A method for improving the top coal caving risk and coordinating the management of strong mine pressure in fully mechanized longwall mining faces

Abstract

This invention discloses a method for improving the top coal caving performance and coordinating the control of strong mine pressure in fully mechanized longwall mining faces. The method includes the following steps: determining the treatment stratum, designing the borehole layout, drilling, electrically controlled fracturing, and outputting equipment from the borehole. The electrically controlled fracturing involves installing multiple fracturing devices into at least one fracturing device roller. Each fracturing device roller has an activation chamber. The drilling rig sends the fracturing device roller to a designated position in the borehole. A voltage is then supplied to the activation chamber under the action of a voltage activation device. When the voltage exceeds the rated voltage, the activation chamber operates, activating the fracturing devices. This achieves instantaneous activation of the fracturing devices under controllable voltage conditions. The electrically controlled fracturing method creates a three-dimensional weakened structure in the treatment stratum, disrupting the overall structure of the overlying roof and top coal on the working face, reducing the strength of the rock and coal mass, and integrating the fracturing effect of the top coal itself. This achieves coordinated forced caving of mine pressure and top coal weakening modification.

Description

Technical Field

[0001] This invention relates to the field of coal mining technology, and in particular to a method for improving the top coal caving risk and coordinating the management of strong mine pressure in fully mechanized longwall mining faces. Background Technology

[0002] my country has abundant coal resources, with thick and extra-thick coal seams accounting for a high proportion of both reserves and production. Fully mechanized longwall mining technology, due to its large production capacity, high efficiency, and good economic benefits, has become the preferred method for mining thick and extra-thick coal seams.

[0003] With the deepening of coal mining and the use of top-coal caving methods in thick coal seams, there are often significant stress concentrations in the roof and the hardness of the top coal, making complete caving difficult. This leads to problems such as strong roof pressure disasters and low coal recovery rates during mining. Existing methods for addressing these issues often include hydraulic fracturing and blasting. However, blasting methods have drawbacks such as the release of harmful gases, uncontrollable energy, and difficulties in obtaining explosive approvals. Hydraulic fracturing technology suffers from uncontrollable fracture direction and size, and a high risk factor associated with high-pressure operations.

[0004] In view of the above-mentioned defects, the designers of this invention have researched and designed a method to improve the top coal caving risk and the synergistic management of strong mine pressure in fully mechanized longwall mining faces, so as to overcome the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for improving the top coal caving risk and coordinating the treatment of strong mine pressure in fully mechanized caving faces. This method solves the problems of difficulty in controlling the direction of fractures and ensuring the treatment effect in current fracturing technology construction, avoids the dangers of high-pressure operations, and realizes remote intelligent fracturing construction.

[0006] The present invention employs a method for improving the top coal (3) caving capability and coordinating the management of strong mine pressure in fully mechanized longwall mining faces.

[0007] Step S1, Determining the treatment layer: Based on the mine geological data, analyze the stress distribution area and stress concentration degree of the working face roof to determine the treatment range, and then determine the treatment layer of the coal seam roof and the treatment layer of the top coal (3);

[0008] Furthermore, the geological structure of the mine includes the basic roof (1), the immediate roof (2), and the top coal (3), with the basic roof (1) and the immediate roof (2) forming the roof;

[0009] Furthermore, theoretical analysis, numerical simulation, physical simulation, and actual mine pressure data are used to analyze the stress distribution area and stress concentration degree of the working face roof, thereby determining the treatment scope;

[0010] Furthermore, based on the characteristics of the overlying strata on the working face, the coal seam mining ratio, and rock mechanics parameters, the treatment strata of the coal seam roof and the treatment strata of the top coal (3) are determined;

[0011] Step S2, Hole layout design: Determine the drilling site location based on the roadway conditions, and determine the treatment stratum of the coal seam roof and the arrangement of boreholes (10) in the treatment stratum of the top coal (3) based on the length of the working face and the treatment range;

[0012] Furthermore, based on the length of the working face and the treatment range, the treatment layer of the coal seam roof and the number of boreholes (10) in the treatment layer of the top coal (3), the design length M of the boreholes (10), the design spacing D of the boreholes (10), the safe distance L between the boreholes (10) and the roadway are determined, and the drilling direction of the boreholes (10) is parallel to the direction of the working face.

