Soft thick coal seam along the empty coal pillar to wear anchor and grouting composite reinforcement system and method

Abstract

This invention discloses a composite reinforcement system and method for through-anchor cables and grouting in soft, thick coal seams, relating to the field of coal mine roadway surrounding rock control technology. It includes a coal pillar goaf-side surface sealing module and a through-anchor cable reinforcement module. The goaf-side surface sealing module constructs a high-level self-flowing grouting hole at the top of the non-goaf side of the coal pillar and injects quick-setting grout, utilizing gravity flow to form a grout-stopping curtain on the goaf-side surface. The through-anchor cable reinforcement module includes an anchor cable body, a distal anchoring mechanism, a proximal anchoring mechanism, and a grouting mechanism. The anchor cable body is inserted into an anchor cable borehole penetrating the coal pillar. The distal anchoring mechanism is anchored to the goaf-side surface, and the proximal anchoring mechanism is anchored to the non-goaf-side surface. The grouting mechanism injects grout into the anchor cable borehole to form a full-length anchor body. This invention achieves bidirectional prestressed anchoring under unilateral construction conditions, effectively controls grout loss, and enables the anchor cable and grouting body to form a synergistic full-length anchoring structure, significantly improving the stability of small coal pillars.

Description

Technical Field

[0001] This invention relates to the field of coal mine roadway surrounding rock control technology, and in particular to a composite reinforcement system and method for soft, thick coal seams with through-and-through anchor cables and grouting along coal pillars. Background Technology

[0002] In coal mining, small coal pillars in goaf-side roadways are located near the goaf and are subject to high stress concentration for extended periods, making them a key and challenging aspect of roadway surrounding rock control. To maintain the stability of these small coal pillars, a combination of anchor cable support and grouting reinforcement is commonly used in engineering. Anchor cable support provides active prestress, limiting the lateral deformation of the coal pillar; grouting reinforcement fills internal fissures in the coal seam, improving the mechanical properties of the pillar. The synergistic effect of both effectively enhances the overall stability of small coal pillars in soft, thick coal seams, reducing the risk of roadway spalling and collapse.

[0003] However, existing reinforcement technologies have significant limitations in application. Firstly, traditional through-cable anchors require simultaneous installation from both sides of the coal pillar. However, access to the goaf side of small coal pillars is often impossible, resulting in anchors being installed only on one side. This makes effective bidirectional through-cable anchoring difficult, limiting the anchoring range and hindering the full utilization of the anchor's support effectiveness. Secondly, during grouting reinforcement, due to the well-developed internal fissures in soft, thick coal seams that connect with the goaf, grout easily leaks away in large quantities along these fissures, leading to material waste and significantly reducing the grouting effect. The grout is difficult to retain effectively within the coal pillar to form a continuous reinforced structure. More importantly, in existing technologies, anchor support and grouting reinforcement are often implemented as independent processes, lacking an effective coordination mechanism. The anchoring force of the anchor and the reinforced layer formed by grouting cannot form an integral load-bearing structure, making it difficult to achieve optimal reinforcement results.

[0004] Therefore, how to develop a composite reinforcement system and method for through-anchor cables and grouting along coal pillars in soft, thick coal seams, which can achieve bidirectional through-anchoring by single-sided construction, effectively control the loss of grout, and enable the anchor cables and grouting bodies to form a full-length anchoring structure that synergistically bears the load, thereby significantly improving the stability of small coal pillars, has become a technical problem that urgently needs to be solved by people in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a composite reinforcement system and method for through-and-through anchor cables and grouting along coal pillars in soft, thick coal seams. This system achieves bidirectional through-and-through anchoring by constructing on one side, while effectively controlling the loss of grout, so that the anchor cable and the grouting body form a full-length anchoring structure that works together to bear load, thereby significantly improving the stability of small coal pillars.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: This invention discloses a composite reinforcement system for soft, thick coal seams with through-anchor cables and grouting along the goaf, used to reinforce small coal pillars adjacent to goaf areas. It includes a sealing module for the goaf side surface of the coal pillar, used to form a grout-stopping curtain on the goaf side surface of the coal pillar. The through-anchor cable reinforcement module is used to provide bidirectional prestressed anchoring for the goaf and non-goaf sides of the coal pillar; The through-anchor reinforcement module includes an anchor body, a far-end anchoring mechanism, a near-end anchoring mechanism, and a grouting mechanism. The anchor body is inserted into the anchor borehole penetrating the coal pillar. The far-end anchoring mechanism is located at one end of the anchor body and anchored to the goaf side surface of the coal pillar. The near-end anchoring mechanism is installed at the other end of the anchor body and anchored to the non-goaf side surface of the coal pillar. The grouting mechanism is used to inject grout into the anchor borehole to form a full-length anchor body that encloses the anchor body.

