A directional continuous-discontinuous seam cutting and roof pressure relief method for coal mining face

Abstract

The present invention discloses a method for directional continuous-discontinuous slotting and roof cutting for pressure relief in a coal mining face, belonging to the technical field of coal mining, which comprises the following steps: S10, drilling holes in the gaps between adjacent hydraulic supports; S20, placing a mining chain arm saw type cutting machine in the roadway; S30, moving the mining chain arm saw type cutting machine along the center line of the roadway; S40, rotating the cutting tool for cutting; S50, repeating and cumulatively cutting; S60, detonating after sealing the holes with gun clay; S70, completing the drilling and blasting of the entire working face and moving the supports; S80, arranging unit supports within the cutting range; S90, withdrawing the unit supports in the gob area of the working face; S100, advancing the working face until the coal mining of the working face is completed. The present invention combines the methods of composite blasting roof cutting and chain arm saw cutting for slotting and roof cutting to control the damage range of the surrounding rock and the continuity of cracks, achieving directional continuous-discontinuous slotting and roof cutting for pressure relief, thereby ensuring the efficient and safe production of the working face.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mining, and particularly relates to a method for directional continuous-discontinuous slotting and roof cutting pressure relief in a coal mine working face. Background Art

[0002] At present, more than one-third of the mining areas in the country have hard roof. In the case of hard roof, the roof cannot collapse in time after coal seam mining, forming a huge load on the coal pillar of the adjacent roadway, which causes serious deformation. Coupled with the collapse of the exposed roof over a long distance, strong mine pressure appears, posing a huge threat to the safe mining of the coal seam. The large deformation and damage induced by strong mine pressure manifestation are closely related to the stress field environment where the underground engineering is located. Therefore, it is necessary to start from improving the migration law of surrounding rock and improve the stress field environment of surrounding rock by transferring the overlying rock pressure relief.

[0003] At present, during the mining of extra-thick coal seam working faces, the thick hard roof cannot collapse in time after coal seam mining, forming a huge load on the coal pillar of the adjacent roadway, which causes serious deformation and poses a danger to the working face mining.

[0004] Directional continuous-discontinuous slotting and roof cutting pressure relief is an effective means to solve the above problems. However, there is still a lack of an effective roof cutting pressure relief method for coal mine working faces. Summary of the Invention

[0005] In order to provide a method for directional continuous-discontinuous slotting and roof cutting pressure relief in a coal mine working face to solve the problem that during the mining of extra-thick coal seam working faces at present, the thick hard roof cannot collapse in time after coal seam mining, forming a huge load on the coal pillar of the adjacent roadway, causing serious deformation and posing a danger to the working face mining, the technical solution adopted by the present invention is as follows:

[0006] A method for directional continuous-discontinuous slotting and roof cutting pressure relief in a coal mine working face includes the following steps:

[0007] S10. Adjust the support resistance of the hydraulic support to P1; drill holes with a diameter of D1 and a depth of D2 in the gap between two adjacent hydraulic supports until the drilling task of the entire working face is completed;

[0008] S20. Place two mining chain arm saw cutters in two roadways respectively; adjust the distance between the cutting tool of the mining chain arm saw cutter and the roadway side wall so that the distance between the cutting tool and the roadway side wall is B;

[0009] S30. Move the mining chain arm saw cutter along the center line of the roadway by a distance S1 away from the goaf;

[0010] S40. Rotate the cutting tool from one horizontal position to another horizontal position at a chain speed of υ and a rotational speed of ω;

[0011] S50. Repeat steps S30 - S40 until the cumulative cutting distance exceeds L1;

[0012] S60. After a shift of mining is completed and before maintenance in the maintenance shift, for the boreholes in step S10, after sealing the boreholes with stemming of depth H, lead out the detonating cord and detonate at a single - shot blasting distance L2 until the blasting of the entire working face is completed; after the maintenance shift finishes the maintenance, the next shift continues mining;

[0013] S70. Repeat step S60 until the borehole blasting of the entire working face is completed and the supports are moved;

[0014] S80. With a row spacing of M, evenly arrange the unit supports with a support resistance of P2 within the cutting range accumulated in step S50;

[0015] S90. When the cumulative distance of the unit supports in the gob of the working face exceeds L3, withdraw the unit supports in the gob of the working face;

[0016] S100. Repeatedly operate steps S10 - S90 to advance the working face at a uniform speed until the coal mining of the working face is completed and at the same time the withdrawal of the unit supports in the gob is completed.

