A directional fracturing roof control and pressure relief device for hard roofs in mines

Abstract

The present invention discloses a directional fracturing roof control and pressure relief device for hard mine roofs, which comprises: a shuttle-shaped hole arranged perpendicular to the hard roof and horizontally, forming a longitudinal dividing surface. A longitudinal fracturing pipe is embedded in the shuttle-shaped hole to divide the hard roof into long strip-shaped hard roofs that are parallel front and back and point left and right; drill holes arranged horizontally, forming a horizontal cutting and moving surface, and the transverse fracturing pipes are sequentially embedded in the drill holes to cut and relieve the pressure on the long strip-shaped hard roofs. A jet cutting device for X-shaped jet cutting is provided in the transverse fracturing pipe to cut the long strip-shaped hard roofs into triangular prisms and quadrangular prisms that point front and back and are longitudinally stacked in cooperation.

Description

Technical Field

[0001] The present invention relates to the technical field of hard roof pressure relief, and specifically to a directional fracturing roof control and pressure relief device for hard roofs in mines. Background Art

[0002] A hard roof is a support layer located above the goaf during coal mining. As the goaf continuously extends and expands, the cavity under the hard roof gradually increases, which may cause the hard roof to be prone to collapse and cracking, posing a great danger. Therefore, it is necessary to divide and relieve the pressure on it to avoid collapse. However, the existing devices for relieving the pressure on hard roofs have poor control over the division shape of the hard roof, resulting in uneven stacking and different cavity sizes of the divided hard roof blocks, and thus the support strength of the stacked hard roof is poor, and there is a potential risk of secondary collapse.

[0003] Therefore, the technical personnel in this field have provided a directional fracturing roof control and pressure relief device for hard roofs in mines to solve the problems raised in the above background art. Summary of the Invention

[0004] To achieve the above object, the present invention provides the following technical solution: A directional fracturing roof control and pressure relief device for hard roofs in mines, which includes:

[0005] Spindle-shaped holes arranged horizontally perpendicular to the hard roof to form a longitudinal division surface. By embedding longitudinal fracturing pipes into the spindle-shaped holes, the hard roof is divided into long strip-shaped hard roofs that are parallel front and back and point left and right.

[0006] Horizontally arranged drill holes to form a horizontal cutting and moving surface, and sequentially embed transverse fracturing pipes into the drill holes to cut and relieve the pressure on the long strip-shaped hard roof. And a jet cutting device for X-shaped jet cutting is provided in the transverse fracturing pipe to cut the long strip-shaped hard roof into triangular prisms and quadrangular prisms that point front and back and are longitudinally stacked in cooperation.

[0007] As a preferred technical solution of the present invention, the height of the triangular cross-section of the triangular prism is relatively consistent with the height of the goaf, and the distance between the upper and lower ends of the rhombic cross-section of the quadrangular prism is twice the height of the goaf.

[0008] As a preferred technical solution of the present invention, both the transverse fracturing pipe and the longitudinal fracturing pipe adopt a hydraulic fracturing structure to fracture the hard roof.

[0009] As a preferred technical solution of the present invention, the jet cutting device includes:

[0010] The jet sub-pipes are coaxially arranged with the horizontal fracturing pipe and axially linearly arranged. In the jet sub-pipes, a shunt arc cavity and a swing arc cavity that are coaxially arranged and centrosymmetric are successively formed from the inside to the outside. Two groups of shunt arc cavities are formed, and four groups of swing arc cavities are formed. The shunt arc cavity, the swing arc cavity, and the horizontal fracturing pipe are interconnected.

[0011] The shunt block, the front side of its semi-elliptical arc-shaped convex part faces the diversion orifice arranged between the shunt arc cavity and the horizontal fracturing pipe.

[0012] The check arc plate is symmetrically installed left and right and is installed obliquely upward on the inner wall of the shunt arc cavity outside the diversion orifice.

[0013] The swing guide rail coaxially installed in the swing arc cavity, and a jet cutting assembly is installed on the swing guide rail.

[0014] As a preferred technical solution of the present invention, the spacing between the coaxially linearly arranged jet sub-pipes is 3m.

[0015] As a preferred technical solution of the present invention, the jet cutting assembly includes:

[0016] The swing box seat slidably connected to the swing arc rail, the arc-shaped side end of which is installed with a guiding swing block embedded in the inner side of the swing arc rail, and a flow-blocking limit plate radially pointing and transversely intercepting the arc-shaped chamber of the shunt arc cavity is installed on the inner end seat on the side of the swing box seat close to the arc-shaped side end wall of the shunt arc cavity. And the guiding swing blocks on the left and right sides of the swing box seat are respectively connected to the inner side wall of the swing arc cavity through a first return spring and a second return spring.

