Prestressed grouting pipe and grouting process suitable for high-pressure grouting water plugging process

Abstract

The application discloses a prestressed grouting pipe suitable for high-pressure grouting water plugging process requirements, which comprises a grouting pipe body, an expansion sleeve, a conical sleeve and an inner end stress beam are arranged at a slurry output end of the grouting pipe body, and an outer end stress beam is arranged at a slurry input end of the grouting pipe body; an inner cavity of the expansion sleeve is conical for the conical sleeve to enter, a tension assembly for relatively moving the conical sleeve and the expansion sleeve is further arranged between the inner end stress beam and the outer end stress beam, the expansion sleeve is expanded and tightly adhered to an inner wall of a grouting hole under the action of the tension assembly. The prestressed grouting pipe suitable for high-pressure grouting water plugging process requirements has the characteristics of convenient installation and high installation strength in a high-pressure water gushing environment.

Description

Technical Field

[0001] This invention belongs to the field of tunnel construction, and in particular relates to a grouting pipe and grouting process. Background Technology

[0002] Encountering water inrush during tunnel construction is common. The engineering community generally employs methods such as water diversion and drainage, or continues construction while the water is still flowing, which usually does not affect the tunnel excavation process. Past tunnel excavation operations have mostly been carried out in areas with relatively simple geological structures. Looking at international and domestic tunnel excavation history, there are no records of water inrushes exceeding 80 degrees Celsius, and the engineering community has conducted very little research on this situation.

[0003] The Sichuan-Tibet Railway is a vital railway line connecting Chengdu, the capital of Sichuan Province in southwestern my country, and Lhasa, the capital of the Tibet Autonomous Region. The railway traverses the Hengduan Mountains and passes through multiple fault zones, resulting in a highly complex geological structure. The Sichuan-Tibet Railway requires the construction of numerous ultra-long tunnels, some of which cross geothermal anomaly zones. Inevitably, construction will encounter the problem of high-temperature and ultra-high-temperature water seeping from rock fissures. This outflow of hot water will rapidly deteriorate the working environment inside the tunnels, quickly increasing temperature and humidity, causing severe difficulties for construction.

[0004] Faced with the heat hazard of ultra-high temperature hot water, the construction unit adopted various available advanced detection methods to try to detect the presence of high-temperature water at a certain distance in front of the tunnel face, and confirmed its presence by drilling advance exploratory boreholes. After detecting the high-temperature water, the main method used is generally drainage, supplemented by water-blocking techniques, which has a good water control effect. However, when dealing with ultra-high temperature rock fissure gushing water of unknown origin during tunnel construction, the drainage effect is limited, and the heat dissipation of this ultra-high temperature hot water during the discharge process will greatly increase the temperature inside the tunnel. Therefore, using advanced grouting to force back and contain this high-temperature and ultra-high temperature hot water outside the tunnel excavation area has become the only option in the construction process.

[0005] Traditional grouting methods have low flow rates and pressures, and the methods used to install grouting pipes are no longer suitable for the high pressure and high flow rates required for high-temperature flowing water. In actual high-temperature and ultra-high-temperature flowing water top-water grouting construction, the commonly used method for installing grouting pipes is to wrap hemp rope around the outside of the grouting pipe and apply cement slurry to the rope, then forcefully press it into the grouting hole. Grouting pipes installed in this way cannot withstand the back pressure of high-pressure grouting, often causing grout to rush out from the pipe joints or even the entire grouting pipe to be blown out by the high pressure, with extremely dangerous consequences.

