Parallel master-slave double-hole tunnel portal construction method for unstable landslide body

Abstract

The present application belongs to the technical field of tunnel portal construction, and specifically discloses a parallel master-slave double-hole tunnel portal construction method for unstable landslide body, which comprises the following steps: firstly, tunnel portal side and high slope excavation and protection engineering are performed to quickly excavate the shape of the portal; pilot hole and main hole advanced long pipe shed construction and portal reinforcement measures are performed to complete all construction preparation work before entering the portal; portal construction is performed, pilot hole excavation construction is performed first, and three-step seven-step excavation method is adopted for main hole portal construction; after the excavation and support of the two holes pass through the position of the communication passage, the communication passage is excavated from the main hole to the service pilot hole to connect the two holes. The present application realizes safe portal construction of parallel master-slave double-hole tunnel for large unstable landslide body by reasonably organizing the construction scheme and measures of master-slave double-hole tunnel portal, and ensures the stability of tunnel portal side and high slope and the safety of tunnel portal construction.

Description

Technical Field

[0001] This invention belongs to the field of tunnel portal construction technology, and specifically relates to a method for constructing parallel master-slave dual-tunnel portals in unstable landslide bodies. Background Technology

[0002] During tunnel portal construction, the portal section is relatively shallow, and construction typically involves shoveling the slope toe to create a side-sloping section. When the tunnel portal is situated within an unstable landslide body, shoveling during the construction of a shallow-buried, biased tunnel crossing the slope reduces the resistance at the slope toe, decreasing slope stability. Furthermore, the disturbance caused by tunnel entry construction further exacerbates slope deformation, increasing construction risks at the tunnel portal. Simultaneously, the deformation and creep of the slope react on the tunnel lining, altering the stress characteristics of the tunnel support structure within the shallow-buried landslide body, leading to cracks and affecting tunnel safety. Therefore, the construction method for tunnel portals crossing large, unstable, shallow-buried, biased landslide bodies is crucial for safe tunnel entry and slope stability.

[0003] like Figure 1 and Figure 2 As shown, during the construction of the Kyrgyzstan North-South Mountain Crossing Tunnel, a pilot tunnel was set up longitudinally parallel to the right side of the main tunnel as a ventilation and material transportation channel. Because the main tunnel entrance section of the Kyrgyzstan North-South Mountain Crossing Tunnel is composed of shallowly buried, strongly weathered surrounding rock with poor overall rock integrity and a steep slope at the tunnel top, construction disturbances during the side-passing slope construction of the shallowly buried, biased tunnel place high demands on the tunnel entrance construction technology. Improper construction techniques can easily lead to collapse of loose material at the main tunnel and pilot tunnel faces, making tunnel access difficult. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of existing technologies that easily cause the collapse of loose bodies at the working faces of the main tunnel and the pilot tunnel, and to provide a method for constructing parallel main and secondary tunnel portals in unstable landslide bodies.

[0005] This invention provides a method for constructing parallel master-slave dual-tunnel entrances in an unstable landslide, comprising the following steps:

[0006] Step 1: Construction of slope protection before excavation;

[0007] Step 2: The main tunnel and pilot tunnel are constructed alternately;

[0008] Step 3: Excavate a connecting passage from the main tunnel to the guide tunnel;

[0009] Step 2 includes:

[0010] Step 2.1: Long pipe roof construction is carried out in sequence for the pilot tunnel and the main tunnel: arches are constructed in sequence at the entrance of the pilot tunnel and the entrance of the main tunnel. The arch feet of the arches are placed on the rock strata. The casing is pre-embedded and the arch formwork is erected and the concrete is poured. Long pipe roof holes for the pilot tunnel and the main tunnel are constructed in the casing of the arches, and long pipe roof grouting pipes are installed.

[0011] Step 2.2: Excavation and support of the full-section section of the pilot tunnel: The full-section method is used for construction, and a full-section I-beam steel frame is constructed for support. The steel frame is fabricated in units outside the tunnel and installed inside the tunnel.