[0013] Furthermore, the borehole (10) design spacing D can be set to twice the radius of the fracture-inducing influence;

[0014] Step S3, Drilling (10) construction: Select a drilling machine according to the requirements of the treatment area and use the drilling machine to complete the drilling (10) construction;

[0015] Furthermore, by utilizing the drilling and measurement capabilities of the directional drilling rig, the three-dimensional spatial trajectory information of the borehole (10) is obtained; and by adjusting the working face angle, the actual trajectory of the borehole (10) is ensured to meet the design requirements of the borehole (10), thereby completing the construction of the directional long borehole (10);

[0016] Step S4, Electrically controlled cracking operation: Multiple cracking devices (4) are installed in at least one cracking device roller (6). The cracking device roller (6) is provided with an excitation chamber (11). The cracking device roller (6) is sent into the designated position of the borehole (10) by the drilling machine. Then, under the action of the voltage excitation device (9), voltage is supplied to the excitation chamber (11). When the voltage exceeds the rated voltage, the excitation chamber (11) operates and the excitation chamber (11) excites the cracking device (4) to perform cracking operation.

[0017] Furthermore, multiple crack-inducing devices (4) are installed in multiple crack-inducing device rollers (6), and the multiple crack-inducing device rollers (6) are connected by connecting rods (7) to form multiple sets of crack-inducing devices; under the action of voltage excitation device (9), excitation chamber (11) excites crack-inducing device (4) to perform crack-inducing operation, forming cracks (8), and the range of cracks (8) is the directional crack-inducing range (12). Multiple sets of crack-inducing devices simultaneously perform crack-inducing modification, realizing one-time segmented crack-inducing modification of long borehole (10);

[0018] Alternatively, multiple crack initiators (4) can be installed into a single ultra-large capacity crack initiator roller (6) to form a single set of crack initiators; under the action of the voltage excitation device (9), the excitation chamber (11) excites the crack initiator (4) to carry out cracking operations, realize the first stage of cracking modification, and form the first stage of crack (8); then use the drilling rig to drag the crack initiator roller (6) to the next cracking stage, realize the second stage of cracking modification through the voltage excitation device (9), and form the second stage of crack (8), and complete the entire stage of cracking construction through multiple cycles;

[0019] Furthermore, 50 to 100 sewing machines (4) are stored in the sewing machine roller (6);

[0020] To facilitate guidance, a guide device (5) is provided at the front end of the fracturing device;

[0021] Step S5, Equipment Output in the Hole: After completing the crack-causing modification construction of the entire designed section in the hole, use the drilling rig to remove all equipment in the hole to complete the construction.

[0022] Compared with the prior art, the advantages of the present invention are as follows:

[0023] 1. The treatment method of this invention enables instantaneous activation of the crack initiator under controllable voltage conditions, effectively weakening the thick and hard roof coal and roof. Under the action of the external voltage activation device, multiple activations of a single crack initiation section can be achieved, effectively increasing the number of cracks in the roof coal and roof, and reducing the overall strength;

[0024] 2. The cracking roller of the present invention is provided with an excitation chamber, which can enable precise control of the energy release direction of the cracking device and improve the cracking effect of top coal and roof.

[0025] 3. This invention can realize the one-time insertion of crack initiator rollers at different intervals to achieve one-time segmented crack initiation modification of long boreholes. Alternatively, a single crack initiator roller can be used to install a large-capacity crack initiator, and the drilling rig can be used for drag-type segmented and point-based crack initiation.

[0026] 4. This invention employs numerical simulation, physical simulation, and actual mine pressure data analysis, and combines the effects of top coal venting and coal recovery rate during different periods of working face pressure to quantitatively analyze the coupling relationship between working face pressure step distance and top coal venting.

[0027] 5. This invention utilizes an electrically controlled fracturing method to form a three-dimensional weakened structure in the treatment layer, thereby disrupting the overall structure of the overlying roof and top coal on the working face, reducing the strength of the rock and coal, shortening the pressure step distance of the working face, increasing the frequency of roof fracture disturbance loads, and superimposing with static load stress to increase the stress on the top coal, thereby increasing the degree of top coal fracture under disturbance, and integrating the fracturing and jointing effect of the top coal itself to achieve coordinated forced venting of mine pressure control and top coal weakening transformation. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0029] Figure 1 This is a schematic diagram of the coal seam and roof.

[0030] Figure 2 A schematic diagram of the borehole layout;

[0031] Figure 3 This is a schematic diagram of the borehole layout.

[0032] Figure 4 A schematic diagram of a modification involving simultaneous fracturing using multiple fracturing devices.

