Directional pressure relief structure for coal mine static fracturing

Abstract

The utility model provides a directional pressure relief structure for coal mine static fracturing. An original supporting structure comprises anchor rods and anchor cables, wherein the anchor rods and the anchor cables are arranged in a roadway. The reinforcing support anchor cables are arranged on a top plate and a non-stoping side of the roadway; the steel frames are door-shaped frames matched with a roadway, the multiple steel frames are evenly distributed in the trend of the roadway, the outer walls of the steel frames are tightly attached to the inner wall of the roadway, and a connecting rod is arranged between any two adjacent steel frames. The joint cutting hole extends from the junction of the top plate and the stoping side to the surrounding rock on the outer side of the roadway, and an expanding agent is poured into the joint cutting hole. By arranging the reinforcing support anchor cable and the steel frame, the integrity of surrounding rock in an anchoring area can be kept to the maximum extent, so that the stability of the surrounding rock of a roadway and the reliability of a support structure are improved, expanding agents are arranged for cracking, directional pressure relief can be achieved under the condition that explosives are not adopted, and the stability of the surrounding rock of the roadway is guaranteed; in the fracturing process, pressure and displacement monitoring is conducted on surrounding rock of the roadway, and safety of the roadway is guaranteed.

Description

Technical Field

[0001] This utility model belongs to the field of goaf retention technology, specifically relating to a static fracturing directional pressure relief structure for coal mines. Background Technology

[0002] Traditional coal mining typically involves leaving coal pillars of a certain width on both sides of the working face to support the roadway and ensure safety during mining. However, these pillars not only consume a large amount of coal resources but also tend to cause stress concentration under long-term mining operations, leading to resource waste and safety hazards. Goaf retention technology aims to eliminate or significantly reduce coal pillars through scientific roadway layout and support methods, achieving continuous pillarless mining between working faces, thereby improving coal resource recovery and reducing resource waste. While the traditional practice of using shaped charge blasting in goaf retention can achieve the purpose of roof cutting, pressure relief, and roadway retention to some extent, its drawbacks cannot be ignored. First, the energy utilization of shaped charge blasting is inefficient. Because explosives often cannot adhere tightly to the rock wall, a large amount of energy is wasted during the blasting process. This not only reduces blasting efficiency but may also lead to disordered energy release, increasing safety risks. Secondly, the management of explosives is difficult, especially high-intrinsicity, high-velocity explosives. These explosives are mostly controlled substances, making civilian use difficult. Their processing, transportation, and use require strict control and specialized skills, which not only increases costs but also limits their widespread application in traditional goaf-side roadway retention. Therefore, although the use of explosives for shaped charge blasting in traditional goaf-side roadway retention may have certain applicability under specific conditions, considering its drawbacks, it is necessary to find more efficient, safe, and environmentally friendly alternatives to achieve the goals of roof cutting, pressure relief, and roadway retention while reducing construction costs and negative environmental impacts.

[0003] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and to provide a static fracturing directional pressure relief structure for coal mines.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A static fracturing directional pressure relief structure for coal mines, comprising:

[0007] The original support structure includes anchor bolts and anchor cables installed in the roadway;

[0008] Reinforcing support anchors are installed on the roof and non-mining sidewalls of the roadway.

[0009] The steel frame is a portal frame adapted to the tunnel. Multiple steel frames are evenly distributed along the tunnel direction. The outer wall of the steel frame is close to the inner wall of the tunnel. A connecting rod is provided between any two adjacent steel frames.

[0010] The slotted hole extends from the junction of the roof and the mining side to the surrounding rock outside the roadway, and an expanding agent is injected into the slotted hole.

[0011] Preferably, the steel frame is made of NPR material.

[0012] Preferably, the angle between the slit hole and the tunnel roof is 60°.

[0013] Preferably, a buffer is provided between the steel frame and the inner wall of the tunnel.

[0014] Preferably, the steel frame includes I-beam structure columns and beams, the buffer is a buffer tube, the diameter of the buffer tube is greater than the depth of the I-beam groove corresponding to the column and beam, and the buffer tube extends along the length direction of the column or beam.

[0015] Preferably, the plurality of slit holes are distributed at intervals along the direction of the roadway, and a plurality of guide holes are distributed at intervals between the plurality of slit holes, the guide holes being at angles corresponding to the slit holes.

[0016] Preferably, a pressure sensor is provided between the steel frame and the inner wall of the tunnel, and a displacement sensor is fixed to the inner wall of the tunnel.