[0017] Further, in step S10, the support resistance P1 of the hydraulic support is associated with the uniaxial compressive strength of the immediate roof of the roadway:

[0018] When 0 < the uniaxial compressive strength of the immediate roof of the roadway ≤ 18 MPa, P1 = 5800 KN;

[0019] When 18 MPa < the uniaxial compressive strength of the immediate roof of the roadway ≤ 50 MPa, P1 = 6600 KN;

[0020] When the uniaxial compressive strength of the immediate roof of the roadway > 50 MPa, P1 = 7200 KN.

[0021] Further, in step S10, the diameter D1 and depth D2 of the borehole are associated with the Proctor coefficient of the immediate roof and the stemming depth H:

[0022] When 0 < the Proctor coefficient of the immediate roof ≤ 5, D1 is 0.025 - 0.030 m and D2 is (2.25 - 2.65)H;

[0023] When 5 < the Proctor coefficient of the immediate roof ≤ 9, D1 is 0.030 - 0.035 m and D2 is (2.65 - 3.05)H;

[0024] When the Proctor coefficient of the immediate roof > 9, D1 is 0.035 - 0.040 m and D2 is (3.05 - 3.55)H.

[0025] Further, in step S20, the distance B between the cutting tool and the roadway rib is associated with the roadway width D:

[0026] When the roadway width D is 3.5 < D < 4.5 m, B is (0.08 - 0.10)D;

[0027] When the roadway width D is 4.5 ≤ D < 5.5 m, B is (0.07 - 0.08)D;

[0028] When the roadway width D is 5.5 ≤ D < 6.5 m, B is (0.06 - 0.07)D.

[0029] Further, in step S30, the distance S1 that the mining chain - arm saw - type cutting machine moves along the roadway center line towards the end away from the goaf is associated with the vertical stress of the surrounding rock where the roadway is located:

[0030] When 0 < the vertical stress of the surrounding rock where the roadway is located ≤ 8 MPa, S1 = 6.5 - 8.5 m;

[0031] When 8 < the vertical stress of the surrounding rock where the roadway is located ≤ 25 MPa, S1 = 5.5 - 6.5 m;

[0032] When the vertical stress of the surrounding rock where the roadway is located > 25 MPa, S1 takes 4.5 - 5.5 m.

[0033] Further, in step S40, the chain speed υ, the rotational speed ω are associated with the uniaxial compressive strength of the immediate roof of the roadway:

[0034] When 0 < the uniaxial compressive strength of the immediate roof of the roadway ≤ 18 MPa, υ is 1.2 - 1.4 m / s, ω is 25 - 30° / h;

[0035] When 18 < the uniaxial compressive strength of the immediate roof of the roadway ≤ 50 MPa, υ is 1.0 - 1.2 m / s, ω is 20 - 25° / h;

[0036] When the uniaxial compressive strength of the immediate roof of the roadway > 50 MPa, υ is 0.8 - 1.0 m / s, ω is 15 - 20° / h.

[0037] Further, in step S50, the cumulative cutting distance L1 is associated with the horizontal stress of the surrounding rock where the roadway is located and the distance S1 that the mining chain - arm saw - type cutting machine moves along the roadway center line towards the end away from the goaf:

[0038] When 0 < the horizontal stress of the surrounding rock where the roadway is located ≤ 8 MPa, L1 is set to (4.5 - 5.5)S1;

[0039] When 8 < the horizontal stress of the surrounding rock where the roadway is located ≤ 25 MPa, L1 is set to (3.5 - 4.5)S1;

[0040] When the horizontal stress of the surrounding rock where the roadway is located > 25 MPa, L1 is set to (2.5 - 3.5)S1.

