Serial-parallel full-length pressure relief hole arrangement method based on long roof horizontal hole
By employing a series-parallel full-length pressure relief hole arrangement method with long horizontal holes in the roof of the soft rock roadway in the deep well isolated working face, the problem of deformation and damage of the surrounding rock under the deep well isolated working face was solved, and the stress control and stability maintenance of the roadway were achieved throughout the entire length.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANXI TIANDI WANGPO COAL IND CO LTD
- Filing Date
- 2023-05-16
- Publication Date
- 2026-07-31
AI Technical Summary
In the case of soft rock tunnels under the deep well isolated working face, the surrounding rock is severely deformed and damaged under strong dynamic pressure. Existing pressure relief methods are difficult to achieve effective control over the entire length, resulting in poor tunnel stability.
The method of series-parallel full-length pressure relief borehole layout based on long horizontal holes in the roof of the fractured surrounding rock is adopted. The drilling site location and fracturing layer are determined by drilling inspection and mine pressure detection. Long horizontal unidirectional and bidirectional boreholes are constructed, and hydraulic fracturing is carried out in combination with different fracturing methods to achieve the pressure relief effect in the entire roadway.
It achieves full-length decompression treatment of the high dynamic pressure roadway in the isolated working face, controls the roadway stress level to the maximum extent, maintains the stability of the surrounding rock of the roadway, and reduces the risk of roof collapse.
Smart Images
Figure CN117167011B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of mining technology, and in particular to a series-parallel full-length pressure relief hole distribution method based on long horizontal holes in the roof of the crushed surrounding rock. Background Technology
[0002] With the increasing intensity of coal mining in my country, many mines have moved towards deep mining. Deep mining is conducted in a "high-temperature, high-volume, high-pressure, and high-disturbance" surrounding rock environment, which is extremely unfavorable for the stability of roadways. At the same time, in order to avoid tight mining succession and prevent disasters such as coal spontaneous combustion and gas outbursts, skip mining methods have been widely used in the mining history, leaving many isolated working faces with goafs on two or even three sides. Due to their large mining depth, irregular shape, and goafs on two or even multiple sides (including those with mining-induced excavation), these working faces are typical high-risk working faces with strong dynamic pressure. Under the combined effects of the original rock stress field, the lateral stress field of the goaf, and the pre-concentrated stress of mining in this working face, there is a high possibility of roof overhang in the mining roadway, resulting in weak surrounding rock. If a soft coal seam is encountered, support failure is very likely to occur, which seriously affects the control effect of the surrounding rock in the roadway. Especially in natural structural areas such as faults, strong mine pressure phenomena are more frequent.
[0003] Existing methods for addressing the hazards of roadways under high dynamic pressure primarily involve large-diameter boreholes for pressure relief. This method utilizes boreholes to transfer peak stress deeper into the coal seam, effectively reducing the high stress values of the surrounding rock mass. However, due to the small pressure relief range formed by a single pressure relief borehole, the pressure relief effect is limited. To achieve the ideal pressure relief effect, the borehole spacing is relatively small, resulting in a large amount of pressure relief work. Later, the method and technology of ultra-long horizontal borehole regional fracturing for pressure relief emerged underground. This method can create numerous network cracks of varying orientations and lengths within intact target rock strata through regional fracturing, significantly weakening the overall strength of the rock strata and playing a role in weakening the thick, hard roof and significantly reducing or even eliminating the risk of impact disasters. However, this method is mostly applied to hard rock strata for impact prevention and disaster reduction. In soft rock roadways in isolated environments, not only are there strong dynamic pressure problems, but the surrounding rock is also relatively weak. Furthermore, while this method is very effective for regional fracturing, it is difficult to cover the entire length of the roadway, making it difficult to achieve the effect of "one-time support, never needing repair" after combined support. Summary of the Invention
[0004] This invention provides a series-parallel full-length pressure relief hole arrangement method based on long horizontal holes in the roof of fractured surrounding rock. This method is used to solve the problem of severe deformation and damage of surrounding rock caused by strong dynamic pressure environment in soft rock roadways under deep well island working faces in the prior art. It realizes full-length pressure relief treatment for roadways under strong dynamic pressure in island working faces, and achieves the purpose of regulating the roadway stress level to the greatest extent and maintaining the stability of the roadway surrounding rock.