[0017] The fracturing nozzle radially pointing and installed in the swing box seat, and a flow control spray sleeve for changing the jet orifice diameter of the fracturing fluid is installed on the fracturing nozzle.

[0018] As a preferred technical solution of the present invention, the jet orifice diameters of the flow control spray sleeves in the jet cutting assemblies located at the lower right, upper right, upper left, and lower left corners in sequence increase in sequence.

[0019] As a preferred technical solution of the present invention, the fracturing nozzle swings under the impact of the fracturing fluid with periodic pressurization and depressurization, and the swing amplitude angle is between 30° - α and 30° + α.

[0020] As a preferred technical solution of the present invention, the straight line connected by the spindle-shaped holes on the front and rear sides is located in the middle of the adjacent drill holes.

[0021] Compared with the prior art, the present invention provides a directional fracturing roof control and pressure relief device for hard roofs in mines, and has the following beneficial effects:

[0022] In the present invention, the hard roof is cut by the relative cutting forms of triangular prisms and quadrangular prisms, and the hard roof is optimally cut according to the height of the goaf, so that the volume of the hard roof cut by the jet cutting at the bottom is not too large or too small, and the jet cutting blocks are stacked in an orderly manner in a relatively regular and symmetrical manner, which not only improves the filling degree and stability strength of the goaf, but also greatly improves the safety of the falling of the cutting blocks of the hard roof and the implementation process. An erosion area at a certain angle is selected for the cutting surface area, and the fracturing fluid after the corresponding cutting surface is completed relatively acts as a lubricant and an auxiliary guiding role to promote the movement of the hard roof after cutting, and then it is convenient for the hard roof to fall off instantaneously, during the falling process, and the stacking process to be more orderly and controllable. In the slit cavity of the stacked hard roof, the fracturing fluid can be filled evenly and smoothly, so that the hard roof after cutting is more firm. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 FIG. 1 is a schematic structural diagram of the first embodiment of the directional fracturing roof control and pressure relief device of the present invention;

[0024] Figure 2 FIG. 2 is a schematic structural diagram of the second embodiment of the directional fracturing roof control and pressure relief device of the present invention;

[0025] Figure 3 FIG. 3 is an enlarged schematic view of a partial cross-sectional structure of the jet cutting device of the present invention;

[0026] Figure 4 FIG. 4 is a partial schematic view of the implementation structure of the hard roof fracturing and pressure relief of the present invention;

[0027] In the figure: 1, hard roof; 2, goaf; 3, borehole; 4, transverse fracturing pipe; 5, jet cutting device; 6, spindle-shaped hole; 7, longitudinal fracturing pipe; 8, jet cutting assembly; 51, jet branch pipe; 52, shunt arc cavity; 53, swing arc cavity; 54, swing guide rail; 55, shunt block; 56, check arc plate; 81, swing box seat; 82, guiding swing block; 83, first return spring; 84, second return spring; 85, flow blocking and limiting plate; 86, fracturing nozzle; 87, flow control spray sleeve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] Referring to Figures 1-4 , the present invention provides a technical solution: a directional fracturing roof control and pressure relief device for hard roofs in mines, which includes:

[0029] The spindle-shaped holes 6 arranged vertically and horizontally with respect to the hard roof 1 form a longitudinal dividing surface. The longitudinal fracturing pipe 7 is inserted into the spindle-shaped holes 6 to divide the hard roof 1 into long strip-shaped hard roofs that are parallel front and back and point left and right;

[0030] The horizontally arranged drill holes 3 form a horizontal cutting and moving surface, and the horizontal fracturing pipes 4 are sequentially embedded in the drill holes 3 to cut and relieve pressure on the long strip-shaped hard roof. And a jet cutting device 5 for X-shaped jet cutting is arranged in the horizontal fracturing pipe 4 to cut the long strip-shaped hard roof into triangular prisms and quadrangular prisms that point forward and backward and are longitudinally stacked in cooperation;

[0031] It should be noted that fusiform holes can be drilled in the hard roof first, longitudinal fracturing pipes can be embedded in each group of fusiform holes, and they can be started synchronously to divide the hard roof. Then, drill holes are drilled in the long strip-shaped hard roof, and jet cutting is carried out through the jet cutting device in sequence.

[0032] In this embodiment, the height of the triangular cross-section of the triangular prism is relatively consistent with the height of the goaf 2, and the distance between the upper and lower ends of the rhombic cross-section of the quadrangular prism is twice the height of the goaf 2. Thus, the volume of the hard roof cut by jet cutting at the bottom falling into the goaf is not too large or too small, and the jet cutting blocks are stacked orderly in a relatively regular and symmetrical manner, which not only improves the filling degree and stability strength of the goaf, but also greatly improves the safety during the falling of the cutting blocks of the hard roof and the implementation process.

