A mine section type deep hole grouting retreat type grouting pipe dismounting grouting support

Abstract

The application discloses a mine sectional deep-hole grouting retreat type grouting pipe withdrawing device, which can effectively guarantee the grouting pressure during grouting and pipe withdrawing, guarantee the pressure of slurry in the grouting hole, prevent slurry overflow, guarantee the grouting reliability and prevent slurry overflow and environmental pollution. When grouting, the control mechanism controls the retreat pressure maintaining control cap to have a certain interval with the retreat type grouting pipe, so that the slurry in the retreat type grouting pipe can flow out from the interval, and the adverse effect on grouting during grouting is prevented. When grouting is completed and the retreat type grouting pipe is withdrawn, the control mechanism controls the retreat pressure maintaining control cap to move towards the retreat type grouting pipe, so that the slurry at the port of the retreat type grouting pipe is extruded by the rear cone body and flows out along the rear cone body, and the flowed-out slurry is extruded to the area pushed out by the retreat pressure maintaining control cap.

Description

Technical Field

[0001] Specifically, this invention relates to a segmented deep-hole grouting retreating grouting pipe dismantling grouting support for mine tunnels, and is connected to the field of grouting equipment. Background Technology

[0002] Grouting, as a major technology for reinforcing and reducing seepage in soft rock formations, is widely used in mineral mining. It is a primary means of improving underground engineering strata, strengthening, water-stopping, leak-proofing, and emergency rescue. Currently, the most common grouting device is the retractable grouting system. This system can effectively perform segmented deep-hole grouting in mine tunnels. However, current retractable grouting equipment generally withdraws directly after grouting. While this can maintain the grouting pressure within the grouting hole during the grouting process, it is difficult to effectively maintain the pressure during the withdrawal operation. Furthermore, the grouting pipe is prone to rotation and grout overflow, which not only affects the reliability of grouting stability but also harms the environment and is susceptible to pollution. Summary of the Invention

[0003] Therefore, in order to overcome the above-mentioned shortcomings, the present invention provides a grouting support for segmented deep hole grouting in mine tunnels with a retractable grouting pipe dismantling mechanism.

[0004] This invention is implemented as follows: a segmented deep-hole grouting support for mine tunnels is constructed, comprising a retractable grouting pipe, a retractable pressure-holding control cap, and a control mechanism. One end of the retractable grouting pipe is connected to the grouting equipment via a fitting, and the other end of the retractable grouting pipe is connected to the retractable pressure-holding control cap via the control mechanism. The end of the retractable grouting pipe connected to the retractable pressure-holding control cap faces into the grouting hole. The key feature is that the end of the retractable pressure-holding control cap away from the retractable grouting pipe is a front cone, and the end of the retractable pressure-holding control cap near the retractable grouting pipe is a rear cone. Furthermore, the control mechanism can control the retractable pressure-holding control cap to move towards or away from the retractable grouting pipe. During grouting, the control mechanism controls the retractable pressure-holding control cap to move towards or away from the retractable grouting pipe. There is a certain gap between the retraction pressure control cap and the retraction grouting pipe so that the grout in the retraction grouting pipe can flow out from the gap. When the retraction is completed and the retraction is completed, when the retraction grouting pipe retracts by one displacement, the control mechanism controls the retraction pressure control cap to move toward the retraction grouting pipe so that the rear cone squeezes the grout at the port of the retraction grouting pipe and flows out along the rear cone, and squeezes the flowing grout into the area pushed out by the retraction pressure control cap. When the rear cone abuts against the retraction grouting pipe, the retraction grouting pipe is controlled to retract by one displacement again. During the retraction process, the grouting equipment continues to inject grout and maintain pressure into the retraction grouting pipe, and the control mechanism controls the retraction pressure control cap for the next cycle.

[0005] Furthermore, preferably, the diameter of the front cone at its maximum cross-section is smaller than the diameter of the rear cone at its maximum cross-section.

[0006] Furthermore, as a preferred embodiment, the front cone and the rear cone are connected by an integrally formed stepped ring.

[0007] Furthermore, as a preferred embodiment, a pneumatic sealing gasket is also fitted on one end of the retractable grouting pipe near the retractable pressure control cap. The pneumatic sealing gasket is designed to expand and contract in order to control the sealing and non-sealing between the retractable grouting pipe and the inner wall of the grouting hole.

