Grouting method for inclined holes in ground surface of subsidence area of coal mine
By using a double-arm straight-hole drilling rig for inclined drilling and grouting in coal mine subsidence areas, the reinforcement area is larger than the construction area. Coal-based solid waste-cement-based composite grout is used, which solves the problems of large land occupation and frequent equipment relocation in the surface reinforcement construction of coal mine subsidence areas, and achieves efficient and low-cost wind power foundation support.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-03-27
AI Technical Summary
Existing surface reinforcement construction in coal mine subsidence areas suffers from problems such as large temporary land occupation, frequent relocation of drilling equipment, and slow construction speed, making it difficult to effectively support the heavy wind power foundations.
A twin-arm straight-hole drilling rig was used to drill holes in the ground construction area. Some holes were drilled at an angle to form a roughly frustum-shaped structure, ensuring that the grouting reinforcement area was larger than the construction area, reducing land occupation and equipment relocation frequency. Coal-based solid waste-cement-based composite grout was used for grouting.
This approach achieves low-cost and efficient grouting reinforcement, reduces temporary land occupation and land acquisition costs, improves construction efficiency, ensures the stability of wind power foundations, and reduces the frequency of drilling equipment relocation and construction costs.
Smart Images
Figure CN121738679A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of coal mine filling technology, specifically to a method for surface inclined hole grouting in coal mine subsidence areas. Background Technology
[0002] The area of surface subsidence zones formed after coal mining in my country is approximately 30 million mu (about 2 million hectares). Some older mining areas have implemented surface shaft backfilling technology to remediate subsidence by filling the mined-out areas with solid waste such as coal gangue and fly ash, thus restoring land function. To fully utilize the abandoned land resources in subsidence areas, taking appropriate safeguards to promote the construction of wind power and photovoltaic new energy buildings (structures) in these areas is an effective approach. To ensure the surface can stably support the heavy wind power foundations, further grouting reinforcement is needed for the unstable deep collapse and fracture strata involved in the mined-out areas. However, the reinforcement construction using this technology suffers from drawbacks such as large temporary land occupation, numerous boreholes, frequent relocation of drilling equipment, and slow construction speed. Summary of the Invention
[0003] The present invention aims to at least partially solve one of the technical problems in the related art.
[0004] Therefore, embodiments of the present invention propose a method for surface inclined hole grouting in coal mine subsidence areas. This method has the advantages of small temporary land occupation area, low land acquisition cost, low frequency of drilling equipment relocation, high construction efficiency, and low cost.
[0005] The surface inclined hole grouting method for coal mine subsidence areas according to this invention includes the following steps: The grouting reinforcement zones for the ground construction area and the underground goaf of the coal mine are determined based on the design of the wind turbine foundation dimensions. Based on the boundary of the ground construction area and the maximum depth of the bottom goaf, design the drilling parameters and calculate the drilling workload. A twin-arm straight hole drilling rig is used to drill holes in the ground construction area, and at least some of the holes are inclined holes, so that the area of the ground construction area is smaller than the area of the grouting reinforcement area. After completing all drilling and grouting work, core samples will be taken for inspection after the predetermined solidification time.
[0006] The inclined hole grouting method for coal mine subsidence areas in this invention employs a dual-arm straight hole drilling rig to drill holes in the ground construction area, with at least some of the holes being inclined. This results in the grouting reinforcement area being larger than the ground construction area, creating a roughly frustum-shaped structure in the land between the ground construction area and the grouting reinforcement area. This allows for more reliable support of wind power foundations on the ground construction area without requiring an excessively large area, effectively mitigating the risk of wind power foundation settlement. It also effectively reduces the area of temporary land occupation, lowers land acquisition costs, and reduces the frequency of drilling equipment relocation. The grouting reinforcement construction in coal mine subsidence areas is more efficient and less costly.
[0007] In some embodiments, both the ground construction area and the grouting reinforcement area are generally circular, and the center of the ground construction area and the center of the grouting reinforcement area are located on the same vertical line.
[0008] In some embodiments, the drilling in the ground construction area using a dual-arm straight-hole drilling rig, with at least some of the holes being inclined, such that the area of the ground construction area is smaller than the area of the grouting reinforcement area, includes: Drill holes sequentially from the boundary to the center of the ground construction area.
[0009] In some embodiments, the drilling in the ground construction area using a dual-arm straight-hole drilling rig, with at least some of the holes being inclined holes, so that the area of the ground construction area is smaller than the area of the grouting reinforcement area, further includes: The drilling sequence is to drill holes at a large angle first, and then drill holes at a small angle.
[0010] In some embodiments, the maximum inclination angle of the inclined borehole is less than or equal to 10°.
