Artificial pillar in goaf and construction method thereof

Abstract

The invention discloses a goaf artificial pillar and a construction method thereof. Relates to the technical field of ore extraction, and comprises a framework and a film bag wrapping the framework, the framework comprises a cylindrical vertical keel, the vertical keel is provided with a plurality of steel bar groups at intervals in the vertical direction, and each steel bar group comprises a plurality of transverse steel bars arranged at intervals in the circumferential direction of the framework; one end of the transverse steel bar is rotationally connected to the vertical keel, a plurality of pull ropes are further arranged on the vertical keel, one end of each pull rope is connected to the vertical keel, the other end of each pull rope is connected to the transverse steel bar of the top steel bar set, and when the pull ropes are in a straightened state, the transverse steel bars are perpendicular to the vertical keel; a plurality of vertical auxiliary ribs are arranged between every two adjacent steel bar sets, and the two ends of each vertical auxiliary rib are rotationally connected to the two steel bar sets correspondingly. A hole is drilled in a goaf in a safe area at the top of the goaf, a reinforcement cage mold bag is lowered into the goaf, the reinforcement cage mold bag is automatically opened to form a reinforcement mesh after being lowered into the goaf, concrete grout is poured into the reinforcement mesh from the drilled hole, and the reinforced concrete artificial ore pillar is formed; and an operator can complete construction of the artificial ore pillar without entering a dangerous goaf, so that the operation risk is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of ore mining, in particular to an artificial ore pillar in a goaf area and a construction method thereof. Background Art

[0002] Goafs, the spaces created after mining of underground ore bodies, are a major source of danger for safe mining. The roof is crucial for goaf management. Artificially constructing pillars to support the roof, applying external forces to balance the roof's loads and improving its stress environment, can significantly enhance its stability and is an effective method for goaf management.

[0003] Artificial pillars are constructed by pouring cement, sand, and gravel, materials with good compressive properties, into goafs. This construction presupposes a safe working environment within the goaf. However, actual engineering practice has shown that goafs, once formed, present significant safety hazards, including the risk of roof collapse, roof caving, and other ground pressure events, making them unsuitable for prolonged operations. These safety hazards in goafs result in low-risk goafs being suitable for artificial pillar construction, while high-risk goafs, lacking construction conditions, become increasingly unstable, directly leading to worsening stability in goafs with high ground pressure risks. Summary of the Invention

[0004] In order to construct artificial pillars in goaf areas with greater safety risks, the present application provides an artificial pillar in goaf areas and a construction method thereof.

[0005] In the first aspect, the present application provides an artificial pillar in a goaf, which adopts the following technical solution:

[0006] An artificial pillar in a goaf, comprising a frame and a membrane bag wrapped around the frame, wherein the frame comprises a cylindrical vertical keel, and the vertical keel is provided with a plurality of groups of steel bars at intervals along the vertical direction, and each group of steel bars comprises a plurality of transverse steel bars arranged at intervals along the circumferential direction of the frame;

[0007] One end of the transverse steel bar is rotatably connected to the vertical keel. The vertical keel is also provided with multiple pull ropes. One end of the pull rope is connected to the vertical keel, and the other end is connected to the transverse steel bar of the top steel bar group. When the pull rope is in a straight state, the transverse steel bar is perpendicular to the vertical keel; multiple vertical auxiliary bars are provided between adjacent steel bar groups, and the two ends of the vertical auxiliary bars are respectively rotatably connected to the two steel bar groups.

[0008] Optionally, the vertical keel includes multiple vertical longitudinal bars and multiple surrounding bars, and the multiple vertical longitudinal bars are arranged in parallel and at intervals, and the surrounding bars simultaneously connect the multiple vertical longitudinal bars to form a cylindrical shape.

[0009] Optionally, the steel bar group further includes a flexible surrounding hoop, which simultaneously connects the outer ends of all transverse steel bars in the same group; the membrane bag is also connected to the flexible surrounding hoop.

[0010] Optionally, the length of the vertical longitudinal reinforcement should be greater than the sum of the height of the goaf and the height of the rock mass of the goaf roof.

[0011] Optionally, the number of vertical longitudinal reinforcements is an even number.