[0006] Therefore, it is essential to develop a high-pressure grouting pipe and grouting process that can adapt to high-pressure and high-flow-rate top-water grouting conditions that can be easily installed and used immediately after installation, which is necessary in actual construction. Summary of the Invention

[0007] The technical problem to be solved by this invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide a prestressed grouting pipe and grouting process that are easy to install, have high bonding strength with grouting holes, and good sealing performance of pipe joints, thus meeting the requirements of high-pressure grouting and water plugging processes. To solve the above technical problem, the technical solution proposed by this invention is as follows:

[0008] A prestressed grouting pipe adapted to high-pressure grouting and water plugging processes includes a grouting pipe body. The grout output end of the grouting pipe body is provided with an expansion sleeve, a frustum-shaped sleeve, and an inner end bearing beam. The grout input end of the grouting pipe body is provided with an outer end bearing beam. The inner cavity of the expansion sleeve is frustum-shaped to allow the frustum-shaped sleeve to enter (making the inner cavity shape of the expansion sleeve match the outer shape of the frustum-shaped sleeve, but smaller than the outer shape of the frustum-shaped sleeve). A tensioning component is also provided between the inner end bearing beam and the outer end bearing beam to allow relative movement between the frustum-shaped sleeve and the expansion sleeve, causing the expansion sleeve to expand and tighten against the inner wall of the grouting hole. The aforementioned frustum-shaped sleeve has a hollow internal structure to facilitate subsequent grouting; the frustum-shaped sleeve can be a truncated cone.

[0009] In the aforementioned prestressed grouting pipe, preferably, the expansion sleeve is disposed between the frustum-shaped sleeve and the grouting pipe body. The larger end of the inner cavity of the expansion sleeve is far from the grouting pipe body, and the smaller end of the frustum-shaped sleeve is close to the larger end of the inner cavity of the expansion sleeve. This arrangement ensures that the expansion sleeve is securely positioned between the frustum-shaped sleeve and the grouting pipe body. When the frustum-shaped sleeve is subjected to tension from the tensioning assembly, the smaller end of the frustum-shaped sleeve enters from the larger end of the inner cavity of the expansion sleeve, expanding the expansion sleeve and achieving a high-strength connection between the grouting pipe and the grouting hole.

[0010] In the aforementioned prestressed grouting pipe, preferably, the tensioning assembly includes a tensioning screw and a tensioning nut. One end of the tensioning screw is fixedly connected to the inner end bearing beam, and the other end is threaded and extends to the outer end bearing beam. The tensioning nut is located at the threaded end of the tensioning screw and cooperates with the outer end bearing beam to realize the relative movement of the frustum sleeve and the expansion sleeve.

[0011] In the aforementioned prestressed grouting pipe, preferably, the inner end bearing beam is fixed to the large end of the frustum-shaped sleeve, and the connection point between the tensioning screw and the inner end bearing beam is located at the center of the large end of the frustum-shaped sleeve; the outer end bearing beam is fixed within the grouting pipe body, and the connection point between the tensioning screw and the outer end bearing beam is located at the center of the inner cavity of the grouting pipe body. This installation method, with the tensioning screw positioned at the center of both the grouting pipe body and the frustum-shaped sleeve, minimizes the impact on the subsequent grouting process.

[0012] An inner end bearing beam is installed at the large end of the truncated cone sleeve. This connecting beam is connected to the outer end bearing beam at one flange end of the grouting pipe body through a tensioning screw. The distance between the two bearing beams can be adjusted by adjusting the tensioning nut, so that the hollow truncated cone sleeve penetrates into the middle of the expansion sleeve to generate an expansion effect, thereby pressing tightly against the rock wall of the grouting hole to generate a tight bond and improve the installation strength of the grouting pipe.

[0013] In the aforementioned prestressed grouting pipe, preferably, the expansion sleeve is tubular in shape when not fully expanded. The expansion sleeve includes multiple expansion teeth with serrated outer surfaces, and the inner cavity formed by the multiple expansion teeth is a frustoconical cavity with a volume smaller than that of the frustoconical sleeve. Using multiple expansion teeth is more conducive to the tight bonding between the expansion sleeve and the inner wall of the grouting hole. The direction of the serrations can be set to an orientation that is unfavorable to the ejection of the grouting pipe body. The expansion sleeve can be pre-machined with serrations on its outer surface, and then divided into multiple expansion teeth. These multiple expansion teeth can be combined into a circular tube and pre-fixed by an elastic sealing ring and annular plate.