[0012] Step 2.3: Three-stage, seven-step excavation and support of the main tunnel: The main tunnel entrance section is constructed using a three-stage, seven-step method, with the upper, middle, and lower stages operating simultaneously in parallel. The excavation and support process is as follows: circumferential excavation of the upper arc-shaped pilot tunnel, followed by initial arch support; staggered excavation of the middle and lower stages, spraying of concrete layers and installation of anchor bolts; excavation of the central reserved core soil, tunnel bottom excavation, and initial tunnel bottom support.

[0013] Step 2.4: Main tunnel and pilot tunnel construction: The pilot tunnel is constructed in advance to conduct geological and groundwater exploration for the main tunnel, ensuring the subsequent construction of the main tunnel;

[0014] Step 2.5: Construction of the main tunnel invert arch;

[0015] Step 2.6: Main tunnel secondary lining construction; The main tunnel secondary lining construction closely follows the excavation work face. The main tunnel lining adopts a lining steel formwork lining trolley. By adjusting the hydraulic components, the formwork is correctly aligned; Concrete is poured through the pouring window, from bottom to top, from the joint of the already poured section to the unpoured direction, horizontally layered and symmetrically poured, tamping while pouring, the layer thickness does not exceed 40cm, the pouring time between two adjacent layers does not exceed 1.5 hours, and the vertical free fall height is controlled not to exceed 2m.

[0016] A further proposed solution is that step 1 includes the following steps:

[0017] Step 1.1 Before excavating the tunnel entrance, construct a water interception ditch on the tunnel top to divert surface water and slope water away from the tunnel entrance, and improve the access road, material workshop, and steel frame processing shed near the tunnel entrance.

[0018] Step 1.2: Excavation and protection of the tunnel entrance side slopes. The open tunnel is excavated by a combination of manual labor and excavators. The open tunnel is excavated mechanically in the order of first the middle and then the two sides, from top to bottom. First, the central trench is excavated until the boundary between the open and dark sections of the tunnel. Then, the side slopes are excavated layer by layer from top to bottom. After the excavation is completed, anchor spraying and wire mesh are used for protection.

[0019] A further embodiment is that step 3 includes:

[0020] After the main tunnel and pilot tunnel are constructed to the location of the connecting passage, the main tunnel will excavate the connecting passage to connect the two tunnels.

[0021] A further proposed solution is that after the main tunnel and the pilot tunnel are connected, the tunnel face is excavated and supported, leaving space at the rear of the pilot tunnel to provide space for the secondary lining construction of the pilot tunnel.

[0022] The later stages of the pilot tunnel construction, including the invert arch and secondary lining concrete work, will commence after the materials and transportation channels in the pilot tunnel have been cleared. The lining of the pilot tunnel will be constructed using a lining trolley. Once the secondary lining concrete of the pilot tunnel reaches the required strength, traffic will be restored.

[0023] A further proposed solution is that, in step 2.3, support is installed after each excavation step, and an invert arch is installed after the initial support at the tunnel bottom to close the tunnel into a ring.

[0024] A further proposed solution is that, in step 2.1, before constructing the long pipe shed, concrete grout-stopping walls are built on both sides of the tunnel opening.

[0025] A further proposed solution is that both the guide tunnel long pipe roof holes and the main tunnel long pipe roof holes are double-row holes.

[0026] A further embodiment is that the long pipe roof grouting conduit includes a grouting section and a grout stopping section, which are integrally formed; a plurality of grouting holes are opened on the grouting section, and a reinforcing steel ring is provided at the end of the long pipe roof grouting conduit away from the opening to prevent cement grout leakage.

[0027] The long pipe grouting conduit and the grouting equipment are connected by a connecting pipe. An impact hammer is fixedly installed in the middle of the connecting pipe. An axial connector is provided on the side of the connecting pipe away from the long pipe grouting conduit so that the connecting pipe is axially connected to the grouting equipment.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention achieves safe parallel construction of main and secondary tunnels in large unstable landslide bodies by rationally organizing the construction scheme and measures of the main and secondary tunnel entrances, ensuring the stability of the tunnel entrance side and slope and the safety of tunnel entrance construction. Attached Figure Description

[0029] The following figures are for illustrative purposes only and are not intended to limit the scope of the invention, wherein:

[0030] Figure 1 Design drawing of the entrance to the Kyrgyz North-South Crossing Tunnel;

[0031] Figure 2 Photos of the entrance to the Kyrgyz North-South Crossing Tunnel;

