Structure and method for rapid bleeding and consolidation of grouting body

Abstract

The invention discloses a structure and method for rapid bleeding and consolidation of a grouting body, the structure comprises drainage drill holes arranged in a sandstone layer, the drainage drill holes comprise horizontal drill holes and vertical drill holes which are communicated with each other, the horizontal drill holes are horizontally arranged in the sandstone layer, and the vertical drill holes penetrate through the sandstone layer and penetrate out of an earth surface unconsolidated formation at the upper part of the sandstone layer. The drainage drill hole is formed in the sandstone layer with good permeability, a channel is provided for slurry moisture diffusion in the sandstone layer with certain permeability, so that the slurry moisture is rapidly bleeding through the drainage drill hole, the bleeding and solidification of the slurry can be accelerated, and the time for compacting the slurry and forming a support body can be greatly shortened; and the construction period of a grouting project is shortened, the grouting project cost is reduced, meanwhile, subsequent slurry bleeding can be reduced, and the influence of later surface deformation on the safety of surface buildings is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining subsidence control, in particular to a structure and method for rapid water exudation and consolidation of a grouting body. Background Art

[0002] In underground coal seam goaf areas, the overlying rock layers are prone to relatively uneven settlement, resulting in delamination. To address this problem, existing technology uses delamination grouting. This involves pumping high-concentration fly ash or coal gangue slurry into the delamination layer at high pressure through surface boreholes. The slurry then uses formation pressure to cause water to seep and compact, thereby supporting the rock layers above the delamination layer, slowing ground subsidence and protecting surface buildings. This technology is currently a commonly used method for localized surface subsidence reduction.

[0003] During delamination grouting, a large volume of slurry is injected into the delamination layer. The slurry gradually seeps and compacts, forming a support structure that supports the overlying strata. Within the delamination space, the large volume of fluid slurry seeps into the rock formation, achieving consolidation through seepage. This low seepage rate often requires years to achieve compaction, significantly impacting the grouting project schedule and cost. Subsequent slurry seepage can easily cause hysteretic deformation of the ground surface, compromising the safety of surface structures. To address this issue, we propose a structure and method for rapid delamination and consolidation of the grouting body. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the existing defects and provide a structure and method for rapid water exudation and consolidation of the grouting body. By quickly exuding water through the water-draining drilling holes, the water exudation and consolidation of the slurry can be accelerated, which can greatly shorten the time for slurry compaction and support body formation, shorten the construction period of the grouting project, and reduce the cost of the grouting project.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a structure for rapid water exudation and consolidation of a grouting body, comprising a drainage borehole arranged in a sandstone layer, the drainage borehole comprising a horizontal borehole and a vertical borehole interconnected with each other, the horizontal borehole being arranged horizontally in the sandstone layer, and the vertical borehole passing through the sandstone layer and out of the loose surface layer above the sandstone layer.

[0006] As a preferred technical solution of the present invention, the horizontal borehole is a bare hole, and the vertical borehole is cemented.

[0007] As a preferred technical solution of the present invention, the water discharge borehole further includes a plurality of horizontal branch boreholes, and the plurality of horizontal branch boreholes are connected to the same vertical borehole, or each horizontal branch borehole is respectively connected to the corresponding vertical branch borehole.

[0008] As a preferred technical solution of the present invention, the borehole opening at the top of the vertical borehole is connected to a water pump via a pipeline, and the water pump is connected to a water pump.

[0009] As a preferred technical solution of the present invention, a water absorbing layer is provided in the horizontal borehole.

[0010] As an optimal technical solution of the present invention, a capillary tube group is provided in the vertical borehole, and an inclined drainage pipe is connected to the borehole opening at the top of the vertical borehole. The top of the capillary tube group extends into the inclined drainage pipe, and the bottom of the capillary tube group extends into the horizontal borehole.

