Method and system for controlling deformation of surrounding rock of gob-side entry in working face of weakened hard coal seam

Abstract

The application relates to the technical field of coal mining, and provides a method and system for controlling deformation of surrounding rock of a gob-side roadway of a working face in a hard coal seam, wherein according to determined basic roof parameters of the gob-side roadway and lateral coal body elastic foundation coefficients, the distance between a basic fracture line and a coal wall of the first working face is determined; and according to the distance and a section coal pillar width, the coal body disposal range for controlling the deformation of the surrounding rock of the gob-side roadway is calculated; the coal body of the first working face is drilled and pressure-released according to the coal body disposal range by using the roadway of the first working face, so that the roof stratum is broken, rotated and touches the gangue behind the first working face, a stable structure is formed after the roof stratum touches the gangue, the roof stratum no longer continuously sinks after the roadway of the next working face is excavated, the amount of heaving of the side part and heaving of the floor is reduced, the deformation of the surrounding rock is controlled, and thus the rotation of the roof rock mass after the roadway of the next working face is excavated is avoided.

Description

Technical Field

[0001] This application relates to the field of coal mining technology, and in particular to a method and system for controlling the deformation of surrounding rock in working faces of hard coal seams along the goaf. Background Technology

[0002] Controlling the deformation of the surrounding rock in roadways has always been a difficult problem for coal mines, with the most challenging being the control of the surrounding rock deformation in roadways along the goaf.

[0003] Deformation of the surrounding rock in goaf roadways is a complex problem influenced by a combination of factors, including high stress, rock properties, asymmetrical structure, and inadequate support. This deformation often exhibits significant asymmetry, large deformation, and continuous rheological properties. Under normal conditions, the greater the coal seam strength, the smaller the roadway deformation at the same location. However, with increasing mining depth, severe side and floor heave phenomena have been observed in hard coal seams along goaf roadways in engineering practice. Summary of the Invention

[0004] The purpose of this application is to provide a method and system for controlling the deformation of the surrounding rock in the working face of a hard coal seam along the goaf, so as to solve or alleviate the problems existing in the prior art.

[0005] To achieve the above objectives, this application provides the following technical solution: This application provides a method for controlling the deformation of the surrounding rock in a goaf-side roadway of a weakened hard coal seam working face, including: based on the determined basic roof parameters of the goaf-side roadway and the elastic foundation coefficient of the lateral coal body. Determine the basic top fracture line and the first The distance between the coal face and the roadway walls of each working face ;in, It is a positive integer. ; According to distance and section coal pillar width Calculate the coal seam disposal range controlled by the deformation of the surrounding rock in the goaf roadway. ; Using the first The roadways of each working face are categorized according to the coal seam disposal area. For the Drilling was performed on the coal seam of each working face to relieve pressure, allowing the roof strata to be depressurized in the first... The working face was broken, rotated, and struck by rock.

[0006] Preferably, according to the constructed borehole cover model: Determine the basic top fracture line and the first The distance between the coal face and the roadway walls of each working face ; In the formula, This is the lateral correction factor. This is the basic top elastic modulus. For the fundamental top moment of inertia, The load is a uniformly distributed load on the top side. The elastic foundation coefficient of the lateral coal seam.

[0007] Preferably, the coal body disposal model is constructed as follows: Determine the scope of coal seam treatment for deformation control of surrounding rock in empty roadways ; In the formula, The basic top fracture line and the first The distance between the coal seams of the roadways in each working face. The width of the coal pillar in the section. This refers to the width of the alleyway along the tunnel.

[0008] Preferred, the first When drilling to relieve pressure in the coal seam of a working face, the plastic zones formed by two adjacent boreholes overlap.

[0009] Preferably, according to the constructed plastic zone model: Determine the radius of the plastic zone formed by a single borehole during borehole pressure relief. ; In the formula, Where is the borehole radius, This refers to the lateral vertical stress in the borehole after drilling. These are dimensionless stress parameters; The uniaxial compressive strength of the rock mass; The internal friction angle of the coal. It represents the cohesion of the coal and rock mass.

