Method for judging filling position and filling opportunity of coal mine goaf

Abstract

The invention provides a coal mine goaf filling position and filling opportunity judgment method, and belongs to the technical field of coal mine goaf filling, and the method comprises the following steps: S1, collecting mine basic data; s2, according to the collected basic data, analyzing an overlying strata migration mode, determining overlying strata three-zone distribution characteristics, a key layer position and a separation layer position, and determining a caving zone height Hf, a fissure zone height Hf and a separation layer position height Hs; s3, designing a monitoring scheme suitable for goaf filling space judgment, and determining implementation details of the monitoring scheme; s4, deriving the subsidence amount according to the data acquisition frequency to obtain the subsidence rate, and outputting the actually measured surface subsidence rate; s5, the filling space and the filling opportunity are judged, and goaf remaining space distribution and judgment standards are provided; and S6, judging whether the goaf corresponding to the observation point has a filling space or not according to the judgment result, and determining a favorable filling opportunity.

Description

Technical Field

[0001] This invention belongs to the field of coal mine goaf filling technology, specifically relating to a method for determining the filling location and timing of coal mine goaf. Background Technology

[0002] Currently, goaf grouting and backfilling has become one of the main methods for coal-based solid waste disposal. Goaf grouting and backfilling does not affect the normal production of the underground working face. However, a core issue in goaf grouting is accurately determining the backfilling location and timing. The detection technologies for goaf backfilling space mainly focus on theoretical calculations, field measurements, and numerical simulations. For example, the grouting and backfilling location is determined based on the key layer theory, the three-zone theory, and the O-ring theory. Numerical simulation is used as an aid, and technologies such as subsidence monitoring, geophysical exploration, and drilling are used to detect the backfilling space and the timing of grouting.

[0003] However, existing detection technologies suffer from high labor intensity and cost, especially drilling, which is difficult to deploy over large areas and at multiple points, and struggles to determine the appropriate timing of filling. Numerical simulations of the mining step distance often fail to match the actual mining operation, limiting the accuracy of the simulation-field matching. Existing subsidence monitoring schemes typically deploy survey lines along the central region of the working face, with dip lines arranged along the planned dip direction, making it difficult to explore the filling space in the goaf and determine the timing of filling. Furthermore, they lack analysis of the main rock strata structure and migration patterns, and lack on-site surface monitoring schemes and indicators for determining filling space and timing. Therefore, this paper proposes a method for determining the location and timing of coal mine goaf filling to address these problems. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides a method for determining the location and timing of filling in coal mine goaf areas, comprising the following steps: S1: Collect basic mine data; S2: Based on the collected basic data, analyze the overburden migration pattern, determine the distribution characteristics of the three overburden zones, the key layer positions, and the delamination layer positions, and determine the height H of the caving zone and fracture zone. f With the height of the delamination layer H s ; S3: Design a monitoring scheme suitable for determining the filling space in goaf areas, and determine the implementation details of the monitoring scheme; S4: Obtain the subsidence rate by differentiating the subsidence amount from the frequency of the collected data, and output the measured surface subsidence rate. S5: Determine the filling space and timing, and propose the distribution and determination criteria of the remaining space in the goaf. S6: Based on the above judgment results, determine whether the goaf corresponding to the observation point has filling space and determine the favorable filling time.

[0005] Furthermore, the basic mine data in step S1 includes coal seam occurrence characteristics and working face mining parameters.

[0006] Furthermore, step S3 involves designing a monitoring scheme suitable for determining the filling space in the goaf, and determining the implementation details of the monitoring scheme, specifically including the following: S301: Collect past subsidence data for this mining area, including the maximum subsidence amount w. max With the maximum subsidence rate v max ; S302: By setting up surface survey lines on the upper part of the goaf, the goaf area specifically refers to the rectangular area composed of the working face, the opening cut, the return air roadway and the transport roadway. The surface monitoring area is mainly the rectangular area directly opposite the surface area. S303: Design a monitoring scheme applicable to the determination of filling space in goaf areas, determine the implementation details of the monitoring scheme, use a total station to monitor the surface subsidence, and obtain the measured surface subsidence w.

[0007] Furthermore, the monitoring scheme in step S303 specifically includes three boundary subsidence survey lines of the goaf and one subsidence survey line in the middle of the goaf. The three subsidence survey lines at the boundaries of the goaf area consist of one main survey line and two auxiliary survey lines at the boundaries of the goaf area. Three subsidence survey lines at the boundary of the goaf are laid out on the ground surface on one side of the return air roadway or transport roadway, and one subsidence survey line in the middle of the goaf is laid out on the ground surface in the middle of the working face.

