 is designed and constructed according to the length c and the width d at Y5, and finally the construction parameters of the cut hole area directional branch long hole of the roof of the cut hole area are designed, and the construction and segmented hydraulic fracturing are carried out in the cut hole area drill field 20. The cut hole area directional branch long hole of the roof of the cut hole area includes the main hole 14 and the branch hole 13, and the construction parameter design method is as follows:

[0153] 1) Determine the drilling construction position

[0154] Referring to step S1, in order to achieve rapid excavation of the coal roadway, the length Y5 of the transport roadway excavation required time T mq and the cut hole area extraction standard required time T dq are the same. The cut hole area extraction standard time includes the construction time T zq of the cut hole area directional branch long hole of the roof of the cut hole area and the extraction time T cq , that is, there is a relationship as follows: T mq =T dq =T zq +T cq ; in the formula: Tmq For block N n The time required for coal roadway excavation in the Y5 section of medium length, in days; T dq The time required for the sampling of the incision area to meet the standard is expressed in "days"; T zq The time required for constructing long, directional branch boreholes in the top slab of the cut-eye area, expressed in days; T cq The sampling time for the incision area is expressed in days.

[0155] Based on the coal roadway excavation speed V of the transport roadway m and coal roadway excavation time T mq (i.e., the construction time T for directional branch long drilling in the top plate of the cut-eye area) zq and sampling time T cq The sum of these factors determines block N. n The formula for calculating the tunneling length Y5 of the coal roadway is:

[0156] Y5 = V m ×T mq =V m ×(T zq +T cq In the formula: V represents the tunneling speed of the coal roadway in the transport roadway. m The unit is "meters per day".

[0157] 2) Design the main hole

[0158] See Figure 5 In the vertical direction, the main borehole 14 of the directional branch long borehole in the cut-in area is located in the same position as the main borehole 6 in block N1, that is, it is generally arranged 1 to 3 m away from the roof strata of the coal seam. The main borehole 14 is arranged parallel to the cut-in excavation direction (coal seam dip), that is, the horizontal distance between the projection of the main borehole 14 and the inner contour line of the cut-in 4 of the longwall face is Y5+c / 2, and the length of the main borehole 14 is X3+X5-d / 2; where Y5 is the distance between the main borehole 14 and the cut-in 4 of the longwall face. n The construction location of the drilling site in the central cut-hole area is the horizontal distance between it and the inner contour line of the longwall face, in meters (m); c is the length of the drilling site in the central cut-hole area, in meters (m); d is the width of the drilling site in the central cut-hole area, in meters (m).

[0159] 3) Design branch hole 13

[0160] See Figure 5 The control range of branch holes 13 is the area outside the control range of transport roadway 2 and return airway 3. Within this area, branch holes 13 are uniformly arranged on one side, and the opening spacing of branch holes 13 is X4, where X4 is 30-50m. The width between the outer contour line of the longwall face and the boundary line 15 of the outburst prevention control area is Y. k The width is generally not less than 20m.

[0161] 4) Construction of main hole 14 and branch hole 13 and segmented hydraulic fracturing

[0162] Construction is carried out according to the above design parameters. This construction still adopts the retreating construction method, that is, after the main hole 14 is drilled to the expected depth, the branch holes are sequentially constructed in the retreating process, and the segmented hydraulic fracturing is carried out on the interval of several branch holes.

[0163] After step S3 is designed, the first type of roof directional branch long borehole 6 and the connecting gas extraction pipeline 16 are constructed in the first transport roadway block and the first return airway block N1 from the mining area uphole 1 to extract gas; when the extraction in the block N1 coal roadway strip area reaches the standard, the coal roadway excavation is carried out; the second type of roof directional branch long borehole in the block N2 is constructed during the excavation of the block N1, and the segmented hydraulic fracturing is carried out. The second type of roof directional branch long borehole in the adjacent block N3, block N4, … block N n and so on, and the transport roadway 2 and the return airway 3 use the same method.

[0164] In order to realize the continuous and rapid excavation of the whole working face, the transport roadway 2 and the return airway 3 are excavated synchronously in the excavation direction (i.e. in the direction of the coal seam), and the horizontal distance between the excavation heads of the transport roadway 2 and the return airway 3 is not less than 50m, until the excavation reaches the cut area of the working face. When the transport roadway 2 and the return airway 3 excavate the cut in the cut area, when the horizontal distance between the excavation heads of the two is less than 60m, the excavation of one of the excavation heads is stopped, and the one-way excavation is changed, until the cut excavation is completed.

[0165] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should be covered in the scope of the claims of the present application.

