Cooperative supporting structure suitable for soft rock large-deformation tunnel and roadway

Abstract

The invention discloses a collaborative supporting structure suitable for a soft rock large-deformation tunnel and roadway, and belongs to the technical field of roadway safety supporting. Comprising a supporting plate, and an inner supporting plate of the supporting plate is composed of a steel arch and supporting piles; a connecting assembly is arranged between every two adjacent steel arches, an adjustable reinforcing assembly is arranged between each supporting pile and the bottom plate, and an inner abutting block is transversely arranged between every two adjacent supporting piles on the same side. An H-shaped splicing support is connected to the middle position of the arch portion of the steel arch frame, and the inner abutting block and the H-shaped splicing support are connected through an abutting piece. A pre-stressed anchor cable is fixed to the top of the outer supporting plate. The stability of transverse supporting is enhanced, and meanwhile a longitudinal supporting structure is formed; and pressure is dispersed to the whole supporting structure through oblique and longitudinal supporting effects, so that the whole supporting effect is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel and roadway safety support, and particularly relates to a collaborative support structure applicable to soft rock large deformation tunnels and roadways. Background Art

[0002] With the continuous deepening of the development and utilization of underground space, the large deformation problem in soft rock areas has become increasingly serious due to the soft, broken, high ground stress, low strength, rheological, weathered, and swelling characteristics of rock masses, greatly increasing the difficulty of controlling the stability of surrounding rocks. In traditional soft rock tunnel or roadway support, whether it is a single support method such as bolts and steel frames or a simple combined support method, there are problems of limited support capacity and lack of synergy. When facing complex and changeable geological conditions, these support methods often cannot achieve ideal support effects, resulting in poor overall support effects. Summary of the Invention

[0003] The invention overcomes the deficiencies of the prior art and provides a collaborative support structure applicable to soft rock large deformation tunnels and roadways; the invention is realized through the following technical solutions: A collaborative support structure applicable to soft rock large deformation tunnels and roadways includes a support plate, which includes an outer support plate and an inner support plate, and the inner wall of the outer support plate is fixedly connected to the inner support plate; the outer wall of the outer support plate is attached to the inner wall of the tunnel or roadway; The inner support plate is composed of a steel arch and support piles; a plurality of the steel arches are evenly distributed along the length direction of the tunnel or roadway, a connecting component is provided between adjacent two steel arches, a support pile is symmetrically fixed at the bottom end of each steel arch, and an adjustable reinforcement component is provided for each support pile, an inner abutting block is horizontally arranged between adjacent support piles on the same side; an H-shaped splicing bracket is connected at the middle position of the arch part of the steel arch, and an abutting pressure member is used to connect the inner abutting block and the H-shaped splicing bracket; a prestressed anchor cable is fixed at the top of the outer support plate; The bottom of the outer support plate is connected to a support plate, the support plate is a concrete structure, bottom I-beams are evenly arranged along the axial direction of the tunnel or roadway at a certain interval inside the support plate, a steel bar mesh with a certain grid spacing is laid on the upper part of the bottom I-beams, W-shaped steel belts are arranged perpendicular to the bottom I-beams at a certain interval on the upper part of the steel bar mesh, and tensile anchor pipes are driven in the middle of the W-shaped steel belts between adjacent two sets of bottom I-beams; The reinforcement component includes a first fixing seat, a fixing rod, an adjusting sleeve, an adjusting rod and a second fixing seat, the first fixing seat is fixedly connected to the outside of the support pile, a fixing rod facing downwards is fixed on the first fixing seat, an adjusting sleeve is fixed at the end of the fixing rod away from the first fixing seat, an adjusting rod is rotationally matched with the adjusting sleeve, a second fixing seat is fixed at the other end of the adjusting rod, and the second fixing seat is fixedly connected to the upper surface of the support plate.

[0004] Furthermore, a sand and gravel layer is filled in the cavity between the outer support plate and the inner support plate.

[0005] Furthermore, the prestressed anchor cables are radially arranged with the center of the upper part of the outer support plate as the center, and the ends of the prestressed anchor cables penetrate into the interior of the outer support plate, and the prestressed anchor cables are inserted into the external rock formation.