[0005] This invention provides a series-parallel full-length pressure relief hole distribution method for fractured surrounding rock based on long horizontal holes in the roof, comprising:
[0006] Step S1: Before mining, obtain information on the surrounding rock of the tunnel and the roof strata structure of the soft rock tunnel in order to obtain drilling site location information and fracturing layer position;
[0007] Step S2: Determine the number of drilling sites to be arranged in the roadway based on the drilling site location obtained in Step S1, and construct long horizontal unidirectional boreholes and bidirectional boreholes respectively in each drilling site according to the fracturing layer obtained in Step S1.
[0008] Step S3: Determine the fracturing method and construction parameters based on the roof structure of the tunnel;
[0009] Step S4: Based on the borehole layout, perform hydraulic fracturing operations on long horizontal boreholes in sequence according to the borehole numbers.
[0010] According to the present invention, a series-parallel full-length pressure relief hole arrangement method based on long horizontal holes in the roof of a fractured surrounding rock is provided. In step S1, the deformation of the surrounding rock in the roadway is detected by a mine pressure detection device, and the roof rock structure of the soft rock roadway is observed by a borehole inspection device.
[0011] According to the present invention, a series-parallel full-length pressure relief hole layout method based on long horizontal holes in the roof is provided. In step S1, the method for determining the drilling site location includes: a measuring station arranged at the same interval along the entire length of the roadway, wherein the measuring station uses the cross-wire method to detect the deformation of the surrounding rock to obtain surrounding rock deformation detection information.
[0012] Based on the surrounding rock deformation detection information, the mining pressure intensity level of the pre-mining roadway is determined, and then the locations of multiple drilling sites are determined.
[0013] According to the present invention, a series-parallel full-length pressure relief drilling method based on long horizontal holes in the roof is provided for fracturing surrounding rock. The selection of the fracturing layer includes combining the suspended roof method of the isolated face roadway, selecting multiple typical measuring points in different mining pressure level areas to inspect the roof borehole structure, so as to select two or more roof rock sections as long horizontal hole fracturing layers.
[0014] According to the present invention, a series-parallel full-length pressure relief hole distribution method based on long horizontal holes in the roof of a fractured surrounding rock is provided. The roof suspension method of the isolated face roadway includes roof suspension of the working face side goaf area, roof suspension of the working face side goaf area, or roof suspension of the upper high-level structure of the working face.
[0015] According to the present invention, a series-parallel full-length pressure relief hole arrangement method for fracturing surrounding rock based on long horizontal holes in the roof is provided. In step S1, the number of drilling sites to be arranged for fracturing construction along the entire length of the working face transport roadway is determined based on the determined drilling site location information, the fracturing layer, and the total length of the roadway. In this method, multiple boreholes in each drilling site are connected in parallel through the drilling site, and multiple bidirectional boreholes in two adjacent drilling sites are connected in series in a one-to-one correspondence.
[0016] According to the present invention, a series-parallel full-length pressure relief drilling method for fractured surrounding rock based on long horizontal holes in the roof is provided. In the roof area with the same roadway direction, one of the drilling sites is selected for unidirectional drilling and fracturing construction, and then bidirectional drilling and fracturing construction is carried out in series with the adjacent drilling site.
[0017] According to the present invention, a series-parallel full-length pressure relief hole distribution method based on long horizontal holes in the top plate is provided for fracturing surrounding rock. In step S3, the fracturing method includes jet fracturing, isolation segmented fracturing, or combined fracturing.
[0018] According to the present invention, a series-parallel full-length pressure relief hole arrangement method for fracturing surrounding rock based on long horizontal holes in the top plate is provided. When the fracturing method is composite fracturing, the composite fracturing is to perform secondary fracturing by jet fracturing after the isolation segmented fracturing is performed in the same borehole.
[0019] According to the present invention, a series-parallel full-length pressure relief hole layout method based on long horizontal holes in the top plate is provided for fractured surrounding rock, wherein in step S1, the drilling depth during borehole inspection is greater than or equal to 30m.