[0008] Furthermore, preferably, when the retractable grouting pipe retracts by one displacement, the pneumatic sealing gasket contracts, and when the grouting equipment injects grout and the control mechanism controls the retractable pressure-holding control cap to move toward the retractable grouting pipe, the pneumatic sealing gasket expands to ensure the sealing between the retractable grouting pipe and the inner wall of the grouting hole.

[0009] Furthermore, preferably, the control mechanism includes a support assembly, a control platform, a control drive assembly, drive swing arms, and drive connecting rods. The support assembly is installed inside the retractable grouting pipe, and its central axis is coaxial with that of the retractable grouting pipe. The control platform is fixedly mounted on the support assembly, and its central axis is coaxial with that of the retractable grouting pipe. The control drive assembly is located on the side of the control platform facing the retractable pressure-holding control cap. Multiple drive swing arms are also circumferentially arranged and hinged on the control platform. The control drive assembly drives each drive swing arm to rotate synchronously. The ends of the drive swing arms are hinged to the drive connecting rods via hinge seats and hinge shafts. The ends of the drive connecting rods are hinged to the side of the retractable pressure-holding control cap facing the retractable grouting pipe. The axial movement of the retractable pressure-holding control cap is driven by the drive swing arms and drive connecting rods.

[0010] Furthermore, preferably, the control drive assembly includes a drive motor, a drive worm gear, and a drive worm wheel. The drive motor is fixed to the control platform, and its output end passes through the control platform and is connected to the drive worm gear. The drive worm wheel is fixedly connected to the hinge shaft between the drive rocker arm and the control platform. The drive worm wheel meshes with the drive worm gear for transmission, and the drive motor, drive worm gear, and drive worm wheel cause the drive rocker arm to swing synchronously.

[0011] Furthermore, preferably, the support assembly includes at least two support rods arranged in an array, the support rods extending along the radial direction of the retractable grouting pipe, with the outer radial end of the support rod fixed to the inner wall of the retractable grouting pipe and the inner radial end of the support rod fixedly connected to the control platform.

[0012] Furthermore, preferably, the distance between the end face of the rear cone and the end of the retractable grouting pipe is greater than the thickness of the front cone in the axial direction of the grouting hole.

[0013] Furthermore, the present invention also provides a method for retracting a grouting support for segmented deep-hole grouting in mine tunnels, which employs the grouting support for segmented deep-hole grouting in mine tunnels described in this invention, characterized by comprising the following steps: (1) Grouting: The retractable grouting pipe is inserted into the grouting hole. The control mechanism is used to control the retractable pressure holding control cap to form the maximum gap between the retractable grouting pipe and the retractable grouting pipe. Grouting equipment is used to inject grout into the retractable grouting pipe to achieve high-pressure grouting of the grouting hole. During grouting, the pneumatic sealing gasket expands to ensure the sealing between the retractable grouting pipe and the inner wall of the grouting hole. (2) Exit after grouting: (2.1) When the grouting in this section is completed and the pipe is retracted, the pneumatic sealing gasket is first controlled to shrink, and then the retracting grouting pipe is controlled to retract by one displacement. During the retraction process, the grouting equipment continues to grout and maintain pressure on the retracting grouting pipe. (2.2) Re-control the pneumatic sealing gasket to expand and seal, and then control the retracting pressure control cap to move toward the retracting grouting pipe so that the rear cone squeezes the grout at the port of the retracting grouting pipe to flow out along the rear cone and squeezes the flowing grout to the area pushed out by the retracting pressure control cap until the rear cone abuts against the retracting grouting pipe; (2.3) Control the pneumatic sealing gasket to shrink and open the control mechanism to make the control mechanism move, and at the same time make the retractable grouting pipe retract by one displacement. During the retraction, try to keep the position of the retraction pressure holding control cap unchanged. (2.4) Return to step (2.2) and perform the next section of backward grouting in sequence until the entire grouting hole is completely grouted and the entire backward grouting pipe and backward pressure control cap are completely removed from the grouting hole.