[0014] In the aforementioned prestressed grouting pipe, preferably, the expansion sleeve is fitted with a first elastic sealing ring at one end near the grouting pipe body, which can expand and fit tightly against the inner wall of the grouting hole as the expansion sleeve expands.

[0015] In the aforementioned prestressed grouting pipe, preferably, the grouting pipe body has an end sealing plate near the expansion sleeve. The expansion sleeve has a second elastic sealing ring near the end sealing plate, which expands to fit tightly against the inner wall of the grouting hole as the expansion sleeve expands, and can be pressed tightly against the end sealing plate. The second elastic sealing ring is partially sleeved on the end of the expansion sleeve. The end sealing plate is annular, and the distance between the inner and outer rings is greater than the wall thickness of the grouting pipe body, facilitating compression and fixation with the second elastic sealing ring.

[0016] The expansion sleeve is equipped with first and second elastic sealing rings at its ends. These rings expand as the expansion sleeve expands, tightly adhering to the rock wall to provide the first layer of sealing. The first and second elastic sealing rings also serve to pre-fix the expansion teeth. The second elastic sealing ring is partially fitted onto the end of the expansion sleeve, facilitating the compression between the second elastic sealing ring and the end sealing plate to achieve a tight connection between the conical sleeve, the expansion sleeve, and the grouting pipe body. The first and second elastic sealing rings can be made of rubber.

[0017] In the aforementioned prestressed grouting pipe, preferably, a grout-stopping steel disc is fixed to the outer wall of the grout input end of the grouting pipe body. The grout-stopping steel disc is located near the grouting hole, and a third elastic sealing ring is provided between the grout-stopping steel disc and the rock wall at the grouting hole. The grout-stopping steel disc, welded onto the grouting pipe body, together with the front-end conical sleeve, expansion sleeve forming an expansion head, two load-bearing beams, and tensioning screw and tensioning nut, constitutes a prestressed fastening structure for the rock wall. A third elastic sealing ring is installed on the grout-stopping steel disc near the rock wall. As the tensioning nut is tightened, a huge pressure is generated between the grout-stopping steel disc and the rock wall, thus pressing the third elastic sealing ring tightly against the rock wall, further preventing the grout from escaping from the grouting pipe joint under high pressure. The aforementioned third elastic sealing ring can be a rubber ring.

[0018] Preferably, in the aforementioned prestressed grouting pipe, the expansion sleeve is further fitted with an annular plate to prevent accidental expansion during installation. To prevent the external force pushing the grouting pipe body during installation from causing the frustum-shaped sleeve to penetrate deeply into the expansion sleeve, thus preventing accidental expansion and installation difficulties, an annular plate is provided on the expansion sleeve. This annular plate can be a disposable product, such as a ring-shaped plastic sheet.

[0019] As a general technical concept, the present invention also provides a grouting process using the above-mentioned prestressed grouting pipe, comprising the following steps:

[0020] S1: The tensioning assembly is used to pre-assemble the grouting pipe body, expansion sleeve and frustum sleeve into a whole, so that the expansion sleeve is kept in a non-expanded state, and the pre-assembled whole is installed into the grouting hole.

[0021] S2: Tension the tensioning assembly to move the frustum sleeve and the expansion sleeve relative to each other. The frustum sleeve enters the expansion sleeve, causing the expansion sleeve to expand and tighten against the inner wall of the grouting hole, thus completing the installation of the prestressed grouting pipe.

[0022] S3: Grout is introduced through the grout input end of the grouting pipe body, thus completing the grouting process.

[0023] The present invention relates to a prestressed grouting pipe adapted to the requirements of high-pressure grouting and water plugging process. The diameter of the grouting pipe body can be between 50 mm and 150 mm, depending on the diameter of the grouting hole, and the length is selected according to the condition of the rock in the grouting hole, generally between 70 mm and 2000 mm.