[0012] In a second aspect, the present application provides a method for constructing artificial pillars in a goaf, which adopts the following technical solution:

[0013] A method for constructing artificial pillars in a goaf area comprises the following steps:

[0014] S1. Drill a hole at the top of the goaf with a diameter slightly larger than the diameter of the vertical keel;

[0015] S2, placing the skeleton with the membrane bag into the goaf through the hole;

[0016] S3. After the transverse keel is unfolded, grouting is performed into the membrane bag through the notch at the top of the keel;

[0017] S4, after solidification, forms reinforced concrete artificial pillars.

[0018] In summary, this application has the following beneficial technical effects:

[0019] This application involves drilling holes into the goaf from a safe area at the top of the goaf, lowering steel cage mold bags into the goaf, and the steel cage mold bags automatically open to form a steel mesh after being lowered into the goaf. Concrete slurry is poured into the steel mesh from the drill holes to form reinforced concrete artificial pillars; this allows operators to complete the construction of artificial pillars without entering dangerous goafs, thereby reducing operational risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the use of an artificial pillar in a goaf area of the present application;

[0021] Figure 2 This is a diagram of the overall structure of an artificial pillar in a goaf area after the skeleton is unfolded;

[0022] Figure 3 yes Figure 2 Zoomed view of the top reinforcement group structure.

[0023] Description of reference numerals:

[0024] 1. Vertical keel; 11. Vertical longitudinal reinforcement; 12. Surrounding reinforcement; 2. Rebar group; 21. Transverse reinforcement; 22. Vertical auxiliary reinforcement; 23. Flexible surrounding hoop; 3. Guy rope; 4. Goaf. DETAILED DESCRIPTION

[0025] The following is combined with Figure 1-3 This application is described in further detail.

[0026] The embodiment of the present application discloses an artificial pillar in a goaf 4 and a construction method thereof. In the prior art, the goaf 4 is a space formed after the ore body existing underground is mined, and is a major source of danger faced by safe mining in mines. For the treatment of the goaf 4, the roof is the most critical. Artificial pillars usually require pouring cement, sand and gravel and other materials in the goaf 4, but there is a risk of roof collapse and roof caving in the high-risk goaf 4, and construction workers cannot work for a long time. Traditional methods cannot solve the construction safety problem in high-risk areas, resulting in the continuous aggravation of safety hazards.

[0027] To address these issues, and given the precarious nature of conventional concrete pouring operations in high-risk goafs (4), a structure requiring rapid deployment without on-site assembly was developed. The inventors discovered that a foldable prefabricated skeleton structure could achieve a compact form for transport and automatic deployment after installation. By rotating connecting members, the two rebar groups can be retracted and deployed. A pull cord mechanism (3) controls the deployment angle, and combined with film bag wrapping to form a grouting cavity, a stable support structure can be quickly constructed in harsh environments.

[0028] Therefore, the present application proposes a skeleton and a membrane bag wrapped outside the skeleton, the skeleton includes a cylindrical vertical keel 1, and the vertical keel 1 is provided with multiple groups of steel bar groups 2 spaced apart along the vertical direction, each group of steel bar group 2 includes multiple transverse steel bars 2 spaced apart along the circumferential direction of the skeleton; one end of the transverse steel bar 2 is rotatably connected to the vertical keel 1, and the vertical keel 1 is also provided with multiple pull ropes 3, one end of the pull rope 3 is connected to the vertical keel 1, and the other end is connected to the transverse steel bar 21 of the top steel bar group 2. When the pull rope 3 is in a stretched state, the transverse steel bar 21 is perpendicular to the vertical keel 1; multiple vertical auxiliary bars 22 are provided between two adjacent steel bar groups 2, and the two ends of the vertical auxiliary bars 22 are respectively rotatably connected to the two steel bar groups 2.

[0029] Among them, the vertical keel 1 refers to a cylindrical frame as the main load-bearing structure, which can be formed by welding multiple longitudinal steel bars with annular stirrups, and can provide axial support stiffness. The transverse steel bar 21 refers to an expandable horizontal support member, which can be installed on the vertical keel 1 by a hinge connection method, folded and attached to the keel surface during transportation, and forms a horizontal support surface when unfolded. The pull rope 3 refers to a limiting device for controlling the unfolding angle, which can be made of a steel wire rope or a high-strength fiber rope. By adjusting the length, it is ensured that the transverse steel bar 21 is in a vertical state after being unfolded. The vertical auxiliary bar 22 refers to a longitudinal restraining member connecting adjacent steel bar groups 2, which can be made of a telescopic sleeve structure or a hinged connecting rod to form a longitudinal truss structure after the transverse steel bar 21 is unfolded.