[0014] The present invention has the following advantages: The grouting support for segmented deep-hole grouting and retraction in mine tunnels provided by the present invention has the following advantages compared with similar equipment: This invention discloses a segmented deep-hole grouting system with a retractable grouting pipe dismantling support. This system effectively ensures grouting pressure after grouting and during pipe dismantling, maintains grout pressure within the grouting hole, and prevents grout overflow. This guarantees grouting reliability and prevents grout overflow from polluting the environment. During grouting, the control mechanism maintains a certain distance between the retractable pressure-maintaining cap and the retractable grouting pipe, allowing grout to flow out through this distance and preventing adverse effects on the grouting process. After grouting is completed and the pipe is dismantled... The control mechanism controls the retracting pressure-holding control cap to move toward the retracting grouting pipe, causing the rear cone to squeeze the grout at the port of the retracting grouting pipe and flow out along the rear cone. The outflowing grout is then squeezed into the area pushed out by the retracting pressure-holding control cap. When the rear cone abuts against the retracting grouting pipe, the retracting grouting pipe is controlled to retract by one displacement. During the retraction process, the grouting equipment continues to inject grout and maintain pressure into the retracting grouting pipe. The control mechanism then controls the retracting pressure-holding control cap for the next cycle, effectively ensuring that the grouting pressure is maintained during the retracting grouting process. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the main structure of the present invention; Figure 2 This is a schematic diagram of the structure of the retraction pressure control cap and control mechanism of the present invention; Figure 3 This is a schematic diagram of the front structure of the retraction pressure control cap of the present invention; Figure 4 This is a schematic diagram of the structure of the front end of the retractable grouting pipe of the present invention after being cut open; Figure 5 This is a rear view structural schematic diagram of the control mechanism of the present invention; Figure 6 This is a three-dimensional structural diagram of the control mechanism of the present invention. Figure 7 This is a front view schematic diagram of the control mechanism of the present invention. Detailed Implementation

[0016] The following will be combined with the appendix Figure 1-7 This invention will be described in detail, and the technical solutions in the embodiments of this invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0017] This invention provides an improved version of a segmented deep-hole grouting support for mine tunnels, comprising a retractable grouting pipe 1, a retractable pressure-holding control cap 4, and a control mechanism 3. One end of the retractable grouting pipe 1 is connected to the grouting equipment via a fitting, and the other end of the retractable grouting pipe 1 is connected to the retractable pressure-holding control cap 4 via the control mechanism 3. The end of the retractable grouting pipe 1 connected to the retractable pressure-holding control cap 4 faces into the grouting hole. The invention is characterized in that the end of the retractable pressure-holding control cap 4 away from the retractable grouting pipe is a front cone 11, and the end of the retractable pressure-holding control cap 4 near the retractable grouting pipe is a rear cone 14. The control mechanism 3 can control the retractable pressure-holding control cap 4 to move towards or away from the retractable grouting pipe 1. During grouting, the control mechanism 3 controls... There is a certain gap between the retracting pressure control cap 4 and the retracting grouting pipe 1 so that the grout in the retracting grouting pipe 1 can flow out from the gap. When the retracting grouting pipe 1 retracts by one displacement after grouting, the control mechanism controls the retracting pressure control cap to move toward the retracting grouting pipe 1 so that the rear cone 14 squeezes the grout at the port of the retracting grouting pipe and squeezes the flowing grout to the area pushed out by the retracting pressure control cap. When the rear cone abuts against the retracting grouting pipe 1, the retracting grouting pipe is controlled to retract by one displacement again. During the retraction process, the grouting equipment continues to inject grout and maintain pressure into the retracting grouting pipe, and the control mechanism controls the retracting pressure control cap for the next cycle.

[0018] In this embodiment, the diameter of the front cone 14 at its maximum cross-section is smaller than the diameter of the rear cone at its maximum cross-section.

[0019] The front cone and the rear cone are connected by an integrally formed stepped ring 13.

[0020] A pneumatic sealing gasket 2 is also fitted on one end of the retractable grouting pipe near the retractable pressure control cap. The pneumatic sealing gasket 2 is designed to expand and contract in order to control the sealing and non-sealing between the retractable grouting pipe and the inner wall of the grouting hole.