[0011] The present invention also provides a method for rapid water exudation and consolidation of a grouting body, comprising the following steps:

[0012] S1) Drainage borehole arrangement: The working face includes a roadway, and drainage boreholes are arranged outside the boundary of the surface subsidence caused by the working face. The horizontal drilling part of the drainage borehole is set at the bottom of the sandstone layer with good permeability, close to the rock layer floor;

[0013] S2) Vertical drilling and cementing: After drilling the horizontal and vertical boreholes, the horizontal boreholes are open-hole, while the vertical boreholes are cemented;

[0014] S3) Installing a blowout prevention valve: Install a blowout prevention valve on the pipe at the top of the vertical borehole;

[0015] S4) Grouting: Grouting is carried out in the lower part of the sandstone layer with good permeability. The sandstone layer with a certain degree of permeability provides a channel for the diffusion of slurry water, allowing the slurry water to quickly seep through the water-draining boreholes, thereby accelerating the consolidation of the slurry;

[0016] S5) Sealing the borehole: After the slurry has seeped water and solidified, the blowout preventer valves and pipelines are removed, and the drainage borehole is sealed by pouring concrete, or high-concentration fly ash or coal gangue slurry is transported into the drainage borehole at high pressure through a ground borehole to seal it.

[0017] As a preferred technical solution of the present invention, the borehole opening of the vertical borehole is located at a distance L from the stop-production line, and L is calculated by the following formula:

[0018] L=(h1 / tanψ)+(h2 / tanφ)+r

[0019] Among them, h1 is the thickness of bedrock above the mined coal seam, m; h2 is the thickness of the surface loose layer, m; r is the turning radius of the horizontal well drilling, m; ψ is the mining boundary angle of the working face, in degrees; φ is the loose layer movement angle, in degrees.

[0020] As a preferred technical solution of the present invention, the distance between the horizontal borehole and the bottom plate of the sandstone layer is h. When the critical hydraulic gradient J of the sandstone layer under the slurry pressure head is taken, the corresponding critical thickness h is 临 To determine, according to the empirical coefficient value, h = (0.8 ~ 0.9) × h 临 .

[0021] As a preferred technical solution of the present invention, in step S1, the horizontal section of the water-draining borehole is drilled horizontally along the bottom of the sandstone layer at a height h to form a horizontal borehole. The position of the horizontal borehole end hole is selected above the initial development point of the separation layer. This point can be obtained through parameters such as the mining boundary angle of the working face and the distance h3 between the bottom of the sandstone layer and the coal seam. The formula is calculated:

[0022] d=h3 / tanψ

[0023] d is the vertical distance between the initial development point of the stratum corneum and the incision plane.

[0024] Compared with the existing technology, the beneficial effects of the present invention are: by setting water drainage holes in sandstone layers with good permeability, a channel is provided for the diffusion of slurry water in the sandstone layers with a certain permeability, so that the slurry water can quickly seep out through the water drainage holes, which can accelerate the slurry water seepage and consolidation, and can greatly shorten the time for slurry compaction and support body formation, shorten the grouting project period, reduce the grouting project cost, and at the same time reduce subsequent slurry water seepage, avoiding the impact of later surface deformation on the safety of surface buildings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a side structural schematic diagram of the present invention;

[0026] Figure 2 It is a schematic diagram of the top view of the structure of the present invention;

[0027] Figure 3 It is a structural schematic diagram of another embodiment of the present invention;

[0028] Figure 4 It is a structural diagram of another embodiment of the present invention.