[0030] Specifically, the skeleton remains folded during transportation, and the transverse reinforcement 21 is folded against the side of the vertical keel 1 to reduce its volume. After passing through the hole above the goaf 4, the transverse reinforcement 21 expands outward under the action of gravity. When the pull rope 3 is fully straightened, the transverse reinforcement 21 forms a vertical angle with the vertical keel 1, and the vertical auxiliary reinforcement 22 then extends to form a longitudinal connection. The unfolded skeleton forms a spatial truss structure, which is then wrapped in a membrane bag to form a closed cavity and then injected with concrete slurry. After solidification, it forms an integral pillar with a three-dimensional steel mesh structure.

[0031] Compared to existing technologies, existing artificial pillars require on-site steel mesh tying and formwork, resulting in long construction times and potential safety hazards. This solution utilizes a prefabricated, foldable frame, enabling rapid installation without the need for complex operations within the goaf. The deployed spatial truss structure provides immediate temporary support, effectively reducing the risk of roof collapse and creating safe conditions for subsequent grouting operations.

[0032] Through the above technical solution, this application realizes the prefabrication and rapid installation of artificial pillars, avoiding the safety hazards of traditional construction in high-risk environments. The volume of the foldable skeleton is reduced to one-third of its original size during transportation, and a stable three-dimensional support system is formed after unfolding. The membrane bag wrapping structure can not only prevent concrete leakage, but also constrain the slurry to evenly fill the gaps in the skeleton, ensuring the overall mechanical properties of the pillars. This solution reduces the time for constructing artificial pillars in high-risk goaf 4 from several days using traditional methods to several hours, and construction personnel can complete the work without entering goaf 4.

[0033] The present application further proposes that the vertical keel 1 includes a plurality of vertical longitudinal bars 11 and a plurality of surrounding bars 12 , wherein the plurality of vertical longitudinal bars 11 are arranged in parallel and spaced apart, and the surrounding bars 12 simultaneously connect the plurality of vertical longitudinal bars 11 to form a cylindrical shape.

[0034] The vertical longitudinal bars 11 are steel bars extending in the vertical direction. Specifically, they can be made of 16mm diameter threaded steel bars. Their parallel and spaced arrangement forms a longitudinal support frame. The surrounding bars 12 are stirrups extending horizontally. Specifically, they can be made of 10mm diameter round steel bars bent into a ring shape. The vertical longitudinal bars 11 are connected by welding or tying to create a spatial restraint.

[0035] Specifically, by providing multiple vertical longitudinal bars 11, the longitudinal bearing capacity is enhanced while maintaining uniform spacing between the longitudinal bars. The surrounding bars 12 connect the vertical longitudinal bars 11 transversely in a continuous ring structure, so that the discretely distributed longitudinal steel bars form an integral force-bearing system. The formation of the cylindrical structure allows the vertical keel 1 to be subjected to uniform force in all directions when subjected to roof pressure, avoiding stress concentration. The cross-connection structure of the longitudinal bars and the surrounding bars 12 effectively improves the bending stiffness and can maintain structural stability when subjected to the complex loads of the goaf 4.

[0036] Compared with existing technologies, traditional pillar support structures often use single columns or simple welded frames, which suffer from poor integrity and weak resistance to lateral forces. This solution, through the combination of multiple longitudinal reinforcements and surrounding reinforcements 12, creates a cylindrical structure with spatial rigidity, significantly improving compressive strength while maintaining the same material usage. The continuous connection of the surrounding reinforcements 12 overcomes the failure-prone nature of traditional spot welding connections, ensuring the structure's reliability under long-term loads.

[0037] Through the above technical solution, this application effectively constructs a high-strength three-dimensional support system. The cylindrical structure fully utilizes the compressive strength of the annular cross-section to maintain stable load-bearing under the complex ground pressure environment of goaf 4. The rational setting of the longitudinal reinforcement spacing takes into account both material economy and structural rigidity. The continuous connection of the surrounding reinforcement 12 ensures that all components work together, providing a reliable skeleton support for the subsequent grouting to form the integral pillar.