[0007] Preferably, the distal anchoring mechanism includes a metal baffle, hinged anchors, a spring, a hoop, and a wire rope. The metal baffle is a disc-shaped structure with a size smaller than the diameter of the anchor hole. The metal baffle is fixedly connected to one end of the anchor body near the goaf side. Multiple hinged anchors are hinged in a petal shape to the edge of the end face of the metal baffle facing the anchor body. One end of the spring is hinged to the middle of the hinged anchor, and the other end of the spring is hinged to the metal baffle. The spring provides an elastic force for opening the hinged anchor. The hoop is sleeved on the outside of the hinged anchor and is used to constrain the multiple hinged anchors to a closed state close to the anchor body in the initial state. One end of the wire rope is fixedly connected to the hoop, and the other end of the wire rope extends along the axial direction of the anchor body to the non-goaf side of the coal pillar. By pulling the wire rope, the hoop is pulled to slip off the outside of the hinged anchor, causing the hinged anchor to open in an umbrella shape under the elastic force of the spring. After opening, the hinged anchor is locked onto the goaf side surface of the coal pillar.

[0008] Preferably, the near-end anchoring mechanism includes an anchor cable tray and an anchor cable lock. The anchor cable tray is sleeved on the anchor cable body, one side of the anchor cable tray is in contact with the non-mining side of the coal pillar, the anchor cable body passes through the anchor cable tray and is locked by the anchor cable lock, and the anchor cable lock abuts against the other side of the anchor cable tray.

[0009] Preferably, the grouting mechanism includes a grouting hole pre-reserved on the anchor cable tray, the grouting hole being connected to the interior of the anchor cable borehole for injecting grout into the anchor cable borehole.

[0010] Preferably, the coal pillar goaf side surface sealing module includes multiple high-level self-flowing grouting holes, which are opened at the top of the non-goaf side of the coal pillar and extend to the goaf side of the coal pillar, for injecting quick-setting grout into the goaf side surface of the coal pillar to form a grout-stopping curtain covering the goaf side surface.

[0011] Preferably, the diameter of the high-level self-flowing grouting holes is set to 40mm-60mm, and the hole spacing is set to 500mm.

[0012] Preferably, the plurality of anchor cable holes are arranged in three rows along the vertical direction, with three anchor cable holes in the middle row and two anchor cable holes in each of the left and right rows. The anchor cable holes in the left and right rows are located in the horizontal direction at the gap between two adjacent anchor cable holes in the middle row, forming an alternating distribution. The drilling spacing of the anchor cable holes is set to 1000mm, the row spacing is set to 3000mm, and the hole diameter of the anchor cable holes is set to 60mm-80mm.

[0013] A method for reinforcing soft, thick coal seams along goaf pillars using a combination of through-cable anchors and grouting includes the following steps: S1. Construct a high-level self-flowing grouting hole at the top of the non-goaf side of the coal pillar, with the end of the high-level self-flowing grouting hole penetrating and extending to the goaf side of the coal pillar. Then, embed and install a grouting hose in the high-level self-flowing grouting hole, and inject quick-setting grout into the goaf side surface of the coal pillar through the grouting hose. The quick-setting grout flows by gravity on the goaf side surface of the coal pillar to form a grout-stopping curtain. S2. Drill anchor cables on the non-mining side of the coal pillar, with the end of the anchor cable drill hole penetrating and extending to the mining side of the coal pillar. Insert one end of the anchor cable body equipped with a distal anchoring mechanism into the anchor cable drill hole and extend it outward until the distal anchoring mechanism extends to the outside of the mining side of the coal pillar. By pulling the steel wire rope connected to the hoop of the distal anchoring mechanism, the hoop is detached from the outside of the hinged anchor. The hinged anchor opens in an umbrella shape under the elastic force of the spring, and the opened hinged anchor is clamped to the surface of the mining side of the coal pillar. Then, on the non-mining side, place the anchor cable tray on the anchor cable body and attach it to the surface of the non-mining side of the coal pillar. Lock the anchor cable body with the anchor cable lock and apply prestress to the anchor cable body to complete the bidirectional anchoring. S3. Grout is injected into the anchor cable borehole through the grouting hole reserved on the anchor cable tray. After the grout fills the borehole, it forms a full-length anchor body that wraps around the anchor cable body.