[0032] Figure 3 Schematic diagram of the installation of the large pipe shed in the pilot tunnel;

[0033] Figure 4 Schematic diagram of the main tunnel pipe shed installation;

[0034] Figure 5 Schematic diagram of grouting conduit structure;

[0035] Figure 6 : Process flow diagram of the construction method of this invention;

[0036] Figure 7 Flowchart of the three-stage, seven-step construction process for the main tunnel;

[0037] In the diagram: 1. Pilot tunnel lining; 2. Pilot tunnel initial support; 3. Concrete grout stop wall; 4. Pilot tunnel long pipe roof hole; 5. Main tunnel lining; 6. Anchor bolt; 7. Shotcrete layer; 8. Main tunnel long pipe roof hole; 9. Long pipe roof grouting guide pipe; 10. Grouting hole; 11. Reinforcing steel ring; 12. Connecting pipe; 13. Impact hammer; 14. Axial connector. Detailed Implementation

[0038] To make the objectives, technical solutions, design methods, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0039] like Figure 6 and Figure 7 As shown, this invention provides a method for constructing parallel main and secondary tunnel portals in an unstable landslide, wherein the main tunnel has an excavation width of 12.6m and the pilot tunnel has an excavation width of 5.2m; according to the actual site conditions, after construction preparation is completed, the following steps are performed:

[0040] Step 1: Ancillary facilities;

[0041] Step 2: Excavation and protection works for the tunnel entrance and slope.

[0042] Step 3: Construction of the long pipe shed in the pilot tunnel;

[0043] Step 4: Construction of the main tunnel long pipe shed;

[0044] Step 5: Excavation and support of the entire cross-section of the pilot tunnel;

[0045] Step 6: Excavation and support of the main tunnel using the three-stage, seven-step method.

[0046] Step 7: The main tunnel and pilot tunnel are constructed simultaneously;

[0047] Step 8: Construction of the main tunnel invert arch;

[0048] Step 9: Construction of the secondary lining of the main tunnel;

[0049] Step 11: Excavate a connecting passage from the main tunnel to the guide tunnel to connect the two tunnels;

[0050] Step 12: Construction of the invert arch and secondary lining concrete in the later stage of the pilot tunnel;

[0051] Step 13: After the secondary lining concrete of the pilot tunnel reaches the required strength, traffic will be restored;

[0052] Construction preparation includes site preparation (leveling, access, and utilities), machinery entry, and material entry. Construction of ancillary facilities includes: constructing a drainage ditch on the tunnel top before excavation to divert surface water and slope water away from the tunnel entrance, and improving ancillary facilities such as access roads, material workshops, and steel frame processing sheds near the tunnel.

[0053] In the specific implementation process, the excavation and protection of the tunnel entrance and slope includes the excavation and protection of the tunnel entrance and slope. The project adopts manual labor and excavators to carry out open tunnel excavation. The open tunnel excavation follows the order of "first the middle, then the two sides, from top to bottom" and uses mechanical excavation. First, the central trench is excavated until the boundary between the open and dark tunnels. Then, the slopes are excavated layer by layer from top to bottom, and slope protection is carried out in a timely manner.

[0054] To ensure the stability of the tunnel entrance slope, the slope protection was carried out in layers from top to bottom, with each layer being 2-3 meters high. Temporary mesh reinforcement and shotcrete support were applied to the slope as excavation progressed to increase the stability of the slope toe. The tunnel entrance slope protection used 7m and 2m R38N self-drilling anchor bolts, 12BP steel mesh, and B25 shotcrete.