[0006] Furthermore, the H-shaped splicing support is spliced by two I-beams in the vertical direction and one I-beam in the horizontal direction. The lower parts of the multiple I-beams on the same side are jointly welded to a cross beam arranged along the length direction of the tunnel or roadway; a pressing member is arranged between each inner abutting block and the corresponding bottom position on the cross beam on the same side.

[0007] Furthermore, the pressing member includes a mounting seat and a pressing rod. Mounting seats are arranged at the bottom of the cross beam and the top of the inner abutting block, and the two ends of the pressing rod are respectively abutted between the mounting seats at the bottom of the cross beam on the same side and the mounting seat at the top of the inner abutting block.

[0008] Furthermore, the connecting assembly includes a rod body, a threaded sleeve, a screw rod, a fixing plate, a movable plate, a through groove and a fixing nut; the rod body is arranged between two adjacent steel arch frames, threaded sleeves are rotatably installed at both ends of the rod body, and screw rods that are threadedly engaged with them are installed on the sides of the two threaded sleeves away from each other; a fixing plate is fixed on the side of the screw rod, and the fixing plate is fixedly connected to the steel arch frame; movable plates are fixed at both ends of the rod body, through grooves for the movable plates to slide are formed in the threaded sleeves, and fixing nuts are fixedly sleeved outside the threaded sleeves.

[0009] Furthermore, the adjusting kit includes a fixing sleeve, a movable shaft, a connecting cover, a clamping block and a fixing screw. The fixing sleeve is fixedly arranged at the end of the fixing rod, the movable shaft is rotatably installed in the fixing sleeve, one side of the movable shaft is fixedly connected to the adjusting rod, a locking strip is slidably installed on the fixing sleeve, a connecting cover is fixed at the end of the locking strip, clamping blocks that are matched with the card slots on the movable shaft are annularly arranged at the end of the connecting cover, and a fixing screw that is in pressing contact with the locking strip is arranged on the top plate of the connecting cover.

[0010] The beneficial effects of the present invention compared with the prior art are as follows: 1. The connecting assembly of the present invention fixes adjacent steel arch frames together by means of threaded connection, and can adjust the length and position of the connecting assembly according to actual needs to meet the connection requirements of steel arch frames with different spacings; in addition, the inner abutting blocks, the H-shaped splicing support and the pressing member are effectively connected, further enhancing the resistance of the steel arch frame in the arch part, and the connecting struts connect adjacent steel arch frames, further enhancing the lateral stability of the support structure. The two disperse the pressure to the entire support structure through the diagonal and longitudinal support effects, thereby improving the overall support effect.

[0011] 2. The present invention forms a longitudinal support system for the support structure through the support piles and the reinforcement components. The reinforcement components enhance the longitudinal stability of the support structure by adjusting the inclined support angle. Through the rotational connection between the adjustment kit and the adjustment rod, the support angle of the reinforcement components can be conveniently adjusted, which not only enables the support structure to better adapt to the longitudinal deformation requirements under different geological conditions, but also enhances the longitudinal load-bearing capacity of the entire support structure through the inclined support. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic diagram of the overall structure of the present invention; Figure 2 is a front view of the overall structure of the present invention; Figure 3 is a structural diagram of the support plate in the present invention; Figure 4 is a schematic diagram of the structure of the connection component in the present invention; Figure 5 is a cross-sectional view of the connection component in the present invention; Figure 6 is a schematic diagram of the structure of the reinforcement component in the present invention; Figure 7 is a schematic diagram of the structure of the adjustment kit in the present invention.

[0013] The reference numerals in the drawings are: 1. Support plate; 101. Outer support plate; 1011. Support plate; 1012. Bottom I-beam; 1013. Steel mesh; 1014. W-shaped steel strip; 1015. Tensile anchor pipe; 102. Inner support plate; 1021. Steel arch frame, 1022 is the support pile; 2. Connection component; 201. Rod body; 202. Threaded sleeve; 203. Screw; 204. Fixed plate; 205. Movable disk; 206. Through groove; 207. Fixed nut; 3. Reinforcement component; 301. First fixed seat; 302. Fixed rod; 303. Adjustment kit; 3031. Fixed sleeve; 3032. Movable shaft; 3033. Connection cover; 3034. Block; 3035. Fixed screw; 304. Adjustment rod; 305. Second fixed seat; 4. Inner abutting block; 5. H-shaped splicing bracket; 501. Vertical I-beam; 502. Horizontal I-beam; 503. Cross beam; 6. Pressing member; 601. Mounting seat; 602. Pressing rod; 7. Prestressed anchor cable. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0014] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail in conjunction with embodiments and drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. The technical solutions of the present invention will be described in detail below in conjunction with embodiments and drawings, but the protection scope is not limited by this.