[0010] Preferably, according to the model: Determine the distance between two adjacent boreholes ; In the formula, Where is the borehole radius, The radius of the plastic zone formed by a single borehole during borehole decompression.

[0011] Preferably, a hole-expanding process is used for the first... Drilling is carried out on the coal seam of each working face; among which, according to the formula: Determine the minimum length of the initial borehole section. In the formula, is the Protodyakonov coefficient of the coal body.

[0012] This embodiment also provides a deformation control system for the surrounding rock of a working face with weakened hard coal seams along the goaf, employing any of the above embodiments for the deformation control method of the surrounding rock of a working face with weakened hard coal seams along the goaf. The system includes: The distance unit is configured based on the determined basic roof parameters of the goaf roadway and the elastic foundation coefficient of the lateral coal seam. Determine the basic top fracture line and the first The distance between the coal face and the roadway walls of each working face ;in, It is a positive integer. ; The handling range unit is configured to be based on distance. and section coal pillar width Calculate the coal seam disposal range controlled by the deformation of the surrounding rock in the goaf roadway. ; The pressure relief control unit is configured to utilize the first The roadways of each working face are categorized according to the coal seam disposal area. For the Drilling was performed on the coal seam of each working face to relieve pressure, allowing the roof strata to be depressurized in the first... The working face was broken, rotated, and struck by rock.

[0013] Beneficial effects: The method and system for controlling the deformation of the surrounding rock in the goaf roadway of a weakened hard coal seam working face provided in this application embodiment are based on the determined basic roof parameters of the goaf roadway and the elastic foundation coefficient of the lateral coal body. Determine the basic fracture line and the first Distance between the channel coal face of each working face And based on distance and section coal pillar width Calculate the coal seam disposal range controlled by the deformation of the surrounding rock in the goaf roadway. Finally, using the first The roadways of each working face are categorized according to the coal seam disposal area. For the Drilling was performed on the coal seam of each working face to relieve pressure, allowing the roof strata to be depressurized in the first... The working face was broken, rotated, and struck by rock.

[0014] Therefore, during the mining of the previous working face, the roadway of the previous working face is used to carry out the construction and treatment project of the coal body of the next working face. The coal body of the next working face is depressurized by drilling, which reduces the strength of the coal body and causes the roof rock to break, rotate, and hit the rock behind the previous working face. After the roof rock hits the rock, it forms a stable structure. After the roadway of the next working face is excavated, the roof rock will no longer continue to sink and the stress of the surrounding rock will not change much. This will reduce the amount of bulging of the sidewall and floor, and control the deformation of the surrounding rock. This avoids the problem of the roof rock rotating after the roadway of the next working face is excavated, which would cause large deformation of the roadway of the next working face. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. Wherein: Figure 1 This is a schematic diagram illustrating the use of existing technology to directly excavate along the goaf without treating the hard coal body, and without the roof support rotating. Figure 2 This is a schematic diagram illustrating how, after tunnel excavation using existing technology, the coal seam is damaged, the roof rotates and sinks, the tunnel walls bulge out, and the floor bulges out. Figure 3 This is a flowchart illustrating a method for controlling the deformation of surrounding rock in a goaf roadway of a working face in a weakened hard coal seam, according to some embodiments of this application. Figure 4 This is a schematic diagram illustrating the process of using large-diameter boreholes to weaken the strength of the coal seam during the mining of the previous working face and before the excavation of the roadway in the next working face, according to some embodiments of this application. Figure 5 for Figure 4 Top view of the embodiment shown; Figure 6 A schematic diagram showing the results of deformation control of the surrounding rock in the tunnel; Figure 7 This is a schematic diagram of the structure of a deformation control system for the surrounding rock of a working face with weakened hard coal seams along the goaf, provided according to some embodiments of this application. Detailed Implementation

[0016] The present application will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation and not by way of limitation. In fact, those skilled in the art will understand that modifications and variations can be made to the present application without departing from the scope or spirit of the present application. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention should fall within the scope of protection of the embodiments of the present invention.