[0055] Before constructing the long pipe shed of the pilot tunnel and the long pipe shed of the main tunnel, concrete grout-stopping walls 3 are built on both sides of the pilot tunnel entrance, and then the pilot tunnel arch is constructed, such as... Figure 3 and Figure 4 As shown, the tunnel entrance is designed with double-row large pipe sheds. The pilot tunnel arch is 90cm thick and 1.5m long. After the pilot tunnel large pipe shed is completed, the main tunnel arch is constructed. The arch is 1.2cm thick and 1.5m long, with the arch foot foundation placed on the rock strata. The steel frames inside the arch are I20 and I30 I-beams. Sleeves are pre-embedded on the steel frames, and the arch is then erected and concrete is poured. The pilot tunnel long pipe shed hole 4 and the main tunnel long pipe shed hole 8 are constructed inside the sleeves of the arch, and the long pipe shed grouting pipe 9 is installed. The fixed hole pipe (φ159, 1.7m long) is welded in the specified orientation. The long pipe sheds all use seamless long pipe grouting guide pipes 9 with a diameter of φ114 and a wall thickness of 7mm. The circumferential spacing is 40cm, and the length is 30m. They are installed in sections, each 4-6m long, connected by "V"-shaped butt welding or threaded connections. The external insertion angle is 3°, and the pipe sheds are arranged in an arched manner. There should be a horizontal overlap length of not less than 3.0m between two sets of pipe sheds in the longitudinal direction. Figure 5As shown, 10 grouting holes 10, each φ10mm, are drilled in a quincunx pattern at 15cm intervals on the long pipe roof grouting conduit 9. The tail section of the conduit is left un-drilled for 2.5m as a grout-stopping section. A reinforcing steel ring 11 is installed at the end of the long pipe roof grouting conduit 9 furthest from the opening to prevent cement grout leakage. The long pipe roof grouting conduit 9 is connected to the grouting equipment via a connecting pipe 12. An impact hammer 13 is fixedly installed in the middle of the connecting pipe 12. An axial connector 14 is installed on the side of the connecting pipe 12 furthest from the long pipe roof grouting conduit 9 to ensure axial connection between the connecting pipe (12) and the grouting equipment. The initial grouting pressure of the cement-water glass double-liquid grout is 0.7-1.0 MPa. After grouting, M10 cement mortar is used for filling, achieving the purpose of pre-support before excavation. The main construction equipment used is a pipe roof drilling rig and a double-slurry grouting pump, etc., allowing for the one-time completion of the 30m long pipe roof construction.

[0056] During the excavation and support of the full-section section of the pilot tunnel, the pilot tunnel was constructed using the full-section method, with holes drilled using pneumatic drills. A full-section I-beam support structure was constructed. The initial support consisted of a #20 I-beam and system anchor bolts + B25 shotcrete. The pilot tunnel used a full-section I-beam support structure, with the I-beams fabricated in units outside the tunnel and installed inside. The initial support included anchor-shotcrete mesh support, with mortar anchor bolts and wet shotcrete applied using a wet shotcrete machine. Muck removal was achieved using trackless transportation. At the tunnel entrance, loaders were used for initial muck removal; later, muck loaders were used for loading, and dump trucks transported the muck outside the tunnel to the spoil disposal site. Forced ventilation was used to ensure fresh air inside the tunnel and improve the working environment.

[0057] After constructing the pilot tunnel for 30m, construction of the main tunnel begins. The main tunnel entrance section is constructed using a three-stage, seven-step method. The excavation and support procedures are as follows: 1. Circumferential excavation of the upper arc-shaped pilot tunnel, providing initial arch support; 2. Staggered excavation of the middle and lower steps, spraying 7 layers of concrete and installing 6 anchor bolts, providing initial wall support; 3. Excavation of the central core soil and tunnel floor excavation, providing initial tunnel floor support. Support should be provided promptly after each excavation step. After the initial tunnel floor support, the invert arch should be constructed promptly to close the tunnel into a ring as soon as possible. The flow chart of the three-stage, seven-step construction process for the main tunnel is shown below. Figure 7 As shown. It is important to note that the three-stage, seven-step method at the main tunnel entrance employs a combination of manual and mechanical excavation, with each excavation cycle advancing 1 meter. The upper, middle, and lower stages are operated simultaneously in parallel. Inside the main tunnel, the three-stage, seven-step method utilizes pre-drilled grouting at the tunnel face for reinforcement. Initial support consists of #30 I-beam supports and a system of anchor bolts + B25 shotcrete. Muck removal utilizes trackless transportation; excavators and loaders load the muck, and dump trucks transport it outside the tunnel to the spoil disposal site. Ventilation employs a forced-draft ventilation system to ensure fresh air within the tunnel and improve the working environment.

