Loose broken coal roof grouting reinforcement device and reinforcement method

Abstract

The application discloses a loose broken coal body roof grouting reinforcement device and a reinforcement method, and particularly relates to the technical field of tunnel construction. The loose broken coal body roof grouting reinforcement method improves the cohesion, elastic modulus and internal friction angle of surrounding rock through fissure filling and compaction and network skeleton effects, and cements the loose broken coal body into a whole, thereby effectively improving the rock mass strength and the bearing capacity of the surrounding rock. The full-length anchoring of the anchor cable is realized through the grouting anchor cable. After the hollow grouting anchor cable is grouted, part of the grout flows to the periphery of the ordinary anchor rod and anchor cable due to high pressure, so that the original anchor rod and cable become full-length anchoring, and at the same time, the anchor cable itself also achieves full-length anchoring, so that the anchor cable and the surrounding rock form a whole, the anchoring force of the anchor rod and the anchor cable is improved, the prestress of the anchor cable is ensured, the active support of the anchor cable to the broken rock stratum is truly realized, the rock mass pressure load is transmitted to the deep and stable rock mass through the anchor cable, and the safety and reliability of the roof support are ensured.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, specifically to a grouting reinforcement device and method for the roof of loose and broken coal seams. Background Technology

[0002] Tunnels are engineering structures buried in the earth's strata and are a form of human utilization of underground space. Tunnels can be divided into traffic tunnels, hydraulic tunnels, municipal tunnels, and mining tunnels. The structure of a tunnel includes two parts: the main building and auxiliary equipment.

[0003] The 40103 Yunshun tunneling face is located at the anticline axis. During the tunneling process, the DF4-6 and DF4-7 faults were continuously exposed. The DF4-6 fault has a dip angle of 31°, an azimuth angle of 126°, and a drop of 2.1m. The DF4-7 fault has a dip angle of 87°, an azimuth angle close to 90°, and is basically parallel to the direction of the roadway extension. The fault drop is also 2.1m. Due to the loose and broken coal body during the passage of the working face through the structural zone, the anchor cables have no reliable anchoring points, and the anchoring force does not meet the design requirements. At the same time, the roof pressure is high, there are many coal blasting sounds, and the roof leaks frequently. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a grouting reinforcement device and method for loose and broken coal seam roofs. It has advantages such as improving rock mass strength and increasing the bearing capacity of surrounding rock. It solves the problems of loose and broken coal seams during the working face crossing structural zones, lack of reliable anchor points for anchor cables, insufficient anchoring force to meet design requirements, high roof pressure, frequent coal blasting noise, and frequent roof leaks.

[0006] (II) Technical Solution

[0007] To achieve the aforementioned objectives of improving rock mass strength and increasing the bearing capacity of surrounding rock, this invention provides the following technical solution: a grouting reinforcement device for the roof of loose and broken coal seams, comprising a grouting drilling and anchor bolt machine body that moves within a tunnel, an anchor bolt movably mounted at the output end of the grouting drilling and anchor bolt machine body, an outer cylinder fixedly connected to the outer surface of the anchor bolt via bearings, a limit groove formed on the surface of the outer cylinder, a pin slidably connected inside the limit groove, a connecting rod rotatably connected to the outer surface of the pin, a hydraulic cylinder fixedly connected to the end of the connecting rod, the outer surface of the hydraulic cylinder fixedly installed inside the grouting drilling and anchor bolt machine body, an angle scale plate fixedly mounted on the surface of the grouting drilling and anchor bolt machine body, and a support shaft end of the angle scale plate fixedly connected to the surface of the outer cylinder.

[0008] Preferably, the diameters at both ends of the pin are larger than the diameter of the middle section.

[0009] Preferably, the outer surface of the outer cylinder is movably installed inside the main body of the grouting drilling anchor bolt machine.

[0010] The reinforcement method for the roof grouting reinforcement device of loose and broken coal seams is as follows:

[0011] 1) Before conducting advanced geological condition exploration, collect construction information of each borehole in the pre-excavation drilling site, analyze the coal slag particle size and blowout conditions, and regularly test coal samples to obtain data on coal adsorption constant, moisture, ash, volatile matter, initial release velocity, density, and calorific value. Use the anti-scour and pressure relief holes at the face and the pre-excavation extraction boreholes to explore geological conditions, accurately grasp the information on coal seam dip angle and degree of fragmentation, and predict and judge the geological structure.