[0041] Further, in step S60, the depth H of the stemming is one - third of the length of the charged explosive; the blasting distance L2 is associated with the face length and the mine working system:

[0042] When the mine has a three - eight working system, L2 is one - third of the face length;

[0043] When the mine has a four - six working system, L2 is one - fourth of the face length.

[0044] Further, in step S80, the row spacing M of the unit support is associated with the support resistance P 2, and is associated with the depth of the roadway burial:

[0045] When the depth of the roadway burial > 600 m, P2 = 2500 KN, and M2 is 0.8 - 1.5 m;

[0046] When the depth of the roadway burial ≤ 600 m, P2 = 1800 KN, and M2 is 1.5 - 2.2 m.

[0047] Further, in step S90, the cumulative distance L3 of the unit support is associated with the uniaxial compressive strength of the immediate roof of the roadway and the cumulative cutting distance exceeding L1:

[0048] When 0 MPa < the uniaxial compressive strength of the immediate roof of the roadway ≤ 25 MPa, L3 is (0.30 - 0.35)L1;

[0049] When 25 MPa < the uniaxial compressive strength of the immediate roof of the roadway ≤ 35 MPa, L3 is (0.35 - 0.40)L1;

[0050] When the uniaxial compressive strength of the immediate roof of the roadway > 35 MPa, L3 is (0.40 - 0.45)L1.

[0051] Advantages of the present invention:

[0052] The present invention provides a method for directional continuous - discontinuous slotting and roof cutting pressure relief in a coal mining face. By combining the methods of compound blasting roof cutting and chain - arm saw cutting for slotting and roof cutting, it controls the damage range of the surrounding rock and the continuity of cracks, achieving directional continuous - discontinuous slotting and roof cutting pressure relief, thereby ensuring the efficient and safe production of the working face.

[0053] During the mining of the hard roof working face at present, the thick hard roof cannot collapse in time after the coal seam is mined, forming a huge load on the coal pillar of the adjacent roadway, causing it to deform severely and posing a danger to the mining of the working face. It can improve the stress environment state of the roadway surrounding rock, reduce the difficulty of roadway surrounding rock control, and has broad application prospects. Brief Description of the Drawings

[0054] Figure 1 It is a schematic plan view of the roadway of a directional continuous-discontinuous slotting roof cutting and pressure relief method for a coal mine working face provided by the present invention;

[0055] Among them, 1. Roadway center line; 2. Cutting range; 3. Borehole; 4. Unit support; 5. Hydraulic support; 6. Mining chain arm saw type cutting machine; 7. Roadway. Detailed Embodiment

[0056] The present invention provides a directional continuous-discontinuous slotting roof cutting and pressure relief method for a coal mine working face. The technical solution of the present invention will be described in detail below with reference to the drawings to make it easier to understand and master.

[0057] Embodiment 1

[0058] A directional continuous-discontinuous slotting roof cutting and pressure relief method for a coal mine working face includes the following steps:

[0059] S10. Adjust the support resistance of the hydraulic support to P1; drill boreholes with a diameter of D1 and a depth of D2 in the gap between two adjacent hydraulic supports until the borehole task of the entire working face is completed.

[0060] In this embodiment, the support resistance P1 of the hydraulic support is associated with the uniaxial compressive strength of the immediate roof of the roadway:

[0061] When 0 < uniaxial compressive strength of the immediate roof of the roadway ≤ 18 MPa, P1 = 5800 KN;

[0062] When 18 MPa < uniaxial compressive strength of the immediate roof of the roadway ≤ 50 MPa, P1 = 6600 KN;

[0063] When the uniaxial compressive strength of the immediate roof of the roadway > 50 MPa, P1 = 7200 KN.

