Layered top cutting method for abrasive water jet top plate

Abstract

The invention discloses an abrasive water jet top plate layered top cutting method which comprises the following steps: S100, determining a weak plane position according to a top plate rock stratum structure and a use purpose so as to layer and weaken a top plate rock stratum; s200, drilling parameters are determined according to the weak plane position and numerical simulation, and construction is conducted; s300, grooving is conducted on the inner wall of the drilled hole; s400, hydraulic fracturing is carried out based on the annular cutting groove; s500, under the action of mine pressure, the fractured top plate is caved along the weak plane; abrasive water jet roof layering top cutting is carried out on the needed weak plane, the expansion direction of rock stratum cracks can be effectively controlled in the preset roof rock stratum position and direction, the preset roof rock stratum weak plane can be formed, and a thick and hard roof rock stratum is broken and caved at the weak plane under the mine pressure effect, so that uncertainty and risks are reduced, and the rock stratum fracture rate is increased. And the damage of the thick and hard roof rock stratum suspended roof to a stope face and surrounding roadways is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining, in particular to a method for layered top cutting of an abrasive water jet top plate. Background Art

[0002] In the case of collapse-type roof mining, due to the presence of thick and hard rock layers on the coal seam, the two ends of the working face are not easy to fall out as they are mined, resulting in a large area of ​​suspended roof; when leaving a lane along the goaf, the roof on the goaf side is not easy to fall out, forming a suspended roof on the goaf side of the goaf along the goaf; when the working face is first mined, due to the hard roof, the initial pressure step is too large, all of which affect coal mine production and safety. In order to solve these problems, pre-splitting blasting or hydraulic fracturing is usually used to destroy the roof rock layer.

[0003] Pre-splitting blasting has the problems of small impact range, and the explosion of explosives may produce carbon monoxide. Traditional hydraulic fracturing injects high-pressure water into the borehole through high-pressure equipment. There is uncertainty in the cracking direction and cracking layer, and the location of the weak surface of the roof cannot be effectively controlled. The effect is not ideal, which restricts the use value of this technology.

[0004] Therefore, it is necessary to design a method for layered top cutting of abrasive water jet top plates. Summary of the invention

[0005] The object of the present invention is to provide a method for layered top cutting of an abrasive water jet top plate to solve the problems raised in the above background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A method for layered top cutting of an abrasive water jet top plate comprises the following steps:

[0008] S100, determining the weak surface position according to the roof rock layer structure and the purpose of use, thereby stratifying and weakening the roof rock layer;

[0009] S200, determining drilling parameters according to the weak surface position and numerical simulation, and performing construction;

[0010] S300, cutting grooves on the inner wall of the drilled hole;

[0011] S400, hydraulic fracturing based on annular grooving;

[0012] S500, under the action of mine pressure, the fractured roof falls down along the weak surface.

[0013] According to the above technical solution, the specific method of S200 is as follows:

[0014] S201. Determine the influence range of the weak surface through FLAC3D numerical simulation;

[0015] S202, determining the spacing of the boreholes, the annular grooves, and the hydraulic fracturing spacing through 3DEC numerical simulation, and finally determining the parameters of the boreholes;

[0016] S203, construction is carried out according to the designed drilling parameters, and during construction, the drilling rig is used to adjust the drill rod azimuth, and the drilling depth is confirmed by recording the number of drill rods entering the hole to ensure that the depth of the drilling hole meets the designed depth.

[0017] According to the above technical solution, the specific steps of S300 are as follows:

[0018] S301, using a drilling rig to deliver a double-layer high-pressure drill pipe and a hydraulic punch to the first annular grooving point at the bottom of the hole;

[0019] S302, turning on the abrasive water jet cutting slit pressure relief device to generate an abrasive water jet through the pipeline, the guide, the double-layer high-pressure drill pipe, and the nozzle of the hydraulic punch;

[0020] S303, rotating the hydraulic puncher so that the abrasive water jet cuts the hole wall of the drilled hole in an annular direction to form an annular groove;

[0021] S304, back off the drill, and repeat steps S301 to S303 to perform grooving construction on subsequent annular grooving points until all the designed annular grooving points are completed.