[0012] 2) Advanced coal seam grouting to reinforce the roof: Grouting is performed on the coal seam at the facing end, and the boreholes are adjusted according to the specific conditions on site.

[0013] Grouting is divided into polymer material grouting and inorganic reinforcement material grouting;

[0014] 3) Construct advance anchor bolts to prevent roof leakage. Construct advance anchor bolts parallel to the direction of roadway extension at an angle greater than the roadway slope by 5-10°. Construct one batch of advance anchor bolts every three rows of excavation.

[0015] 4) Grouting anchor cable support, the top slab is supported by anchor cables and steel strips.

[0016] (III) Beneficial Effects

[0017] Compared with the prior art, the present invention provides a grouting reinforcement device and method for the roof of loose and broken coal seams, which has the following beneficial effects:

[0018] 1. The grouting reinforcement device and method for the roof of loose and broken coal seams improves the properties of the surrounding rock through advanced coal seam grouting. Through the filling and compaction of fissures and the network skeleton effect, it increases the cohesion, elastic modulus and internal friction angle of the surrounding rock, and cements the loose and broken coal seams into a whole, thereby effectively improving the rock mass strength, increasing the bearing capacity of the surrounding rock, and eliminating the phenomenon of collapse during excavation.

[0019] 2. The grouting reinforcement device and method for the roof of loose and fractured coal seams achieves full-length anchoring of the anchor cables through grouting anchor cables. After grouting, some of the grout seeps through the cracks to the periphery of the ordinary anchor rods and cables due to high pressure, making the original anchor rods and cables fully anchored. At the same time, the anchor cables themselves also achieve full-length anchoring, making the anchor cables and surrounding rock form an integral whole, improving the anchoring force of the anchor rods and cables, ensuring the prestress of the anchor cables, and truly realizing the active support of the anchor cables for the fractured rock layers. The rock mass pressure load is then transferred to the deep stable rock mass through the anchor cables, and the self-stabilizing potential of the deep stable rock mass layer is fully utilized, ensuring the safety and reliability of the roof support.

[0020] 3. The grouting reinforcement device and method for the roof of loose and broken coal seam, due to the fast solidification speed and small amount of polymer grouting material, can bear the load immediately after installation, which improves the tunneling speed. The single advance rate during the passage of the loose and broken zone is increased from 60m / month to 100m / month.

[0021] 4. The grouting reinforcement device and method for loose and broken coal seam roof can be widely used in the rapid construction of tunneling faces through faults, folds, fractured surrounding rock zones, and soft coal seam zones. By improving the strength of the surrounding rock and the full-length anchoring of the anchor cables, the prestress and anchoring force of the support structure are guaranteed, preventing roof leakage and roof collapse accidents and ensuring roof safety. Attached Figure Description

[0022] Figure 1 Plan view of the 40103 Yunshun Fault;

[0023] Figure 2 This is a schematic diagram of the grouting borehole arrangement in this invention;

[0024] Figure 3 This is a schematic diagram of the coal and rock exploration borehole in the present invention;

[0025] Figure 4 This is a diagram showing the arrangement of the advanced anchor bolts in this invention;

[0026] Figure 5 This is a schematic diagram of the main body of the grouting drilling anchor bolt machine in this invention;

[0027] Figure 6 for Figure 5 Enlarged view of point A in the middle.

[0028] In the diagram: 3. Main body of the grouting drilling anchor bolt machine; 4. Anchor bolt; 5. Outer cylinder; 6. Limiting groove; 7. Pin; 8. Connecting rod; 9. Hydraulic cylinder. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Please see Figure 5-6The grouting reinforcement device for the roof of a loose and broken coal seam includes a grouting drilling and anchor bolt machine body 3 that moves inside the tunnel. An anchor bolt 4 is movably installed at the output end of the grouting drilling and anchor bolt machine body 3. An outer cylinder 5 is fixedly connected to the outer surface of the anchor bolt 4 via bearings. The outer surface of the outer cylinder 5 is movably installed inside the grouting drilling and anchor bolt machine body 3. A limit groove 6 is opened on the surface of the outer cylinder 5. A pin 7 is slidably connected inside the limit groove 6. The diameters at both ends of the pin 7 are larger than the diameter of the middle section. A connecting rod 8 is rotatably connected to the outer surface of the pin 7. A hydraulic cylinder 9 is fixedly connected to the end of the connecting rod 8. The outer surface of the hydraulic cylinder 9 is fixedly installed inside the grouting drilling and anchor bolt machine body 3. An angle scale 10 is fixedly installed on the surface of the grouting drilling and anchor bolt machine body 3. The support shaft end of the angle scale 10 is fixedly connected to the surface of the outer cylinder 5. By setting the outer cylinder 5 and the angle scale 10, the angle of the anchor bolt 4 can be precisely adjusted to facilitate precise drilling and grouting.