[0021] Preferably, an annular groove can be provided on the retractable grouting pipe, and the pneumatic sealing gasket is located in the annular groove. When it contracts, it is located in the annular groove, and when it expands, the outer peripheral surface of the pneumatic sealing gasket expands and extends out of the annular groove.

[0022] Specifically, when the retractable grouting pipe retracts by one displacement, the pneumatic sealing gasket 2 contracts; when the grouting equipment injects grout and the control mechanism controls the retractable pressure-holding control cap to move toward the retractable grouting pipe, the pneumatic sealing gasket expands to ensure the sealing between the retractable grouting pipe and the inner wall of the grouting hole.

[0023] In a preferred embodiment, the control mechanism includes a support assembly, a control platform 19, a control drive assembly 12, drive swing rods 22, and a drive connecting rod 7. The support assembly is installed inside the retractable grouting pipe 1, and the central axis of the support assembly is coaxial with the central axis of the retractable grouting pipe. The control platform 19 is fixedly mounted on the support assembly, and the central axis of the control platform 19 is coaxial with the retractable grouting pipe. The control drive assembly 12 is mounted on the side of the control platform 19 facing the retractable pressure-holding control cap 4. Multiple drive swing rods 22 are also circumferentially arranged and hinged on the control platform. The control drive assembly drives each drive swing rod to rotate synchronously. The end of each drive swing rod 22 is hinged to the drive connecting rod 7 via a hinge seat 8 and a hinge shaft. The end of the drive connecting rod 7 is hinged to the side of the retractable pressure-holding control cap facing the retractable grouting pipe. The axial movement of the retractable pressure-holding control cap is driven by the drive swing rods and the drive connecting rod.

[0024] The control drive assembly includes a drive motor 20, a drive worm 23, and a drive worm wheel 25. The drive motor 20 is fixed on the control platform, and the output end of the drive motor passes through the control platform 19 and is connected to the drive worm 23. The drive swing arm 22 is fixedly connected to the hinge shaft 26 of the control platform, and the drive worm wheel 25 meshes with the drive worm 23 for transmission. The drive swing arm swings synchronously through the drive motor 20, the drive worm, and the drive worm wheel.

[0025] The support assembly includes at least two support rods 21 arranged in an array. The support rods 21 extend along the radial direction of the retractable grouting pipe, and the radial outer end of the support rod 21 is fixed to the inner wall of the retractable grouting pipe, while the radial inner end of the support rod is fixedly connected to the control platform 19.

[0026] In a preferred embodiment, the distance between the end face of the rear cone and the end of the retractable grouting pipe is greater than the thickness of the front cone in the axial direction of the grouting hole.

[0027] Furthermore, the present invention also provides a method for retracting a grouting support for segmented deep-hole grouting in mine tunnels, which employs the grouting support for segmented deep-hole grouting in mine tunnels described in this invention, characterized by comprising the following steps: (1) Grouting: The retractable grouting pipe is inserted into the grouting hole. The control mechanism is used to control the retractable pressure holding control cap to form the maximum gap between the retractable grouting pipe and the retractable grouting pipe. Grouting equipment is used to inject grout into the retractable grouting pipe to achieve high-pressure grouting of the grouting hole. During grouting, the pneumatic sealing gasket expands to ensure the sealing between the retractable grouting pipe and the inner wall of the grouting hole. (2) Exit after grouting: (2.1) When the grouting in this section is completed and the pipe is retracted, the pneumatic sealing gasket is first controlled to shrink, and then the retracting grouting pipe is controlled to retract by one displacement. During the retraction process, the grouting equipment continues to grout and maintain pressure on the retracting grouting pipe. (2.2) Re-control the pneumatic sealing gasket to expand and seal, and then control the retracting pressure control cap to move toward the retracting grouting pipe so that the rear cone squeezes the grout at the port of the retracting grouting pipe to flow out along the rear cone and squeezes the flowing grout to the area pushed out by the retracting pressure control cap until the rear cone abuts against the retracting grouting pipe; (2.3) Control the pneumatic sealing gasket to shrink and open the control mechanism to make the control mechanism move, and at the same time make the retractable grouting pipe retract by one displacement. During the retraction, try to keep the position of the retraction pressure holding control cap unchanged. (2.4) Return to step (2.2) and perform the next section of backward grouting in sequence until the entire grouting hole is completely grouted and the entire backward grouting pipe and backward pressure control cap are completely removed from the grouting hole.