[0014] Preferably, in step S1, the injected quick-setting grout is a cement-water glass two-component grout, wherein the cement is 32.5 grade ordinary Portland cement with a water-cement ratio of 0.6 to 0.8; and the concentration of the water glass is 35 to 40°Be. The volume ratio of the cement to the water glass is 1:0.5 to 1:0.8.

[0015] Preferably, in step S3, the injected grout is a cement-water glass two-component grout, wherein the cement is 32.5 grade ordinary Portland cement with a water-cement ratio of 0.6 to 0.8; the concentration of the water glass is 15°Be′; and the volume ratio of the cement to the water glass is 1:1.

[0016] Compared with the prior art, the beneficial technical effects of the present invention are as follows: 1) The soft, thick coal seam goaf pillar through-anchor cable and grouting composite reinforcement system provided by this invention, through the design of a remotely triggerable umbrella-type self-anchoring mechanism, enables the anchor cable body to be pushed from the non-goaf side of the coal pillar to the goaf side, and automatically forms a mechanical anchoring end on the goaf side. Combined with the anchor cable locking device on the non-goaf side, it realizes bidirectional prestressed anchoring under completely unilateral construction conditions. This structural design effectively solves the problem of construction difficulties caused by the inability of personnel to enter the goaf side of traditional through-anchor cables, greatly reduces operational risks, improves construction efficiency, and at the same time ensures the reliability of the anchoring end and the full utilization of the anchoring force. 2) This invention first constructs high-level self-flowing grouting holes and injects quick-setting grout. Utilizing gravity, a continuous and complete grout-stopping curtain is formed on the goaf side surface of the coal pillar, effectively sealing tensile fractures and creating sealing conditions for subsequent anchor cable drilling and grouting. Based on this, grout is injected into the anchor cable borehole through pre-reserved grouting holes on the anchor cable tray. The grout fully fills the gap between the borehole wall and the anchor cable body, forming a full-length anchor body that envelops the anchor cable body. This process sequence of sealing before grouting ensures that the grout is effectively retained inside the coal pillar, preventing significant grout loss to the goaf area and significantly improving the utilization rate of the grouting material and the uniformity of the grouting reinforcement. 3) This invention organically integrates the sealing of the goaf side surface of the coal pillar, the bidirectional anchoring of the through-bolt cables, and the grouting of the anchor cables, forming a systematic synergistic reinforcement effect. The grout-stopping curtain provides a sealed environment for subsequent grouting, ensuring that the grout forms an effective reinforcement layer inside the coal pillar; the through-bolt cables provide preliminary active support before grouting, stabilizing the initial deformation of the coal pillar; after grouting, the full-length anchor body forms a strong bond and mechanical interlock with the anchor cable body, transforming the anchor cable from end anchoring to full-length anchoring, significantly improving the pull-out bearing capacity of the anchor cable. The three elements work together to form an integrated load-bearing structure from the surface to the interior of the coal pillar, effectively improving the shear and compressive strength of small coal pillars in soft, thick coal seams, reducing the risk of roadway deformation, and achieving optimization and multiplication of the reinforcement effect. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings.

[0018] Figure 1 This is a schematic diagram of the overall structure of a composite reinforcement system for soft, thick coal seams with through-anchor cables and grouting along coal pillars, as described in this invention. Figure 1 ; Figure 2 This is a schematic diagram of the overall structure of a composite reinforcement system for soft, thick coal seams with through-anchor cables and grouting along coal pillars, as described in this invention. Figure 2 ; Figure 3 In this invention Figure 2 The left view; Figure 4 This is a schematic diagram of the planar arrangement of the high-level self-flowing grouting holes and anchor cable boreholes on the non-mining side of the coal pillar in this invention; Figure 5 This is a schematic diagram of the connection structure between the through-anchor cable reinforcement module and the coal pillar in this invention; Figure 6 This is a schematic diagram of the actual application of the composite reinforcement system of through-anchor cable and grouting along the coal column in soft and thick coal seams according to the present invention.