[0064] Among them, the diameter D1 and depth D2 of the borehole are associated with the immediate roof Prandtl coefficient and the depth H of the stemming:

[0065] When 0 < immediate roof Prandtl coefficient ≤ 5, D1 is 0.025 - 0.030 m, and D2 is (2.25 - 2.65)H;

[0066] When 5 < the Proctor coefficient of the immediate roof ≤ 9, D1 is 0.030 - 0.035 m, and D2 is (2.65 - 3.05)H;

[0067] When the Proctor coefficient of the immediate roof > 9, D1 is 0.035 - 0.040 m, and D2 is (3.05 - 3.55)H.

[0068] S20. Place two mine - used chain - arm saw - type cutting machines in two roadways respectively; adjust the distance between the cutting tool of the mine - used chain - arm saw - type cutting machine and the roadway wall to make the distance between the cutting tool and the roadway wall be B.

[0069] In this embodiment, the distance B between the cutting tool and the roadway wall is associated with the roadway width D:

[0070] When the roadway width D is 3.5 < D < 4.5 m, B is (0.08 - 0.10)D;

[0071] When the roadway width D is 4.5 ≤ D < 5.5 m, B is (0.07 - 0.08)D;

[0072] When the roadway width D is 5.5 ≤ D < 6.5 m, B is (0.06 - 0.07)D.

[0073] S30. Move the mine - used chain - arm saw - type cutting machine along the roadway center line by a distance S1 away from the goaf.

[0074] In this embodiment, the distance S1 that the mine - used chain - arm saw - type cutting machine moves along the roadway center line away from the goaf is associated with the vertical stress of the surrounding rock where the roadway is located:

[0075] When 0 < the vertical stress of the surrounding rock where the roadway is located ≤ 8 MPa, S1 = 6.5 - 8.5 m;

[0076] When 8 < the vertical stress of the surrounding rock where the roadway is located ≤ 25 MPa, S1 = 5.5 - 6.5 m;

[0077] When the vertical stress of the surrounding rock where the roadway is located > 25 MPa, S1 takes 4.5 - 5.5 m.

[0078] S40. Rotate the cutting tool from one horizontal position to another horizontal position at a chain speed of υ and a rotational speed of ω.

[0079] In this embodiment, the chain speed υ and the rotational speed ω are associated with the uniaxial compressive strength of the immediate roof of the roadway:

[0080] When 0 < the uniaxial compressive strength of the immediate roof of the roadway ≤ 18 MPa, υ is 1.2 - 1.4 m / s and ω is 25 - 30° / h;

[0081] When 18 < the uniaxial compressive strength of the immediate roof of the roadway ≤ 50 MPa, υ is 1.0 - 1.2 m / s and ω is 20 - 25° / h;

[0082] When the uniaxial compressive strength of the immediate roof of the roadway > 50 MPa, υ is 0.8 - 1.0 m / s and ω is 15 - 20° / h.

[0083] S50. Repeat steps S30 - S40 until the cumulative cutting distance exceeds L1.

[0084] In this embodiment, the cumulative cutting distance L1 is associated with the horizontal stress of the surrounding rock where the roadway is located and the moving distance S1 of the mining chain - arm saw - type cutting machine along the center line of the roadway away from the goaf:

[0085] When 0 < the horizontal stress of the surrounding rock where the roadway is located ≤ 8 MPa, L1 is set to (4.5 - 5.5)S1;

[0086] When 8 < the horizontal stress of the surrounding rock where the roadway is located ≤ 25 MPa, L1 is set to (3.5 - 4.5)S1;

[0087] When the horizontal stress of the surrounding rock where the roadway is located > 25 MPa, L1 is set to (2.5 - 3.5)S1.

[0088] S60. When the mining of one shift is completed, before the maintenance shift for maintenance, for the boreholes in step S10, after sealing the boreholes with gun - clay with a depth of H, lead out the detonating cord and detonate with a single - shot blasting distance L2 until the blasting of the entire working face is completed; after the maintenance shift finishes the maintenance, the next shift continues the mining.