[0008] Furthermore, the boundary subsidence survey line of the goaf is selected at the distance between the goaf and the transport roadway and the return air roadway. l Within the specified range, the calculation is based on the overlying fracture angle and is performed using the following formula: l = H s / tan i .

[0009] Furthermore, the main survey line of the goaf boundary is arranged at a distance from the roadway. d 1 = 0.5*( H s / tan i At position +10, it is arranged along the direction of the working face advance; Supplement auxiliary survey lines to the goaf boundary on both sides of the main survey line. The auxiliary survey lines are along the working face advancement direction, and one of the survey lines is located at a distance from the surface of the return air roadway. d 2= H s / tan i The other survey line is located at the corresponding surface of the return air duct. d 3 = 10m.

[0010] Furthermore, step S5, determining whether the goaf corresponding to the observation point has filling space and identifying a favorable filling opportunity, specifically includes the following: During the initial formation stage of the filling space, the surface subsidence value is the smallest and the subsidence rate is relatively low. During the initial closure stage of the filling space, the surface subsidence value and subsidence rate gradually increase; During the accelerated closure phase of the filling space, the surface subsidence value gradually increases; During the filling space closure stage, the surface subsidence value is close to the maximum subsidence value, and the subsidence rate is relatively low.

[0011] The advantages of this invention are: This invention provides a method for determining the location and timing of filling in coal mine goaf areas, which has the following advantages: (1) High efficiency: By replacing drilling geophysical exploration technology with multi-point surface monitoring technology, the efficiency of single-point measurement is improved. Evaluation indicators simplify the judgment process; (2) Low cost: By deploying a subsidence observation system on the surface, surface drilling is avoided, saving drilling and geophysical exploration costs.

[0012] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the process flow of the present invention.

[0014] Figure 2 This is a schematic diagram of the surface survey line layout of the present invention. Detailed Implementation

[0015] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the specific implementation methods, structural features and effects of the present invention are described in detail below with reference to the accompanying drawings and embodiments.

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "aligned", "overlapping", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not 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.

[0018] 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 one or more of that feature; in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0019] Example 1

[0020] This embodiment provides, for example Figure 1 and Figure 2 The method for determining the location and timing of filling in coal mine goaf, as shown, includes the following steps: S1: Collect basic mine data, including coal seam occurrence characteristics, working face mining parameters, etc. S2: Based on the collected basic data, analyze the overburden migration pattern, determine the distribution characteristics of the three overburden zones, identify the key strata K1, K2..., and the delamination strata, and determine the height H of the caving zone and fracture zone. f With the height of the delamination layer H s Among them, based on the structure of the overlying rock strata, the migration pattern of the overlying rock is calculated, such as the "two-zone, three-zone" migration pattern; Based on previous measured data from mining areas and the obtained rock strata structure, the possible compaction areas of the grouting strata were determined, mainly divided into the goaf caving zone and the delamination layer. For typical key strata structures, when there is only one key stratum K1, and the key stratum structure is located within the caving zone or fracture zone, it is determined that the time for surface subsidence to be transmitted to the surface is relatively short, and the filling space mainly exists within the goaf caving zone and fracture zone strata.

[0021] For typical key strata, there is only one key stratum K1. When the key stratum is located above the overlying caving zone or fracture zone, the filling space mainly exists in the caving zone and the delamination space. When there are multiple key rock strata, K1, K2..., after the coal seam is mined, the rock strata fractures from the roof to higher layers of the overlying rock strata. The height of the caving zone and fracture zone is determined, and the location of the overlying strata separation is further determined. At this time, the post-mining filling space is mainly distributed within the rock strata and has not been converted into surface subsidence. Therefore, it can be determined that the location of the filling space is mainly concentrated in the caving zone broken rock blocks and the overlying strata separation space. S3: Design a monitoring scheme suitable for determining the filling space in goaf areas, determine the implementation details of the monitoring scheme, use a total station to monitor the surface subsidence, and obtain the measured surface subsidence. w Based on the analysis of the rock strata structure, the implementation details of the monitoring scheme were proposed. The monitoring scheme includes three boundary subsidence survey lines for the goaf and one central subsidence survey line for the goaf. The three boundary subsidence survey lines for the goaf consist of one main boundary survey line and two auxiliary boundary survey lines for the goaf. The three boundary subsidence survey lines for the goaf are arranged on the surface of one side of the return air roadway or transport roadway. The central subsidence survey line for the goaf is arranged on the surface of the central part of the working face. First, collect historical subsidence data for this mining area, including the maximum subsidence amount. w max With maximum subsidence rate v max This is used to determine the distribution and timing of filling space, and serves as a prerequisite for subsequent determinations of filling space distribution and timing. Specifically, the maximum surface subsidence in the central part of the goaf area of ​​the non-filled working face is... w max-m The maximum subsidence rate is v max-m The maximum surface subsidence in the boundary area of ​​the goaf is w max-b The maximum subsidence rate is v max-b Under normal circumstances, the maximum subsidence and maximum subsidence rate in the middle of the goaf are greater than those at the boundary of the goaf. Secondly, by laying surface survey lines above the goaf, the goaf specifically refers to the rectangular area composed of the working face, the opening, the return air roadway, and the transport roadway. The surface monitoring area is mainly the rectangular area directly opposite the surface area. Figure 2 The design of the surface survey line layout on one side of the return air roadway is only shown in the image; the layout on the side of the transport roadway is the same as that on the return air roadway. The boundary subsidence survey line of the goaf is generally selected at the distance between the goaf and the transport roadway and the return air roadway. l Within the specified range, based on the overlying fracture angle, the calculation can be performed using the following formula: l = H s / tan i ; i: is the angle of fracture of the overlying rock; H s : This refers to the height of the stratigraphic level. The main survey line of the goaf boundary is arranged at a distance from the roadway. d 1 = 0.5*( H s / tan i At the +10) position, the measuring points are arranged along the direction of the working face advance, and the spacing between measuring points within the measuring line is generally 15m.