[0033] In this embodiment, both the horizontal fracturing pipe 4 and the longitudinal fracturing pipe 7 adopt a hydraulic fracturing structure to fracture the hard roof 1, so that the cutting surface of the hard roof is relatively symmetrical, and it is more convenient for the hard roof to fall off instantaneously, during the falling process, and during the stacking process to be more orderly and controllable.

[0034] In this embodiment, the jet cutting device 5 includes:

[0035] Jet sub-pipes 51 arranged coaxially with the horizontal fracturing pipe 4 and linearly arranged axially. Coaxially arranged and centrally symmetric shunt arc cavities 52 and swing arc cavities 53 are sequentially opened in the jet sub-pipes 51 from the inside to the outside. And two groups of shunt arc cavities 52 are opened, and four groups of swing arc cavities 53 are opened. The shunt arc cavities 52, the swing arc cavities 53, and the horizontal fracturing pipe 4 are communicated with each other;

[0036] A shunt block 55, the semi-elliptical arc convex part of which faces the diversion port arranged between the shunt arc cavity 52 and the horizontal fracturing pipe 4 to divert and separate the fracturing fluid inside the horizontal fracturing pipe;

[0037] A check arc plate 56, which is symmetrically installed on the left and right and is installed obliquely upward on the inner wall of the shunt arc cavity 52 outside the diversion port, cooperates with the shunt block to divert the fracturing fluid, and further reduces the diversion diameter to perform secondary pressurization on the fracturing fluid;

[0038] A swing guide rail 54 coaxially installed in the swing arc cavity 53, and a jet cutting assembly 8 is installed on the swing guide rail 54.

[0039] In this embodiment, the spacing between the jet branch pipes 51 arranged coaxially and linearly is 3 m, thereby improving the efficiency of jet cutting and the smoothness at the moment when the hard roof falls off.

[0040] In this embodiment, the jet cutting assembly 8 includes:

[0041] A swing box seat 81 slidably connected to the swing arc rail 54, with a guiding swing block 83 embedded in the inner side of the swing arc rail 54 installed at its arc-shaped side end. A flow-blocking and limiting plate 85 radially pointing and transverse to the arc-shaped chamber of the flow-dividing arc chamber 52 is installed on the inner end seat on one side of the arc-shaped side end wall of the flow-dividing arc chamber 52. The guiding swing blocks 83 located on the left and right sides of the swing box seat 81 are respectively connected to the inner side wall of the swing arc chamber 53 through a first return spring 83 and a second return spring 84;

[0042] A fracturing nozzle 86 radially pointing and installed in the swing box seat 81, and a flow-control spray sleeve 87 for changing the jet diameter of the fracturing fluid is installed on the fracturing nozzle 86. Through the impact of the fracturing fluid and the flow blocking of the flow-blocking and limiting plate, the fracturing nozzle is urged to swing, so as to erode a certain area of the dividing surface of the hard roof, thereby reducing the frictional pressure intensity on the transverse fracturing pipe during the sliding process, as well as the smoothness and accuracy of the falling and stacking of the hard roof, and making the gap form formed by the stacking more uniform. It can also cooperate with the filling of the fracturing fluid to make the stacked hard roof more firm, easy to fill, and with a better filling effect.

[0043] In this embodiment, the jet diameters of the flow-control spray sleeves 87 in the jet cutting assemblies 8 located in the lower right, upper right, upper left, and lower left corners in sequence increase, and they move and cut from left to right. Each time during cutting, when the hard roof is separated by the jet, the cutting rates of its cutting surfaces are arranged from large to small as the lower right cutting surface, the upper right cutting surface, the upper left cutting surface, and the lower left cutting surface. The falling-off sequence and falling-off displacement trajectory of the formed triangular prism and quadrangular prism are as Figure 4 shown. It should be noted here that during the falling-off process, the fracturing fluid corresponding to the cutting surface relatively acts as a lubricant and an auxiliary guiding function to promote the movement of the hard roof after cutting.

[0044] In this embodiment, the fracturing nozzle 86 swings under the impact of the fracturing fluid with periodic pressure increase and decrease, and the swing amplitude angle is between 30° - α and 30° + α, so as to erode the hard roof by an arc center angle of 2α. As the best embodiment, α is selected as an included angle of 2.5° as the erosion area.

[0045] In this embodiment, the straight line connected by the spindle-shaped holes 6 on the front and rear sides is located in the middle of the adjacent drill holes 3, promoting more symmetrical division of the hard roof.