[0020] This invention provides a series-parallel full-length pressure relief drilling method based on long horizontal holes in the roof of fractured surrounding rock. First, pre-mining pressure monitoring and borehole inspection are used to observe the deformation of the surrounding rock in the roadway before mining, considering the roof overhang method, and inspecting the roof strata structure of soft rock roadways to determine suitable drilling locations and fracturing layers. Second, multiple drilling sites are set up in the high-dynamic-pressure roadway of the isolated working face. Long horizontal unidirectional and bidirectional boreholes are drilled in different preset layers within each drilling site, achieving a "parallel" pressure relief effect of long horizontal holes in different layers of the roof in the same area of the roadway, and a "series" pressure relief effect of long water holes in different areas of the entire roadway. Then, based on the selected fracturing layers and different roof overhang methods, different fracturing methods and parameters are determined. Finally, according to the borehole layout, long horizontal hole hydraulic fracturing is carried out sequentially according to the borehole number. By constructing long horizontal unidirectional and bidirectional boreholes in different preset layers within each drilling site, the pressure relief effect of long horizontal boreholes in different layers of the roadway roof in the same area is achieved in "parallel" manner, and the pressure relief effect of long water boreholes in different areas of the entire roadway is achieved in "series" manner. This enables full-length treatment of pressure relief for the strong dynamic pressure roadway in the isolated working face, maximizing the control of roadway stress level and maintaining the stability of the surrounding rock. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0022] Figure 1 These are the three types of roof suspension methods present in the isolated working face mining roadway in this invention;
[0023] Figure 2 This is a schematic diagram of the hole layout in an embodiment of the series-parallel full-length pressure relief hole layout method based on long horizontal holes in the top plate provided by the present invention for fractured surrounding rock;
[0024] Figure 3 yes Figure 2 A cross-sectional view of the borehole arrangement in drilling site a, facing the cutting direction;
[0025] Figure 4 yes Figure 2 A cross-sectional view of the strata in which the boreholes in borehole a are arranged, facing the stop-mining line;
[0026] Figure 5 yes Figure 2 Cross-sectional view of the layout of the drilling site (a);
[0027] Figure 6 yes Figure 2 Cross-sectional view of the layout of drilling site b.
[0028] Figure label:
[0029] 10. Roof of the working face is suspended in the side goaf area; 20. Roof of the working face is suspended in the side goaf area; 30. Roof of the upper high structure of the working face is suspended.
[0030] 100. Alleyway;
[0031] 200. Drilling site a; 210. Unidirectional borehole a; 220. Unidirectional borehole b; 230. Unidirectional borehole c; 240. Bidirectional borehole d; 250. Bidirectional borehole e; 260. Bidirectional borehole f;
[0032] 300, Drilling site b; 310, Bidirectional drilling g; 320, Bidirectional drilling h; 330, Bidirectional drilling i; 340, Unidirectional drilling j; 350, Unidirectional drilling k; 360, Unidirectional drilling l;
[0033] 400. Micro-vibration pickup. Detailed Implementation
[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0035] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "first" and "second" are used to clearly indicate the product components and do not represent any substantial difference. The directions of "upper" and "lower" are based on the directions shown in the accompanying drawings. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances. Furthermore, "multiple" means two or more. In the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.
[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0037] The following description, in conjunction with the accompanying drawings, describes the present invention's method for series-parallel full-length pressure relief hole arrangement based on long horizontal holes in the roof of a fractured surrounding rock.
[0038] According to embodiments of the present invention, such as Figures 1-6 As shown, the series-parallel full-length pressure relief hole distribution method based on long horizontal holes in the roof of the fractured surrounding rock provided by the present invention mainly includes the following steps:
[0039] Step S1: Before mining, obtain information on the surrounding rock of tunnel 100 and the roof rock structure of soft rock tunnel 100 in order to obtain drilling site location information and fracturing layer.
[0040] Step S2: Determine the number of drilling sites to be arranged in the tunnel 100 based on the drilling site location obtained in Step S1. In each drilling site, construct long horizontal unidirectional boreholes and bidirectional boreholes on the fracturing layer obtained in Step S1.