[0022] According to the above technical solution, the specific steps of S400 are as follows:

[0023] S401, sending a fixed-point hole sealer to the first fracturing point through a high-pressure sealing drill pipe;

[0024] S402, turning on the high-pressure water pump of the abrasive water jet type slotting pressure relief device, so that the high-pressure water reaches the fixed-point hole sealer through the high-pressure sealing drill pipe, so that the two expansion capsules of the fixed-point hole sealer expand, thereby completing the rock formation sealing;

[0025] S403, high pressure water cuts the rock formation along the annular cutting groove position;

[0026] S404, after the first fracturing point is completed, the drill is withdrawn, and steps S401 to S403 are repeated to hydraulically fracture the subsequent fracturing points until all fracturing is completed.

[0027] According to the above technical solution, the construction parameters of the annular grooving are as follows:

[0028] The construction time is 5-10min, the grooving depth is 10-20cm, the abrasive water jet flow rate is 50L / min, the abrasive water jet pressure is 35-40MPa, the nozzle diameter of the hydraulic punch is Φ1.0-1.5mm, the abrasive particle size is 60-80 mesh, and the abrasive concentration is 5%-10%.

[0029] According to the above technical solution, the fixed-point hole sealer of S402 includes an upper expansion capsule, a lower expansion capsule and a connecting steel pipe. The upper expansion capsule and the lower expansion capsule are connected through a connecting steel pipe. A water outlet is opened in the middle of the connecting steel pipe. The bottom end of the lower expansion capsule is connected to a high-pressure sealing drill pipe. The working steps are as follows:

[0030] A) Turn on the high-pressure water pump, and the high-pressure water reaches the lower expansion capsule through the pipeline, the deflector, and the high-pressure sealed drill pipe, and flows out from the water outlet on the telescopic rod in the lower expansion capsule to expand the lower expansion capsule;

[0031] B) After the lower expansion capsule is placed, the water volume in the lower expansion capsule, the pipeline and the guide device reaches a water balance state, and the high-pressure water pump continues to inject water to reach the water outlet in the middle of the connecting steel pipe. When the pumped water volume is greater than the total volume of the pipeline, the guide device and the connecting steel pipe, the water flowing out of the water outlet of the connecting steel pipe is removed, and the remaining water reaches the upper expansion capsule, causing the upper expansion capsule to expand;

[0032] C) After the lower expansion capsule (702) and the upper expansion capsule (703) are both expanded, a closed space is temporarily formed between the two. At this time, high-pressure water flow is continuously injected to form stress concentration in the annular groove (5). When the pressure of the high-pressure water is greater than the sum of the tensile strength of the rock formation and the difference between the maximum principal stress and the minimum principal stress, the high-pressure water will split the rock formation along the two groove directions.

[0033] According to the above technical solution, an upper connecting head is fixedly installed on the lower end of the upper expansion capsule, a lower connecting head is fixedly installed on the upper end of the lower expansion capsule, the upper connecting head and the lower connecting head are fixedly combined by connecting steel pipes, a centralizer is fixedly installed on the upper end of the upper expansion capsule through an end compression sleeve, a telescopic rod mounting head is fixedly installed on the lower end of the lower expansion capsule, a telescopic rod is slidably installed in the telescopic rod mounting head, and the lower end of the telescopic tube is connected to the high-pressure sealed drill rod.

[0034] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0035] The present invention can effectively control the expansion direction of rock stratum cracks in a preset roof stratum position and direction by performing abrasive water jet roof layer cutting at the required weak surface, and can create a preset roof stratum weak surface. Under the action of mine pressure, the thick and hard roof stratum is broken and fallen at the weak surface, thereby reducing uncertainty and risk and greatly reducing the harm of the hanging roof of the thick and hard roof stratum to the mining working face and its surrounding tunnels. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is the construction structure diagram of the roof rock strata of different layers of the present invention;

[0037] Figure 2 for Figure 1 Schematic diagram of stress rupture at point A in the middle;

[0038] Figure 3 for Figure 1 The structure diagram of the annular groove at B in the middle;

[0039] Figure 4 The schematic diagram of the annular grooving principle of the present invention;

[0040] Figure 5 for Figure 6 The grooving state diagram at D in the middle;

[0041] Figure 6 This is a schematic diagram of the expansion pressure structure of the present invention;

[0042] Figure 7 for Figure 4 The flushing pressure status diagram at C in the middle;

[0043] Figure 8 It is a schematic diagram of the structure of the fixed-point hole sealer of the present invention.

