Partition grouting and full-length prestress collaborative roof supporting system and method

Abstract

The invention relates to the technical field of geotechnical engineering support, and discloses a partition grouting and full-length prestress collaborative roof support system and method. The system comprises a hollow grouting anchor cable, an expansion piece lock, a lock pushing rod, a lock expanding rod and the like. Firstly, installation and bonding fixation of an anchoring section of the hollow grouting anchor cable are completed; the expansion piece lock is moved to a preset position through a lock pushing rod, and the expansion piece lock is fully expanded through a lock expanding rod; and a leaking stoppage block is arranged below the drill hole located in the middle damage area of the top plate, then the expansion piece lock continues to be installed, and finally after the tray and the lock are installed, grouting is conducted in the shallow crushing area through the grouting opening, and the shallow crushing area is reinforced. A shallow crushing area and a deep stable rock mass are anchored into a whole through multi-stage prestress, and the bearing capacity of the deep rock mass is fully transferred; accurate grouting is conducted on the shallow broken area to enhance the strength of the shallow broken area; the supporting effect and economical efficiency of the middle damaged area which is not grouted are improved in a controllable yielding mode under bidirectional constraint formed by prestress.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of geotechnical engineering support, and relates to a roof support system and method of zonal grouting and full-length prestress cooperation. BACKGROUND

[0002] Anchor rod (cable) support is the core technology to ensure the stability of the surrounding rock of the coal mine roadway. Under the condition of deep mining, high ground stress and strong mining disturbance lead to the typical zonal damage characteristics of the roadway roof rock mass, including the shallow broken zone, the middle damage zone and the deep bearing zone. Grouting reinforcement can effectively improve the integrity of the broken rock mass, but implementing full-zone grouting in the deep roadway with a large damage range has the defects of high economic cost and insufficient technical rationality, and it is urgent to develop a precise grouting and efficient prestress cooperative support system.

[0003] There are two major bottlenecks in the current grouting and anchoring cooperative support technology: first, the blindness of grouting depth and poor economy. The roadway roof D is divided into a shallow broken zone A, a middle damage zone B and a deep bearing zone C from bottom to top, as shown in FIG. Figure 9 The traditional grouting lacks a control mechanism for the damage zoning of the roadway roof (shallow broken zone A, middle damage zone B and deep bearing zone C). Implementing full-zone grouting in a large range of damage areas not only causes material waste and high economic cost, but also has limited grouting reinforcement effect on the deep stable rock mass, which is technically unreasonable. Second, the interruption of prestress diffusion and the lack of middle constraint. When the anchor cable length is too large, the free section length will also be large. Only the axial prestress generated by the single anchor tension at the hole mouth can not effectively transmit to the deep surrounding rock due to the energy dissipation effect in the stress wave transmission process of the rod body. Experiments show that the prestress attenuation rate in the middle region of the free section increases significantly, forming a prominent stress diffusion interruption zone, resulting in a lack of sufficient effective constraint on the middle rock mass within the anchoring range. SUMMARY

[0004] In view of the problems existing in the prior art, the present application provides a roof support system and method of zonal grouting and full-length prestress cooperation. The present application anchors the shallow broken zone and the deep stable rock mass as a whole through multi-stage prestress, fully mobilizes the bearing capacity of the deep rock mass, implements precise grouting in the shallow broken zone to enhance its strength, and significantly improves the support effect and economy through controllable pressure relief under the bidirectional constraint formed by the prestress in the middle damage zone which is not grouted.

[0005] In order to achieve the above-mentioned purpose and other purposes, the technical scheme adopted by the present application is as follows: A roof support system of zonal grouting and full-length prestress cooperation, comprising: a grouting device, a hollow grouting anchor cable, a tray, and a lock that cooperates with the hollow grouting anchor cable to install the tray and provide prestress; The hollow grouting anchor cable is provided with a grouting outlet, and the grouting outlet is located at the junction of the shallow broken zone and the middle damaged zone. Further, the expansion-leaf lock comprises a plurality of expansion leaves arranged in a ring shape, and the upper part of each expansion leaf is connected to each other by a variable-diameter elastic coil in an extended state, and the two sides of the upper part of each expansion leaf are provided with chamfers. The hollow grouting anchor cable is provided with a grouting outlet, and the grouting outlet is located at the junction of the shallow broken zone and the middle damaged zone. The lock pushing rod is a hollow rod body, and the inner diameter of the lock pushing rod is greater than the diameter of the hollow grouting anchor cable. The lock pushing rod is a hollow rod body, and the inner diameter of the lock pushing rod is greater than the diameter of the hollow grouting anchor cable.