[0015] See Figures 1 to 7 , in this embodiment, a collaborative support structure applicable to soft rock large deformation tunnels and roadways is proposed, including a support plate 1. The support plate 1 includes an outer support plate 101 and an inner support plate 102. The inner wall of the outer support plate 101 is fixedly connected to the inner support plate 102; the outer wall of the outer support plate 101 is attached to the inner wall of the tunnel or roadway; a sand layer is filled in the cavity between the outer support plate 101 and the inner support plate 102, and the filled sand layer is used to improve the connection relationship between the outer support plate 101 and the inner support plate 102, thereby improving the strength of the overall support structure.

[0016] The inner support plate 102 is composed of a steel arch 1021 and a support pile 1022; wherein, a plurality of the steel arches 1021 are evenly distributed along the body of the outer support plate 101, that is, the length direction of the tunnel or roadway. A connecting component 2 is provided between two adjacent steel arches 1021. The bottom end of each steel arch 1021 is symmetrically fixed with a support pile 1022, and each support pile 1022 is provided with an adjustable reinforcement component 3. The reinforcement component 3 enhances the bearing capacity and stability of the support structure. An inner abutting block 4 is horizontally arranged between adjacent support piles 1022 on the same side; an H-shaped splicing bracket 5 is connected to the middle position of the arch part of the steel arch 1021, and the inner abutting block 4 and the H-shaped splicing bracket 5 are connected by a pressing member 6 to form a stable support network. A prestressed anchor cable 7 is fixed to the top of the outer support plate 101. The prestressed anchor cables 7 are radially arranged with the center of the upper part of the outer support plate 101 as the center, and the ends of the prestressed anchor cables 7 penetrate into the interior of the outer support plate 101. The prestressed anchor cables 7 are inserted into the external rock formation to generate sufficient pulling force.

[0017] Specifically, see Figure 3, a support plate 101 is connected to the bottom of the external support plate 101. The support plate 1011 is a concrete structure. Bottom I-beams 1012 are uniformly arranged along the axial direction of the tunnel or roadway at a certain interval inside the support plate 1011. A steel mesh 1013 with a certain grid spacing is laid on the upper part of the bottom I-beams 1012. W-steel strips 1014 are arranged perpendicular to the bottom I-beams 1012 at a certain interval on the upper part of the steel mesh 1013. Tensile anchor pipes 1015 are driven in the middle of the W-steel strips 1014 between two adjacent sets of bottom I-beams 1012. The bottom I-beams 1012 and the steel mesh 1013 can enhance the stiffness of the support plate 1011. The grouting effect of the tensile anchor pipes 1015 can reinforce the bottom surrounding rock. At the same time, in cooperation with the W-steel strips 1014, the support plate 1011 can be anchored to the stable rock stratum at the bottom of the tunnel or roadway, reducing the heaving deformation of the bottom surrounding rock of the tunnel or roadway and further improving the stability of the support plate 1011.

[0018] See Figure 2 , a H-shaped splicing bracket 5 is connected to the middle of the arch part of each steel arch frame 1021. The H-shaped splicing bracket 5 is formed by splicing two vertical I-beams 501 and one horizontal I-beam 502. The lower parts of multiple vertical I-beams 501 on the same side are jointly welded to a cross beam 503 arranged along the length direction of the tunnel or roadway; the H-shaped splicing bracket 5 can enhance the overall stability of the steel arch frame 1021. A pressing member 6 is arranged between each inner abutting block 4 and the corresponding bottom position on the cross beam 503 on the same side. Through the pressing action of the pressing member 6, the stability and bearing capacity of the support structure are further enhanced.