[0089] In this embodiment, the depth H of the gun - clay is one - third of the length of the charged explosive; the blasting distance L2 is associated with the length of the working face and the mine working system:

[0090] When the mine has a three - eight working system, L2 is one - third of the length of the working face;

[0091] When the mine has a four - six working system, L2 is one - fourth of the length of the working face.

[0092] S70. Repeat step S60 until the drilling and blasting of the entire working face are completed, and then move the supports;

[0093] S80. With a row spacing of M, uniformly arrange the unit supports with a support resistance of P2 within the cumulative cutting range in step S50.

[0094] In this embodiment, the row spacing M of the unit supports is associated with the support resistance P 2, and the depth of the roadway burial:

[0095] When the tunnel depth is greater than 600m, P2=2500KN, M2 is 0.8~1.5m;

[0096] When the tunnel depth is ≤600m, P2=1800KN, and M2 is 1.5~2.2m.

[0097] S90. When the cumulative distance of the unit supports in the goaf of the working face exceeds L3, withdraw the unit supports in the goaf of the working face.

[0098] In this embodiment, the cumulative distance L3 of the unit support is related to the uniaxial compressive strength of the direct top of the tunnel and the cumulative cutting distance exceeds L1:

[0099] When 0MPa<uniaxial compressive strength of the direct roof of the tunnel≤25MPa, L3 is (0.30~0.35)L1;

[0100] When 25MPa<uniaxial compressive strength of the direct roof of the tunnel≤35MPa, L3 is (0.35~0.40)L1;

[0101] When the uniaxial compressive strength of the direct roof of the tunnel is greater than 35MPa, L3 is (0.40~0.45)L1.

[0102] S100, repeat steps S10 to S90 to advance the working face at a uniform speed until the working face is mined and the unit supports in the goaf are withdrawn.

[0103] Example 2

[0104] This embodiment is based on the embodiment 1 and is described by taking a comprehensive mining face of Jinneng Holding Group as an example.

[0105] The tunnel width of this embodiment is 4.4m, the uniaxial compressive strength of the direct top of the tunnel is 24MPa, the vertical stress of the surrounding rock in the tunnel is 15MPa, the horizontal stress is 20MPa, the normal coefficient of the direct top of the tunnel is 5, the length of the filling explosive is 1.8m, the tunnel burial depth is 650m, the working face length is 255m, and the working system is the 38 system.

[0106] S10, adjusting the support resistance of the hydraulic support 5 to 6600 KN, drilling a borehole 3 with a diameter of 0.025 m and a depth of 4.05 m in the gap between two adjacent hydraulic supports 5, until the drilling task of the entire working surface is completed.

[0107] S20, placing two mining chain arm saw type cutting machines 6 in two tunnels 7 respectively, and adjusting the cutting tools so that the distance between the cutting tools and the tunnel wall is 400 mm.

[0108] S30. Move the mining chain - arm cutter 6 along the roadway center line 1 by a distance S1 of 5.60 m towards the end away from the goaf.

[0109] S40. Rotate the cutting tool from one horizontal position to another horizontal position at a chain speed of 1.2 m / s and a rotation speed of 25° / h.

[0110] S50. Repeat steps S30 - S40 until the cumulative cutting distance exceeds 24.8 m.

[0111] S60. After a shift of mining is completed and before the maintenance shift for maintenance, for the borehole 3 in step S10, after sealing the borehole with stemming clay with a depth of 0.6 m, initiate detonation with a primary blasting distance of 85 m after leading out the detonating cord until the blasting of the entire working face is completed; after the maintenance shift finishes the maintenance, the next shift continues mining.

[0112] S70. Repeat step S60 until the borehole blasting of the entire working face is completed and move the hydraulic support 5.

[0113] S80. Arrange the unit supports 4 with a support resistance of 2500 KN evenly within the cutting range 2 accumulated in step S50 at a row spacing of 1.2 m.