[0006] As a further scheme, the outer surface of the hollow grouting anchor cable is provided with an outward convex anti-skid pattern.

[0007] Further, the inner wall of the expansion leaf is provided with a friction layer.

[0008] As a further scheme, the lower end of the expansion-leaf lock is provided with a step A, and the upper end of the lock pushing rod is provided with a step B matched with the step A.

[0009] Further, the material of the expansion leaf is selected from high-strength metal, and the lock pushing rod and the lock expansion rod are high-strength flexible metal sleeves.

[0010] A partition grouting and full-length prestress cooperative roof support method uses the multi-stage full-length prestress applied anchor cable system, and comprises the following steps. S1, drilling a hole in a roadway rock mass, installing a resin anchoring agent and a hollow grouting anchor cable in the hole, starting a drilling machine to stir the resin anchoring agent, and promoting the hollow grouting anchor cable to be fully bonded and anchored, so that the hollow grouting anchor cable and the resin anchoring agent are bonded and fixed to form an anchoring section; S2, multi-stage full-length prestress application: a. The expansion-leaf lock is installed at the top of the lock pushing rod, and the lock pushing rod is used to push the expansion-leaf lock in a contracted state to a position above the free section of the anchor cable close to the starting point of the anchoring section, and then the lock pushing rod is removed. b. Use the lock support expansion rod to pass through the hollow grouting anchor cable and insert into the drill hole, reach the expansion lock, the top end of the lock support expansion rod enters the expansion lock, and the expansion lock is fully expanded. Then, the lock support expansion rod is removed; c. Install the tray and lock at the tail of the hollow grouting anchor cable, and tension the anchor cable to the designed pre-tightening force through the tensioning equipment; d. Remove the tray and lock, and repeat steps S2, S3 and S4 to install multiple expansion locks at the preset positions; S3, leakage plugging in the middle damage area: After installing the lowermost expansion lock in the middle damage area, a circular truncated cone-shaped leakage plugging block is sleeved on the hollow grouting anchor cable. The leakage plugging block is pushed to the position of the lowermost expansion lock in the middle damage area using a lock pushing rod, the leakage plugging block further expands the expansion lock, and the drill hole is plugged. Then, repeat step S2 to install the expansion lock. Then, install the tray and lock, and tension the anchor cable to the designed pre-tightening force through the professional equipment.

[0011] S4, precise grouting reinforcement: Connect the hollow grouting anchor cable and the grouting equipment to perform grouting. The slurry 10 is limited to seepage through the slurry outlet to reinforce the broken area.

[0012] Further, the distance between the expansion locks is 60-80 cm, the uppermost expansion lock is 40-60 cm away from the anchoring segment, and the lowermost expansion lock is less than 60 cm away from the drill hole opening.

[0013] Advantages: 1) Improved partitioned collaborative support efficiency: The multi-stage expansion lock realizes continuous diffusion of full-length prestress, anchoring the shallow broken area and deep stable rock mass as a whole bearing body. Precise grouting only reinforces the shallow broken area, avoiding ineffective grouting. The middle damage area allows for crack yielding under the constraint of prestress, forming a partitioned collaborative mechanism of "grouting reinforced shallow area + prestress penetrating deep area + controllable deformation in the middle".

[0014] 2) Optimization of construction reliability and economy: Inherit the standardized process of multi-stage expansion lock pushing, expansion and tensioning, which is simple and efficient. The grouting range is strictly limited to the shallow broken area (about 30% of the damage area), reducing the consumption of grouting materials by more than 60% and significantly reducing the support cost.

[0015] 3) Full mobilization of surrounding rock self-bearing capacity: Full-length prestress effectively stimulates the bearing capacity of deep stable rock mass; the shallow broken area reinforced by grouting forms a rigid connection with the deep rock mass, avoiding the failure risk of "strong-weak rock mass disconnection" in traditional grouting reinforcement.