[0011] In some embodiments, the step of completing all borehole grouting and performing core sampling after a predetermined solidification time includes: After drilling a ring of holes at the same inclination angle and grouting that part of the holes, drilling and grouting at another inclination angle are carried out.
[0012] In some embodiments, the drilling in the ground construction area using a dual-arm straight-hole drilling rig, with at least some of the holes being inclined, such that the area of the ground construction area is smaller than the area of the grouting reinforcement area, includes: A vertical borehole is set up at the center of the ground construction area, and coal-based solid waste-cement-based composite slurry is injected into the vertical borehole under pressure.
[0013] In some embodiments, the borehole density in the ground construction area increases sequentially or stepwise from the boundary to the center of the ground construction area.
[0014] In some embodiments, the grouting method adopts a segmented single-isolation retreat process, with each borehole undergoing 2-3 segmented grouting.
[0015] In some embodiments, the slurry injected into the borehole is prepared by mixing coal gangue powder from coal mine washing, ordinary silicate cement and mine water, and the water-cement ratio in the slurry is not greater than 0.3. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the ground construction area and the grouting reinforcement area in the inclined hole grouting method for coal mine subsidence areas according to an embodiment of the present invention.
[0017] Figure label: 1. Ground construction area; 2. Grouting reinforcement area; 3. Inclined drilling; 4. Vertical drilling. Detailed Implementation
[0018] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.
[0019] The following is combined with Figure 1 A method for surface inclined hole grouting in coal mine subsidence areas according to an embodiment of the present invention is described.
[0020] The surface inclined hole grouting method for coal mine subsidence areas according to this invention includes the following steps: Based on the design of the wind power foundation dimensions, the ground construction zone 1 and the grouting reinforcement zone 2 of the underground goaf in the coal mine are determined. Based on the boundary of the ground construction area 1 and the maximum depth of the bottom goaf, design the drilling parameters and calculate the drilling workload. A double-arm straight hole drilling rig is used to drill holes in the ground construction area 1, and at least some of the holes are inclined holes 3, so that the area of the ground construction area 1 is smaller than the area of the grouting reinforcement area 2. After completing all drilling and grouting work, core samples will be taken for inspection after the predetermined solidification time.
[0021] The inclined hole grouting method for coal mine subsidence areas in this invention uses a double-arm straight hole drilling rig to drill holes in the ground construction area 1, with at least some of the holes being inclined holes 3. This makes the area of the grouting reinforcement area 2 larger than the area of the ground construction area 1, so that the land in the area between the ground construction area 1 and the grouting reinforcement area 2 forms a roughly frustum-shaped structure. At this time, the area of the ground construction area 1 does not need to be too large to achieve more reliable support for the wind power foundation on the ground construction area 1, effectively avoiding the risk of wind power foundation settlement. It also effectively reduces the area of temporary land occupation, reduces land acquisition costs, and effectively reduces the frequency of moving drilling equipment. The grouting reinforcement construction in the coal mine subsidence area is more efficient and less costly.
[0022] It should be noted that "inclined borehole 3" refers to a borehole whose extension direction is at an angle to the vertical direction, and "grouting reinforcement zone 2" refers to the area formed after the grout injected into the goaf solidifies. By using a double-arm straight-hole drilling rig, during borehole construction, the outer wall effectively prevents debris from the fractured zone from falling into the borehole and affecting borehole flow, effectively ensuring smooth and reliable subsequent grouting. Furthermore, after completing all borehole grouting construction, core sampling is conducted 2 to 3 months after solidification. At this time, the grout is largely solidified, and if the core sampling results meet the requirements, it indicates that the grouting reinforcement of the coal mine subsidence area is complete. Additionally, the wind turbine foundation can be a heavy wind turbine foundation, with the area of the wind turbine foundation roughly equal to the area of the ground construction area 1.
[0023] In some embodiments, both the ground construction area 1 and the grouting reinforcement area 2 are generally circular, and the center of the ground construction area 1 and the center of the grouting reinforcement area 2 are located on the same vertical line.
[0024] Therefore, the grouting reinforcement zone 2, located directly below the ground construction zone 1, can better withstand the force from the wind turbine foundation in the ground construction zone 1, and the probability of settlement in the ground construction zone 1 where the wind turbine foundation is located is lower. Moreover, by setting the boundary of the ground construction zone 1 to be roughly circular, it is easier to design a more reasonable number and arrangement of boreholes within the ground construction zone 1.
[0025] In some embodiments, drilling is performed in the ground construction area 1 using a dual-arm straight hole drilling rig, with at least some of the holes being inclined holes 3, so that the area of the ground construction area 1 is smaller than the area of the grouting reinforcement area 2, including drilling holes sequentially from the boundary to the center of the ground construction area 1.