[0022] Simultaneously, auxiliary survey lines were added to both sides of the main survey line at the boundary of the goaf. The auxiliary survey lines are along the direction of the working face advance, and one of the survey lines is located at the surface corresponding to the return air roadway. d 2= H s / tan i The other survey line is located at the corresponding surface of the return air duct. d 3 = 10m The spacing between measuring points within the auxiliary measuring lines of the two goaf boundaries is generally 60m, but the distance between measuring points can be adjusted according to monitoring needs. The subsidence monitoring line in the middle of the goaf is generally arranged along the middle of the working face towards the working face advance direction. The spacing between the monitoring points is determined according to the monitoring frequency, etc., and is generally about 15m. The monitoring is to monitor the subsidence of the goaf / separation area in the middle of the goaf directly opposite the ground surface. Then, a total station was used to monitor the surface subsidence and obtain the measured surface subsidence amount. w ; S4: Obtain the subsidence rate by differentiating the subsidence amount from the frequency of the collected data. Output the measured surface subsidence rate. v This is used to determine the location of injectable space in the goaf and the timing of grouting; S5: Criteria for determining the spatial distribution and timing of backfilling in goaf areas are proposed, including the amount of subsidence. w As the primary criterion for judgment, the subsidence rate is used as an auxiliary criterion. v As a second criterion, according to the law of surface subsidence, the surface subsidence rate of the mining area starts from zero and goes through a process of first increasing and then decreasing, which can be roughly divided into four cases; 1. In the initial formation stage of the filling space, the surface subsidence value is the smallest. w <0.1* h ), h Due to the thickness of the coal seam at the working face, the subsidence rate is relatively small. v <0.10* w max At this time, the available space in the goaf is the largest, and it is the best time for filling; the monitoring frequency is once every 2 to 3 weeks; 2. During the initial closure stage of the filling space, the surface subsidence value and subsidence rate gradually increase (0.1* h < w <0.3* h 0.1* v max < v <0.4* v max At this point, the key strata fracture, the subsidence rate increases, and the filling space gradually decreases, which is a favorable period for filling; the monitoring frequency is once every 1 to 2 weeks; 3. During the accelerated closure phase of the filling space, the surface subsidence value gradually increases (0.3*). h < w <0.6* h The subsidence rate gradually decreased (0.4*). v max < v <0.8* v max The filling space is gradually closing, and the filling process is in an unfavorable period; the monitoring frequency is once every 1 to 2 weeks. 4. During the closure stage of the filling space, the surface subsidence value approaches the maximum subsidence value. w >0.6* h The subsidence rate is relatively low (0.1*). v max < v <0.4* v max Considering the fragmentation and swelling properties of the fractured rock blocks in the collapse zone, the filling space in the goaf has already closed. At this time, the possibility of filling at the monitoring point is small, and it is in an unfavorable period for filling. The monitoring frequency is once every 4 to 5 weeks. S6: Based on the above judgment results, determine whether the surface corresponding to the observation point has filling space and whether it is in a favorable grouting time. Repeatedly monitor the surface subsidence monitoring point. By analyzing the development stage of the filling space in the goaf, determine whether it is groutable and whether it is in the best filling time for grouting. This method is applicable to coal seams with small key rock strata, shallow burial depth, and obvious staged surface migration after mining. For overburden with multiple key layers, surface monitoring of subsidence and subsidence rate is not significant, indicating that this type of method has limited applicability. However, it can be determined that the infill space still mainly exists in the overburden and has not been converted into surface subsidence.