[0114] S90. When the cumulative distance of the unit supports 4 in the goaf of the working face exceeds 7.44 m, withdraw the unit supports 4 in the goaf of the working face.

[0115] S100. Repeatedly operate steps S10 - S90 to advance the working face at a uniform speed until the extraction of the working face is completed and at the same time the withdrawal of the unit supports 4 in the goaf is completed.

[0116] The above fully describes the technical solution of the present invention. It should be noted that the specific implementation manners of the present invention are not limited by the above description. All technical solutions formed by those of ordinary skill in the art through equivalent transformation or equivalent substitution in terms of structure, method or function and other aspects based on the spirit essence of the present invention fall within the protection scope of the present invention.

Claims

1. A method for directional continuous-discontinuous slotting and roof cutting pressure relief in a coal mining face, characterized in that, It includes the following steps: S10. Adjust the support resistance of the hydraulic support to P1; drill holes with a diameter of D1 and a depth of D2 in the gap between two adjacent hydraulic supports until the drilling task of the entire working face is completed; Among them, the support resistance P1 of the hydraulic support is associated with the uniaxial compressive strength of the direct roof of the roadway: When 0 < the uniaxial compressive strength of the direct roof of the roadway ≤ 18 MPa, P1 = 5800 KN; When 18 MPa < the uniaxial compressive strength of the direct roof of the roadway ≤ 50 MPa, P1 = 6600 KN; When the uniaxial compressive strength of the direct roof of the roadway > 50 MPa, P1 = 7200 KN; S20. Place two mine-used chain arm saw type cutting machines in two roadways respectively; adjust the distance between the cutting tool of the mine-used chain arm saw type cutting machine and the roadway side wall so that the distance between the cutting tool and the roadway side wall is B; S30. Move the mine-used chain arm saw type cutting machine along the center line of the roadway by a distance S1 away from the goaf; S40. Rotate the cutting tool from one horizontal position to another horizontal position at a chain speed of υ and a rotational speed of ω; S50. Repeat steps S30 - S40 until the cumulative cutting distance exceeds L1; S60. After one shift of mining is completed and before the maintenance shift for maintenance, for the holes in step S10, after sealing the holes with gun mud with a depth of H, lead out the detonating cord and detonate at a one-time blasting distance L2 until the blasting of the entire working face is completed; after the maintenance shift finishes the maintenance, the next shift continues mining; S70. Repeat step S60 until the drilling and blasting of the entire working face are completed and the supports are moved; S80. Uniformly arrange unit supports with a support resistance of P2 at a row spacing of M within the cumulative cutting range in step S50; S90. When the cumulative distance of the unit supports in the goaf of the working face exceeds L3, withdraw the unit supports in the goaf of the working face; S100. Repeatedly operate steps S10 - S90 to advance the working face at a uniform speed until the extraction of the working face is completed and at the same time the withdrawal of the unit supports in the goaf is completed.

2. The method for directional continuous-discontinuous seam cutting and roof caving pressure relief in a coal mining face according to claim 1, characterized in that In step S10, the diameter D1 and depth D2 of the holes are associated with the direct roof's Protodyakonov coefficient and the gun mud depth H: When 0 < the direct roof's Protodyakonov coefficient ≤ 5, D1 is 0.025 - 0.030 m and D2 is (2.25 - 2.65)H; When 5 < the direct roof's Protodyakonov coefficient ≤ 9, D1 is 0.030 - 0.035 m and D2 is (2.65 - 3.05)H; When the direct roof's Protodyakonov coefficient > 9, D1 is 0.035 - 0.040 m and D2 is (3.05 - 3.55)H.

3. The method for directional continuous-discontinuous slotting roof cutting and pressure relief in a coal mining face according to claim 1, characterized in that, In step S20, the distance B between the cutting tool and the roadway side wall is associated with the roadway width D: When the roadway width D is 3.5 < D < 4.5 m, B is (0.08 - 0.10)D; When the roadway width D is 4.5 ≤ D < 5.5 m, B is (0.07 - 0.08)D; When the roadway width D is 5.5 ≤ D < 6.5 m, B is (0.06 - 0.07)D.