[0028] This invention discloses a segmented deep-hole grouting system with a retractable grouting pipe dismantling support. This system effectively ensures grouting pressure after grouting and during pipe dismantling, maintains grout pressure within the grouting hole, and prevents grout overflow. This guarantees grouting reliability and prevents grout overflow from polluting the environment. During grouting, the control mechanism maintains a certain distance between the retractable pressure-maintaining cap and the retractable grouting pipe, allowing grout to flow out through this distance and preventing adverse effects on the grouting process. After grouting is completed and the pipe is dismantled... The control mechanism controls the retracting pressure-holding control cap to move toward the retracting grouting pipe, causing the rear cone to squeeze the grout at the port of the retracting grouting pipe and flow out along the rear cone. The outflowing grout is then squeezed into the area pushed out by the retracting pressure-holding control cap. When the rear cone abuts against the retracting grouting pipe, the retracting grouting pipe is controlled to retract by one displacement. During the retraction process, the grouting equipment continues to inject grout and maintain pressure into the retracting grouting pipe. The control mechanism then controls the retracting pressure-holding control cap for the next cycle, effectively ensuring that the grouting pressure is maintained during the retracting grouting process.

[0029] The above description shows and illustrates the basic principles, main features, and advantages of the present invention. Standard parts used in the present invention can be purchased from the market, and irregular parts can be customized according to the description and drawings. The specific connection methods of each part adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts, and equipment adopt conventional models in the prior art, and the circuit connection adopts conventional connection methods in the prior art, which will not be described in detail here.

[0030] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A segmented deep-hole grouting device for mine tunnels, comprising a retractable grouting pipe, a retractable pressure-maintaining control cap, and a control mechanism, wherein one end of the retractable grouting pipe is connected to grouting equipment via a fitting, and the other end of the retractable grouting pipe is connected to the retractable pressure-maintaining control cap via the control mechanism, wherein the end of the retractable grouting pipe connected to the retractable pressure-maintaining control cap faces into the grouting hole, characterized in that... The end of the retractable pressure-holding control cap furthest from the retractable grouting pipe is a front cone, and the end of the retractable pressure-holding control cap closest to the retractable grouting pipe is a rear cone. The control mechanism can control the retractable pressure-holding control cap to move towards or away from the retractable grouting pipe. During grouting, the control mechanism maintains a certain distance between the retractable pressure-holding control cap and the retractable grouting pipe to allow the grout in the retractable grouting pipe to flow out from the distance. After grouting is completed and the retractable grouting pipe retracts by one displacement... At that time, the control mechanism controls the retracting pressure holding control cap to move toward the retracting grouting pipe, so that the rear cone squeezes the grout at the port of the retracting grouting pipe and flows out along the rear cone, and squeezes the flowing grout into the area pushed out by the retracting pressure holding control cap. When the rear cone abuts against the retracting grouting pipe, the control mechanism controls the retracting grouting pipe to retract by one displacement again. During the retraction process, the grouting equipment continues to inject grout and maintain pressure into the retracting grouting pipe, and the control mechanism controls the retracting pressure holding control cap for the next cycle.

2. The segmented deep-hole grouting and retraction grouting pipe withdrawal device for mine tunnels according to claim 1, characterized in that: The diameter at the maximum cross-section of the front cone is smaller than the diameter at the maximum cross-section of the rear cone.

3. The segmented deep-hole grouting and retraction grouting pipe withdrawal device for mine tunnels according to claim 1, characterized in that: The front cone and the rear cone are connected by an integrally molded stepped ring.

4. The segmented deep-hole grouting and retraction grouting pipe withdrawal device for mine tunnels according to claim 2, characterized in that: A pneumatic sealing gasket is also fitted on one end of the retractable grouting pipe near the retractable pressure control cap. The pneumatic sealing gasket is designed to expand and contract in order to control the sealing and non-sealing between the retractable grouting pipe and the inner wall of the grouting hole.