[0019] Explanation of reference numerals in the attached drawings: 1. Anchor cable body; 2. Anchor cable lock; 3. Anchor cable tray; 4. Hoop; 5. Spring; 6. Wire rope; 7. Hinged anchor; 8. Metal baffle; 9. Grouting hole; 10. High-level self-flowing grouting hole; 11. Anchor cable borehole; 12. Coal pillar; 13. Grout-stopping curtain; 14. Full-length anchor body. Detailed Implementation

[0020] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0021] like Figure 1-6 As shown, a composite reinforcement system of through-anchor cable and grouting for soft thick coal seam coal pillars along the goaf is used to reinforce small coal pillars in adjacent goaf areas. It includes a coal pillar goaf side surface sealing module for forming a grout-stopping curtain 13 on the goaf side surface of the coal pillar 12. The through-anchor cable reinforcement module is used to provide bidirectional prestressed anchoring for the goaf side and non-goaf side of the coal pillar 12; The through-anchor reinforcement module includes an anchor body 1, a far-end anchoring mechanism, a near-end anchoring mechanism, and a grouting mechanism. The anchor body 1 is inserted into the anchor borehole 11 that penetrates the coal pillar 12. The far-end anchoring mechanism is located at one end of the anchor body 1 and is anchored to the goaf side surface of the coal pillar 12. The near-end anchoring mechanism is installed at the other end of the anchor body 1 and is anchored to the non-goaf side surface of the coal pillar 12. The grouting mechanism is used to inject grout into the anchor borehole 11 to form a full-length anchor body 14 that encloses the anchor body 1.

[0022] Specifically, the function of the grout-stopping curtain 13 is to form a sealing layer on one side of the goaf before subsequent grouting reinforcement of the coal pillar 12. Due to the well-developed fractures in the soft, thick coal seam, if grout is injected directly into the coal pillar, the grout can easily flow away in large quantities along the tensile fractures on the goaf side into the goaf behind, and cannot be effectively retained. By first forming the grout-stopping curtain 13, it is equivalent to constructing a barrier layer on the goaf side surface of the coal pillar 12, ensuring that the subsequently injected grout can be confined inside the coal pillar 12 and fully penetrate into the fractures around the borehole, thereby significantly improving the grouting reinforcement effect.

[0023] Specifically, the distal anchoring mechanism includes a metal baffle 8, hinged anchors 7, a spring 5, a hoop 4, and a steel wire rope 6. The metal baffle 8 has a disc-shaped structure, and its size is smaller than the diameter of the anchor cable borehole 11. The metal baffle 8 is fixedly connected to one end of the anchor cable body 1 near the goaf side. Multiple hinged anchors 7 are hinged in a petal shape to the edge of the end face of the metal baffle 8 facing the anchor cable body 1. One end of the spring 5 is hinged to the middle of the hinged anchor 7, and the other end of the spring 5 is hinged to the metal baffle 8. The spring 5 is used to provide an elastic force for opening the hinged anchor 7. The hoop 4 is sleeved on the outside of the hinged anchor 7 and is used to constrain multiple hinged anchors 7 to a closed state close to the anchor cable body 1 in the initial state. One end of the steel wire rope 6 is fixedly connected to the hoop 4, and the other end of the steel wire rope 6 extends along the axial direction of the anchor cable body 1 to the non-goaf side of the coal pillar 12. By pulling the wire rope 6, the hoop 4 is pulled to slip off the outside of the hinged anchor 7, causing the hinged anchor 7 to open in an umbrella shape under the elastic force of the spring 5. After opening, the hinged anchor 7 is locked onto the goaf side surface of the coal pillar 12.

[0024] Specifically, during construction, the anchor cable body 1, along with the distal anchoring mechanism, is pushed into the anchor cable borehole 11 from a single-sided roadway on the non-goaf side. At this time, the articulated anchor 7 is bound by the hoop 4 and tightly adheres to the anchor cable body 1. Its relatively small overall outer diameter allows it to pass smoothly through the borehole. When the anchor cable body 1 is pushed to the designed depth, i.e., when the distal anchoring mechanism fully extends to the goaf side, the operator only needs to pull the wire rope 6 on the non-goaf side to remotely trigger the hoop 4 to slip, causing the articulated anchor 7 to automatically open under the push of the spring 5. This design solves the problem of personnel being unable to access the goaf side for construction, enabling the establishment of the distal anchor point through completely single-sided operation, greatly improving the feasibility and safety of construction.

[0025] Specifically, when the hinged anchor 7 is fully opened under the action of the spring 5, the metal baffle 8 and the hinged anchor 7 together form a combined anchoring end with a diameter larger than that of the anchor cable borehole 11. During the subsequent tensioning of the anchor cable body 1, this combined anchoring end will be tightly locked onto the surface of the goaf side of the coal pillar 12, providing reliable anchoring force and preventing the anchor cable body 1 from slipping out of the anchor cable borehole 11 during the tensioning process.