Claims

1. A method for rapid tunneling of coal roadways in ultra-long working faces of outburst coal seams, characterized in that... Includes the following steps: S1. Determine the spatiotemporal relationship of drilling, extraction, and tunneling in n different blocks of the coal roadway strip; S2. Design and construct the first type of roof directional branch long borehole in block N1 near the mining area uphill (1), and carry out hydraulic fracturing in sections; S3. In coal roadway blocks N2 to N n The design and construction of the second type of roof directional branch long borehole and the roof directional branch long borehole in the cut-eye area were carried out in sections for hydraulic fracturing. Coal roadways include transport roadways (2) and return air roadways (3); In step S1, the transport lane (2) and the return air lane (3) are divided into n blocks of equal length: n = (Y + Y k )÷Y1; Where: Y is the length of the transport roadway or return airway in the direction of the coal seam strike, in meters; Y k Y1 represents the control width outside the outer contour line of the longwall face, in meters; Y1 represents the total length of the first block N1, in meters. In the direction of coal seam strike, the time relationship between seamless connection of coal roadway excavation and gas drainage between adjacent blocks should meet the following requirement: T my1 = T dy2 =T zy2 + T cy2 In the formula: T my1 T represents the time required for coal roadway excavation in section Y3 of block N1, in days; dy2 The time required for gas extraction in block N2 to meet standards, in days; T zy2 The time required for drilling long directional branch boreholes in the roof slab of block N2, in days; T cy2 The sampling time for block N2; When blocks N1 and N2 are continuously excavated without time gaps, the mathematical expression for the coal roadway excavation length of the Y3 section in block N1 is: Y3 = V m ×T my1 =V m ×(T zy2 + T cy2 ); where: V m This refers to the coal roadway excavation speed, expressed in meters per day. The total length Y1 of block N1 is: Y1 = V m ×(T zy2 + T cy2 )+Y c +Y2; where: Y c Y1 is the advance distance required for coal roadway excavation in block N1, in meters, and it shall not be less than 20 meters; Y2 is the distance between the drilling site of the second type of roof directional branch long borehole construction roadway in block N1 and the uphill section of the mining area, in meters, and the value of Y2 ranges from 50 to 100 meters. In step S2, the block near the uphill (1) of the mining area is the first block N1 in the transport roadway (2) and return airway (3). The first type of roof directional branch long borehole in block N1 includes a main hole (6) and a branch hole (7). In the vertical direction, the main hole (6) is 1~3m away from the roof strata of the coal seam. In the direction of coal roadway excavation, the main hole (6) is located directly above the center line of coal roadway excavation. The length of the main hole (6) is the same as the total length Y1 of block N1. The branch holes (7) are evenly and symmetrically arranged on both sides of the main hole (6). The anti-outburst control distance of the branch hole (7) in block N1 on both sides of the main hole (6) is X. k +W / 2; where: W is the width of the transport tunnel or return air tunnel, in meters; X k It is the horizontal distance between the boundary line of the transport lane or return air lane in block N1 and the boundary line of the corresponding block anti-outburst control area; In step S3, the second type of roof directional branch long boreholes set along the tunneling direction in the coal roadway include "roof directional branch long boreholes in the transport roadway area" and "roof directional branch long boreholes in the return airway area"; In each block of the transport roadway (2) and the return air roadway (3), starting from the second block N2, a roadway drilling site (9) is set up at a distance of Y2 from the starting end in each block. Block N2 to Block N of transport lane (2) and return air lane (3) n In the second type of roof directional branch long borehole, there are main holes (12) and branch holes. The main holes (12) in each block start from the roadway drilling site (9) in the previous block and extend to the end of the block. The branch holes are divided into mining side branch holes (11) and coal roadway side branch holes (10). In the vertical direction, the main borehole (12) is spaced 1-3m from the roof strata of the coal seam; in the dip direction of the coal seam, the horizontal distance between the main borehole (12) and the corresponding coal roadway excavation centerline is D / 2+W / 2; where: D is the width of the roadway drilling site in each block, in meters; the length Y6 of the main borehole (12) in each block is: Y6=Y1+Y c +Y3; Block N2 to Block N n In the formula, the horizontal projection length X7 of the branch hole (11) on the mining side is: X7 = X1 - D / 2 - W / 2; the horizontal projection length X6 of the branch hole (10) on the coal roadway side is: X6 = X1 + D / 2 + W / 2; where: X1 is the horizontal projection length of the branch hole of the first type of roof directional branch long drill hole in N1, in meters; the anti-outburst control distance X3 of the branch hole (11) on the mining side is: X3 = X K -D / 2-W / 2; The anti-outburst control distance X2 of the branch hole (10) on the side of the coal roadway is: X2=X K +D / 2+W / 2; In the last block N of the transport lane (2) or return air lane (3) n The construction location of the directional branch long borehole in the top plate of the cut eye area is determined. The directional branch long borehole in the top plate of the cut eye area includes the main hole (14) and the branch hole (13). The main borehole (14) is arranged in the same direction as the excavation of the longwall face cut-out (4). The horizontal distance between the main borehole (14) and the inner contour line of the longwall face cut-out (4) is Y5+c / 2, and the length of the main borehole (14) is X3+X5-d / 2. In the formula, Y5 is the block N. n The horizontal distance between the drilling site of the directional branch long borehole in the roof of the central cutting area and the inner contour line of the cutting area of ​​the longwall face, in meters; c is the length of the drilling site in the cutting area, in meters; d is the width of the drilling site in the cutting area, in meters. Branch holes (13) are evenly distributed on one side in areas outside the control range of transport roadways and return airways.