[0017] After the previous working face was mined out, the roof fractured and collapsed. The basic roof strata (rock block A) above the goaf subsided to the top of the goaf gangue. Due to the hardness of the coal seam, the coal seam in the next working face could form a stable whole. The rock block above the roadway (rock block B) was supported by the coal seam and did not fracture or rotate. Figure 1 As shown.

[0018] like Figure 2 As shown, after the next working face roadway is excavated, the integrity of the coal body is destroyed, the supporting effect weakens, rock block B rotates until it hits the rock. At this time, the section coal pillar is subjected to increased stress, the coal body is compressed, the roadway goaf side bulges out, the roadway solid side is subjected to increased stress and transmits the force to the floor, causing the floor to bulge out. This is the main reason for the large deformation of the surrounding rock in the roadway along the goaf of hard coal seams.

[0019] To address the issue of large deformation of the surrounding rock in roadways along hard coal seams, the current approach involves leaving wide coal pillars, leading to a significant waste of coal resources. Therefore, this embodiment provides a method for controlling the deformation of the surrounding rock in roadways along hard coal seams, specifically for controlling the deformation of the surrounding rock in these roadways. Firstly, in this embodiment, "lateral" refers to the transverse direction relative to the working face's advancing direction; that is, the direction perpendicular to the working face's advancing direction, which is the direction of the rock mass on both sides of the working face.

[0020] like Figures 3 to 6 As shown, the method includes: step S101, based on the determined basic roof parameters of the goaf roadway and the elastic foundation coefficient of the lateral coal body. Determine the basic fracture line and the first ( It is a positive integer. The distance between the coal face and the roadway walls of each working face Step S102, based on the basic fracture line and the first The distance between the coal face and the roadway walls of each working face and section coal pillar width Calculate the coal seam disposal range controlled by the deformation of the surrounding rock in the goaf roadway. Step S103, using the first The roadways of each working face are categorized according to the coal seam disposal area. For the Drilling was performed on the coal seam of each working face to relieve pressure, allowing the roof strata to be depressurized in the first... The working face was broken, rotated, and struck by rock.

[0021] Therefore, during the mining of the previous working face, the roadway of the previous working face is used to carry out the construction and treatment project of the coal body of the next working face. The coal body of the next working face is depressurized by drilling, which reduces the strength of the coal body and causes the roof rock to break, rotate, and hit the rock behind the previous working face. After the roof rock hits the rock, it forms a stable structure. After the roadway of the next working face is excavated, the roof rock will no longer continue to sink and the stress of the surrounding rock will not change much. This will reduce the amount of bulging of the sidewall and floor, and control the deformation of the surrounding rock. This avoids the problem of the roof rock rotating after the roadway of the next working face is excavated, which would cause large deformation of the roadway of the next working face.

[0022] In this embodiment, coal seam treatment involves pre-constructing large-diameter boreholes in the area of ​​the next working face roadway. This serves two purposes: firstly, it disrupts the coal seam, rendering it unable to bear loads, allowing the roof strata to rotate, subside, and contact the rock; secondly, it relieves pressure on the coal seam, effectively reducing the surrounding rock stress during tunneling. Specifically, the coal seam treatment range is determined based on the deformation control of the surrounding rock along the goaf roadway. First, according to the constructed borehole cover model: Determine the basic top fracture line and the first The distance between the coal face and the roadway walls of each working face In the formula, This is the lateral correction factor. This is the basic top elastic modulus. For the fundamental top moment of inertia, The load is a uniformly distributed load on the top side. The elastic modulus of the lateral coal seam is defined as the elastic modulus of the foundation. This is achieved by using a microseismic monitoring system to capture microseismic events during the instability process of the surrounding rock in the mining area, and analyzing the spatial distribution, energy magnitude, and occurrence time of these microseismic events. This allows for the determination of the elastic modulus of the basic roof by analyzing the actual fracture location and evolution process of the fundamental rock strata. Basic top moment of inertia Basic top lateral uniformly distributed load Physical parameters, etc. Simultaneously, mechanical experiments are conducted on the sampled coal in the laboratory, and numerical inversion is performed on the obtained laboratory data to obtain lateral correction coefficients. and the lateral coal seam elastic foundation coefficient .