4. The method for directional continuous-discontinuous slotting roof cutting and pressure relief in a coal mining face according to claim 1, characterized in that In step S30, the distance S1 that the mining chain-arm saw type cutting machine moves along the roadway center line towards the end away from the goaf is associated with the vertical stress of the surrounding rock of the roadway: When 0 < the vertical stress of the surrounding rock of the roadway ≤ 8 MPa, S1 = 6.5 - 8.5 m; When 8 < the vertical stress of the surrounding rock of the roadway ≤ 25 MPa, S1 = 5.5 - 6.5 m; When the vertical stress of the surrounding rock of the roadway > 25 MPa, S1 takes 4.5 - 5.5 m.

5. The method for directional continuous-discontinuous slotting roof cutting and pressure relief in a coal mining face according to claim 1, characterized in that, In step S40, the chain speed υ, the rotational speed ω are associated with the uniaxial compressive strength of the immediate roof of the roadway: When 0 < the uniaxial compressive strength of the immediate roof of the roadway ≤ 18 MPa, υ is 1.2 - 1.4 m / s, ω is 25 - 30° / h; When 18 < the uniaxial compressive strength of the immediate roof of the roadway ≤ 50 MPa, υ is 1.0 - 1.2 m / s, ω is 20 - 25° / h; When the uniaxial compressive strength of the immediate roof of the roadway > 50 MPa, υ is 0.8 - 1.0 m / s, ω is 15 - 20° / h.

6. The method for directional continuous-discontinuous seam cutting and roof pressure relief in a coal mining face according to claim 1, characterized in that In step S50, the accumulated cutting distance L1 is associated with the horizontal stress of the surrounding rock of the roadway and the distance S1 that the mining chain-arm saw type cutting machine moves along the roadway center line towards the end away from the goaf: When 0 < the horizontal stress of the surrounding rock of the roadway ≤ 8 MPa, L1 is set to (4.5 - 5.5)S1; When 8 < the horizontal stress of the surrounding rock of the roadway ≤ 25 MPa, L1 is set to (3.5 - 4.5)S1; When the horizontal stress of the surrounding rock of the roadway > 25 MPa, L1 is set to (2.5 - 3.5)S1.

7. The method for directional continuous-discontinuous seam cutting and roof pressure relief in a coal mining face according to claim 1, characterized in that In step S60, the stemming depth H is one-third of the length of the charged explosive; the blasting distance L2 is associated with the face length and the mine working system: When the mine has a three-shift-eight-hours working system, L2 is one-third of the face length; When the mine has a four-shift-six-hours working system, L2 is one-fourth of the face length.

8. The method for directional continuous-discontinuous slotting and roof cutting pressure relief in a coal mining face according to claim 1, characterized in that In step S80, the row spacing M of the unit support, the support resistance P2, are associated with the roadway burial depth: When the roadway burial depth > 600 m, P2 = 2500 KN, M2 is 0.8 - 1.5 m; When the roadway burial depth ≤ 600 m, P2 = 1800 KN, M2 is 1.5 - 2.2 m.

9. The method for directional continuous-discontinuous slotting and roof cutting pressure relief in a coal mining face according to claim 1, wherein In step S90, the accumulated distance L3 of the unit support is associated with the uniaxial compressive strength of the immediate roof of the roadway, and the accumulated cutting distance exceeds L1: When 0 MPa < the uniaxial compressive strength of the immediate roof of the roadway ≤ 25 MPa, L3 is (0.30 - 0.35)L1; When 25 MPa < the uniaxial compressive strength of the immediate roof of the roadway ≤ 35 MPa, L3 is (0.35 - 0.40)L1; When the uniaxial compressive strength of the immediate roof of the roadway > 35 MPa, L3 is (0.40 - 0.45)L1.

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