[0031] Please see Figure 1-4 The reinforcement method for the roof grouting reinforcement device of loose and broken coal seam is as follows:

[0032] 1) Before conducting advanced geological condition exploration, collect construction data from each borehole in the pre-excavation drilling site. Analyze the coal slag particle size and blowout conditions, and regularly test coal samples to obtain data such as coal adsorption constant, moisture, ash content, volatile matter, initial release velocity, density, and calorific value. Use the anti-scouring and pressure relief boreholes at the face and the pre-excavation extraction boreholes to explore geological conditions, accurately grasp information such as coal seam dip angle and degree of fragmentation, and predict and judge the geological structure.

[0033] 2) Pre-grouting reinforcement of the coal face roof: To improve the strength and integrity of the surrounding rock, grouting reinforcement of the coal face roof is required. Grouting is performed every 3m of excavation, and this cycle is repeated. A composite support process of pre-grouting + pre-anchor bolts + anchor mesh (grouting anchor cables) + scaffolding is adopted. Grouting uses shallow-hole polymer material grouting combined with deep-hole inorganic reinforcement material grouting. Grouting boreholes are drilled using an MQT-120 anchor cable machine with a borehole diameter of Ф30mm. It is planned to drill 7 grouting holes per grouting cycle (3 shallow polymer material holes for sealing shallow fractures and 4 deep inorganic reinforcement material holes for high-pressure grouting). Before grouting, temporary support is provided at the face using anchor mesh to prevent splintering and injury during grouting. The 3 shallow polymer material holes are drilled and grouted in stages; the 4 deep inorganic reinforcement material holes are drilled and grouted sequentially. Technicians can adjust the drilling according to the specific conditions on-site underground. The arrangement of grouting holes is shown in the table below. Figure 2

[0034]

[0035] 3) Grouting of polymer materials, grouting equipment and grouting pressure: 2ZBQ-6 / 12 type pneumatic high pressure double liquid grouting pump is used for grouting. The maximum grouting pressure can reach 21MPa. According to the actual site conditions, the air supply capacity of the construction site shall not be less than 3m3 / min, the air supply pressure shall not be less than 0.5MPa, and the grouting pressure shall not be less than 4MPa. Generally, the grouting pressure is 4 to 8MPa.

[0036] Grouting material and proportion: SCPJG-2 polymer composite reinforcement material is used. This reinforcement material is a composite product of two components, A and B. After mixing, components A and B react rapidly to produce a high-strength polymer. In use, components A and B are mixed evenly in a 1:1 volume ratio and then injected into the coal and rock mass.

[0037] Grouting Holes and Pipes: The grouting pipes are made of 4′ steel pipes, 4m in length, and are divided into solid pipes and perforated pipes. Three grouting pipes (2m solid pipe + 1m solid pipe + 1m perforated pipe) are placed in each borehole. A special sealing device is used to seal the borehole. If there are problems such as low grout intake or rapid increase in grouting pressure, the three grouting pipes in each borehole are adjusted to (2m solid pipe + 1m perforated pipe + 1m perforated pipe). To ensure the actual grouting effect and achieve the effect of stabilizing the roadway, the initial design is to grout 500Kg per hole, which can be adjusted according to the actual situation on site.

[0038] 4) Grouting of inorganic reinforcement materials, grouting equipment and grouting pressure: Use ZBQ-25 / 5 mining pneumatic grouting pump, and the grouting pressure should not be less than 5 MPa.

[0039] (1) The distance between the grouting equipment and the grouting anchor cable should be within 10m.

[0040] (2) Assemble the grouting pump and mixer, and connect the air and water pipelines to the grouting pump. Rinse the mixing tank with clean water, and ensure that there are no foreign objects or hard lumps of grouting material inside the tank.