[0024] To meet the requirements of the new high-pressure, high-flow grouting process, the grouting pipe must be able to withstand extremely high instantaneous back pressure during grouting, which can reach over 10 MPa. This invention addresses the need for sealing against high-temperature, ultra-high-temperature, and high-pressure water inrush in tunnels by designing an expansion-type, double-sealed, high-pressure-resistant prestressed grouting pipe. Its basic structural design and functional analysis are as follows:

[0025] 1) An expansion joint consisting of an expansion sleeve and a frustum-shaped sleeve with expansion sealing function: This expansion joint consists of a frustum-shaped sleeve, an expansion sleeve, and an elastic sealing ring. Under the action of external tension, the frustum-shaped sleeve penetrates into the middle of the expansion sleeve, causing the expansion sleeve to expand and generate enormous pressure on the rock wall. As the expansion sleeve expands, the first elastic sealing ring installed on it expands accordingly, blocking the grout. The second elastic sealing ring installed on it, in addition to having the same function as the first elastic sealing ring, also forms a squeezing effect with the end sealing plate welded to the end of the grouting pipe body. After deformation, the enlarged diameter of the second elastic sealing ring fits tightly against the rock wall, further enhancing the sealing effect of stopping the grout.

[0026] 2) Prestressed tensioning assembly and double sealing at the ends: The tensioning beams (inner and outer load-bearing beams) installed at the large end of the truncated cone sleeve and the grout inlet end of the grouting pipe body constitute the prestressed tensioning structure of the grouting pipe through the tensioning screw and tensioning nut in the middle and the grout-stopping steel disc welded on the grouting pipe body. By rotating the tensioning nut on the outer load-bearing beam, the truncated cone sleeve is subjected to tension force, penetrating into the expansion sleeve, which expands and forms a bonding force with the rock wall; after the expansion sleeve tightens, the tensioning nut continues to rotate, causing the grout-stopping disc welded on the grouting pipe body to press against the rock wall and the third elastic sealing ring, forming prestress on the grouting pipe, further achieving the effect of double sealing.

[0027] 3) Initial State Holding Device: To prevent the truncated cone sleeve from penetrating deep into the expansion sleeve under external force during the installation of the grouting pipe body, causing installation difficulties, this invention provides first and second elastic sealing rings and an annular plastic sheet on the expansion sleeve. This structure can effectively prevent the expansion sleeve from accidentally expanding open during the installation of the grouting pipe.

[0028] Through the above structural design, the prestressed grouting pipe of this invention, adapted to the requirements of high-pressure grouting and water plugging processes, is suitable for use in high-temperature, ultra-high-temperature, high-pressure, and water-rushing environments during tunnel construction. This grouting pipe features a simple structure, ease of use, easy installation in high-pressure water-rushing environments, high installation strength, and good pipe joint sealing performance. It solves the problem of grouting failure caused by mismatch between the grouting pipe installation and joint sealing and the grouting pressure during high-temperature and ultra-high-temperature water-rushing treatment in tunnels, resulting in instantaneous pressure exceeding the installation and sealing strength. Furthermore, the design of the expansion sleeve and its auxiliary structure ensures that the grouting pipe will not expand unexpectedly during initial installation, making installation even more convenient.

[0029] Compared with the prior art, the advantages of the present invention are as follows:

[0030] 1. The prestressed grouting pipe of the present invention, adapted to the requirements of high-pressure grouting and water plugging process, is provided with an expansion sleeve, a frustum sleeve, an inner end force beam and an outer end force beam. Under the action of the tensioning component, the frustum sleeve and the expansion sleeve move relative to each other, causing the expansion sleeve to expand and tighten against the inner wall of the grouting hole. It has the characteristics of easy installation in high-pressure water inrush environment and high installation strength. It solves the problem of grouting failure caused by excessive instantaneous pressure during grouting due to the mismatch between the installation of the grouting pipe and the grouting pressure in the treatment of high-pressure water inrush in tunnels.

[0031] 2. The grouting process of the prestressed grouting pipe of the present invention, which is adapted to the high-pressure grouting and water plugging process, is simple and convenient to construct. It can adapt to the high-pressure and high-flow top water grouting situation of high temperature and ultra-high temperature flowing water. It has strong adaptability to special construction environments and can be widely used in tunnel construction in harsh environments. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the prestressed grouting pipe structure adapted to the high-pressure grouting and water plugging process in the embodiment.