[0033] Figure 5 A schematic diagram of a single fracturing device for simultaneous fracturing;

[0034] Figure 6 This is a cross-sectional view of the fracture initiator.

[0035] In the attached diagram, 1-basic roof; 2-direct roof; 3-top coal; 4-fracturer; 5-guide device; 6-fracturer roller; 7-connecting rod; 8-fracture; 9-voltage excitation device; 10-drill hole; 11-excitation chamber; 12-directional fracturing range. Detailed Implementation

[0036] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0037] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by those skilled in the art to which this invention pertains.

[0038] like Figure 1-6 As shown, a method for improving the top coal caving performance and coordinating the management of strong mine pressure in a fully mechanized longwall mining face includes the following steps:

[0039] Step S1, Determining the treatment strata: Based on the mine geological data, analyze the stress distribution area and stress concentration degree of the working face roof to determine the treatment range, and then determine the treatment strata of the coal seam roof and the treatment strata of top coal 3;

[0040] The geological structure of the mine includes the main roof 1, the immediate roof 2, and the top coal 3. The main roof 1 and the immediate roof 2 together form the roof.

[0041] The stress distribution area and stress concentration degree of the working face roof are analyzed by theoretical analysis, numerical simulation, physical simulation and actual mine pressure data, so as to determine the treatment scope; and the treatment strata of the coal seam roof and the treatment strata of top coal 3 are determined based on the characteristics of the overlying strata, the coal seam mining ratio and rock mechanics parameters of the working face.

[0042] Step S2, Hole layout design: Determine the drilling site location based on the roadway conditions, and determine the treatment layer of the coal seam roof and the arrangement of boreholes 10 in the treatment layer of top coal 3 based on the length of the working face and the treatment range.

[0043] like Figure 2 , 3 As shown, the number of boreholes 10 in the roof treatment layer and the top coal 3 treatment layer, the design length M of borehole 10, the design spacing D of borehole 10, and the safety distance L between borehole 10 and the roadway are determined according to the length of the working face and the treatment range. The drilling direction of borehole 10 is parallel to the direction of the working face. The design length of borehole 10 can be set to M1, M2, and M3 respectively, the design spacing of borehole 10 is D1 and D2 respectively, and the safety distances between borehole 10 and the upper and lower parts of the roadway are L1 and L2 respectively.

[0044] Step S3, Drilling 10: Select a drilling rig according to the requirements of the treatment area and use the drilling rig to complete the drilling 10 construction;

[0045] To ensure the smooth construction of borehole 10, a directional drilling rig was selected to drill borehole 10. The directional drilling rig's ability to perform drilling and testing was utilized to obtain the three-dimensional spatial trajectory information of borehole 10. By adjusting the working face angle, the actual trajectory of borehole 10 was ensured to meet the design requirements of borehole 10, thereby completing the construction of the long directional borehole 10.

[0046] Step S4, Electrically controlled cracking operation: Multiple cracking devices 4 are installed in at least one cracking device roller 6. The cracking device roller 6 is provided with an excitation chamber 11. The cracking device roller 6 is sent into the designated position of the drill hole 10 by the drilling machine. Then, under the action of the voltage excitation device 9, voltage is supplied to the excitation chamber 11. When the voltage exceeds the rated voltage, the excitation chamber 11 operates and the excitation chamber 11 excites the cracking device 4 to perform cracking operation.

[0047] like Figure 4 As shown, multiple crack-inducing devices 4 can be installed in multiple crack-inducing device rollers 6, and the multiple crack-inducing device rollers 6 are connected by connecting rods 7 to form multiple sets of crack-inducing devices; under the action of voltage excitation device 9, excitation chamber 11 excites crack-inducing device 4 to perform crack-inducing operation, forming cracks 8, and the range of cracks 8 is the directional crack-inducing range 12. Multiple sets of crack-inducing devices simultaneously carry out crack-inducing modification, realizing one-time segmented crack-inducing modification of long borehole 10.

[0048] like Figure 5As shown, multiple crack initiators 4 are installed into a single ultra-large capacity crack initiator roller 6 to form a single set of crack initiators; under the action of voltage excitation device 9, excitation chamber 11 excites crack initiator 4 to carry out cracking operation, realizing the first stage of cracking modification and forming the first stage of crack 8; then the drilling rig is used to drag the crack initiator roller 6 to the next cracking stage, and the voltage excitation device 9 realizes the second stage of cracking modification, forming the second stage of crack 8, and the entire cracking construction is completed by multiple cycles;

[0049] To facilitate crack initiation, 50 to 100 crack initiators 4 are stored in the crack initiator roller 6;

[0050] To facilitate guidance, a guide device 5 is installed at the front end of the fracturing device;

[0051] Step S5, Equipment Output in the Hole: After completing the crack-causing modification construction of the entire designed section in the hole, use the drilling rig to remove all equipment in the hole to complete the construction.