2. The method for rapid tunneling of coal roadways in ultra-long working faces of outburst-prone coal seams according to claim 1, characterized in that: In step S1, the first type of roof directional branch long borehole is constructed according to the total length Y1 of block N1, and gas extraction is carried out. After block N1 meets the extraction standard, the coal roadway of block N1 is excavated. When the coal roadway of block N1 is excavated to a distance of Y2, the roadway drilling site (9) in block N1 is constructed. Then, the second type of roof directional branch long borehole of block N2 is constructed in the roadway drilling site (9). This design is followed sequentially until the coal roadway of section Y3 in block N1 is just completed and the extraction standard of block N2 is just met. The adjacent blocks N3, N4, ... block N n This pattern is repeated cyclically.

3. The method for rapid excavation of coal roadways in ultra-long working faces of outburst-prone coal seams according to claim 1, characterized in that: In step S2, in the direction of coal seam strike, in the first type of roof directional branch long borehole corresponding to the mining area uphill (1), the interval Y4 between adjacent branch holes (7) is determined according to the hydraulic fracturing radius r; In step S3, in the direction of coal seam strike, the interval between the adjacent coal seam side branch holes (10) and the interval between the mining side branch holes (11) in the second type of roof directional branch long boreholes in the transport roadway (2) and return air roadway (3) are Y4, which is determined according to the hydraulic fracturing radius r.

4. The method for rapid tunneling of coal roadways in ultra-long working faces of outburst-prone coal seams according to claim 1, characterized in that: In step S2, the length of the main hole (6) of the first type of top plate directional branch long drill hole is 600~1000m.

5. The method for rapid excavation of coal roadways in ultra-long working faces of outburst-prone coal seams according to claim 1, characterized in that: In steps S2 and S3, along the coal seam direction, in inclined and steeply inclined coal seam roadways, X k ≥20m; in other coal seam roadways, X k ≥15m.

6. The method for rapid tunneling of coal roadways in ultra-long working faces of outburst-prone coal seams according to claim 1, characterized in that: In step S3, the last block N in the transport lane (2) and the return air lane (3) n The time relationship between seamlessly connecting coal roadway excavation and gas extraction in the cut area should meet the following requirements: T mq = T dq = T zq +T cq In the formula: T mq For block N n The time required for coal roadway excavation in the Y5 section of medium length, in days; T dq The time required for the sampling of the incision area to meet the standard is expressed in "days"; T zq The time required for constructing long, directional branch boreholes in the top slab of the cut-eye area, expressed in days; T cq The sampling time for the incision area is expressed in days. The last block N in the transport tunnel or return air tunnel n When the coal roadway excavation and gas extraction in the cut-off area are seamlessly connected to meet the standards, the last block N n The formula for calculating the tunneling length Y5 in the coal roadway is: Y5 = V m ×T mq =V m ×(T zq + T cq ); where: V m This refers to the coal roadway excavation speed, expressed in meters per day.

7. The method for rapid tunneling of coal roadways in ultra-long working faces of outburst-prone coal seams according to claim 1, characterized in that: In step S3, in the directional branch long borehole of the roof in the cutting area, the main hole (14) is arranged at a distance of 1~3m from the roof strata of the coal seam; the length of the main hole (14) is X3+X5-d / 2; where X3 is the anti-outburst control range of the branch hole on the mining side of the second type of directional branch long borehole of the roof, in meters; X5 is the block N in the transport roadway. n The boundary line of the anti-outburst control area and the N block in the return airway n The horizontal distance between the boundary lines of the anti-breakout control area, in meters; d represents the width of the drilling area in meters; The opening spacing between adjacent branch holes (13) is X4, where X4 is 30~50m; Y k Not less than 20m.

8. The method for rapid tunneling of coal roadways in ultra-long working faces of outburst-prone coal seams according to claim 1, characterized in that: In steps S2 and S3, the construction of the first type of roof directional branch long borehole, the second type of roof directional branch long borehole, and the roof directional branch long borehole in the cut-eye area all adopt the retreat construction method. That is, after the main hole reaches the expected depth, the branch holes are constructed sequentially during the retreat process, and hydraulic fracturing is performed in sections with several branch holes at intervals.

Images