[0019] Furthermore, the pressing member 6 includes a mounting seat 601 and a pressing rod 602. Mounting seats 601 are arranged at the bottom of the cross beam 503 and the top of the inner abutting block 4. The two ends of the pressing rod 602 are respectively abutted between the mounting seat 601 at the bottom of the cross beam 503 on the same side and the mounting seat 601 at the top of the inner abutting block 4. The pressing member 6 has the function of resisting pressure, further dispersing the pressure of the support structure to the floor of the tunnel or roadway, enhancing the connection relationship between the support structure and the floor of the tunnel or roadway, and further improving the stability and bearing capacity of the support structure.

[0020] As Figure 4 and 5As shown in the figure, the connecting component 2 includes a rod body 201, a threaded sleeve 202, a screw rod 203, a fixing plate 204, a movable plate 205, a through groove 206 and a fixing nut 207. The rod body 201 is arranged between two adjacent steel arch frames 1021. Threaded sleeves 202 are rotatably installed at both ends of the rod body 201. The threaded sleeves 202 can move along the rod body of the rod body 201. Screw rods 203 that are threadedly engaged with the threaded sleeves 202 are installed on the sides of the two threaded sleeves 202 that are away from each other. The threaded engagement between the screw rod 203 and the threaded sleeve 202 can facilitate the adjustment of the overall length of the two, and at the same time, the threaded connection has strong stability, which can improve the firmness of the connection between two adjacent steel arch frames 1021. A fixing plate 204 is fixed to the side of the screw rod 203. The fixing plate 204 is fixedly connected to the steel arch frame 1021 by bolts; Specifically, movable plates 205 are fixed to both ends of the rod body 201. A through groove 206 for the movable plate 205 to slide is formed in the threaded sleeve 202, and a fixing nut 207 is fixedly sleeved outside the threaded sleeve 202. The threaded sleeve 202 can move along the length direction of the rod body 201. At the same time, the threaded sleeve 202 and the rod body 201 can rotate, and a wrench can be used to rotate the fixing nut 207 during installation to drive the threaded sleeve 202 to rotate.

[0021] Specifically, fix the fixing plate 204 on one of the screw rods 203 to an adjacent steel arch frame 1021, and then control the overall length of the two threaded sleeves 202 and the rod body 201 so that the fixing plate 204 on the other screw rod 203 can be installed on the other adjacent steel arch frame 1021. Connect and fix the two according to the actual distance between the two steel arch frames 1021, which greatly saves the construction time. At the same time, this device does not require welding operations.

[0022] As Figure 6 and 7 shown in the figure, the reinforcement component 3 includes a first fixing seat 301, a fixing rod 302, an adjustment kit 303, an adjustment rod 304 and a second fixing seat 305. The first fixing seat 301 is fixedly connected to the outside of the support pile 1022 by rivets. A fixing rod 302 facing downward is fixed on the first fixing seat 301. An adjustment kit 303 is fixed to the end of the fixing rod 302 away from the first fixing seat 301. An adjustment rod 304 is rotatably fitted on the adjustment kit 303. A second fixing seat 305 is fixed to the other end of the adjustment rod 304. The second fixing seat 305 is fixedly connected to the upper surface of the support plate 1011 by rivets.

[0023] Further, the adjustment kit 303 includes a fixed sleeve 3031, a movable shaft 3032, a connecting cover 3033, a clamping block 3034 and a fixing screw 3035. The fixed sleeve 3031 is fixedly arranged at the end of the fixed rod 302. A movable shaft 3032 is rotatably installed in the fixed sleeve 3031. One side of the movable shaft 3032 is fixedly connected to the adjusting rod 304. A locking bar is slidably installed on the fixed sleeve 3031, and a connecting cover 3033 is fixed to the end of the locking bar. A clamping block 3034 that matches the card slot on the movable shaft 3032 is annularly arranged at the end of the connecting cover 3033. A fixing screw 3035 that is in pressing contact with the locking bar is provided on the top plate of the connecting cover 3033.

[0024] Specifically, first slide and adjust the position of the first fixing seat 301 relative to the support pile 1022 to determine the acting point position of the entire reinforcement assembly 3. Subsequently, rotate the movable shaft 3032 to make the adjusting rod 304 find a suitable oblique support angle. After the adjustment is completed, it is necessary to fasten the movable structures in the reinforcement assembly 3. Slide the locking bar towards the side close to the fixed sleeve 3031 until the clamping block 3034 on the connecting cover 3033 engages with the card slot of the movable shaft 3032. Then lock the rotation of the adjusting rod 304, and then tighten the fixing screw 3035 to fix the locking bar and complete the locking of the adjusting rod 304. For the fastening of the first fixing seat 301 and the second fixing seat 305, only the rivets on the first fixing seat 301 and the second fixing seat 305 need to be fastened.