[0044] In the figure: 1. tunnel, 2. roof rock layer, 3. borehole, 4. fracturing mark, 5. annular groove, 6. stress direction, 7. fixed-point hole sealer, 701. connecting steel pipe, 702. lower expansion capsule, 703. upper expansion capsule, 704. centralizer, 705. lower connecting head, 706. upper connecting head, 707. telescopic rod, 708. telescopic rod mounting head, 8. high-pressure sealed drill pipe, 9. high-pressure water pump, 10. deflector, 11. hydraulic puncher, 12. double-layer sealed drill pipe. DETAILED DESCRIPTION

[0045] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0046] like Figure 1-8 As shown, the present invention provides a technical solution: a method for layered top cutting of an abrasive water jet top plate, comprising the following steps:

[0047] S100, determining the position of the weak surface according to the structure of the roof rock layer 2 and the purpose of use, thereby stratifying and weakening the roof rock layer 2;

[0048] S200, determining the parameters of the drilling hole 3 according to the weak surface position and numerical simulation, and performing construction;

[0049] S300, cutting grooves on the inner wall of the borehole 3;

[0050] S400, performing hydraulic fracturing based on the annular groove 5;

[0051] S500, under the action of mine pressure, the fractured roof falls down along the weak surface.

[0052] Specifically, the specific method of S200 is as follows:

[0053] S201. Determine the influence range of the weak surface through FLAC3D numerical simulation;

[0054] S202, determining the spacing of the borehole 3, the annular groove 5, and the hydraulic fracturing spacing through 3DEC numerical simulation, and finally determining the parameters of the borehole 3;

[0055] S203, construction is performed according to the designed parameters of the borehole 3, and during construction, the drill rig is used to adjust the drill rod azimuth, and the drilling depth is confirmed by recording the number of drill rods entering the hole to ensure that the depth of the borehole 3 meets the designed depth.

[0056] Specifically, the specific steps of S300 are as follows:

[0057] S301, using a drilling rig to deliver the double-layer high-pressure drill pipe 12 and the hydraulic punch 11 to the first annular groove 5 at the bottom of the hole;

[0058] S302, turning on the abrasive water jet cutting slit pressure relief device to generate an abrasive water jet through the pipeline, the guide device 10, the double-layer high-pressure drill pipe 12, and the nozzle of the hydraulic punch 11;

[0059] S303, rotating the hydraulic punch 11, so that the abrasive water jet cuts the hole wall of the drill hole 3 in an annular direction, forming an annular groove 5;

[0060] S304, back off the drill, and repeat steps S301 to S303 to perform grooving construction on the subsequent annular groove 5 points, until all the designed annular groove 5 points are completed.

[0061] Specifically, the specific steps of S400 are as follows:

[0062] S401, sending the fixed-point sealer 7 to the first fracturing point through the high-pressure sealing drill pipe 8;

[0063] S402, turning on the high-pressure water pump 9 of the abrasive water jet type slotting pressure relief device, and high-pressure water reaches the fixed-point hole sealer 7 through the high-pressure sealing drill pipe 8, so that the two expansion capsules of the fixed-point hole sealer 7 expand, completing the rock formation sealing;

[0064] S403, high pressure water cuts the rock layer along the position of the annular cutting groove 5;

[0065] S404, after the first fracturing point is completed, the drill is withdrawn, and steps S401 to S403 are repeated to hydraulically fracture the subsequent fracturing points until all fracturing is completed.

[0066] Specifically, the construction parameters of the annular grooving 5 are as follows:

[0067] The construction time is 5-10min, the grooving depth is 10-20cm, the abrasive water jet flow rate is 50L / min, the abrasive water jet pressure is 35-40MPa, the nozzle diameter of the hydraulic punch 11 is Φ1.0-1.5mm, the abrasive particle size is 60-80 mesh, and the abrasive concentration is 5%-10%.