[0046] In specific implementation, it includes the following steps:

[0047] S1: According to the height of the goaf, select the height of the triangular cross-section to be divided into triangular prisms, the spacing length between the upper and lower ends of the rhombic cross-section of the quadrangular prism, and set the front and rear spacing of the shuttle-shaped holes for segmentation, drill the shuttle-shaped holes, embed longitudinal fracturing pipes into each group of shuttle-shaped holes, and start synchronously to divide the hard roof into strip-shaped hard roofs;

[0048] S2: Then drill holes in the strip-shaped hard roof, and perform jet cutting through a jet cutting device in sequence, and select α as 2.5° as the erosion area to complete the cutting of the hard roof in sequence, so as to complete the pressure relief of the hard roof.

[0049] As mentioned above, it is only a preferred specific implementation manner of the invention, but the protection scope of the invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the invention, according to the technical solution of the invention and its inventive concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the invention.

Claims

1. A directional fracturing roof control and pressure relief device for hard roofs in mines, characterized in that: It includes: Spindle-shaped holes (6) perpendicular to the hard roof (1) and arranged horizontally to form a longitudinal splitting surface. The longitudinal fracturing pipe (7) is embedded in the spindle-shaped holes (6) to split the hard roof (1) into long strip-shaped hard roofs that are parallel front and back and point left and right. Horizontally arranged drill holes (3) form a horizontal cutting and moving surface, and the transverse fracturing pipes (4) are sequentially embedded in the drill holes (3) to cut and relieve pressure on the long strip-shaped hard roof. A jet cutting device (5) for X-shaped jet cutting is provided in the transverse fracturing pipe (4) to cut the long strip-shaped hard roof into triangular prisms and quadrangular prisms that point front and back and are longitudinally stacked in cooperation. The jet cutting device (5) includes: Jet sub-pipes (51) coaxially arranged with the transverse fracturing pipe (4) and linearly arranged axially. In the jet sub-pipes (51), a flow splitting arc cavity (52) and a swinging arc cavity (53) that are coaxially arranged and centrosymmetric are successively opened from the inside to the outside. Two groups of the flow splitting arc cavities (52) are opened, and four groups of the swinging arc cavities (53) are opened. The flow splitting arc cavity (52), the swinging arc cavity (53), and the transverse fracturing pipe (4) are interconnected. A flow splitting block (55) whose semi-elliptical arc-shaped convex part faces the flow guiding port arranged between the flow splitting arc cavity (52) and the transverse fracturing pipe (4). Check arc plates (56) are symmetrically installed left and right and are installed obliquely upward on the inner wall of the flow splitting arc cavity (52) outside the flow guiding port. A swinging guide rail (54) coaxially installed in the swinging arc cavity (53), and a jet cutting assembly (8) is installed on the swinging guide rail (54). The jet cutting assembly (8) includes: A swinging box seat (81) slidably connected to the swinging guide rail (54). Its arc-shaped side end is provided with a guiding swing block (82) embedded in the inner side of the swinging guide rail (54). A flow blocking and limiting plate (85) that points radially and transversely across the arc-shaped cavity of the flow splitting arc cavity (52) is installed on the inner end seat on the side of its inner side adjacent to the arc-shaped side end wall of the flow splitting arc cavity (52). The guiding swing blocks (82) on the left and right sides of the swinging box seat (81) are respectively connected to the inner side wall of the swinging arc cavity (53) through a first return spring (83) and a second return spring (84). A fracturing nozzle (86) that points radially and is installed in the swinging box seat (81), and a flow control spray sleeve (87) for changing the jet orifice diameter of the fracturing fluid is installed on the fracturing nozzle (86).

2. The directional fracturing roof control and pressure relief device for hard roofs in mines according to claim 1, characterized in that: The height of the triangular cross-section of the triangular prism is relatively consistent with the height of the goaf (2), and the distance between the upper and lower ends of the rhombic cross-section of the quadrangular prism is twice the height of the goaf (2).

3. The directional fracturing roof control and pressure relief device for hard roofs in mines according to claim 1, characterized in that: Both the transverse fracturing pipe (4) and the longitudinal fracturing pipe (7) use a hydraulic fracturing structure to fracture the hard roof (1).

4. The directional fracturing roof control and pressure relief device for hard roofs in mines according to claim 1, characterized in that: The interval distance between the coaxially and linearly arranged jet sub-pipes (51) is 3 m.

5. The directional fracturing roof control and pressure relief device for hard roofs in mines according to claim 1, characterized in that: The jet orifices of the flow control spray sleeves (87) in the jet cutting assemblies (8) located at the lower right, upper right, upper left, and lower left corners in sequence increase in sequence.

6. The directional fracturing roof control and pressure relief device for hard roofs in mines according to claim 1, characterized in that: The fracturing nozzle (86) swings under the impact of the fracturing fluid with periodic pressure increase and decrease.

7. The directional fracturing roof control and pressure relief device for hard roofs in mines according to claim 1, characterized in that: The straight line connected by the spindle-shaped holes (6) on the front and back sides is located in the middle of the adjacent drill holes (3).

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