[0023] Then, through the constructed coal body disposal model: Determine the scope of coal seam treatment for deformation control of surrounding rock in empty roadways In the formula, The basic top fracture line and the first The distance between the coal seams of the roadways in each working face. The width of the coal pillar in the section (the first) The first working face and the first (width of coal pillar between working faces) This refers to the width of the alleyway along the tunnel.

[0024] In this embodiment, after the large-diameter pressure relief borehole is completed and the drill string is withdrawn, the borehole wall is exposed to the geostress environment. Following the drilling of the large-diameter pressure relief borehole, an elastic-plastic zone will form around the borehole wall, creating a plastic zone radius. Specifically, according to the constructed plastic zone model: Determine the radius of the plastic zone formed by a single borehole during borehole pressure relief. In the formula, Where is the borehole radius, The lateral vertical stress in the borehole after drilling (the ground stress can be measured using a borehole stress gauge (such as a hollow inclusion stress gauge or a hydraulic fracturing method)). This is a dimensionless stress parameter that reflects the strength characteristics of the material; The uniaxial compressive strength of the rock mass; The internal friction angle of the coal. It represents the cohesion of the coal and rock mass.

[0025] Simultaneously, the plastic zones formed by two adjacent large-diameter boreholes overlap to achieve the purpose of destroying and weakening the coal body; that is to say, the first When drilling to relieve pressure on the coal seam in a working face, the plastic zones formed by two adjacent boreholes overlap. Specifically, after determining the diameter of a large-diameter borehole, according to the model: Determine the distance between two adjacent boreholes In the formula, Where is the borehole radius, The radius of the plastic zone formed by a single borehole during borehole decompression.

[0026] After determining the coal seam disposal area controlled by the deformation of the surrounding rock in the goaf roadway... Subsequently, a large-diameter pressure relief borehole was constructed using a borehole enlargement technique, which involves drilling a small-diameter borehole (with a length of...) into the existing coal face. After drilling a small-diameter hole to a certain depth, it becomes a large-diameter construction (construction length). ), that is, the scope of coal body disposal At least the construction length of small-diameter boreholes must be covered. and the construction length of large-diameter boreholes .

[0027] By using small-diameter borehole sections, the coal seam and embankment of the roadway where the drilling rig is operating can be protected from damage, thus achieving the goal of weakening the coal seam in the target area without damaging the roadway's embankment. When using the reaming technique to... When drilling into the coal seam of a working face, follow the formula: Determine the minimum length of the initial borehole section (i.e., the small-diameter borehole section). In the formula, is the Protodyakonov coefficient of the coal body.

[0028] After the coal body was weakened during construction, its strength was reduced. After the previous working face was mined out, the strength of the coal body was insufficient to support the roof strata. Therefore, the roof strata fractured and subsided. After the roof strata hit the rock, they formed a stable structure. After the next working face was excavated, the roof strata no longer continued to subside. The stress of the surrounding rock did not change much, which reduced the amount of bulging of the sidewalls and floor, and controlled the deformation of the surrounding rock.

[0029] This embodiment also provides a control system for the deformation of the surrounding rock in the goaf roadway of a weakened hard coal seam working face. The deformation of the surrounding rock in the goaf roadway is controlled using any of the above embodiments of the weakened hard coal seam working face deformation control method. Figure 7 As shown, the system includes: Distance unit 701, configuration question based on the determined basic roof parameters of the goaf roadway and the elastic foundation coefficient of the lateral coal body. Determine the basic top fracture line and the first The distance between the coal face and the roadway walls of each working face ;in, It is a positive integer. ; The handling range unit 702 is configured to operate based on distance. and section coal pillar width Calculate the coal seam disposal range controlled by the deformation of the surrounding rock in the goaf roadway. ; The pressure relief control unit 703 is configured to utilize the first The roadways of each working face are categorized according to the coal seam disposal area. For the Drilling was performed on the coal seam of each working face to relieve pressure, allowing the roof strata to be depressurized in the first... The working face was broken, rotated, and struck by rock.