[0016] 4) Long-term stability guarantee: The high friction force (≥ design pre-tightening force) provided by the multi-stage lock ensures the long-term maintenance of the pre-stress; the pressure relief function of the middle damage zone under the constraint of both directions can adapt to the mining pressure fluctuation and prevent the overall structure from being unstable. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed for the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0018] Figure 1 It is a schematic diagram of a partition grouting and full-length pre-stress coordinated roof support system of the present application. Figure 2 It is a bonded anchoring segment with a length of L1 formed after the hollow grouting anchor cable end resin anchoring agent is fully bonded and anchored in the present application. Figure 3 It is the state of the first flange lock being pushed to the predetermined position by the lock push rod in the present application. Figure 4 It is the state of the first flange lock being pushed to the predetermined position by the lock push rod in the present application.

[0019] Figure 5 It is the state of the first flange lock being pushed to the predetermined position by the lock push rod in the present application. Figure 6 It is a schematic diagram of the structure of the lock push rod in the present application.

[0020] Figure 7 It is a schematic diagram of the structure of the lock push rod in the present application.

[0021] Figure 8 It is a schematic diagram of the state of the flange lock before the flange is expanded in the present application. Figure 9 It is a schematic diagram of the state of the flange lock after the flange is expanded in the present application.

[0022] Figure 10 In the present application, Figure 8 It is a bottom view of the middle flange lock. Figure 11 It is a schematic diagram of the structure of the plugging block. Figure 12 It is a schematic diagram of different regions of the roadway roof. Figure 13 It is an effect diagram of a partition grouting and full-length pre-stress coordinated roof support method.

[0023] In the figure: 1. Drill hole; 2. Hollow grouting anchor cable, 2-1. Grout outlet; 3. Resin anchoring agent; 4. Expanding plate lock, 4-1. Expanding plate one, 4-2. Expanding plate two, 4-3. Expanding plate three, 4-4. Variable diameter elastic coil, 4-5. Step A; 5. Pallet; 6. Locks; 7. Lock push rod, 7-1. Step B; 8. Lock expansion rod; 9. Leak-stopping block; 10. Slurry.

[0024] A is the shallow fractured zone, B is the medium damaged zone, C is the deep pressure zone, and D is the roadway. Detailed Implementation

[0025] The following description, in conjunction with the implementation of this invention, is merely an example and illustration of the concept of this invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the inventive concept or exceed the scope defined in these claims, all of which should fall within the protection scope of this invention.

[0026] like Figure 1 As shown, a roof support system combining zoned grouting and full-length prestressing includes: Grouting equipment, hollow grouting anchor cable 2, tray 5, and locking device 6 installed in conjunction with hollow grouting anchor cable 2 to fix tray 5 and provide prestress; like Figure 1 As shown, the hollow grouting anchor cable 2 is provided with a grout outlet 2-1, which is located at the junction of the shallow fracture zone and the middle damage zone. The position of the grout outlet 2-1 on the hollow grouting anchor cable 2 varies depending on the condition of the roadway roof.

[0027] like Figures 8-10 As shown, it also includes multiple cylindrical expansion bolt locks 4, each expansion bolt lock 4 containing multiple arc-shaped expansion bolts distributed in a ring. Figure 8 The embodiment given in the text uses three expansion pieces, including expansion piece one 4-1, expansion piece two 4-2, and expansion piece three 4-3, arranged in a ring shape. The number of expansion pieces is preferably within 3-6.

[0028] The upper part of the expansion sheet is connected to each other by the variable-diameter elastic coil 4-4 in the stretched state, and the two sides of the upper part of each expansion sheet are provided with a chamfer to provide space for the expansion of the expansion sheet; the inner diameter of the expansion sheet lock 4 matches the outer diameter of the hollow grouting anchor cable 2, and is sleeved on the free section of the hollow grouting anchor cable 2; in the actual design process, the inner radius of the expansion sheet lock 4 can be 1-1.5mm larger than the radius of the grouting anchor cable rod body, and the outer diameter r1 can be 2-3mm larger than the radius of the anchor cable rod body; Also includes a round table-shaped plugging block as shown in Figure 1 sleeved on the hollow grouting anchor cable 2, which can cooperate with the expansion sheet lock 4, when the expansion sheet lock 4 expands downward in the borehole 1 to form a round table shape, the plugging block can be inserted into the expansion sheet lock 4 to plug the borehole 1, preventing the grout 10 from entering other areas through the gap of the expansion sheet lock 4 during grouting; As shown in Figure 6 , the lock pushing rod 7 is a hollow rod body with an inner diameter larger than the diameter of the hollow grouting anchor cable 2, which is used to push the expansion sheet lock 4 along the hollow grouting anchor cable 2 to the predetermined position; the outer diameter R1 of the lock pushing rod 7 is close to the initial outer diameter r1 of the expansion sheet lock 4. As shown in Figure 7 , the lock expanding rod 8 is a hollow rod body with an inner diameter larger than the diameter of the hollow grouting anchor cable 2, and the outer diameter R2 of the upper end is smaller than the inner diameter of the expansion sheet lock 4 and gradually increases from top to bottom, which is used to expand the expansion sheet lock 4.