[0023] In summary, this invention provides a method for determining the location and timing of grouting in coal mine goafs. By establishing a correlation between surface subsidence parameters and the grouting space in the underground goaf, it can not only identify the distribution characteristics and timing of grouting space in the goaf, but also deploy grouting lines within a 10-20m range from the coal pillar in the goaf. This further clarifies the criteria for determining the location and timing of grouting, thereby solving the problems of high labor intensity and high detection costs in existing technologies, greatly reducing costs and improving efficiency.

[0024] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for determining the location and timing of filling in coal mine goaf areas, characterized in that: Includes the following steps: S1: Collect basic mine data; S2: Based on the collected basic data, analyze the overburden migration pattern, determine the distribution characteristics of the three overburden zones, the key layer positions, and the delamination layer positions, and determine the height H of the caving zone and fracture zone. f With the height of the delamination layer H s ; S3: Design a monitoring scheme suitable for determining the filling space in goaf areas, and determine the implementation details of the monitoring scheme; S4: Obtain the subsidence rate by differentiating the subsidence amount from the frequency of the collected data, and output the measured surface subsidence rate. S5: Determine the filling space and timing, and propose the distribution and determination criteria of the remaining space in the goaf. S6: Based on the above judgment results, determine whether the goaf corresponding to the observation point has filling space and determine the favorable filling time.

2. The method for determining the location and timing of filling in coal mine goaf as described in claim 1, characterized in that: The basic mine data in step S1 includes coal seam occurrence characteristics and working face mining parameters.

3. The method for determining the location and timing of filling in coal mine goaf as described in claim 1, characterized in that: Step S3 involves designing a monitoring scheme suitable for determining the backfill space in goaf areas, and determining the implementation details of the monitoring scheme, specifically including the following: S301: Collect past subsidence data for this mining area, including the maximum subsidence amount w. max With the maximum subsidence rate v max ; S302: By setting up surface survey lines on the upper part of the goaf, the goaf area specifically refers to the rectangular area composed of the working face, the opening cut, the return air roadway and the transport roadway. The surface monitoring area is mainly the rectangular area directly opposite the surface area. S303: Design a monitoring scheme applicable to the determination of filling space in goaf areas, determine the implementation details of the monitoring scheme, use a total station to monitor the surface subsidence, and obtain the measured surface subsidence w.

4. The method for determining the location and timing of filling in coal mine goaf as described in claim 3, characterized in that: The monitoring scheme in step S303 specifically includes three boundary subsidence survey lines of the goaf and one subsidence survey line in the middle of the goaf; The three subsidence survey lines at the boundaries of the goaf area consist of one main survey line and two auxiliary survey lines at the boundaries of the goaf area. Three subsidence survey lines at the boundary of the goaf are laid out on the ground surface on one side of the return air roadway or transport roadway, and one subsidence survey line in the middle of the goaf is laid out on the ground surface in the middle of the working face.

5. The method for determining the location and timing of filling in coal mine goaf areas as described in claim 4, characterized in that: The boundary subsidence survey line of the goaf is selected at the distance between the goaf and the transport roadway and the return air roadway. l Within the specified range, the calculation is based on the overlying fracture angle and is performed using the following formula: l = H s / tan θ .

6. The method for determining the location and timing of filling in coal mine goaf as described in claim 4, characterized in that: The main survey line of the goaf boundary is arranged at a distance from the roadway. d 1 = 0.5*( H s / tan θ At position +10, it is arranged along the direction of the working face advance; Supplement auxiliary survey lines to the goaf boundary on both sides of the main survey line. The auxiliary survey lines are along the working face advancement direction, and one of the survey lines is located at a distance from the surface of the return air roadway. d 2= H s / tan θ The other survey line is located at the corresponding surface of the return air duct. d 3 = 10m.

7. The method for determining the location and timing of filling in coal mine goaf as described in claim 1, characterized in that: Step S5, determining whether the goaf corresponding to the observation point has filling space and identifying a favorable filling opportunity, specifically includes the following: During the initial formation stage of the filling space, the surface subsidence value is the smallest and the subsidence rate is relatively low. During the initial closure stage of the filling space, the surface subsidence value and subsidence rate gradually increase; During the accelerated closure phase of the filling space, the surface subsidence value gradually increases; During the filling space closure stage, the surface subsidence value is close to the maximum subsidence value, and the subsidence rate is relatively low.

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