[0029] In the figure: 1 coal seam, 2 surface loose layer, 3 sandstone layer, 4 drainage borehole, 5 horizontal borehole, 6 vertical borehole, 7 initial development point of separation layer, 8 surface subsidence boundary, 9 loose layer movement angle, 10 working face mining boundary angle, 11 slurry development boundary line, 12 borehole mouth, 13 tunnel, 14 working face, 15 cut eye, 16 stop mining line, 17 horizontal support borehole, 18 blowout preventer valve, 19 suction pipe, 20 suction pump, 21 inclined drainage pipe, 22 water absorption layer, 23 capillary tube group, 24 mesh pipe, 25 support member. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] See also Figure 1-2 The present invention provides a technical solution: a structure for rapid water seepage and consolidation of a grouting body, comprising a drainage borehole 4 arranged in a sandstone layer 3, wherein the drainage borehole 4 comprises a horizontal borehole 5 and a vertical borehole 6 that are interconnected, wherein the horizontal borehole 5 is horizontally arranged in the sandstone layer 3, and the vertical borehole 6 passes through the sandstone layer 3 and out of the surface loose layer 2 above the sandstone layer 3. By arranging the drainage borehole 4 in the sandstone layer 3 with good permeability, a channel is provided for the diffusion of slurry water in the sandstone layer 3 with a certain permeability, so that the slurry water can quickly seep water through the drainage borehole 4, which can accelerate the water seepage and consolidation of the slurry, greatly shorten the time for slurry compaction and support body formation, shorten the construction period of the grouting project, and reduce the cost of the grouting project. At the same time, it can reduce subsequent slurry water seepage, and avoid the impact of later surface deformation on the safety of surface buildings.

[0032] In the process of grouting the delamination layer, the present invention arranges a drainage borehole 4 including a horizontal transverse borehole in a sandstone layer 3 with a certain permeability to extract (or discharge by self-flow) the water lost in the slurry (the dotted line 11 in the figure is the boundary line of the slurry volume as the delamination layer continues to develop), thereby providing a channel for the slurry water loss, thereby achieving the effect of accelerating the slurry water loss and slurry consolidation.

[0033] In a preferred technical solution, the horizontal borehole 5 is an open hole. Set within the highly permeable sandstone layer 3, the horizontal borehole 5 is able to maintain its natural permeability with the sandstone layer to the greatest extent possible, allowing the slurry's moisture to more smoothly converge within the sandstone layer toward the horizontal borehole. This effectively improves moisture collection efficiency, accelerates the grouting process, and thus promotes the consolidation rate of the grouting body, shortening the time it takes for the grouting body to form an effective support structure. This is of great significance for controlling ground subsidence and protecting the safety of surface buildings. Furthermore, the open hole avoids the use of materials such as casing in the horizontal borehole, reducing the procurement cost of construction materials and construction complexity, improving construction efficiency, helping to shorten the overall construction period, and further reducing the overall cost of the grouting project.

[0034] The vertical borehole 6 is cemented. Since the vertical borehole 6 passes through the sandstone layer 3 and extends to the surface loose layer 2, cement cementing can effectively enhance the stability of the vertical borehole 6 wall, prevent borehole blockage due to wall collapse, ensure the long-term unobstructed drainage channel, and enable the slurry water to be discharged continuously and stably, avoiding the influence of the grouting body's water seepage and consolidation effect due to the blocked channel. At the same time, cement cementing can also effectively control the flow state of the slurry in the vertical borehole, preventing the slurry from running out of pressure or causing blowout accidents, thereby improving the safety of the construction process, reducing construction risks, and ensuring the smooth progress of the grouting project.

[0035] In a preferred technical solution, the drainage borehole 4 further includes a plurality of horizontal branch boreholes 17. Depending on the specific rock permeability, a corresponding number of horizontal branch boreholes 17 or a single horizontal borehole 5 can be selected for drainage to further improve the drainage efficiency.

[0036] Several horizontal branch boreholes 17 are respectively connected to one vertical branch borehole or are all connected to the vertical borehole 6. When the terminal hole position of the horizontal branch borehole 17 is far away, multiple vertical boreholes 6 can be selected to ensure water seepage and pumping effects.

[0037] The preferred technical solution is that the drilling hole 12 at the top of the vertical borehole 6 is connected to a pumping pipe 19 through a pipeline, and the pumping pipe 19 is connected to a pumping pump 20, which is used to pump water through the pumping pump 20 when the water pressure in the hole is insufficient, thereby accelerating the secretion and drainage speed, accelerating the consolidation of the grouting body, and improving the construction flexibility and adaptability.