[0052] The working principle of this invention is as follows: The cracking roller is equipped with an excitation chamber and a cracking device. Under the action of an external voltage excitation device, the cracking device is instantaneously excited under controllable voltage conditions. This enables the formation of a three-dimensional weakened structure in the treatment layer using the electrically controlled cracking method, thereby destroying the overall structure of the overlying roof and top coal on the working face, reducing the strength of the rock and coal, shortening the pressure step distance of the working face, increasing the frequency of roof fracture disturbance loads, and superimposing with static load stress to increase the stress on the top coal, thereby increasing the degree of top coal fracture under disturbance. This, combined with the cracking and fracturing effect of the top coal itself, achieves coordinated forced release of mine pressure control and top coal weakening transformation.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for improving the top coal caving safety and coordinating the management of strong mine pressure in a fully mechanized longwall mining face, comprising the following steps: Step S1, Determining the treatment layer: Based on the mine geological data, analyze the stress distribution area and stress concentration degree of the working face roof to determine the treatment range, and then determine the treatment layer of the coal seam roof and the treatment layer of the top coal. Step S2, Hole layout design: Determine the drilling site location based on the roadway conditions, and determine the coal seam roof treatment stratum and the borehole layout in the roof coal treatment stratum based on the working face length and treatment range; Step S3, Drilling: Select a drilling rig according to the requirements of the treatment area and use the drilling rig to complete the drilling. Step S4, Electrically Controlled Fracture Construction: Multiple fracture actuators are installed in multiple fracture actuator rollers. The multiple fracture actuator rollers are connected by connecting rods to form multiple sets of fracture actuators. Each fracture actuator roller is equipped with an excitation chamber. The fracture actuator roller is sent into the designated position of the borehole by a drilling rig. Then, under the action of a voltage excitation device, voltage is supplied to the excitation chamber. When the voltage exceeds the rated voltage, the excitation chamber operates. Multiple sets of fracture actuators simultaneously fracture and modify the borehole, realizing one-time segmented fracture modification of long boreholes. Step S5, Equipment Output in the Hole: After completing the crack-causing modification construction of the entire designed section in the hole, use the drilling rig to remove all equipment in the hole to complete the construction.

2. The method for improving the top coal caving resistance and coordinating the management of strong mine pressure in a fully mechanized longwall mining face according to claim 1, characterized in that: In step S1, theoretical analysis, numerical simulation, physical simulation, and actual mine pressure data are used to analyze the stress distribution area and stress concentration degree of the working face roof, thereby determining the treatment scope.

3. The method for improving the top coal caving resistance and coordinating the management of strong mine pressure in a fully mechanized longwall mining face according to claim 2, characterized in that: In step S1, the treatment strata of the coal seam roof and the treatment strata of the top coal are determined based on the characteristics of the overlying strata on the working face, the coal seam mining ratio, and rock mechanical parameters.

4. The method for improving the top coal caving resistance and coordinating the management of strong mine pressure in a fully mechanized longwall mining face according to claim 1, characterized in that: The treatment strata of the coal seam roof and the number of boreholes, the design length M of the boreholes, the design spacing D of the boreholes, and the safe distance L between the boreholes and the roadway are determined based on the length of the working face and the treatment range.

5. The method for improving the top coal caving risk and coordinating the management of strong mine pressure in a fully mechanized longwall mining face according to claim 4, characterized in that: In step S2, the drilling direction is parallel to the direction of the working face.

6. The method for improving the top coal caving resistance and coordinating the management of strong mine pressure in a fully mechanized longwall mining face according to claim 1, characterized in that: In step S3, the drilling and testing capabilities of the directional drilling rig are utilized to obtain the three-dimensional spatial trajectory information of the borehole.

7. The method for improving the top coal caving resistance and coordinating the management of strong mine pressure in a fully mechanized longwall mining face according to claim 6, characterized in that: In step S3, by adjusting the angle of the working face, the actual borehole trajectory is ensured to meet the borehole design requirements, thereby completing the directional long borehole construction.

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