[0025] It should be further noted that the outer support plate 101 and the inner support plate 102, as the main load-bearing parts of the support structure, jointly bear the radial pressure generated by the tunnel surrounding rock. The outer support plate 101, as the first line of defense directly facing the surrounding rock, its strong structure can effectively resist the initial extrusion of the surrounding rock. The inner support plate 102 further disperses and bears these pressures through the coordinated action of the steel arch 1021 and the support pile 1022. The steel arch 1021 is linearly distributed along the inner wall of the outer support plate 101, forming a plurality of arc-shaped support structures. These structures can evenly disperse the pressure of the surrounding rock to the entire support structure. At the same time, the support pile 1022, as the bottom support of the steel arch 1021, not only enhances the stability of the steel arch 1021 but also transmits the pressure to the deeper surrounding rock, thereby effectively resisting the deformation of the surrounding rock.

[0026] The support piles 1022 and the reinforcement components 3 together constitute the longitudinal support system of the support structure. The reinforcement components 3 enhance the longitudinal stability of the support structure by adjusting the inclined support angle. The reinforcement components 3 are composed of components such as the first fixed seat 301, the fixed rod 302, the adjustment kit 303, and the adjustment rod 304. By rotating the connection between the adjustment kit 303 and the adjustment rod 304, the support angle of the reinforcement components 3 can be conveniently adjusted, which not only enables the support structure to better adapt to the longitudinal deformation requirements under different geological conditions, but also enhances the longitudinal bearing capacity of the entire support structure through the inclined support.

[0027] The connection components 2 tightly connect the adjacent steel arch frames 1021 together to form a stable support network. The connection components 2 are composed of components such as the rod body 201, the threaded sleeve 202, and the screw rod 203. The adjacent steel arch frames 1021 are fixed together by means of threaded connection, and the length and position of the connection components 2 can be adjusted according to actual needs to meet the connection requirements of the steel arch frames 1021 with different spacings. In addition, the inner abutting block 4, the H-shaped splicing bracket 5, and the pressing member 6 are effectively connected to further enhance the resistance of the arch steel arch frame 1021. The connecting struts 2 connect the adjacent steel arch frames, further enhancing the lateral stability of the support structure. Through the inclined and longitudinal support effects, the pressure is dispersed to the entire support structure, thereby improving the overall support effect.

[0028] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific embodiments of the present invention are limited thereto. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the premise of the present invention, several simple deductions or substitutions can be made, which should all be regarded as belonging to the patent protection scope determined by the claims submitted for the present invention.

Claims

1. A collaborative support structure suitable for soft rock large deformation tunnels and lanes, characterized in that: The support plate (1) comprises an outer support plate (101) and an inner support plate (102); the inner wall of the outer support plate (101) is fixedly connected to the inner support plate (102); the outer wall of the outer support plate (101) is in contact with the inner wall of the tunnel or lane; The inner support plate (102) is composed of a steel arch frame (1021) and a support pile (1022); a plurality of the steel arch frames (1021) are evenly distributed along the length direction of the tunnel or laneway, a connection assembly (2) is provided between two adjacent steel arch frames (1021), a support pile (1022) is symmetrically fixed at the bottom end of each steel arch frame (1021), and each support pile (1022) is provided with an adjustable reinforcement assembly (3), and an inner abutment block (4) is horizontally provided between adjacent support piles (1022) on the same side; an H-shaped splicing bracket (5) is connected to the middle position of the arch portion of the steel arch frame (1021), and a pressure piece (6) is used to connect the inner abutment block (4) and the H-shaped splicing bracket (5); a prestressed anchor cable (7) is fixed to the top of the outer support plate (101); The bottom of the outer support plate (101) is connected to a support plate (1011), the support plate (1011) being a concrete structure, bottom I-beams (1012) being evenly arranged inside the support plate (1011) along the axial direction of the tunnel or laneway at a fixed interval, a steel mesh (1013) having a fixed grid interval is laid on the top of the bottom I-beams (1012), a W-shaped steel strip (1014) is arranged on the top of the steel mesh (1013) perpendicular to the bottom I-beams (1012) at a fixed interval, and a tensile anchor pipe (1015) is driven in the middle of the W-shaped steel strip (1014) between two adjacent bottom I-beams (1012); The reinforcement assembly (3) comprises a first fixing seat (301), a fixing rod (302), an adjustment kit (303), an adjustment rod (304) and a second fixing seat (305); the first fixing seat (301) is fixedly connected to the outer side of the support pile (1022); a fixing rod (302) facing downward is fixed to the first fixing seat (301); an adjustment kit (303) is fixed to the end of the fixing rod (302) away from the first fixing seat (301); the adjustment rod (304) is rotatably engaged with the adjustment kit (303); the other end of the adjustment rod (304) is fixed to the second fixing seat (305); and the second fixing seat (305) is fixedly connected to the upper surface of the support plate (1011).