[0038] The water pump 20 used in this application are all commonly used electronic components in the prior art, which are powered by an external power supply, and their specific structure, working principle, control method and circuit connection are all well-known technologies and will not be described in detail here.

[0039] See also Figure 3 The present invention provides another embodiment that is substantially the same as the above embodiment, except that a water-absorbing layer 22 is disposed within the horizontal borehole 5. The water-absorbing layer 22 can be a sponge layer or other highly absorbent material, such as a sodium polyacrylate (SAP)-based water-absorbing material. In the later stages of slurry exudation, as the water content decreases, water absorption within the borehole becomes more difficult, and the borehole is less likely to absorb the remaining water. However, the water-absorbing layer still exhibits excellent water absorption properties, continuously absorbing the remaining water, reducing residual water and further improving the exudation effect.

[0040] An optional technical solution is that a capillary group 23 is provided in the vertical borehole 6, and the borehole opening 12 at the top of the vertical borehole 6 is connected to an inclined drainage pipe 21. The top of the capillary group 23 extends into the inclined drainage pipe 21, and the bottom end of the capillary group 23 extends into the horizontal borehole 5. It can actively absorb slurry moisture, expand the water seepage range, achieve precise drainage, and improve water seepage efficiency. At the same time, it cooperates with the inclined drainage pipe 21 to use gravity to accelerate drainage, prevent water retention in the vertical borehole, reduce the risk of blockage, and ensure long-term stable operation of the drainage system.

[0041] Alternatively, the capillary tube assembly 23 and the inclined drain pipe 21 can replace the suction pipe 19 and the pump 20, allowing for automatic capillary drainage and drainage. This design requires no additional power, saves energy, and reduces project costs, making it particularly suitable for drainage and drainage in small-scale grouting projects.

[0042] See also Figure 4 The present invention provides another embodiment, which is substantially the same as the aforementioned embodiment, except that a mesh tube 24 is provided in the horizontal borehole 5. The mesh tube 24 may be composed of a steel cage. The mesh tube 24 may support the horizontal borehole 5 to prevent the sandstone layer 3 from collapsing and damaging the borehole, thereby causing poor water seepage and prolonged consolidation time.

[0043] Optionally, several supports 25 are evenly arranged inside the mesh tube 24. These supports 25 comprise at least two intersecting fixing rods extending through the axis of the mesh tube 24. These supports evenly distribute pressure, enhance the stability of the mesh tube, effectively prevent deformation under pressure, ensure support for the horizontal borehole 5, and maintain the integrity of the borehole structure. This allows the mesh tube to better adapt to complex geological conditions and prevent local collapse caused by external pressure. Furthermore, it provides a stable installation foundation for drainage components such as the water absorption layer and capillary tube assembly, ensuring long-term and stable drainage, improving the water exudation efficiency of the grouting body, and ensuring project quality and safety.

[0044] The present invention also provides a technical solution: a method for rapid water exudation and consolidation of a grouting body, comprising the following steps:

[0045] S1) Arrangement of drainage boreholes: The working face 14 includes a roadway 13. To prevent mining subsidence from damaging the borehole structure, drainage boreholes 4 are arranged outside the surface subsidence boundary 8 affected by the mining of the working face 14. The horizontal borehole 5 of the drainage borehole 4 is partially set at the bottom of the sandstone layer 3 with good permeability, close to the rock layer floor.

[0046] The distance between the horizontal borehole 5 and the bottom of the sandstone layer 3 is h. When the critical hydraulic gradient J of the sandstone layer 3 under the slurry pressure head is taken, the corresponding critical thickness h is 临 To determine, according to the empirical coefficient value, h = (0.8 ~ 0.9) × h 临 .