[0038] The present application further proposes that the steel bar group 2 also includes a flexible surrounding hoop 23 , which simultaneously connects the outer ends of all the transverse steel bars 21 in the same group, and the membrane bag is also connected to the flexible surrounding hoop 23 .

[0039] The flexible surrounding hoop 23 is an annular restraining member made of a flexible material. Specifically, it can be implemented by braiding a steel wire rope or a high-strength fiber belt into an annular structure. Its function is to converge the outer ends of the same group of transverse reinforcements 21 into a uniformly distributed circular shape, thereby preventing the reinforcement from shifting during transportation and causing the structure to become loose. The connection between the film bag and the flexible surrounding hoop 23 means that the inner surface of the film bag is fixed to the outer edge of the flexible surrounding hoop 23 by sewing or binding. Its function is to utilize the elastic deformation capacity of the flexible surrounding hoop 23 to transfer the stress between the film bag and the reinforcement group 2, so that the grouting pressure acts evenly on the inner wall of the film bag.

[0040] Specifically, after the transverse reinforcement 21 is placed in a folded state on the vertical keel 1 and placed in the goaf 4, the flexible surrounding hoop 23 uses its own elastic restoring force to pull the outer end of the transverse reinforcement 21 outward to the designed position, ensuring that the deployment angle and spacing of each transverse reinforcement 21 meet the preset distribution requirements. The connection points between the membrane bag and the flexible surrounding hoop 23 are evenly arranged along the circumference. During the grouting process, the flexible surrounding hoop 23 expands radially as the membrane bag expands. At this time, the deployment angle of the transverse reinforcement 21 is maintained fixed by the pull rope 3. The elastic deformation of the flexible surrounding hoop 23 compensates for the stress changes caused by the sinking of the roof of the goaf 4, preventing local tearing of the membrane bag.

[0041] Compared to existing technologies, the transverse reinforcement 21 of traditional artificial pillars is fixed to the vertical keel 1 only by welding or bolts. This can easily cause the reinforcement to dislocate due to collisions during lowering. Furthermore, when the film bag is directly wrapped around the steel skeleton, there is no intermediate connection layer, which can easily cause the film bag to separate from the steel. This solution uses flexible surrounding hoops 23 to form a transverse constraint network, allowing the steel bar group 2 to automatically return to its preset shape after deployment. At the same time, the multi-point anchoring of the flexible surrounding hoops 23 and the film bag creates a stress buffer layer, preventing grouting pressure from directly impacting the film bag seams.

[0042] Through the above technical solution, this application solves the problem of uneven distribution of transverse reinforcement 21 during artificial pillar construction, resulting in a loose structure, while also eliminating the potential for grouting leakage caused by a loose connection between the membrane bag and the frame. The deployment accuracy of the transverse reinforcement 21 is ensured by the elastic constraint of the flexible surrounding hoop 23. The continuous connection between the membrane bag and the flexible surrounding hoop 23 forms a closed grouting cavity, ensuring that after the concrete solidifies, it forms a dense integrated structure with the steel bar group 2.

[0043] The present application further proposes that the length of the vertical longitudinal reinforcement 11 should be greater than the sum of the height of the goaf 4 and the height of the rock mass at the top of the goaf 4, to ensure that the skeleton can move through the hole above the goaf 4 as a whole and connect to the ground and the roof at the upper and lower ends respectively. The present application further proposes that the number of vertical longitudinal reinforcements 11 be an even number.

[0044] The present application further proposes a method for constructing an artificial pillar in the goaf 4, comprising the following steps: drilling a hole at the top of the goaf 4, wherein the diameter of the hole is slightly larger than the diameter of the vertical keel 1; placing a skeleton with a membrane bag into the goaf 4 through the hole; after the horizontal keel is unfolded, grouting the membrane bag through the notch at the top of the keel; and forming an artificial reinforced concrete pillar after solidification.