2. A collaborative support structure suitable for soft rock large deformation tunnels and lanes according to claim 1, characterized in that: The cavity between the outer supporting plate (101) and the inner supporting plate (102) is filled with a sand and gravel layer.

3. The collaborative support structure suitable for soft rock large deformation tunnels and lanes according to claim 1, characterized in that: The prestressed anchor cables (7) are arranged radially with the upper center of the outer support plate (101) as the center, and the ends of the prestressed anchor cables (7) penetrate into the interior of the outer support plate (101), and the prestressed anchor cables (7) are inserted into the external rock formation.

4. The collaborative support structure suitable for soft rock large deformation tunnels and lanes according to claim 1, characterized in that: The H-shaped spliced ​​bracket (5) is formed by splicing two vertical I-beams (501) and one horizontal I-beam (502); the lower parts of a plurality of vertical I-beams (501) on the same side are welded to a crossbeam (503) arranged along the length direction of the tunnel or laneway; and a pressure piece (6) is provided between each inner support block (4) and a corresponding bottom position on the crossbeam (503) on the same side.

5. A collaborative support structure suitable for soft rock large deformation tunnels and lanes according to claim 4, characterized in that: The pressing member (6) comprises a mounting seat (601) and a pressing rod (602). The mounting seats (601) are both provided at the bottom of the cross beam (503) and the top of the inner pressing block (4). The two ends of the pressing rod (602) are respectively abutted between the mounting seat (601) at the bottom of the cross beam (503) and the mounting seat (601) at the top of the inner pressing block (4) on the same side.

6. The cooperative support structure suitable for soft rock large deformation tunnels and lanes according to claim 1, characterized in that: The connecting assembly (2) comprises a rod body (201), a threaded sleeve (202), a screw rod (203), a fixing plate (204), a movable disk (205), a through groove (206) and a fixing nut (207); the rod body (201) is arranged between two adjacent steel arch frames (1021); the threaded sleeves (202) are rotatably mounted on both ends of the rod body (201); the two threaded sleeves (202) are mounted on the sides away from each other with screw rods (203) threadedly matched therewith; the fixing plate (204) is fixed to the side of the screw rod (203); the fixing plate (204) and the steel arch frame (1021) are fixedly connected; the movable disks (205) are fixed to both ends of the rod body (201); a through groove (206) for the movable disk (205) to slide is provided in the threaded sleeve (202); and a fixing nut (207) is provided on the fixed sleeve outside the threaded sleeve (202).

7. The cooperative support structure suitable for soft rock large deformation tunnels and lanes according to claim 1, characterized in that: The adjustment kit (303) comprises a fixed sleeve (3031), a movable shaft (3032), a connecting cover (3033), a clamping block (3034) and a fixing screw (3035). The fixed sleeve (3031) is fixedly arranged at the end of the fixed rod (302). The movable shaft (3032) is rotatably installed in the fixed sleeve (3031). One side of the movable shaft (3032) is fixedly connected to the adjustment rod (304). A locking strip is slidably installed on the fixed sleeve (3031), and a connecting cover (3033) is fixed on the end of the locking strip. A clamping block (3034) matching with a clamping groove on the movable shaft (3032) is arranged around the end of the connecting cover (3033). A fixing screw (3035) that is in compression contact with the locking strip is arranged on the top plate of the connecting cover (3033).

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