[0041] Step S3: Determine the fracturing method and construction parameters based on the roof structure of tunnel 100;
[0042] Step S4: Based on the borehole layout, perform hydraulic fracturing operations on long horizontal boreholes in sequence according to the borehole numbers.
[0043] This invention provides a series-parallel full-length pressure relief drilling method based on long horizontal holes in the roof of fractured surrounding rock. First, using pre-mining pressure monitoring and borehole inspection, the deformation of the surrounding rock in roadway 100 is observed before mining, and the roof suspension method of roadway 100 is considered. The roof strata structure of soft rock roadway 100 is inspected to determine suitable drilling site locations and fracturing layers. Second, multiple drilling sites are laid out in the high-dynamic-pressure roadway 100 of the isolated working face. Long horizontal unidirectional and bidirectional boreholes are drilled in different preset layers within each drilling site. This achieves the "parallel" pressure relief effect of long horizontal holes in different layers of the roof of roadway 100 in the same area, and the "series" pressure relief effect of long water holes in different areas of the entire roadway 100. Then, based on the selected fracturing layers and different roof suspension methods, different fracturing methods and parameters are determined. Finally, according to the borehole layout, long horizontal hole hydraulic fracturing is carried out sequentially according to the borehole number. By constructing long horizontal unidirectional and bidirectional boreholes in different preset layers within each drilling site, the pressure relief effect of long horizontal boreholes in different layers of the roof of the same roadway 100 is achieved in parallel, and the pressure relief effect of long water holes in different areas of the entire roadway 100 is achieved in series. This enables full-length treatment of pressure relief for the high dynamic pressure roadway 100 in the isolated working face, maximizing the control of the stress level of roadway 100 and maintaining the stability of the surrounding rock of roadway 100.
[0044] Reference Figure 2 In some embodiments, in step S1, the deformation of the surrounding rock of roadway 100 is detected using a mine pressure detection device, and the roof rock structure of soft rock roadway 100 is observed using a borehole inspection device. Specifically, before mining of the isolated working face, monitoring stations are arranged in sections throughout roadway 100. A measuring point can be set at a certain distance to monitor the deformation of the surrounding rock. The mine pressure is detected using a mine pressure detection device such as a micro-vibration pickup 400. Then, the mine pressure intensity level of roadway 100 before mining is comprehensively evaluated, and the area with the lowest intensity is selected to set up drilling sites. The number of drilling sites is generally two or more, and no special limitation is made here. Considering the possible overhang of the roof in the isolated working face roadway 100, multiple typical measuring points are selected in different mine pressure level areas, and the borehole structure is observed using a borehole inspection device. Two or more roof rock sections are selected as long horizontal hole fracturing layers.
[0045] In one embodiment, the determination of drilling site locations in step S1 includes: setting up monitoring stations at equal intervals along the entire length of roadway 100; using a cross-shaped wiring method to detect surrounding rock deformation at the monitoring stations to obtain surrounding rock deformation detection information; and determining the mine pressure intensity level of pre-mining roadway 100 based on the surrounding rock deformation detection information, thereby determining multiple drilling site locations. It is understood that this embodiment uses the detection results obtained from the mine pressure detection device to comprehensively evaluate the mine pressure intensity level of pre-mining roadway 100, selecting the area with the lowest mine pressure intensity for drilling site placement. This leverages the advantage of using mine pressure monitoring and borehole inspection methods to guide drilling site location and fracturing layer selection before mining the isolated working face. This allows for observation of the surrounding rock deformation in roadway 100, enabling the identification of severely damaged areas and targeted reinforcement of support. For drilling site placement, it is advantageous to select areas with minimal surrounding rock deformation to prevent damage to the integrity of the surrounding rock caused by drilling and borehole construction.