[0034] Figure 2 for Figure 1 A magnified view of part A in the image.

[0035] Figure 3 This is a schematic diagram of the cone-shaped sleeve and tensioning screw in the prestressed grouting pipe, which is adapted to the high-pressure grouting and water plugging process in the embodiment.

[0036] Figure 4 for Figure 3 Side view.

[0037] Legend:

[0038] 1. Grouting pipe body; 2. Expansion sleeve; 3. Frustum sleeve; 4. Inner end load-bearing beam; 5. Outer end load-bearing beam; 6. Tensioning bolt; 7. Tensioning nut; 8. First elastic sealing ring; 9. End sealing plate; 10. Second elastic sealing ring; 11. Grout-stopping steel disc; 12. Third elastic sealing ring; 13. Annular plate; 14. Grouting hole; 15. Flange; 16. Rock wall. Detailed Implementation

[0039] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0040] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0041] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0042] Example:

[0043] like Figures 1-4 As shown, the prestressed grouting pipe adapted to the high-pressure grouting and water plugging process of this embodiment includes a grouting pipe body 1. An expansion sleeve 2, a frustum sleeve 3, and an inner end bearing beam 4 are provided at the grout output end of the grouting pipe body 1, and an outer end bearing beam 5 is provided at the grout input end of the grouting pipe body 1. The inner cavity of the expansion sleeve 2 is frustum-shaped for the frustum sleeve 3 to enter. A tensioning assembly is also provided between the inner end bearing beam 4 and the outer end bearing beam 5 to allow the frustum sleeve 3 and the expansion sleeve 2 to move relative to each other, causing the expansion sleeve 2 to expand and tighten against the inner wall of the grouting hole 14. The expansion sleeve 2 is located between the frustum sleeve 3 and the grouting pipe body 1. The larger end of the inner cavity of the expansion sleeve 2 is away from the grouting pipe body 1, and the smaller end of the frustum sleeve 3 is close to the larger end of the inner cavity of the expansion sleeve 2.

[0044] In this embodiment, the tensioning assembly includes a tensioning screw 6 and a tensioning nut 7. One end of the tensioning screw 6 is fixedly connected to the inner end bearing beam 4, and the other end is threaded and extends to the outer end bearing beam 5. The tensioning nut 7 is located at the threaded end of the tensioning screw 6 and cooperates with the outer end bearing beam 5 to realize the relative movement of the frustum sleeve 3 and the expansion sleeve 2.

[0045] like Figure 3 , Figure 4As shown, in this embodiment, the inner end bearing beam 4 is fixed to the large end of the frustum sleeve 3, and the connection between the tensioning screw 6 and the inner end bearing beam 4 is located at the center of the large end of the frustum sleeve 3; the outer end bearing beam 5 is fixed inside the grouting pipe body 1, and the connection between the tensioning screw 6 and the outer end bearing beam 5 is located at the center of the inner cavity of the grouting pipe body 1.

[0046] In this embodiment, the expansion sleeve 2 is tubular in shape when it is not expanded. The expansion sleeve 2 includes multiple expansion teeth with serrated outer surfaces. The inner cavity formed by the multiple expansion teeth is a frustum-shaped inner cavity with a volume smaller than that of the frustum sleeve 3.

[0047] In this embodiment, the expansion sleeve 2 is fitted with a first elastic sealing ring 8 at one end near the grouting pipe body 1, which can expand and fit tightly against the inner wall of the grouting hole 14 as the expansion sleeve 2 expands.

[0048] In this embodiment, the grouting pipe body 1 is provided with an end sealing plate 9 near the expansion sleeve 2. The expansion sleeve 2 is provided with a second elastic sealing ring 10 near the end sealing plate 9, which can expand and fit tightly against the inner wall of the grouting hole 14 as the expansion sleeve 2 expands, and can be squeezed and tightly contacted with the end sealing plate 9. The second elastic sealing ring 10 is partially sleeved on the end of the expansion sleeve 2.