[0041] (3) Use water to clean the grouting pump, mixing tank and connecting pipes, add a small amount of water to the mixing tank, slowly turn on the air, and test run the mixer and grouting pump.

[0042] (4) If the agitator and grouting pump are operating normally, the water injected by the grouting pump has sufficient pressure, and all pipelines and switches are connected correctly, the grouting solution can be prepared.

[0043] Grouting material and proportion: SCJG-2 type inorganic grouting reinforcement material is used, and the water-cement ratio is 0.4:1. After stirring evenly, it can be used for grouting.

[0044] Grouting holes and grouting pipes: DN15mm grouting pipes are used for sealing, with a sealing length of 4m. KJ10 ball valves are welded to the outer opening, and the external exposed length of the grouting pipe is 0.5m. The grouting pipe is sealed with GBD-2 (FKJ) type sealing agent by adding a woven bag between the grouting pipe and the hole wall.

[0045] 5) Install advance anchor bolts to prevent roof collapse. Install the advance anchor bolts parallel to the roadway extension direction at an angle 5-10° greater than the roadway slope. Use φ22 anchor bolts. 2500mm threaded steel anchor bolts are used with a spacing of 500mm. Each anchor bolt uses 2 resin anchoring agents. The outer end of the anchor bolt is pressed on top of the steel strip. An advance anchor bolt is installed every 3 rows of tunneling, and every two advance anchor bolts are staggered by 300mm.

[0046] 6) Grouting anchor cable support: The roof slab is supported by anchor cables in combination with steel strips. The anchor cables consist of alternating φ21.8×10000mm ordinary anchor cables and φ22×10000mm hollow grouting anchor cables, with a spacing of 1800mm between rows. 600mm, meaning that each row of odd-numbered steel strips has 3 ordinary anchor cables + 4 φ22×2500mm threaded steel anchor rods, and each row of even-numbered steel strips has 4 grouting anchor cables + 3 φ22×2500mm threaded steel anchor rods. Each anchor cable uses 1 MSK23 / 35 resin cartridge and 3 MSZ23 / 35 resin cartridges, with an anchoring force of 250KN and a preload of 220KN.

[0047] It should be noted that 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 a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0048] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A reinforcement method for a grouting reinforcement device for the roof of a loose and broken coal seam, characterized in that, The grouting reinforcement device for the roof of loose and broken coal seam includes a grouting drilling anchor bolt machine body (3) that moves inside the tunnel. An anchor bolt (4) is movably installed at the output end of the grouting drilling anchor bolt machine body (3). An outer cylinder (5) is connected to the outer surface of the anchor bolt (4) through a bearing. A limit groove (6) is opened on the surface of the outer cylinder (5). A pin (7) is slidably connected inside the limit groove (6). A connecting rod (8) is rotatably connected to the outer surface of the pin (7). A hydraulic cylinder (9) is fixedly connected to the end of the connecting rod (8). The outer surface of the hydraulic cylinder (9) is fixedly installed inside the grouting drilling anchor bolt machine body (3). An angle scale (10) is fixedly installed on the surface of the grouting drilling anchor bolt machine body (3). The support shaft end of the angle scale (10) is fixedly connected to the surface of the outer cylinder (5). The diameter of the two ends of the pin (7) is larger than the diameter of the middle section. The outer surface of the outer cylinder (5) is movably installed inside the grouting drilling anchor bolt machine body (3). The specific method is as follows: 1) Before conducting advanced geological condition exploration, collect construction information of each borehole in the pre-excavation drilling site, analyze the coal slag particle size and blowout conditions, and regularly test coal samples to obtain data on coal adsorption constant, moisture, ash, volatile matter, initial release velocity, density, and calorific value. Use the anti-scour and pressure relief holes at the face and the pre-excavation extraction boreholes to explore geological conditions, accurately grasp the information on coal seam dip angle and degree of fragmentation, and predict and judge the geological structure. 2) Advanced coal seam grouting to reinforce the roof: Grouting is performed on the coal seam at the facing end, and the boreholes are adjusted according to the specific conditions on site. Grouting is divided into polymer material grouting and inorganic reinforcement material grouting; 3) Construct advance anchor bolts to prevent roof leakage. Construct advance anchor bolts parallel to the direction of roadway extension at an angle greater than the roadway slope by 5-10°. Construct one row of advance anchor bolts every three rows of excavation. 4) Grouting anchor cable support, the top slab is supported by anchor cables and steel strips.

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