[0047] The horizontal section of the drainage borehole is drilled horizontally along the bottom of the sandstone layer 3 at a height h to form a horizontal borehole 5. The final hole position of the horizontal borehole 5 is selected above the initial development point 7 of the separation layer. This point can be obtained through parameters such as the mining boundary angle 10 of the working face and the distance h3 between the bottom of the sandstone layer 3 and the coal seam. The formula is calculated:

[0048] d=h3 / tanψ

[0049] d is the vertical distance between the initial development point 7 of the stratum and the incision eye 15 on the plane.

[0050] S2) Vertical drilling and cementing: After drilling the horizontal borehole 5 and the vertical borehole 6, the horizontal borehole 5 is open-hole, while the vertical borehole 6 is cemented. After cementing, the connectivity between the vertical borehole 6 and the horizontal borehole 5 is more stable and reliable, which is conducive to maintaining the normal operation of the entire water discharge system, allowing the slurry water to be quickly discharged along the expected path, and ensuring the uniformity and stability of the grouting body's water seepage and consolidation process.

[0051] The borehole opening 12 of the vertical borehole 6 is located at a distance L from the stop line 16, where L is calculated by the following formula:

[0052] L=(h1 / tanψ)+(h2 / tanφ)+r

[0053] Among them, h1 is the thickness of the bedrock above the mined coal seam, m; h2 is the thickness of the surface loose layer 4, m; r is the turning radius of the horizontal well drilling, m; ψ is the mining boundary angle 10 of the working face, in degrees; φ is the loose layer movement angle 9, in degrees.

[0054] S3) Setting a blowout valve: A blowout prevention valve 18 is installed on the pipe provided at the borehole opening 12 at the top of the vertical borehole 6 to prevent a blowout due to excessive water pressure in the drain borehole 4 and to prevent high-pressure spraying due to the connection between the grouting body and the borehole fissure.

[0055] S4) Grouting: Grouting is carried out in the lower part of the sandstone layer 3 with good permeability. The sandstone layer 3 with a certain degree of permeability provides a channel for the diffusion of slurry water, so that the slurry water can quickly seep through the water-draining boreholes 4, thereby accelerating the water seepage and consolidation of the slurry.

[0056] S5) Closing the borehole: After the slurry has solidified, the blowout preventer valve 18 and pipelines are removed, and the drainage borehole 4 is sealed by pouring concrete, or high-concentration fly ash or coal gangue slurry is delivered to the drainage borehole 4 through a ground borehole at high pressure to seal it.

[0057] When a water-absorbing layer 22 such as a sponge and a capillary tube group 23 are provided in the drainage borehole 4, the capillary tube group 23 is first removed before closing the borehole and can be recycled to further reduce costs; then the water-absorbing layer 22 is removed by a spring dredge or other tools, and the borehole is cleaned as much as possible to ensure that the borehole after pouring and closing is more stable and not easy to collapse.

[0058] Any undisclosed portions of the present invention are prior art, and their specific structures, materials, and operating principles will not be described in detail. Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A structure for rapid water secretion and consolidation of a grouting body, characterized by: The invention comprises a drainage borehole (4) arranged in a sandstone layer (3), wherein the drainage borehole (4) comprises a horizontal borehole (5) and a vertical borehole (6) which are interconnected, wherein the horizontal borehole (5) is arranged horizontally in the sandstone layer (3), and the vertical borehole (6) passes through the sandstone layer (3) and passes through a loose surface layer (2) above the sandstone layer (3).

2. The structure for rapid water exudation and consolidation of a grouting body according to claim 1, characterized in that: The horizontal borehole (5) is a bare hole, and the vertical borehole (6) is cemented.

3. The structure for rapid water exudation and consolidation of a grouting body according to claim 1, characterized in that: The drainage borehole (4) further comprises a plurality of horizontal branch boreholes (17), wherein the plurality of horizontal branch boreholes (17) are connected to the same vertical borehole (6), or each horizontal branch borehole (17) is respectively connected to a corresponding vertical branch borehole.