[0046] In some embodiments, the selection of fracturing sites includes combining the suspended roof method of the isolated face roadway 100 with the selection of multiple typical measuring points in different mining pressure levels to inspect the roof borehole structure, so as to select two or more roof rock strata as long horizontal borehole fracturing sites. It is understandable that in this embodiment, the roof rock structure of the soft rock roadway 100 is observed through a borehole inspection device. Based on the observation results, a roof rock section with high lithological strength and intact rock strata is selected as the long horizontal borehole fracturing site. In this way, by inspecting the roof rock structure of the soft rock roadway 100, the distribution of lithological strata in the roof of the roadway 100 can be determined, and the potential overhanging layers around the isolated working face mining roadway 100 can be identified. When selecting the long horizontal borehole fracturing site, it is beneficial to select medium-deep rock strata with high lithological strength and intact rock strata as the long horizontal borehole fracturing site as much as possible, so as to prevent the fracturing in the fractured strata from having a destructive effect on the roof surrounding rock that is greater than the effect of regulating the stress level of the roadway 100 and weakening the transfer of strong mine pressure, thus having the opposite effect.
[0047] Reference Figure 1In some embodiments, the roof suspension method of the isolated face roadway 100 includes the roof suspension 10 of the working face lateral goaf area, the roof suspension 20 of the working face goaf area lateral surface, or the roof suspension 30 of the upper high-level structure of the working face. Specifically, the roof suspension method of the isolated face roadway 100 is determined based on borehole observation to determine different fracturing strata. For example, when considering the roof suspension 10 of the working face lateral goaf area, the borehole observation results show that, due to historical mining reasons, the fine sandstone old roof below 25m is highly fragmented, and the sandstone interbedded strata in the range of 25-30m are relatively intact, so 30m is determined as the fracturing stratum on the goaf side; when considering the roof suspension 20 of the working face goaf area lateral surface, the results of borehole observation are used to determine the fracturing stratum. It is clear that the fine sandstone roof 25m below the working face is highly intact, with a suspended roof phenomenon. This will transmit pressure to roadway 100. Therefore, the 20m section of the roof is determined as the fracturing layer to cut off the stress transmission of the suspended roof of the working face. Considering the possibility of large-scale collapse of the upper high-level structure 30m above the working face roof, the 40m section of the working face roof is determined as the fracturing layer to arrange high-level fracturing boreholes, reducing the suspended roof area of this rock stratum near roadway 100, and promoting timely collapse of the roof to fill the goaf.
[0048] Reference Figure 2 In some embodiments, in step S1, based on the determined drilling site location information, fracturing layer, and the total length of the roadway 100, the total number of drilling sites to be arranged for fracturing the entire length of the working face transport roadway is determined. Multiple boreholes within each drilling site are connected in parallel, and multiple bidirectional boreholes in adjacent drilling sites are connected in series, corresponding to each other. It is understood that the number of drilling sites can be selected based on the total length of the roadway 100 and the magnitude of the surrounding rock deformation. The number of drilling sites can be greater than or equal to two, and can be three, four, five, six, seven, eight, nine, or ten, etc., and is not limited thereto. This application uses the example of arranging two drilling sites for fracturing the entire length of the working face transport roadway as an example; other embodiments can refer to this embodiment for implementation. Specifically, two drilling sites are spaced apart from each other, and multiple bidirectional boreholes are set up facing each other in the two drilling sites. The bidirectional boreholes are set towards the two drilling sites and connected in series. Multiple unidirectional boreholes are set up in opposite directions in the two drilling sites. The multiple unidirectional boreholes in the same direction and the bidirectional boreholes in opposite directions are connected in parallel through the drilling sites. Optionally, the drilling sites include unidirectional drilling sites and bidirectional drilling sites.
[0049] Furthermore, within the roof area of the same roadway 100 direction, one of the drilling sites is selected for unidirectional drilling and fracturing operations, followed by bidirectional drilling and fracturing operations in series with the adjacent drilling site.
[0050] In some embodiments, in step S3, the fracturing method includes jet fracturing, isolation fracturing, or combined fracturing. It is understood that the fracturing method for the borehole can be selected based on the roof overhang configuration and the fracturing layer at which the borehole is located. Combined fracturing involves using isolation fracturing in the same borehole followed by jet fracturing for secondary fracturing.
[0051] In some embodiments, the drilling depth of the borehole inspection device in step S1 is greater than or equal to 30m. It is understood that, in order to facilitate the determination of the three types of overhang in the isolated face roadway 100, this application uses a borehole inspection device with a drilling depth greater than or equal to 30m, so as to better extend into the deep well and better observe the structural form of the isolated face.