[0026] That is, first drill holes in the area near the boundary of the ground construction area 1, and extend the lower end of the drill holes to the area near the boundary of the grouting reinforcement area 2. Then, complete the remaining drill holes in sequence along the center of the ground construction area 1. This setup can gradually explore the boundary range and internal geological conditions of the goaf, avoid blindly drilling directly into the core area of the goaf and causing safety accidents. Moreover, when drilling in the outer area, geological exploration, grout ratio test and other preliminary work can be completed simultaneously, avoiding work stoppages and adjustments due to unclear parameters during later construction and shortening the construction period.
[0027] For example, drilling in the ground construction area 1 can be divided into multiple batches of drilling carried out sequentially. Each batch of drilling includes multiple boreholes arranged at intervals along the circumference of the ground construction area 1, and the multiple batches of drilling are arranged at intervals along the radial direction of the ground construction area 1.
[0028] In some embodiments, such as Figure 1As shown, drilling is carried out in the ground construction area 1 using a double-arm straight hole drilling rig, and at least some of the holes are inclined holes 3, so that the area of the ground construction area 1 is smaller than the area of the grouting reinforcement area 2. The drilling sequence is to drill holes with a large inclination angle first, and then drill holes with a small inclination angle.
[0029] That is, the closer the borehole is to the boundary of the ground construction area 1, the larger its inclination angle is. This ensures that the distribution of multiple boreholes in the grouting reinforcement area 2 is more uniform and reasonable. As a result, with a certain amount of grout injected into the grouting reinforcement area 2 by each borehole, the grouting uniformity in the grouting reinforcement area 2 is higher, effectively improving the utilization rate of grout.
[0030] In some embodiments, the maximum inclination angle of the inclined borehole 3 is less than or equal to 10°.
[0031] This setup, while ensuring a certain ground construction area 1, aims to ensure that the grouting reinforcement area 2 is large enough to better support the wind power foundation on the ground construction area 1. On the other hand, it also avoids excessively large distribution area of the grouting reinforcement area 2 or too many boreholes, which would result in construction redundancy and high construction costs.
[0032] For example, the maximum inclination angle of the inclined borehole 3 can be 10°, 9°, and 8°.
[0033] In some embodiments, completing all borehole grouting construction and performing core sampling inspection after a predetermined solidification time includes: after drilling a ring of boreholes at the same inclination angle, grouting that portion of the boreholes, and then drilling and grouting at another inclination angle.
[0034] In other words, grouting is first applied to the periphery of grouting reinforcement zone 2 to form a protective barrier. This effectively constrains the deformation of internal cavities, preventing sudden collapse of the boundary of grouting reinforcement zone 2 during subsequent construction and ensuring the safety of ground construction equipment and personnel. Furthermore, grouting is carried out gradually from the outside in, following a layered construction approach that fills large cavities first and then small cracks. The grout mix ratio is adjusted according to the geological conditions of different locations (e.g., high-strength grout is used for reinforcement on the periphery, while a more fluid grout is used for filling the interior), achieving comprehensive and dense filling of grouting reinforcement zone 2 and effectively controlling surface subsidence. Simultaneously, completing the periphery grouting first enhances the stability of the boundary of grouting reinforcement zone 2. During subsequent internal drilling, the drilling environment is more stable, reducing drilling deviations caused by geological deformation and lowering the rework rate.
[0035] In some embodiments, drilling is performed in the ground construction area 1 using a double-arm straight hole drilling rig, with at least some of the holes being inclined holes 3, so that the area of the ground construction area 1 is smaller than the area of the grouting reinforcement area 2. This includes: setting a vertical hole 4 at the center of the ground construction area 1, and injecting coal-based solid waste-cement-based composite grout into the vertical hole 4 under pressure.
[0036] At this time, the coal-based solid waste-cement-based composite grout has greater fluidity than the grout injected into the inclined borehole 3, and under pressure, it can achieve full-range dense filling of the grouting reinforcement zone 2, effectively controlling surface subsidence.
[0037] In some embodiments, the borehole density in the ground construction area 1 increases sequentially or stepwise from the boundary to the center of the ground construction area 1.
[0038] This setup ensures the structural strength of the grouting reinforcement zone 2 and effectively controls surface subsidence. On the other hand, it effectively reduces the number of boreholes, further improving the efficiency of grouting reinforcement in coal mine subsidence areas and reducing grouting reinforcement costs.
[0039] In some embodiments, the grouting method adopts a segmented single-isolation retreat process, with each borehole undergoing 2-3 segmented grouting.