[0049] In this embodiment, a grout-stopping steel disc 11 is also fixed on the outer wall of the grout input end of the grouting pipe body 1. The grout-stopping steel disc 11 is close to the grouting hole 14, and a third elastic sealing ring 12 is provided between the grout-stopping steel disc 11 and the rock wall at the grouting hole 14.

[0050] In this embodiment, the expansion sleeve 2 is also fitted with an annular piece 13 to ensure that the expansion sleeve 2 does not accidentally expand during installation.

[0051] This embodiment also provides a grouting process using the above-mentioned prestressed grouting pipe, including the following steps:

[0052] S1: Use the tensioning component to pre-assemble the grouting pipe body 1, expansion sleeve 2 and frustum sleeve 3 into a whole, so that the expansion sleeve 2 is kept in a non-expanded state, and install the pre-assembled whole into the grouting hole 14.

[0053] S2: Tensioning the tensioning assembly causes the frustum sleeve 3 and the expansion sleeve 2 to move relative to each other. The frustum sleeve 3 enters the expansion sleeve 2, causing the expansion sleeve 2 to expand. The expansion sleeve 2 is then tightly attached to the inner wall of the grouting hole 14, completing the installation of the prestressed grouting pipe.

[0054] S3: Grout is introduced through the grout input end of the grouting pipe body 1, thus completing the grouting process.

[0055] To better understand the prestressed grouting pipe that meets the requirements of high-pressure grouting and water plugging technology, this embodiment uses the grouting hole 14 with a diameter of 89 mm, commonly used for high-temperature and high-pressure water inrush grouting and sealing in tunnels, as an example to illustrate the structure and manufacturing process of the prestressed grouting pipe as follows:

[0056] For the grouting hole 14 with a diameter of 89 mm, this embodiment uses a grouting pipe body 1 with a diameter of 80 mm and a length of 1200 mm, and a flange 15 at the end. A thick-walled seamless steel pipe with a diameter of 80 mm is used to machine a frustum sleeve 3 and an expansion sleeve 2 using a lathe. After the expansion sleeve 2 is machined, it is divided into four equal parts to form a four-lobed expansion sleeve 2. The inner end bearing beam 4 is a steel plate with a thickness of 20 mm and a width of 15 mm, which is welded to the middle of the large end of the frustum sleeve 3. The outer end bearing beam 5 can be made of the same steel plate as the inner end bearing beam 4 and is welded to the flange 15 near the end inside the grouting pipe body 1. The tensioning screw 6 is a single-ended screw with a diameter of 10 mm. One end without threads is welded to the inner end bearing beam 4, and the other end passes through the outer end bearing beam 5 and is tightened with a tensioning nut 7.

[0057] A small number of frustum sleeves 3 and expansion sleeves 2 can be machined using thick-walled seamless steel pipes. For larger quantities, molds can be used to cast them from cast steel, which can reduce costs.

[0058] The first elastic sealing ring 8 and the second elastic sealing ring 10 can be ordinary rubber sealing rings with an outer diameter of 85 mm and a cross-sectional diameter of 20 mm; the grout-stopping steel disc 11 at the rock wall 16 is welded to the outer end of the grouting pipe body 1 200 mm away; the third elastic sealing ring 12 at the grout-stopping steel disc 11 can be an ordinary rubber ring with an inner diameter of 90 mm and a cross-sectional diameter of 30 mm. The annular plate 13 on the expansion sleeve 2 can be a one-time use annular plastic sheet.

[0059] After the tensioning components are pre-installed, use a socket torque wrench to turn the tensioning nut 7 to perform tensioning, and the tensioning torque should reach 30 MPa.

[0060] The above is a specific embodiment of a practical application. The size and material of the prestressed grouting pipe can also be adjusted according to different grouting environments.