[0058] After the main tunnel portal support is completed, construction of the main tunnel and the pilot tunnel proceeds simultaneously. The pilot tunnel is primarily constructed rapidly, serving as a preliminary site for geological and groundwater surveys to assess conditions for the main tunnel, providing relevant data and creating favorable construction conditions for subsequent main tunnel work. Therefore, to expedite the construction process, pilot tunnel construction continues uninterrupted after the main tunnel construction begins, following the aforementioned pilot tunnel construction methods. Muck removal and material transportation are carried out within the pilot tunnel itself.

[0059] Optionally, to resolve the conflict between the construction of the invert arch and vehicle traffic during the main tunnel construction, a 20m self-made trestle bridge can be used as a passage for vehicles in the invert arch construction section, providing space for the invert arch construction.

[0060] During the construction of the secondary lining of the main tunnel, the secondary lining construction closely followed the excavation work face. For the main tunnel lining, a custom-made 12-meter steel formwork lining trolley was used. Hydraulic components were adjusted to ensure correct formwork alignment. Concrete was poured through the pouring window, from bottom to top, from the joint of the already poured section towards the unpoured section, in horizontal, symmetrical layers, tamping as it poured. Each layer thickness did not exceed 40cm, and the pouring time between adjacent layers did not exceed 1.5 hours, ensuring good bonding between the upper and lower concrete layers before initial setting to prevent cold joints. The vertical free fall height was controlled to not exceed 2m. Compaction was performed using attached vibrators and immersion vibrators, with dedicated personnel responsible for ensuring the concrete lining was solid inside and smooth outside.

[0061] To reduce air bubbles on the surface of the secondary lining concrete, drainage holes are installed in layers of end caps to drain grout. During concrete vibration, grout is produced and easily adheres to the formwork, forming air bubbles on the concrete surface. Sealable holes (φ10-14 screw holes are sufficient) are installed every 20-30cm vertically on the end caps. During pouring, the holes are opened sequentially according to the concrete layers to drain the water, and then sealed promptly after drainage.

[0062] A connecting passage will be excavated between the main tunnel and the pilot tunnel to link the two tunnels. Specifically, after the excavation and support of both tunnels have passed the location of the connecting passage, the connecting passage will be excavated from the main tunnel to the pilot tunnel, ensuring a safe distance. The connected passage must meet the normal passage requirements for muck removal vehicles in the pilot tunnel. After the connection, all vehicles and materials for excavation and support at the pilot tunnel face will travel from the connecting passage to the main tunnel route, freeing up space at the rear of the pilot tunnel to provide space for the secondary lining construction. After the materials and transportation channels in the pilot tunnel are cleared, the later stages of the pilot tunnel will involve the construction of the invert arch and secondary lining concrete. The lining of the pilot tunnel will be carried out using a 12m long lining trolley. Once the secondary lining concrete of the pilot tunnel reaches the required strength, traffic will be restored.

[0063] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for constructing parallel master-slave dual-tunnel entrances in an unstable landslide, characterized in that, Includes the following steps: Step 1: Construction of slope protection before excavation; Step 2: The main tunnel and pilot tunnel are constructed alternately; Step 3: Excavate a connecting passage from the main tunnel to the guide tunnel; Step 2 includes: Step 2.1: Long pipe roof construction is carried out in sequence for the pilot tunnel and the main tunnel: arches are constructed in sequence at the entrance of the pilot tunnel and the entrance of the main tunnel. The arch feet of the arches are placed on the rock strata. The casing is pre-embedded and the arch formwork is erected and the concrete is poured. The long pipe roof holes (4) of the pilot tunnel and the long pipe roof holes (8) of the main tunnel are constructed in the casing of the arches, and the long pipe roof grouting pipes (9) are installed. Step 2.2: Excavation and support of the full-section section of the pilot tunnel: The full-section method is used for construction, and a full-section I-beam steel frame support is constructed (2). The steel frame is fabricated in units outside the tunnel and installed inside the tunnel. Step 2.3: Three-stage seven-step excavation and support of the main tunnel: The main tunnel entrance section is constructed using the three-stage seven-step method, with the upper, middle and lower stages operating in parallel at the same time. The excavation and support process is as follows: the upper arc-shaped pilot tunnel is excavated circumferentially, and the initial support of the arch is constructed; the middle and lower stages are excavated in a staggered manner, and a layer of shotcrete (7) is sprayed and anchor bolts (6) are installed; the core soil reserved in the center is excavated, the tunnel bottom is excavated, and the initial support of the tunnel bottom is constructed. Step 2.4: Main tunnel and pilot tunnel construction: The pilot tunnel is constructed in advance to conduct geological and groundwater exploration for the main tunnel, ensuring the subsequent construction of the main tunnel; Step 2.5: Construction of the main tunnel invert arch; Step 2.6: Main tunnel secondary lining construction; The main tunnel secondary lining construction closely follows the excavation work face. The main tunnel lining (5) adopts the lining steel formwork lining trolley. By adjusting the hydraulic components, the formwork is correctly aligned; Concrete is poured through the pouring window, from bottom to top, from the joint of the poured section to the unpoured direction, horizontally layered and symmetrically poured, while pouring and tamping, the layer thickness does not exceed 40cm, the pouring time between two adjacent layers does not exceed 1.5 hours, and the vertical free fall height is controlled not to exceed 2m.