[0029] That is, as shown in Figures 8-10 , three annular expansion sheets form a cylindrical expansion sheet lock 4, and the upper part, such as 1 / 4 to 1 / 3 from the top, is connected by a variable-diameter elastic coil 4-4, which can be a metal spring; under the action of the variable-diameter elastic coil 4-4, the expansion sheet lock 4 in the unstressed state presents a round table shape, as shown in Figure 9 , the radius is r2, that is, the lower part of the expansion sheet expands outward, and the upper part contracts inward. Figure 1 As shown in , the expansion sheet lock 4 is sleeved on the anchor cable rod body, the expansion sheet lock 4 is pushed into the borehole 11 by the lock pushing rod 7, the lock pushing rod 7 is removed, the lower part of each expansion sheet expands outward under the action of the variable-diameter elastic coil 4-4, and the upper part contracts to clamp the anchor cable rod body; then the expansion sheet lock 4 is completely expanded by the lock expanding rod 8 to form a certain pre-tightening force; finally, the expansion sheet lock 4 is completely locked by the tray 5, the lock, and the professional tensioning equipment to form a predetermined pre-tightening force.

[0030] When the hollow grouting anchor cable 2 is grouting, the grout outlet 2-1 is located at the junction of the shallow broken zone and the middle damaged zone; the grout outlet 2-1 is blocked by the plugging block above and the tray 5 below in the borehole 1, therefore, the slurry 10 can maintain pressure in this area and gradually infiltrate into the shallow broken zone, thereby completing the grouting work in this area.

[0031] As a further scheme, the outer surface of the hollow grouting anchor cable 2 is provided with an outer convex anti-skid pattern; further, the inner wall of the expansion piece is provided with a friction layer. When the expansion piece expands, the upper end portion thereof can be clamped on the anti-skid pattern. In the design, it is necessary to ensure that the friction between the expansion piece lock 4 after expansion and the rod body of the hollow grouting anchor cable 2 is ≥ the designed pre-tightening force, and the friction between the expansion piece lock 4 after expansion and the hole wall is ≥ the designed pre-tightening force.

[0032] As shown in Figure 8 and Figure 6 As a further scheme, the lower end portion of the expansion piece lock 4 is provided with a step A4-5, and the upper end inner edge of the lock pushing rod 7 is provided with a step B7-1 matched with the step A4-5. The lock pushing rod 7 can be matched with the step A4-5 through the step B7-1, so as to place the expansion piece lock 4 in the contracted state on the upper end of the lock pushing rod 7.

[0033] Further, in order to ensure that the expansion piece can provide sufficient pre-tightening force, the material of the expansion piece is selected to be high-strength metal. Since the construction position of the present application is generally located in the roadway, due to the limited space, if the lock pushing rod 7 and the lock expansion rod 8 are too long and not easy to bend, it will bring inconvenience to the construction, therefore, the lock pushing rod 7 and the lock expansion rod 8 adopt high-strength flexible metal sleeves, which have certain bending characteristics.