[0026] Specifically, the near-end anchoring mechanism includes an anchor cable tray 3 and an anchor cable lock 2. The anchor cable tray 3 is sleeved on the anchor cable body 1. One side of the anchor cable tray 3 is in contact with the non-mining side of the coal pillar 12. The anchor cable body 1 passes through the anchor cable tray 3 and is locked by the anchor cable lock 2. The anchor cable lock 2 abuts against the other side of the anchor cable tray 3.

[0027] Specifically, with the remote anchoring mechanism already secured to the goaf side surface, bidirectional prestressed anchoring is achieved by installing an anchor cable tray 3 on the non-goaf side and locking it using the anchor cable lock 2. The anchor cable tray 3 is designed to be relatively large, allowing for the even distribution of the concentrated tension of the anchor cable body 1 to the non-goaf side surface of the coal pillar 12, preventing coal collapse due to excessive local stress. The main function of the anchor cable lock 2 is to lock the anchor cable body 1 after tensioning and maintain the set prestress value for a long period. In practical applications, any device that can lock the anchor cable body 1 is acceptable; this invention is not limited to any particular device.

[0028] Specifically, the grouting mechanism includes a grouting hole 9 pre-reserved on the anchor cable tray 3. The grouting hole 9 is connected to the interior of the anchor cable borehole 11 and is used to inject grout into the anchor cable borehole 11.

[0029] Specifically, the grouting hole 9 is pre-formed during the processing of the anchor cable tray 3, and its inner wall is threaded to facilitate the connection of the grouting joint. After the anchor cable body 1 is tensioned and locked, grout is injected into the anchor cable borehole 11 through the grouting hole 9. The grout can flow along the gap between the borehole wall and the anchor cable body 1 until it fills the entire anchor cable borehole 11. After grouting, the grout solidifies to form a full-length anchor body 14. The full-length anchor body 14 not only bonds and reinforces the coal body around the anchor cable borehole 11, but also forms a strong bond and mechanical interlock with the surface of the anchor cable body 1, changing the anchor cable body 1 from the original end anchoring to a full-length anchoring state, significantly improving the overall load-bearing capacity of the anchoring system.

[0030] Specifically, the coal pillar goaf side surface sealing module includes multiple high-level self-flowing grouting holes 10. The high-level self-flowing grouting holes 10 are opened at the top of the non-goaf side of the coal pillar 12 and extend to the goaf side of the coal pillar 12. They are used to inject quick-setting grout into the goaf side surface of the coal pillar 12 to form a grout-stopping curtain 13 covering the goaf side surface.

[0031] Specifically, after the high-level self-flowing grouting hole 10 is constructed, the injected quick-setting grout will naturally flow from high to low level under the action of gravity, flowing along the high-level self-flowing grouting hole 10 to the surface of the goaf side, and spreading from top to bottom along the goaf side facade of the coal pillar 12, thereby forming a continuous and closed curtain with a certain thickness on the surface of the goaf side. This method does not require any operation on the goaf side, and relies entirely on gravity to achieve automatic spreading, which is simple to construct and provides uniform coverage.

[0032] Specifically, the diameter of the high-level self-flowing grouting hole 10 is set to 40mm-60mm, and the hole spacing is set to 500mm.

[0033] Specifically, the diameter of the high-level self-flowing grouting holes 10 is controlled between 40mm and 60mm. This diameter ensures smooth insertion of the grouting hose without excessively weakening the top structural strength of the coal pillar 12 due to excessively large diameter. The hole spacing is set at 500mm, determined based on the effective diffusion radius of the quick-setting grout on the goaf side surface. At this spacing, the grout coverage areas formed by two adjacent grouting holes can overlap, ensuring that the formed grout-stopping curtain 13 is continuous and uninterrupted on the entire goaf side surface of the coal pillar 12, with no uncovered weak areas, thus providing reliable sealing conditions for subsequent grouting reinforcement.

[0034] Specifically, the multiple anchor holes 11 are arranged in three rows along the vertical direction. The middle row has three anchor holes 11, and the left and right rows each have two anchor holes 11. The anchor holes 11 in the left and right rows are located in the gap between two adjacent anchor holes 11 in the middle row in the horizontal direction, forming an alternating distribution. The drilling spacing of the anchor cable borehole 11 is set to 1000mm, the row spacing is set to 3000mm, and the diameter of the anchor cable borehole 11 is set to 60mm-80mm.

[0035] Specifically, the core of this "2-3-2" staggered perforation pattern lies in creating a three-dimensional, intersecting reinforcement network within the coal pillar 12 using the full-length anchor body 14. The horizontally staggered arrangement of adjacent rows of anchor holes 11 ensures a more uniform distribution of anchoring force across the entire cross-section of the coal pillar 12, avoiding the weak reinforcement zones formed by traditional aligned perforation patterns. The hole spacing of 1000mm and the row spacing of 3000mm are determined based on the mechanical properties and stress influence range of the soft, thick coal seam, ensuring that the reinforcement rings of each anchor can overlap, forming a unified load-bearing structure, thereby effectively controlling the overall deformation of the coal pillar 12.