4. The structure for rapid water exudation and consolidation of a grouting body according to claim 1, characterized in that: The drilling hole (12) at the top of the vertical drilling hole (6) is connected to a water pump (19) through a pipeline, and the water pump (19) is connected to a water pump (20).

5. The structure for rapid water exudation and consolidation of a grouting body according to claim 1, characterized in that: A water absorbing layer (22) is provided in the horizontal borehole (5).

6. A structure for rapid water exudation and consolidation of a grouting body according to claim 1 or 5, characterized in that: A capillary tube group (23) is provided in the vertical borehole (6), and a borehole opening (12) at the top of the vertical borehole (6) is connected to an inclined drainage pipe (21). The top end of the capillary tube group (23) extends into the inclined drainage pipe (21), and the bottom end of the capillary tube group (23) extends into the horizontal borehole (5).

7. A method for rapid water exudation and consolidation of a grouting body, using the structure for rapid water exudation and consolidation of a grouting body according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1) Arranging drainage boreholes: the working face (14) includes the roadway (13), and drainage boreholes (4) are arranged outside the boundary (8) of the ground subsidence affected by the mining of the working face (14), and the horizontal boreholes (5) of the drainage boreholes (4) are arranged at the bottom of the sandstone layer (3) with good permeability, close to the bottom plate of the rock layer; S2) Vertical drilling and cementing: After drilling the horizontal borehole (5) and the vertical borehole (6), the horizontal borehole (5) is open-hole cemented, while the vertical borehole (6) is cemented; S3) Installing a blowout prevention valve: Installing a blowout prevention valve (18) on a pipe provided at the borehole opening (12) at the top of the vertical borehole (6); S4) Grouting: grouting is carried out at the lower part of the sandstone layer (3) with good permeability. The sandstone layer (3) with a certain permeability provides a channel for the diffusion of slurry water, so that the slurry water can quickly seep through the water-draining borehole (4), thereby accelerating the consolidation of the slurry; S5) Closing the borehole: After the slurry has solidified, the blowout prevention valve (18) and the pipeline are removed, and the drain borehole (4) is sealed by pouring concrete, or a high-concentration fly ash or coal gangue slurry is transported into the drain borehole (4) at high pressure through a ground borehole to seal it.

8. The method for rapid water exudation and consolidation of a grouting body according to claim 7, characterized in that: The borehole opening (12) of the vertical borehole (6) is located at a distance L from the stop-production line (16), where L is calculated by the following formula: L=(h1 / tanψ)+(h2 / tanφ)+r Among them, h1 is the thickness of the bedrock above the mined coal seam, m; h2 is the thickness of the surface loose layer 4, m; r is the turning radius of the horizontal well drilling, m; ψ is the mining boundary angle of the working face (10), in degrees; φ is the loose layer movement angle (9), in degrees.

9. The method for rapid water exudation and consolidation of a grouting body according to claim 7, characterized in that: The distance between the horizontal borehole (5) and the bottom plate of the sandstone layer (3) is h. When the critical hydraulic gradient J of the sandstone layer (3) under the slurry pressure head is taken, the corresponding critical thickness h is 临 To determine, according to the empirical coefficient value, h = (0.8 ~ 0.9) × h 临 .

10. The method for rapid water exudation and consolidation of a grouting body according to claim 9, characterized in that: In the step S1, the horizontal section of the water-draining borehole is drilled horizontally along the bottom of the sandstone layer (3) at a height h to form a horizontal borehole (5). The terminal position of the horizontal borehole (5) is selected above the initial development point (7) of the separation layer. This point can be obtained through parameters such as the mining boundary angle (10) of the working face and the distance h3 between the bottom of the sandstone layer (3) and the coal seam. The formula is calculated: d=h3 / tanψ d is the vertical distance between the initial development point of the stratum corneum (7) and the incision eye (15) on the plane.

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