[0030] The deformation control system for the surrounding rock of the goaf roadway in the weakened hard coal seam working face provided in this embodiment can realize the steps and process of the deformation control method for the surrounding rock of the goaf roadway in the weakened hard coal seam working face in any of the above embodiments, and achieve the same technical effect, which will not be described in detail here.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0033] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] In this 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," "over," and "on top" of 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.

[0035] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0036] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for controlling the deformation of surrounding rock in a goaf roadway of a working face in a hard coal seam, characterized in that, include: Based on the determined basic roof parameters of the goaf and the elastic foundation coefficient of the lateral coal seam Determine the basic top fracture line and the first The distance between the coal face and the roadway walls of each working face ;in, It is a positive integer. ; According to distance and section coal pillar width Calculate the coal seam disposal range controlled by the deformation of the surrounding rock in the goaf roadway. ; Using the first The roadways of each working face are categorized according to the coal seam disposal area. For the Drilling was performed on the coal seam of each working face to relieve pressure, allowing the roof strata to be depressurized in the first... The working face was broken, rotated, and struck by rock.

2. The method according to claim 1, characterized in that, Based on the constructed borehole cover model: Determine the basic top fracture line and the first The distance between the coal face and the roadway walls of each working face ; In the formula, This is the lateral correction factor. This is the basic top elastic modulus. For the fundamental top moment of inertia, The load is a uniformly distributed load on the top side. The elastic foundation coefficient of the lateral coal seam.

3. The method according to claim 1, characterized in that, Through the constructed coal body disposal model: Determine the scope of coal seam treatment for deformation control of surrounding rock in empty roadways ; In the formula, The basic top fracture line and the first The distance between the coal seams of the roadways in each working face. The width of the coal pillar in the section. This refers to the width of the alleyway along the tunnel.

4. The method according to claim 1, characterized in that, No. When drilling to relieve pressure in the coal seam of a working face, the plastic zones formed by two adjacent boreholes overlap.

5. The method according to claim 4, characterized in that, According to the constructed plastic zone model: Determine the radius of the plastic zone formed by a single borehole during borehole pressure relief. ; In the formula, Where is the borehole radius, This refers to the lateral vertical stress in the borehole after drilling. These are dimensionless stress parameters; The uniaxial compressive strength of the rock mass; The internal friction angle of the coal. It represents the cohesion of the coal and rock mass.

6. The method according to claim 4, characterized in that, According to the model: Determine the distance between two adjacent boreholes ; In the formula, Where is the borehole radius, The radius of the plastic zone formed by a single borehole during borehole decompression.

7. The method according to claim 1, characterized in that, The hole expansion process is used for the first Drilling is carried out on the coal seam of each working face; among which, according to the formula: Determine the minimum length of the initial borehole section. ; In the formula, is the Protodyakonov coefficient of the coal body.

8. A control system for weakening the deformation of surrounding rock in a goaf roadway of a hard coal seam working face, characterized in that, The method for controlling the deformation of surrounding rock in the working face of a weakened hard coal seam, as described in any one of claims 1-7, comprises: The distance unit is configured based on the determined basic roof parameters of the goaf roadway and the elastic foundation coefficient of the lateral coal seam. Determine the basic top fracture line and the first The distance between the coal face and the roadway walls of each working face ;in, It is a positive integer. ; The handling range unit is configured to be based on distance. and section coal pillar width Calculate the coal seam disposal range controlled by the deformation of the surrounding rock in the goaf roadway. ; The pressure relief control unit is configured to utilize the first The roadways of each working face are categorized according to the coal seam disposal area. For the Drilling was performed on the coal seam of each working face to relieve pressure, allowing the roof strata to be depressurized in the first... The working face was broken, rotated, and struck by rock.

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