[0036] A method for reinforcing soft, thick coal seams along goaf pillars using a combination of through-cable anchors and grouting includes the following steps: S1. Construct a high-level self-flowing grouting hole 10 at the top of the non-goaf side of the coal pillar 12, with the end of the high-level self-flowing grouting hole 10 penetrating and extending to the goaf side of the coal pillar 12. Then, install a grouting hose in the high-level self-flowing grouting hole 10 and inject quick-setting grout into the goaf side surface of the coal pillar 12 through the grouting hose. The quick-setting grout flows by gravity to form a grout-stopping curtain 13 on the goaf side surface of the coal pillar 12. S2. Construct anchor cable borehole 11 on the non-mining side of the coal pillar 12, with the end of the anchor cable borehole 11 penetrating and extending to the mining side of the coal pillar 12. Insert one end of the anchor cable body 1, which is equipped with a remote anchoring mechanism, into the anchor cable borehole 11 and extend it outward until the remote anchoring mechanism extends to the outside of the mining side of the coal pillar 12. By pulling the steel wire rope 6 connected to the hoop 4 of the remote anchoring mechanism, the hoop 4 is detached from the outside of the hinged anchor 7. The hinged anchor 7 opens in an umbrella shape under the elastic force of the spring 5, and the opened hinged anchor 7 is clamped to the surface of the mining side of the coal pillar 12. Then, on the non-mining side, the anchor cable tray 3 is placed on the anchor cable body 1 and attached to the surface of the non-mining side of the coal pillar 12. The anchor cable body 1 is locked by the anchor cable lock 2 and prestress is applied to the anchor cable body 1 to complete the bidirectional anchoring. S3. Grout is injected into the anchor cable borehole 11 through the grouting hole 9 reserved on the anchor cable tray 3. After the grout fills the borehole, it forms a full-length anchor body 14 that wraps around the anchor cable body 1.

[0037] Specifically, in step S1, after the high-level self-flowing grouting hole 10 is constructed, when installing the grouting hose, it is necessary to ensure that the end of the grouting hose does not extend beyond the far end of the borehole, that is, the outlet of the grouting hose is located exactly at the position of the goaf side surface of the coal pillar 12. In this way, during grouting, the grout flowing out of the grouting hose will directly contact the goaf side surface of the coal pillar 12 and flow downward along the surface under the action of gravity, forming a complete closed layer from top to bottom, instead of being directly sprayed into the goaf area and wasting it.

[0038] Specifically, in step S2, after the anchor cable borehole 11 is completed, the pushing depth of the anchor cable body 1 must be strictly controlled to ensure that the entire far-end anchoring mechanism extends a certain length beyond the goaf side surface, typically 200mm to 300mm, to ensure that the articulated anchor 7 has sufficient space to fully open outside the borehole. After the traction wire rope 6 triggers the opening, the anchor cable body 1 must be slightly pulled back first, so that the opened articulated anchor 7 and the metal baffle 8 are tightly attached to the goaf side surface of the coal pillar 12, and then the tensioning and locking of the non-goaf side is carried out to ensure that the far-end anchoring point truly plays its role.

[0039] Specifically, in step S3, when grouting into the anchor cable borehole 11, the grouting pressure is controlled within the range of 0.5 to 1.0 MPa. This pressure value ensures that the grout fully penetrates into the tiny cracks around the borehole wall without causing splitting damage to the coal pillar 12 due to excessive pressure. During the grouting process, the contact surface between the anchor cable tray 3 and the coal pillar 12 is continuously observed. When grout return is observed at this point, it indicates that the borehole is basically filled with grout. At this time, grouting is stopped to prevent a large amount of grout from overflowing from the non-mining side.

[0040] Specifically, in step S1, the injected quick-setting grout is a cement-water glass two-component grout. The cement used is 32.5 grade ordinary Portland cement with a water-cement ratio of 0.6 to 0.8; the concentration of the water glass is 35 to 40°Be. The volume ratio of the cement to the water glass is 1:0.5 to 1:0.8.