2. The method for constructing parallel master-slave dual-tunnel entrances to an unstable landslide body according to claim 1, characterized in that, Step 1 includes the following steps: Step 1.1 Before excavating the tunnel entrance, construct a water interception ditch on the tunnel top to divert surface water and slope water away from the tunnel entrance, and improve the access road, material workshop, and steel frame processing shed near the tunnel entrance. Step 1.2: Excavation and protection of the tunnel entrance side slopes. The open tunnel is excavated by a combination of manual labor and excavators. The open tunnel is excavated mechanically in the order of first the middle and then the two sides, from top to bottom. First, the central trench is excavated until the boundary between the open and dark sections of the tunnel. Then, the side slopes are excavated layer by layer from top to bottom. After the excavation is completed, anchor spraying and wire mesh are used for protection.

3. The method for constructing parallel master-slave dual-tunnel entrances to an unstable landslide body according to claim 1, characterized in that, Step 3 includes: After the main tunnel and pilot tunnel are constructed to the location of the connecting passage, the main tunnel will excavate the connecting passage to connect the two tunnels.

4. The method for constructing parallel master-slave dual-tunnel entrances to an unstable landslide body according to claim 3, characterized in that, After the main tunnel and the pilot tunnel are connected, the excavation and support of the pilot tunnel face will open up the space behind the pilot tunnel, providing space for the secondary lining construction of the pilot tunnel; The construction of the invert arch and secondary lining concrete in the later stage of the pilot tunnel is carried out after the materials and transportation channels in the pilot tunnel are cleared. The lining of the pilot tunnel (1) is carried out by lining trolley. After the secondary lining concrete of the pilot tunnel reaches the strength requirements, the passage is restored.

5. The method for constructing parallel master-slave dual-tunnel entrances to an unstable landslide body according to claim 1, characterized in that, In step 2.3, support is installed after each excavation step, and an invert arch is installed after the initial support at the tunnel bottom to close the loop.

6. The method for constructing parallel master-slave dual-tunnel entrances to an unstable landslide body according to claim 1, characterized in that, In step 2.1, before the construction of the long pipe shed, concrete grout-stopping walls are built on both sides of the opening of the guide tunnel (3).

7. The method for constructing parallel master-slave dual-tunnel entrances to an unstable landslide body according to claim 1, characterized in that, Both the pilot tunnel long pipe roof hole (4) and the main tunnel long pipe roof hole (8) are double-row holes.

8. A method for constructing parallel master-slave dual-tunnel entrances to an unstable landslide body according to any one of claims 1-7, characterized in that, The long pipe grouting conduit (9) includes a grouting section and a grout stopping section, which are integrally formed; a number of grouting holes (10) are provided on the grouting section, and a reinforcing steel ring (11) is provided at the end of the long pipe grouting conduit (9) away from the opening to prevent cement grout leakage. The long pipe grouting conduit (9) is connected to the grouting equipment via a connecting pipe (12). An impact hammer (13) is fixedly installed in the middle of the connecting pipe (12). An axial connector (14) is provided on the side of the connecting pipe (12) away from the long pipe grouting conduit (9) so that the connecting pipe (12) is axially connected to the grouting equipment.

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