[0017] Beneficial effects: The installation of reinforcing support anchor cables and steel frames can maximize the integrity of the surrounding rock in the anchorage zone, thereby improving the stability of the roadway surrounding rock and the reliability of the support structure. The installation of expansion agent fracturing can achieve directional pressure relief without the use of explosives, ensuring the stability of the roadway surrounding rock. The installation of pressure sensors and displacement sensors can monitor the pressure and displacement of the roadway surrounding rock during the fracturing process, ensuring the safety of the roadway. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. Wherein:

[0019] Figure 1 This is a schematic diagram of the pressure relief structure in a specific embodiment provided by this utility model;

[0020] Figure 2 This is a schematic diagram showing the distribution of guide holes in a specific embodiment of the present invention.

[0021] In the diagram: 1. Original support structure; 2. Reinforcing support anchor cable; 3. Cut hole; 4. Horizontal beam; 5. Column; 6. Buffer pipe; 7. Guide hole. Detailed Implementation

[0022] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art are within the protection scope of this utility model.

[0023] In the description of this utility model, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and do not require that this utility model be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this utility model. The terms "connected" and "linked" used in this utility model should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0024] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0025] The purpose of this invention is to provide a pressure relief structure for coal mine roadways that combines static fracturing with directional pressure relief through drilling, avoiding strong disturbance to the roadway roof caused by blasting and maximizing the directional pressure relief effect. Figure 1-2 As shown, a static fracturing directional pressure relief structure for coal mines includes an original support structure 1, reinforcing support anchor cables 2, slotted holes 3, and a steel frame. The original support structure 1 includes anchor bolts and anchor cables installed in the roadway. This application does not impose many restrictions on the original support structure 1. The reinforcing support anchor cables 2 are installed on the roof and non-mining side of the roadway. The reinforcing support anchor cables 2 provide reinforcement support according to the deformation of the surrounding rock in the roadway. The reinforcing support anchor cables 2 adopt NPR anchor cables, with a preload of 280kN and a constant resistance of 3. 50kN, high preload is applied to compensate for the surrounding rock of the roadway; the steel frame is a portal frame adapted to the roadway, and the shape of the steel frame is adapted to the shape of the roadway, so as to support the roadway and improve its stability. In this embodiment, the arch frame material is NPR material, which can withstand a large bearing capacity and a large deformation. A pressure-relieving filling body is set between the arch frame and the surrounding rock to allow the surrounding rock to have a certain space for energy release. When the surrounding rock comes into contact with the arch frame, the roadway is supported by the rigidity of the arch frame and the NPR anchor cable.

[0026] Multiple steel frames are evenly distributed along the roadway direction, with their outer walls tightly attached to the inner wall of the roadway. Connecting rods are installed between any two adjacent steel frames. The slotted holes (3) extend from the intersection of the roof and the mining sidewalls towards the surrounding rock outside the roadway. Expanding agents are injected into the slotted holes (3). This structure uses drilling combined with static expanding agents to replace the original shaped charge blasting, dense drilling for pressure relief, and hydraulic fracturing techniques. This method features directional fracturing and pressure relief, a fixed working area, simple construction process, fast operation speed, low construction cost, high slotting efficiency, good safety, and strong adaptability. Simultaneously, this method operates without dynamic disturbance, maximizing the integrity of the surrounding rock in the anchoring zone, thereby improving the stability of the roadway surrounding rock and the reliability of the support structure.

[0027] The reinforcing support anchors 2 located on the roof and non-mining side are all in 3 rows. The length of the reinforcing support anchors 2 is greater than the length of the anchors in the original support structure 1. In the roof, the middle row of reinforcing support anchors 2 extends longitudinally, and the other two rows of reinforcing support anchors 2 extend to both sides of the roadway. In the non-mining side, the three rows of reinforcing support anchors 2 extend horizontally.

[0028] Furthermore, grouting anchor bolts are installed in the fractured surrounding rock area, corresponding to the roof, mined side, and non-mined side. Grouting through these anchor bolts connects the shallow and deep surrounding rock, forming a unified structure and enhancing its integrity and strength. After grouting, the effect is evaluated through borehole inspection. Grouting includes shallow rock cap grouting, deep rock fracturing grouting, and grouting anchor cable grouting. The position and angle of the grouting holes must meet requirements, and the sealing device must be installed to sufficient depth to ensure the grouting reaction occurs within the dense column.

[0029] In one optional embodiment, the expanding agent is pumped, with the grouting pump pressure ranging from 1 to 4 MPa and the pump flow rate at 20 L / min. The angle between the slotted hole 3 and the roadway roof is 60° to ensure the accuracy of the roadway surrounding rock collapse after the slotted hole 3 is fractured.

[0030] In one optional embodiment, in order to maximize the adaptation to the large deformation of the roadway during the fracturing process and improve the large deformation capacity of the steel frame, a buffer is provided between the steel frame and the inner wall of the roadway. In the early stage of large deformation of the roadway, the buffer is used to buffer the deformation of the roadway.