[0052] The following describes the series-parallel full-length pressure relief hole distribution method for fractured surrounding rock based on long horizontal holes in the roof provided by the present invention with reference to a specific embodiment, which mainly includes the following steps.
[0053] Select drilling site location: Refer to Figure 2 Before mining the isolated working face in Example 3203, monitoring stations were set up every 100m along the entire length of roadway 100. The deformation of the surrounding rock was monitored using the cross-line method. The monitoring showed that the deformation of the surrounding rock was the smallest in the range of 1700m to 1600m from the entrance of roadway 100 and 700m to 650m from the entrance of roadway 100. Therefore, drilling sites a200 and b300 were set up at 1280m and 680m from roadway 100, respectively.
[0054] Selection of fracturing layers: Refer to Figure 1 and Figure 2 Five measuring points were selected on the roof of roadway 100 near the goaf and on the working face side for roof structure inspection. Considering the three types of overhanging roofs in roadway 100 of the isolated working face and historical mining factors, when selecting the stratum: 1) Considering the overhanging roof 10 on the working face side towards the goaf, the inspection results showed that due to historical mining reasons, the fine sandstone roof below 25m was highly fractured, and the sandstone interbedded strata within the range of 25-30m were relatively intact. Therefore, 30m was determined as the fracturing stratum on the goaf side; 2) Considering the goaf area of this working face... The side roof is suspended at 20 meters. The observation results show that the fine sandstone roof below 25 meters at the end of the working face is highly intact and there is a suspended roof phenomenon. In this way, the pressure will be transmitted to the roadway 100. Therefore, the 20-meter section of the roof is determined as the fracturing layer to cut off the stress transmission of the suspended roof of the working face; 3) Considering that there is a large-scale collapse of the upper high-level structure 30 meters above the roof of this working face, the 40-meter section of the roof of the working face is determined as the fracturing layer to arrange high-level fracturing boreholes, reduce the suspended roof area of this rock stratum near the roadway 100, and at the same time promote the timely collapse of the roof to fill the goaf.
[0055] Determine the drilling layout for long horizontal holes: Refer to Figures 2 to 6 Based on the determined drilling site location and fracturing layer, and combined with the total length of roadway 100, it was finally determined that two drilling sites would be arranged for the fracturing construction of the entire length of the transport roadway in Example 3203. Each drilling site would construct three parallel boreholes in one direction and achieve bidirectional series connection. A total of 12 boreholes were drilled in roadway 100 to achieve the treatment of the entire length of the transport roadway. Specifically, drilling site a200 includes unidirectional boreholes a210, b220, c230, d240, e250, and f260; drilling site b300 includes bidirectional boreholes g310, h320, i330, j340, k350, and l360, wherein bidirectional borehole d240 is connected in series with bidirectional borehole g310, bidirectional borehole e250 is connected in series with bidirectional borehole i330, and bidirectional borehole f260 is connected in series with bidirectional borehole g310. Two-way borehole h320 is connected in series, while unidirectional boreholes a210, b220, c230, d240, e250, and f260 are connected in parallel through drilling site a200; two-way boreholes g310, h320, i330, j340, k350, and l360 are connected in parallel through drilling site b300. All boreholes are fracturing holes in the 100-meter roof cutting area of the roadway. The borehole parameters along the roof direction are shown in Table 1 below.
[0056] Secondly, fracturing parameter design: Based on the roof structure of tunnel 100 in the embodiment, the different fracturing methods and construction parameters finally determined are shown in Table 2 below.
[0057] Then, hydraulic fracturing operations were carried out on long horizontal holes in the drilling site: according to the layout of the boreholes, hydraulic fracturing operations on long horizontal holes were carried out in sequence according to the borehole numbers.
[0058] Specifically:
[0059] 1) Drilling of unidirectional borehole a210 within drilling site a200 and fracturing of unidirectional borehole a210 according to the fracturing method and construction parameters determined above.
[0060] 2) After the unidirectional borehole a210 is completed, the parallel unidirectional boreholes b220, c230, d240, e250 and f260 with the same direction as the roadway 100 but different layers will be constructed in sequence.