[0040] This setup can precisely control the grout diffusion range, improve the overall density of the grouting reinforcement zone 2, and enhance the stability of the underlying layer. On the other hand, it can also reduce the risk of hole collapse and drill bit jamming, facilitate the adjustment of construction parameters, and simplify process monitoring and quality control. In addition, it can differentiate the use of grouting materials, reduce grout waste, and reduce equipment wear.
[0041] In some embodiments, the slurry injected into the borehole is prepared by mixing coal gangue powder from coal mine washing, ordinary silicate cement and mine water, and the water-cement ratio in the slurry is not greater than 0.3.
[0042] This setup effectively utilizes coal mine solid waste resources, reduces grouting costs, and the water-cement ratio of no more than 0.3 effectively reduces the porosity of the grout after solidification, improves compressive strength, and meets the bearing requirements of the grouting reinforcement zone 2.
[0043] For example, the water-cement ratio refers to the ratio of the mass of mine water to the mass of coal gangue powder and ordinary Portland cement. In addition, to ensure the function of the slurry, auxiliary materials such as high-efficiency water-reducing agents, retarders / accelerators and defoamers can be added.
[0044] 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.
[0045] 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.
[0046] 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.
[0047] 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.
[0048] 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. 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.
[0049] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.
Claims
1. A method for surface inclined hole grouting in coal mine subsidence areas, characterized in that, Includes the following steps: The ground construction area (1) and the grouting reinforcement area (2) of the underground goaf of the coal mine are determined according to the design of the wind power foundation size; Based on the boundary of the ground construction area (1) and the maximum depth of the bottom goaf, design the drilling parameters and calculate the drilling workload; A double-arm straight hole drilling rig is used to drill holes in the ground construction area (1), and at least some of the holes are inclined holes (3) so that the area of the ground construction area (1) is smaller than the area of the grouting reinforcement area (2). After completing all drilling and grouting work, core samples will be taken for inspection after the predetermined solidification time.
2. The inclined hole grouting method for coal mine subsidence areas according to claim 1, characterized in that, Both the ground construction area (1) and the grouting reinforcement area (2) are roughly circular, and the center of the ground construction area (1) and the center of the grouting reinforcement area (2) are located on the same vertical line.
3. The surface inclined hole grouting method for coal mine subsidence areas according to claim 1 or 2, characterized in that, The method of drilling holes in the ground construction area (1) using a double-arm straight hole drilling rig, with at least some of the holes being inclined holes (3), so that the area of the ground construction area (1) is smaller than the area of the grouting reinforcement area (2), includes: Holes were drilled sequentially from the boundary to the center of the ground construction area (1).
4. The inclined hole grouting method for coal mine subsidence areas according to claim 3, characterized in that, The method of drilling holes in the ground construction area (1) using a double-arm straight hole drilling rig, with at least some of the holes being inclined holes (3), so that the area of the ground construction area (1) is smaller than the area of the grouting reinforcement area (2), further includes: The drilling sequence is to drill holes at a large angle first, and then drill holes at a small angle.
5. The inclined hole grouting method for coal mine subsidence areas according to claim 4, characterized in that, The maximum inclination angle of the inclined borehole (3) is less than or equal to 10°.
6. The inclined hole grouting method for coal mine subsidence areas according to claim 4, characterized in that, The completion of all borehole grouting work, followed by core sampling after a predetermined solidification time, includes: After drilling a ring of holes at the same inclination angle and grouting that part of the holes, drilling and grouting at another inclination angle are carried out.
7. The inclined hole grouting method for coal mine subsidence areas according to claim 4, characterized in that, The method of drilling holes in the ground construction area (1) using a double-arm straight hole drilling rig, with at least some of the holes being inclined holes (3), so that the area of the ground construction area (1) is smaller than the area of the grouting reinforcement area (2), includes: A vertical borehole (4) is set at the center of the ground construction area (1), and coal-based solid waste-cement-based composite slurry is injected into the vertical borehole (4) under pressure.
8. The inclined hole grouting method for coal mine subsidence areas according to claim 1, characterized in that, The borehole density in the ground construction area (1) increases sequentially or stepwise from the boundary to the center of the ground construction area (1).
9. The inclined hole grouting method for coal mine subsidence areas according to claim 1, characterized in that, The grouting method adopts a segmented single-isolation retreat process, with each borehole undergoing 2-3 segmented grouting.
10. The surface inclined hole grouting method for coal mine subsidence areas according to claim 9, characterized in that, The grout injected into the borehole is prepared by mixing coal gangue powder from coal mine washing, ordinary silicate cement and mine water, and the water-cement ratio in the grout is no more than 0.3.