[0031] Specifically, the steel frame includes I-beam structure columns 5 and beams 4. The web of the I-beam corresponds to the inner wall of the roadway, serving as the mounting groove for the buffer pipe 6. The buffer component is the buffer pipe 6, whose diameter is greater than the depth of the I-beam groove corresponding to the column 5 and beam 4. The buffer pipe 6 extends along the length of the column 5 or beam 4, thus supporting the inner wall of the roadway.

[0032] The length of the buffer tube 6 can be adapted to the corresponding column 5 and beam 4, or the buffer tube 6 can be a short section, with multiple buffer tube sections 6 distributed at intervals along the column 5 or beam 4.

[0033] In an optional embodiment, multiple slotted holes 3 are distributed at intervals along the roadway direction. The spacing between the holes is determined according to the cracking range of the single hole expansion agent. No further limitations are made here. The main component of the expansion agent is CaO, which causes cracking by reacting with water to achieve volume expansion. Since the crack direction is not obvious after the expansion agent causes cracking, a set of holes needs to be added between the two expansion agent holes as guide holes 7.

[0034] Multiple guide holes 7 are spaced apart between multiple slit holes 3. Specifically, a guide hole 7 is set after every two slit holes 3, and the angle of the guide hole 7 corresponds to that of the slit hole 3. The diameter of the guide hole 7 can be less than or equal to the diameter of the slit hole 3. The parameters of the slit holes 3 include the hole spacing, hole diameter, and hole depth. The main parameter of the expanding agent is the water-to-agent ratio. The formula for calculating the hole depth is H = (H... 采高 -h) / (k-1), H 采高 Where h is the coal seam mining height, k is the roadway roof and floor convergence, and k is the rock fragmentation coefficient above the coal seam, usually taken as 1.3-1.5. The hole diameter can be determined according to the on-site construction conditions. The total diameter range of the slotted holes 3 is 42mm to 65mm. The amount of expanding agent used varies with the hole diameter. For example, when the hole diameter is 42mm, the amount of expanding agent used is 2.6kg / m; when the hole diameter is 46mm, the amount of expanding agent used is 2.8kg / m; when the hole diameter is 50mm, the amount of expanding agent used is 3.5kg / m; and when the hole diameter is 65mm, the amount of expanding agent used is 6kg / m. The spacing of the slotted holes 3 is determined according to the fracturing range of the expanding agent in a single hole.

[0035] Pressure sensors are installed between the steel frame and the inner wall of the tunnel, and displacement sensors are fixed to the inner wall of the tunnel. The reinforcing support anchor cable 2 corresponding to the steel frame passes through the web of the corresponding I-beam to fix the reinforcing support anchor cable 2 and the steel frame, thereby forming an anchor and improving the support capacity.

[0036] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be within the scope of protection of the pending claims of the present utility model.

Claims

1. A static fracturing directional pressure relief structure for coal mines, characterized in that, include: The original support structure includes anchor bolts and anchor cables installed in the roadway; Reinforcing support anchors are installed on the roof and non-mining sidewalls of the roadway. The steel frame is a portal frame adapted to the tunnel. Multiple steel frames are evenly distributed along the tunnel direction. The outer wall of the steel frame is close to the inner wall of the tunnel. A connecting rod is provided between any two adjacent steel frames. The slotted hole extends from the junction of the roof and the mining side to the surrounding rock outside the roadway, and an expanding agent is injected into the slotted hole.

2. The static fracturing directional pressure relief structure for coal mines according to claim 1, characterized in that, The steel frame is made of NPR material.

3. The static fracturing directional pressure relief structure for coal mines according to claim 1, characterized in that, The angle between the slit hole and the tunnel roof is 60°.

4. The static fracturing directional pressure relief structure for coal mines according to claim 1, characterized in that, A buffer is provided between the steel frame and the inner wall of the tunnel.

5. The static fracturing directional pressure relief structure for coal mines according to claim 4, characterized in that, The steel frame includes I-beam structure columns and beams, and the buffer component is a buffer tube. The diameter of the buffer tube is greater than the depth of the I-beam groove corresponding to the column and beam, and the buffer tube extends along the length of the column or beam.

6. The static fracturing directional pressure relief structure for coal mines according to claim 1, characterized in that, Multiple slotted holes are spaced apart along the roadway direction, and multiple guide holes are spaced apart between the multiple slotted holes, with the guide holes corresponding to the angles of the slotted holes.

7. The static fracturing directional pressure relief structure for coal mines according to claim 1, characterized in that, A pressure sensor is installed between the steel frame and the inner wall of the tunnel, and a displacement sensor is fixed to the inner wall of the tunnel.

Images