[0061] 3) After the parallel drilling in the roof area of the same roadway 100 direction is completed, hydraulic fracturing construction is carried out in drilling site b300 connected in series. The drilling and fracturing steps are the same as the construction procedures in drilling site a200, and will not be repeated here.
[0062] 4) Perform hydraulic fracturing operations in all drilling sites in sequence according to the drilling site order until the full length of the 100-meter roof fracturing and pressure relief treatment of the isolated working face is completed.
[0063] Table 1: Drilling Parameters Along Top Plate Path in Example 1
[0064]
[0065]
[0066]
[0067] Table 2: Drilling Fracturing Construction Parameters for Examples
[0068]
[0069]
[0070] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0071] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0072] 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 of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A roof long horizontal hole based series-parallel full-length pressure relief hole arrangement method for breaking surrounding rock, characterized in that, Includes the following steps: Step S1: Before mining, obtain information on the surrounding rock of the tunnel and the roof strata structure of the soft rock tunnel in order to obtain drilling site location information and fracturing layer position; Step S2: Determine the number of drilling sites arranged in the roadway based on the drilling site location information obtained in Step S1. In each drilling site, construct long horizontal unidirectional boreholes and bidirectional boreholes on the fracturing layer obtained in Step S1. Step S3: Determine the fracturing method and construction parameters based on the roof structure of the tunnel; Step S4: Based on the borehole layout, perform hydraulic fracturing operations on long horizontal boreholes in sequence according to the borehole numbers; The selection of the fracturing layer includes combining the suspended roof method of the isolated face roadway, selecting multiple typical measuring points in different mining pressure levels to inspect the roof borehole structure, so as to select two or more roof rock sections as long horizontal hole fracturing layers. In step S1, based on the determined drilling site location information, the fracturing layer, and the total length of the roadway, the total number of drilling sites to be arranged for fracturing construction along the entire length of the working face transport roadway is determined. In this case, multiple boreholes set in each drilling site are connected in parallel through the drilling site, and multiple bidirectional boreholes of two adjacent drilling sites facing each other are connected in series one by one. In the roof area with the same roadway orientation, one of the drilling sites is selected for unidirectional drilling and fracturing operations, and then bidirectional drilling and fracturing operations are carried out in series with the adjacent drilling site.
2. The serial-parallel full-length pressure-relief holing method based on the roof long horizontal hole for breaking surrounding rock according to claim 1, characterized in that, In step S1, the deformation of the surrounding rock in the roadway is detected by a mine pressure detection device, and the roof rock structure of the soft rock roadway is observed by a borehole inspection device.
3. The serial-parallel full-length pressure-relief holing method based on a roof long horizontal hole for breaking surrounding rock according to claim 1, characterized in that, In step S1, the method for determining the drilling site location includes: setting up monitoring stations at equal intervals along the entire length of the tunnel, wherein the monitoring stations use the cross-wire method to detect the deformation of the surrounding rock in order to obtain surrounding rock deformation detection information; Based on the surrounding rock deformation detection information, the mining pressure intensity level of the pre-mining roadway is determined, and then the locations of multiple drilling sites are determined.
4. The serial-parallel full-length pressure-relief holing method based on a roof long horizontal hole for breaking surrounding rock according to claim 1, characterized in that, The roof suspension methods for the isolated face roadway include roof suspension on the side of the working face goaf, roof suspension on the side of the working face goaf, or roof suspension of the upper high-level structure of the working face.
5. The serial-parallel full-length pressure-relief holing method based on a roof long horizontal hole for breaking surrounding rock according to any one of claims 1-4, characterized in that, In step S3, the fracturing method includes jet fracturing, isolation segmented fracturing, or combined fracturing.
6. The serial-parallel full-length pressure-relief holing method based on the roof long horizontal hole of broken surrounding rock according to claim 5, characterized in that, When the fracturing method is composite fracturing, the composite fracturing is to perform secondary fracturing by using the isolation segment fracturing in the same borehole and then using the jet fracturing.
7. The method for series-parallel full-length pressure relief hole distribution based on long horizontal holes in the roof of fractured surrounding rock according to claim 2, characterized in that, In step S1, the drilling depth in the borehole inspection device is greater than or equal to 30m.