[0041] Specifically, in step S1, a cement-water glass two-liquid slurry is selected and its ratio is strictly controlled, mainly due to its rapid setting characteristics. The water glass concentration is controlled between 35 and 40 Baume degrees, and with a volume ratio of 1:0.5 to 1:0.8, the slurry can quickly lose its fluidity after contacting the coal body, with the initial setting time controlled within 30 seconds and the final setting time not exceeding 5 minutes. This rapid setting effect is crucial for the formation of the slurry-stopping curtain 13, because the slurry needs to solidify rapidly after flowing to the surface of the goaf side in order to adhere to the surface of the coal pillar 12 and form an effective sealing layer, rather than continuing to flow into the goaf due to slow solidification.

[0042] Specifically, in step S3, the injected grout is a cement-water glass two-component grout. The cement is 32.5 grade ordinary Portland cement with a water-cement ratio of 0.6 to 0.8. The concentration of the water glass is 15°Be′. The volume ratio of the cement to the water glass is 1:1.

[0043] Specifically, in step S1, a cement-water glass two-liquid slurry is selected and its ratio is strictly controlled, mainly due to its rapid setting characteristics. The water glass concentration is controlled between 35 and 40 Baume degrees, and with a volume ratio of 1:0.5 to 1:0.8, the slurry can quickly lose its fluidity after contacting the coal body, with the initial setting time controlled within 30 seconds and the final setting time not exceeding 5 minutes. This rapid setting effect is crucial for the formation of the slurry-stopping curtain 13, because the slurry needs to solidify rapidly after flowing to the surface of the goaf side in order to adhere to the surface of the coal pillar 12 and form an effective sealing layer, rather than continuing to flow into the goaf due to slow solidification.

[0044] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0045] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A composite reinforcement system of through-anchor cables and grouting for soft, thick coal seams with coal pillars along the goaf, used to reinforce small coal pillars adjacent to goaf areas, characterized in that: include A coal pillar goaf side surface sealing module is used to form a grout-stopping curtain (13) on the goaf side surface of the coal pillar (12). The through-anchor cable reinforcement module is used to provide bidirectional prestressed anchoring for the goaf side and non-goaf side of the coal pillar (12); The through-anchor reinforcement module includes an anchor body (1), a far-end anchoring mechanism, a near-end anchoring mechanism, and a grouting mechanism. The anchor body (1) is inserted into the anchor borehole (11) that penetrates the coal pillar (12). The far-end anchoring mechanism is located at one end of the anchor body (1) and is anchored to the goaf side surface of the coal pillar (12). The near-end anchoring mechanism is installed at the other end of the anchor body (1) and is anchored to the non-goaf side surface of the coal pillar (12). The grouting mechanism is used to inject grout into the anchor borehole (11) to form a full-length anchor body (14) that wraps around the anchor body (1).

2. The composite reinforcement system of through-anchor cable and grouting along a soft, thick coal seam coal pillar according to claim 1, characterized in that: The distal anchoring mechanism includes a metal baffle (8), hinged anchors (7), a spring (5), a hoop (4), and a wire rope (6). The metal baffle (8) is a disc-shaped structure, and its size is smaller than the diameter of the anchor hole (11). The metal baffle (8) is fixedly connected to one end of the anchor body (1) near the goaf side. Multiple hinged anchors (7) are hinged in a petal shape to the edge of the end face of the metal baffle (8) facing the anchor body (1). One end of the spring (5) is hinged to the middle of the hinged anchor (7). The other end of the spring (5) is hinged to the metal baffle (8). The spring (5) is used to provide the opening elastic force for the hinged anchor (7). The hoop (4) is sleeved on the outside of the hinged anchor (7) and is used to constrain the multiple hinged anchors (7) in a closed state close to the anchor body (1) in the initial state. One end of the wire rope (6) is fixedly connected to the hoop (4). The other end of the wire rope (6) extends along the axial direction of the anchor body (1) to the non-mining side of the coal pillar (12). By pulling the wire rope (6), the hoop (4) is pulled to slip off the outside of the hinged anchor (7), so that the hinged anchor (7) opens in an umbrella shape under the elastic force of the spring (5), and the opened hinged anchor (7) is clamped on the goaf side surface of the coal pillar (12).

3. The composite reinforcement system of through-anchor cable and grouting along a soft, thick coal seam coal pillar according to claim 2, characterized in that: The near-end anchoring mechanism includes an anchor cable tray (3) and an anchor cable lock (2). The anchor cable tray (3) is fitted on the anchor cable body (1). One side of the anchor cable tray (3) is in contact with the non-mining side of the coal pillar (12). The anchor cable body (1) passes through the anchor cable tray (3) and is locked by the anchor cable lock (2). The anchor cable lock (2) abuts against the other side of the anchor cable tray (3).