[0045] Among them, the diameter of the drill hole is slightly larger than the diameter of the vertical keel 1, and can be achieved by using a hole diameter 50-100 mm larger than the keel diameter. This size range can ensure the smooth lowering of the skeleton while avoiding excessive damage to the top rock structure. Among them, the skeleton with a membrane bag can be achieved by using a structure in which a high-strength fiber membrane bag is wrapped around a prefabricated steel cage. The membrane bag and the steel cage are connected by a flexible surrounding hoop 23 to form a closed casting space. Among them, the horizontal keel is unfolded, which can be achieved by the pull rope 3 being automatically tensioned by gravity. The horizontal steel bar 21 is perpendicular to the vertical keel 1 when the pull rope 3 is straight, forming a three-dimensional support frame. Among them, the top notch grouting can be achieved by using a reserved grouting hole in combination with a pumping equipment for pressure injection. The slurry evenly fills the internal space of the skeleton under the constraint of the membrane bag.

[0046] Specifically, after the drilling is completed, the skeleton with pre-installed membrane bags is lowered as a whole to the goaf 4, and the transverse steel bars 21 automatically unfold under the action of gravity to form a spatial support system. The membrane bag wraps the skeleton to form a closed cavity to prevent the slurry from leaking out. During the grouting process, the concrete slurry is pumped into the membrane bag through the top notch, filling the gaps in the skeleton and wrapping the steel bars. After the slurry solidifies, the membrane bag combines with the concrete to form a reinforced concrete structure, and the steel bar group 2 and the vertical auxiliary bars 22 form a three-dimensional force network to improve the overall compressive strength of the pillar.

[0047] Compared with existing technologies, which require on-site reinforcement and formwork operations within the goaf 4, this method exposes construction workers to the risk of roof collapse. This method combines a prefabricated on-ground framework with remote grouting, allowing workers to complete pillar construction without entering the goaf 4. Furthermore, the enclosed space created by the film bags replaces traditional formwork, eliminating the need for formwork support and shortening the construction period.

[0048] Through the above-mentioned technical solution, this application effectively solves the problem of unsafe operations in high-risk goaf 4. By combining the lowering of the prefabricated structure with a closed grouting process, on-site construction in a high-risk environment is transformed into ground prefabrication and remote operation, significantly reducing personnel safety risks. The resulting three-dimensional steel network works synergistically with the membrane-contained concrete to ensure uniform stress distribution and high load-bearing capacity of the artificial pillars.

[0049] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. An artificial pillar in a goaf, characterized by: The frame includes a frame and a membrane bag wrapped around the frame, wherein the frame includes a cylindrical vertical keel, and the vertical keel is provided with a plurality of steel bar groups at intervals along the vertical direction, and each steel bar group includes a plurality of transverse steel bars spaced apart along the circumferential direction of the frame; One end of the transverse steel bar is rotatably connected to the vertical keel. The vertical keel is also provided with multiple pull ropes. One end of the pull rope is connected to the vertical keel, and the other end is connected to the transverse steel bar of the top steel bar group. When the pull rope is in a straight state, the transverse steel bar is perpendicular to the vertical keel; multiple vertical auxiliary bars are provided between adjacent steel bar groups, and the two ends of the vertical auxiliary bars are respectively rotatably connected to the two steel bar groups.

2. The artificial pillar in the goaf according to claim 1, characterized in that: The vertical keel includes multiple vertical longitudinal bars and multiple surrounding bars. The multiple vertical longitudinal bars are arranged in parallel and at intervals. The surrounding bars simultaneously connect the multiple vertical longitudinal bars to form a cylindrical shape.

3. The artificial pillar in the goaf according to claim 2, characterized in that: The steel bar group further comprises a flexible surrounding hoop, which simultaneously connects the outer ends of all transverse steel bars in the same group; the membrane bag is also connected to the flexible surrounding hoop.

4. The artificial pillar in the goaf according to claim 3, characterized in that: The length of the vertical longitudinal reinforcement should be greater than the sum of the height of the goaf and the height of the rock mass on the top of the goaf.

5. The artificial pillar in the goaf according to claim 3, characterized in that: The number of the vertical longitudinal reinforcements is an even number.

6. A method for constructing an artificial pillar in a goaf, using the artificial pillar in a goaf according to claim 3, characterized in that The steps include: S1. Drill a hole at the top of the goaf with a diameter slightly larger than the diameter of the vertical keel; S2, placing the skeleton with the membrane bag into the goaf through the hole; S3. After the transverse keel is unfolded, grouting is performed into the membrane bag through the notch at the top of the keel; S4. After solidification, reinforced concrete artificial pillars are formed.

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