[0068] Specifically, the fixed-point hole sealer 7 of S402 includes an upper expansion capsule 703, a lower expansion capsule 702 and a connecting steel pipe 701. The upper expansion capsule 703 and the lower expansion capsule 702 are connected through the connecting steel pipe 701. A water outlet is opened in the middle of the connecting steel pipe 701. The bottom end of the lower expansion capsule 702 is connected to the high-pressure sealing drill pipe 8. The working steps are as follows:

[0069] A) Turn on the high-pressure water pump 9, and the high-pressure water reaches the lower expansion capsule 702 through the pipeline, the flow guide 10, and the high-pressure sealing drill rod 8, and flows out from the water outlet on the telescopic rod mounting head 708 in the lower expansion capsule 702, expanding the lower expansion capsule 702;

[0070] B) After the lower expansion capsule 702 is lowered, the water volume in the lower expansion capsule 702, the pipeline and the deflector 10 reaches a state of water balance, and the high-pressure water pump 9 continues to inject water to the water outlet in the middle of the connecting steel pipe 701. When the pumped water volume is greater than the total volume of the pipeline, the deflector 10 and the connecting steel pipe 701, the water flowing out of the water outlet of the connecting steel pipe 701 is removed, and the remaining water reaches the upper expansion capsule 703, causing the upper expansion capsule 703 to expand;

[0071] C) After the lower expansion capsule (702) and the upper expansion capsule (703) are both expanded, a closed space is temporarily formed between the two. At this time, high-pressure water flow is continuously injected to form stress concentration in the annular groove (5). When the pressure of the high-pressure water is greater than the sum of the tensile strength of the rock formation and the difference between the maximum principal stress and the minimum principal stress, the high-pressure water will split the rock formation along the two groove directions.

[0072] Specifically, an upper connecting head 706 is fixedly installed on the lower end of the upper expansion capsule 703, and a lower connecting head 705 is fixedly installed on the upper end of the lower expansion capsule 702. The upper connecting head 706 and the lower connecting head 705 are fixedly combined by connecting a steel pipe 701. A straightener 704 is fixedly installed on the upper end of the upper expansion capsule 703 through an end compression sleeve. A telescopic rod mounting head 708 is fixedly installed on the lower end of the lower expansion capsule 702. A telescopic rod mounting head 708 is slidably installed in the telescopic rod mounting head 708. The lower end of the telescopic tube is connected to the high-pressure sealed drill pipe 8.

[0073] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0074] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for layered top cutting of abrasive water jet top plate, characterized in that: The following steps are involved: S100, determining the position of the weak surface according to the structure of the roof rock layer (2) and the purpose of use, thereby stratifying and weakening the roof rock layer (2); S200, determining the parameters of the drilling (3) according to the weak surface position and numerical simulation, and performing construction; S300, cutting grooves on the inner wall of the borehole (3); S400, performing hydraulic fracturing based on the annular groove (5); S500, under the action of mine pressure, the fractured roof falls down along the weak surface.

2. The method for layered top cutting of abrasive water jet top plate according to claim 1, characterized in that: The specific method of S200 is as follows: S201. Determine the influence range of the weak surface through FLAC3D numerical simulation; S202, determining the spacing of the boreholes (3), the annular grooves (5), and the hydraulic fracturing spacing through 3DEC numerical simulation, and finally determining the parameters of the boreholes (3); S203, construction is carried out according to the designed parameters of the borehole (3), and during construction, the drill rig is used to adjust the drill rod azimuth, and the drilling depth is confirmed by recording the number of drill rods entering the hole, so as to ensure that the depth of the borehole (3) meets the designed depth.

3. The method for layered top cutting of abrasive water jet top plate according to claim 1, characterized in that: The specific steps of S300 are as follows: S301, using a drilling rig to deliver a double-layer high-pressure drill pipe (12) and a hydraulic punch (11) to the first annular groove (5) point at the bottom of the hole; S302, opening the abrasive water jet type cutting slit pressure relief device to generate an abrasive water jet through the pipeline, the guide device (10), the double-layer high-pressure drill pipe (12), and the nozzle of the hydraulic punch (11); S303, rotating the hydraulic punch (11) so that the abrasive water jet cuts the hole wall of the drill hole (3) in an annular direction to form an annular groove (5); S304, back off the drill, and repeat steps S301 to S303 to perform grooving construction on subsequent annular groove (5) points, until all the designed annular groove (5) points are completed.