Claims

1. A prestressed grouting pipe adapted to the requirements of high-pressure grouting and water plugging process, comprising a grouting pipe body (1), characterized in that, The grouting pipe body (1) has an expansion sleeve (2), a frustum sleeve (3), and an inner end bearing beam (4) at the grout output end, and an outer end bearing beam (5) at the grout input end. The inner cavity of the expansion sleeve (2) is frustum-shaped for the frustum sleeve (3) to enter. Between the inner end bearing beam (4) and the outer end bearing beam (5) is a structure for relative movement between the frustum sleeve (3) and the expansion sleeve (2), causing the expansion sleeve (2) to expand and... A tensioning assembly is tightly attached to the inner wall of the grouting hole (14); the tensioning assembly includes a tensioning screw (6) and a tensioning nut (7). One end of the tensioning screw (6) is fixed to the inner end force beam (4), and the other end is threaded and extends to the outer end force beam (5). The tensioning nut (7) is located at the threaded end of the tensioning screw (6) and cooperates with the outer end force beam (5) to realize the relative movement of the frustum sleeve (3) and the expansion sleeve (2). The expansion sleeve (2) is located between the frustum sleeve (3) and the grouting pipe body (1). The large end of the inner cavity of the expansion sleeve (2) is far away from the grouting pipe body (1), and the small end of the frustum sleeve (3) is close to the large end of the inner cavity of the expansion sleeve (2). When the expansion sleeve (2) is not expanded, it is tubular in shape. The expansion sleeve (2) includes multiple expansion teeth with serrated outer surfaces. The inner cavity formed by the multiple expansion teeth is a frustum-shaped inner cavity with a volume smaller than that of the frustum sleeve (3).

2. The prestressed grouting pipe according to claim 1, characterized in that, The inner end bearing beam (4) is fixed to the large end of the frustum sleeve (3), and the connection between the tensioning screw (6) and the inner end bearing beam (4) is located at the center of the large end of the frustum sleeve (3); the outer end bearing beam (5) is fixed inside the grouting pipe body (1), and the connection between the tensioning screw (6) and the outer end bearing beam (5) is located at the center of the inner cavity of the grouting pipe body (1).

3. The prestressed grouting pipe according to any one of claims 1-2, characterized in that, The expansion sleeve (2) has a first elastic sealing ring (8) fitted on one end near the grouting pipe body (1), which can expand and fit tightly against the inner wall of the grouting hole (14) as the expansion sleeve (2) expands.

4. The prestressed grouting pipe according to any one of claims 1-2, characterized in that, The grouting pipe body (1) is provided with an end sealing plate (9) at one end near the expansion sleeve (2). The expansion sleeve (2) is provided with a second elastic sealing ring (10) near the end sealing plate (9), which can expand and fit tightly against the inner wall of the grouting hole (14) as the expansion sleeve (2) expands, and can be squeezed and tightly contacted with the end sealing plate (9). The second elastic sealing ring (10) is partially sleeved on the end of the expansion sleeve (2).

5. The prestressed grouting pipe according to any one of claims 1-2, characterized in that, The grout input end of the grouting pipe body (1) is also fixed with a grout-stopping steel disc (11), which is close to the grouting hole (14), and a third elastic sealing ring (12) is provided between the grout-stopping steel disc (11) and the rock wall at the grouting hole (14).

6. The prestressed grouting pipe according to any one of claims 1-2, characterized in that, The expansion sleeve (2) is also fitted with an annular piece (13) to ensure that the expansion sleeve (2) does not expand accidentally during installation.

7. A grouting process using the prestressed grouting pipe according to any one of claims 1-6, characterized in that, Includes the following steps: S1: The tensioning assembly is used to pre-assemble the grouting pipe body (1), expansion sleeve (2) and frustum sleeve (3) into a whole, so that the expansion sleeve (2) is kept in a non-expanded state, and the pre-assembled whole is installed into the grouting hole (14). S2: Tension the tensioning assembly to cause the relative movement of the frustum sleeve (3) and the expansion sleeve (2). The frustum sleeve (3) enters the expansion sleeve (2) to expand the expansion sleeve (2). The expansion sleeve (2) is tightly attached to the inner wall of the grouting hole (14) to complete the installation of the prestressed grouting pipe. S3: Grout is injected through the grout input end of the grout pipe body (1) to complete the grouting.

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