4. The composite reinforcement system of through-anchor cable and grouting along a soft, thick coal seam coal pillar according to claim 3, characterized in that: The grouting mechanism includes a grouting hole (9) pre-reserved on the anchor cable tray (3), the grouting hole (9) being connected to the interior of the anchor cable borehole (11) for injecting grout into the anchor cable borehole (11).

5. The composite reinforcement system of through-anchor cable and grouting along a soft, thick coal seam coal pillar according to claim 1, characterized in that: The coal pillar goaf side surface sealing module includes multiple high-level self-flowing grouting holes (10). The high-level self-flowing grouting holes (10) are opened at the top of the non-goaf side of the coal pillar (12) and extend to the goaf side of the coal pillar (12) to inject quick-setting grout into the goaf side surface of the coal pillar (12) to form a grout-stopping curtain (13) covering the goaf side surface.

6. The composite reinforcement system of through-anchor cable and grouting along a soft, thick coal seam coal pillar according to claim 5, characterized in that: The diameter of the high-level self-flowing grouting hole (10) is set to 40mm-60mm, and the hole spacing is set to 500mm.

7. The composite reinforcement system of through-anchor cable and grouting along a soft, thick coal seam coal pillar according to claim 5, characterized in that: The anchor holes (11) are arranged in three rows along the vertical direction. The middle row has three anchor holes (11), and the left and right rows each have two anchor holes (11). The anchor holes (11) in the left and right rows are located in the gap between two adjacent anchor holes (11) in the middle row in the horizontal direction, forming an alternating distribution. The drilling spacing of the anchor cable borehole (11) is set to 1000mm, the row spacing is set to 3000mm, and the diameter of the anchor cable borehole (11) is set to 60mm-80mm.

8. A method for composite reinforcement of soft, thick coal seams along goaf pillars using through-cable anchors and grouting, based on the composite reinforcement system of soft, thick coal seams along goaf pillars using through-cable anchors and grouting as described in any one of claims 1 to 7, characterized in that: Includes the following steps: S1. Construct a high-level self-flowing grouting hole (10) at the top of the non-mining side of the coal pillar (12), and the end of the high-level self-flowing grouting hole (10) extends through and to the mining side of the coal pillar (12). Then, install a grouting hose in the high-level self-flowing grouting hole (10) and inject quick-setting grout into the mining side surface of the coal pillar (12) through the grouting hose. Utilize the gravity of the quick-setting grout to flow by gravity to form a grout-stopping curtain (13) on the mining side surface of the coal pillar (12). S2. Construct an anchor cable borehole (11) on the non-mining side of the coal pillar (12), with the end of the anchor cable borehole (11) penetrating and extending to the mining side of the coal pillar (12). Insert one end of the anchor cable body (1) equipped with a remote anchoring mechanism into the anchor cable borehole (11) and extend it outward until the remote anchoring mechanism extends to the outside of the mining side of the coal pillar (12). By pulling the steel wire rope (6) connected to the hoop (4) of the remote anchoring mechanism, the hoop (4) is... The hinged anchor (7) slips off from the outside and opens in an umbrella shape under the elastic force of the spring (5). After opening, the hinged anchor (7) is clamped on the goaf side surface of the coal pillar (12). Then, on the non-goaf side, the anchor cable tray (3) is put on the anchor cable body (1) and attached to the non-goaf side surface of the coal pillar (12). The anchor cable body (1) is locked by the anchor cable lock (2) and prestress is applied to the anchor cable body (1) to complete the bidirectional anchoring. S3. Grout is injected into the anchor hole (11) through the grouting hole (9) reserved on the anchor tray (3). After the grout fills the hole, it forms a full-length anchor body (14) that wraps the anchor body (1).

9. A method for composite reinforcement of soft, thick coal seams along goaf pillars using through-cable anchors and grouting, as described in claim 8, is characterized in that: In step S1, the injected quick-setting grout is a cement-water glass two-component grout. The cement used is 32.5 grade ordinary Portland cement with a water-cement ratio of 0.6–0.8; the concentration of the water glass is 35–40°Be. The volume ratio of the cement to the water glass is 1:0.5 to 1:0.

8.

10. A method for composite reinforcement of soft, thick coal seams along goaf pillars using through-cable anchors and grouting, as described in claim 8, is characterized in that: In step S3, the injected grout is a cement-water glass two-component grout. The cement is 32.5 grade ordinary Portland cement with a water-cement ratio of 0.6 to 0.

8. The concentration of the water glass is 15°Be′. The volume ratio of the cement to the water glass is 1:1.

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