4. The method for layered top cutting of abrasive water jet top plate according to claim 1, characterized in that: The specific steps of S400 are as follows: S401, sending the fixed-point hole sealer (7) to the first fracturing point through the high-pressure sealing drill pipe (8); S402, turning on the high-pressure water pump (9) of the abrasive water jet type slotting pressure relief device, so that the high-pressure water reaches the fixed-point hole sealer (7) through the high-pressure sealing drill pipe (8), causing the two expansion capsules of the fixed-point hole sealer (7) to expand, thereby completing the sealing of the rock formation; S403, high pressure water cuts the rock layer along the position of the annular cutting groove (5); S404: After the first fracturing point is completed, the drill is withdrawn and steps S401 to S403 are repeated to hydraulically fracture the subsequent fracturing points until all fracturing is completed.

5. The method for layered top cutting of abrasive water jet top plate according to claim 3, characterized in that: The construction parameters of the annular grooving (5) are as follows: The construction time is 5-10min, the grooving depth is 10-20cm, the abrasive water jet flow rate is 50L / min, the abrasive water jet pressure is 35-40MPa, the nozzle diameter of the hydraulic punch (11) is Φ1.0-1.5mm, the abrasive particle size is 60-80 mesh, and the abrasive concentration is 5%-10%.

6. The method for layered top cutting of abrasive water jet top plate according to claim 4, characterized in that: The fixed-point hole sealer (7) of S402 comprises an upper expansion capsule (703), a lower expansion capsule (702) and a connecting steel pipe (701), wherein the upper expansion capsule (703) and the lower expansion capsule (702) are connected via the connecting steel pipe (701), a water outlet is provided in the middle of the connecting steel pipe (701), and the bottom end of the lower expansion capsule (702) is connected to a high-pressure sealing drill pipe (8), and the working steps are as follows: A) turning on the high-pressure water pump (9), the high-pressure water reaches the lower expansion capsule (702) through the pipeline, the flow guide (10), and the high-pressure sealing drill rod (8), and flows out from the water outlet on the telescopic rod (707) in the lower expansion capsule (702), thereby expanding the lower expansion capsule (702); B) After the lower expansion capsule (702) is placed, the water volume in the lower expansion capsule (702) and the pipeline and the guide device (10) reaches a water volume balance state, and the high-pressure water pump (9) continues to inject water to reach the water outlet in the middle of the connecting steel pipe (701). When the pumped water volume is greater than the total volume of the pipeline, the guide device (10) and the connecting steel pipe (701), the water flowing out of the water outlet of the connecting steel pipe (701) is removed, and the remaining water reaches the upper expansion capsule (703), causing the upper expansion capsule (703) to expand; C) After the lower expansion capsule (702) and the upper expansion capsule (703) are both expanded, a closed space is temporarily formed between the two. At this time, high-pressure water flow is continuously injected to form stress concentration in the annular groove (5). When the pressure of the high-pressure water is greater than the sum of the tensile strength of the rock formation and the difference between the maximum principal stress and the minimum principal stress, the high-pressure water will split the rock formation along the two groove directions.

7. The method for layered top cutting of abrasive water jet top plate according to claim 6, characterized in that: An upper connecting head (706) is fixedly installed at the lower end of the upper expansion capsule (703), and a lower connecting head (705) is fixedly installed at the upper end of the lower expansion capsule (702). The upper connecting head (706) and the lower connecting head (705) are fixedly assembled via a connecting steel pipe (701). A centralizer (704) is fixedly installed at the upper end of the upper expansion capsule (703) via an end compression sleeve. A telescopic rod mounting head (708) is fixedly installed at the lower end of the lower expansion capsule (702), and a telescopic rod (707) is slidably installed in the telescopic rod mounting head (708). The lower end of the telescopic tube is connected to a high-pressure sealed drill pipe (8).

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