[0034] A partition grouting and full-length pre-stress cooperative roof supporting method uses the above-mentioned multi-stage full-length pre-stress applying anchor cable system, including the following steps: S1, drilling a borehole 1 in the roadway rock mass, installing a resin anchoring agent 3 and a hollow grouting anchor cable 2 in the borehole 1, starting the drilling machine to stir the resin anchoring agent 3, and promoting the anchor segment of the hollow grouting anchor cable 2 to be fully bonded and anchored, so that the hollow grouting anchor cable 2 and the resin anchoring agent 3 are bonded and fixed to form an anchor segment L1, as shown in Figure 2 ; S2, multi-stage full-length pre-stress application: a. Install the expansion piece lock 4 on the top of the lock pushing rod 7, use the lock pushing rod 7 to push the expansion piece lock 4 in the contracted state to a position above the free segment of the anchor cable close to the starting point of the anchor segment, then remove the lock pushing rod 7, and the variable-diameter elastic coil 4-4 on the expansion piece lock 4 restores to the expanded state, so that the lower end of each expansion piece expands outward to clamp the inner wall of the borehole 1, and the upper end shrinks inward to clamp the hollow grouting anchor cable 2, as shown in Figure 3 ; b. Use the lock support expansion rod 8 to insert the hollow grouting anchor cable 2 into the drill hole 1, reaching the expansion lock 4, the top end of the lock support expansion rod 8 enters the expansion lock 4, and the expansion piece is fully expanded. Then, the lock support expansion rod 8 is removed, as shown in Figure 4 ; c. Install the tray 5 and the lock 6 at the tail of the hollow grouting anchor cable 2, and tension the anchor cable to the designed pre-tightening force by the tensioning device; d. Remove the tray 5 and the lock 6, and repeat steps S2, S3, and S4 to install multiple expansion locks 4 at the preset positions, as shown in Figure 5 ; S3, middle damage area plugging: After installing the lowermost expansion lock 4 in the middle damage area, a circular truncated cone-shaped plugging block is sleeved on the hollow grouting anchor cable 2, and the plugging block is pushed to the position of the lowermost expansion lock 4 in the middle damage area using the lock pushing rod 7. The plugging block further expands the expansion lock 4 and completes the plugging of the drill hole 1. Then, repeat step S2 to install the expansion lock 4. Then, install the tray 5 and the lock 6, and tension the anchor cable to the designed pre-tightening force by the professional equipment.

[0035] S4, precise grouting reinforcement: Connect the hollow grouting anchor cable 2 and the grouting equipment, and perform grouting. The slurry 10 is limited to seepage through the slurry outlet 2-1, reinforcing the fractured zone.

[0036] Through the multi-stage prestress application of step S2, the shallow fractured zone and the deep pressure-bearing zone are locked as a whole, and the middle damage area is formed in a bidirectional constraint, allowing the middle damage area to allow pressure relief through crack closure. Under the action of grouting pressure, the diffusion range of the slurry 10 is limited within the shallow fractured zone and does not penetrate into the middle damage area.

[0037] As shown in Figure 5 , further, the spacing L3 between the expansion locks 4 is 60-80 cm, the uppermost expansion lock 4 is 40-60 cm away from the anchoring segment L2, and the lowermost expansion lock 4 is less than 60 cm away from the drill hole 1.

[0038] The application proposes a zoning grouting and full-length prestress collaborative support system: 1. Multi-stage prestress active diffusion: based on the multi-expansion piece lock 4 system, distributed mechanical anchorage points are established in the free section of the anchor cable. By gradually tensioning and locking, the prestress is continuously diffused along the full length of the rod, completely eliminating stress interruption, and high-strength series connection of the shallow broken zone and the deep stable rock mass. 2. Grouting precise limited reinforcement: hollow grouting anchor cable is used, and the grouting outlet is accurately positioned at the junction of the shallow broken zone and the middle damaged zone. During grouting, the grout 10 is strictly limited to the shallow broken zone, which not only reinforces the broken rock mass, but also retains the pressure relief function of the middle damaged zone. Through the cooperation of uniform diffusion of prestress throughout the process and accurate control of grouting space, the application first realizes the unity of active reinforcement of the broken zone, controllable deformation of the damaged zone and mobilization of the bearing capacity of the deep rock mass.

Claims

1. A roof support system that combines zoned grouting with full-length prestressing, comprising: Grouting equipment, hollow grouting anchor cable (2), tray (5), and locking device (6) installed in conjunction with the hollow grouting anchor cable (2) to fix the tray (5) and provide prestress; characterized in that: The hollow grouting anchor cable (2) is provided with a grout outlet (2-1), which is located at the junction of the shallow fracture zone and the middle damage zone; It also includes multiple cylindrical expansion locking devices (4), each expansion locking device (4) containing multiple arc-shaped expansion pieces distributed in a ring, the upper part of the expansion pieces being interconnected by a variable diameter elastic coil (4-4) in an extended state, and each expansion piece having chamfers on both sides of its upper part; the inner diameter of the expansion locking device (4) matches the outer diameter of the hollow grouting anchor cable (2) and is fitted onto the free section of the hollow grouting anchor cable (2); A frustum-shaped plugging block (9) fitted onto the hollow grouting anchor cable (2); Lock push rod (7), which is a hollow rod body with an inner diameter larger than the diameter of the hollow grouting anchor cable (2), is used to push the expansion plate lock (4) to the predetermined position along the hollow grouting anchor cable (2). Lock expansion rod (8) is a hollow rod with an inner diameter larger than that of the hollow grouting anchor cable (2) and an upper outer diameter smaller than that of the expansion plate lock (4), which gradually increases from top to bottom. It is used to expand the expansion plate lock (4).