5. The segmented deep-hole grouting and retraction grouting pipe withdrawal device for mine tunnels according to claim 4, characterized in that: When the retractable grouting pipe retracts by one displacement, the pneumatic sealing gasket contracts. When the grouting equipment injects grout and the control mechanism controls the retractable pressure-holding control cap to move toward the retractable grouting pipe, the pneumatic sealing gasket expands to ensure the sealing between the retractable grouting pipe and the inner wall of the grouting hole.

6. The segmented deep-hole grouting and retraction grouting pipe withdrawal device for mine tunnels according to claim 5, characterized in that: The control mechanism includes a support assembly, a control platform, a control drive assembly, drive swing arms, and drive connecting rods. The support assembly is installed inside the retractable grouting pipe, and its central axis is coaxial with that of the retractable grouting pipe. The control platform is fixedly mounted on the support assembly, and its central axis is coaxial with that of the retractable grouting pipe. The control drive assembly is located on the side of the control platform facing the retractable pressure-holding control cap. Multiple drive swing arms are also circumferentially arranged and hinged on the control platform. The control drive assembly drives each drive swing arm to rotate synchronously. The ends of the drive swing arms are hinged to the drive connecting rods via hinge seats and hinge shafts. The ends of the drive connecting rods are hinged to the side of the retractable pressure-holding control cap facing the retractable grouting pipe. The axial movement of the retractable pressure-holding control cap is driven by the drive swing arms and drive connecting rods.

7. The segmented deep-hole grouting and retraction grouting pipe withdrawal device for mine tunnels according to claim 6, characterized in that: The control drive assembly includes a drive motor, a drive worm, and a drive worm wheel. The drive motor is fixed to the control platform, and the output end of the drive motor passes through the control platform and is connected to the drive worm. The drive worm wheel is fixedly connected to the hinge shaft of the drive swing arm and the control platform. The drive worm wheel meshes with the drive worm for transmission. The drive swing arm swings synchronously through the drive motor, drive worm, and drive worm wheel.

8. The segmented deep-hole grouting and retraction grouting pipe withdrawal device for mine tunnels according to claim 6, characterized in that: The support assembly includes at least two support rods arranged in an array, the support rods extending radially along the retractable grouting pipe, with the outer radial end of the support rod fixed to the inner wall of the retractable grouting pipe and the inner radial end of the support rod fixedly connected to the control platform.

9. The segmented deep-hole grouting and retraction grouting pipe withdrawal device for mine tunnels according to claim 1, characterized in that: The distance between the end face of the rear cone and the end of the retractable grouting pipe is greater than the thickness of the front cone in the axial direction of the grouting hole.

10. A method for withdrawing the grouting pipe of a segmented deep-hole grouting system in a mine, comprising the grouting pipe withdrawal device of any one of claims 1-9, characterized in that: It includes the following steps: (1) Grouting: The retractable grouting pipe is inserted into the grouting hole. The control mechanism is used to control the retractable pressure holding control cap to form the maximum gap between the retractable grouting pipe and the retractable grouting pipe. Grouting equipment is used to inject grout into the retractable grouting pipe to achieve high-pressure grouting of the grouting hole. During grouting, the pneumatic sealing gasket expands to ensure the sealing between the retractable grouting pipe and the inner wall of the grouting hole. (2) Withdraw after grouting: (2.1) When the grouting in this section is completed and the pipe is retracted, the pneumatic sealing gasket is first controlled to shrink, and then the retracting grouting pipe is controlled to retract by one displacement. During the retraction process, the grouting equipment continues to inject grout into the retracting grouting pipe to maintain pressure. (2.2) Re-control the pneumatic sealing gasket expansion seal, and then control the retracting pressure control cap to move toward the retracting grouting pipe so that the rear cone squeezes the grout at the port of the retracting grouting pipe and flows out along the rear cone, and squeezes the flowing grout to the area pushed out by the retracting pressure control cap until the rear cone abuts against the retracting grouting pipe; (2.3) Control the pneumatic sealing gasket to shrink and open the control mechanism to make the control mechanism move, and at the same time make the retractable grouting pipe retract by one displacement. During the retraction, try to keep the position of the retraction pressure holding control cap unchanged. (2.4) Return to step (2.2) and perform the next section of backward grouting in sequence until the entire grouting hole is completely grouted and the entire backward grouting pipe and backward pressure control cap are completely removed from the grouting hole.

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