2. The roof support system combining zoned grouting and full-length prestressing as described in claim 1, characterized in that, The hollow grouting anchor cable (2) has convex anti-slip textures on its outer surface.

3. The roof support system combining zoned grouting and full-length prestressing according to claim 2, characterized in that, The inner wall of the expansion plate is provided with a friction layer.

4. A roof support system combining zoned grouting and full-length prestressing according to any one of claims 1 to 3, characterized in that, The lower end of the expansion lock (4) is provided with a step A (4-5) on the outer edge, and the upper end of the lock push rod (7) is provided with a step B (7-1) that cooperates with the step A (4-5). The lock push rod (7) cooperates with the step A (4-5) through the step B (7-1), so that the expansion lock (4) can be placed on the upper end of the lock push rod (7) in the retracted state.

5. The roof support system combining zoned grouting and full-length prestressing according to claim 4, characterized in that, Furthermore, the expansion plate is made of high-strength metal, and the lock push rod (7) and lock expansion rod (8) are high-strength flexible metal sleeves.

6. A method for roof support combining zoned grouting and full-length prestressing, characterized in that: The roof support system using the combined sectional grouting and full-length prestressing as described in any one of claims 1-5 includes the following steps: S1. Drill a hole (1) in the rock mass of the tunnel, install resin anchoring agent (3) and hollow grouting anchor cable (2) in the hole (1), start the drilling machine to stir the resin anchoring agent (3) to promote the hollow grouting anchor cable (2) anchor section to fully bond and anchor, and the hollow grouting anchor cable (2) and resin anchoring agent (3) bond and fix to form an anchor section. S2, Multi-stage full-length prestressing application: a. Install the expansion plate lock (4) on the top of the lock push rod (7), and use the lock push rod (7) to push the expansion plate lock (4) in the contracted state to the position above the free section of the anchor cable near the starting point of the anchoring section. Then remove the lock push rod (7), and the variable diameter elastic coil (4-4) on the expansion plate lock (4) will return to the expansion state, so that the lower end of each expansion plate expands outward to lock the inner wall of the borehole (1), and the upper end contracts inward to lock the hollow grouting anchor cable (2). b. Use the lock expansion rod (8) to pass through the hollow grouting anchor cable (2) and insert it into the borehole (1) until it reaches the expansion plate lock (4). The top of the lock expansion rod (8) enters the expansion plate lock (4) and presses the expansion plate to fully expand. Then, take out the lock expansion rod (8). c. Install a tray (5) and a lock (6) at the tail of the hollow grouting anchor cable (2), and tension the anchor cable to the design preload using a tensioning device; d. Remove the tray (5) and lock (6), and repeat steps S2, S3 and S4 to install multiple expansion locks (4) in the preset positions; S3, Leak sealing in the central damaged area: After installing the lowest expansion joint lock (4) in the middle damage zone, the frustum-shaped plugging block (9) is fitted onto the hollow grouting anchor cable (2). The plugging block (9) is pushed to the position of the lowest expansion joint lock (4) in the middle damage zone using the lock pusher rod (7). The plugging block (9) further expands the expansion joint lock (4) and completes the sealing of the borehole (1). Then, step S2 is repeated to install the expansion joint lock (4). Then, the tray (5) and lock are installed, and the anchor cable is tensioned to the design preload using a tensioning device with professional equipment. S4. Precision grouting reinforcement: Connect the hollow grouting anchor cable (2) and the grouting equipment to perform grouting; the grout (10) seeps out through the grout outlet (2-1) to reinforce the fractured area.

7. The method for roof support combining zoned grouting and full-length prestressing according to claim 6, characterized in that: The spacing between the expansion plate locks (4) is 60-80cm. The uppermost expansion plate lock (4) is 40-60cm away from the anchoring section, and the lowermost expansion plate lock (4) is less than 60cm away from the opening of the drill hole (1).

Images