Adaptive adjustment temporary supporting structure for variable cross-section water delivery tunnel and construction method thereof

Abstract

The invention discloses an adaptive adjustment temporary supporting structure of a variable cross-section water delivery tunnel and a construction method of the adaptive adjustment temporary supporting structure. Comprising a temporary support, columns on two sides of the temporary support are connected with an upper fixed beam and a lower fixed beam through hinged supports and provided with an upper movable beam and a lower movable beam which can slide, and the end of the upper fixed beam can be driven to ascend and descend by adjusting the length of a pull rod connected between the upper movable beam and the lower movable beam. The arched support is formed by hinging a first support and a second support to an upper fixed beam and is connected with the first support and the second support through an inhaul cable. During construction, the supporting frame and the arch-shaped support are installed firstly, then the outline of the arch-shaped support is matched with the tunnel section by adjusting the inhaul cables, and finally the supporting height fine adjustment and close attachment are achieved by adjusting the pull rods. Through the synergistic effect of the openable arch support and the adjustable lever mechanism, flexible and accurate adaptation of the arch height and the contour of the variable cross-section tunnel is achieved, and the structure is stable.

Description

Technical Field

[0001] This invention belongs to the field of water conveyance tunnel construction support technology, specifically relating to an adaptive and adjustable temporary support structure for variable cross-section water conveyance tunnels and its construction method. It is applicable to temporary support operations during the excavation of variable cross-section water conveyance tunnels and can adapt to the support needs of tunnels with different cross-sectional dimensions and different lengths. Background Technology

[0002] During the excavation and construction of water conveyance tunnels, temporary support must be applied to the excavation face in a timely manner to ensure construction safety and the stability of the surrounding rock. Existing temporary support structures mostly adopt steel arch frames or lattice steel frames, whose shapes and dimensions are usually prefabricated according to the tunnel design cross-section, or use simple mechanical expansion structures. Their span and height adjustment range is limited and the adjustment process is cumbersome, making it difficult to quickly and accurately adapt to the continuous changes in the tunnel cross-section dimensions in width and arch height. As a result, in areas with variable cross-sections, it is often necessary to customize various support components of different specifications or carry out a large amount of on-site cutting and welding modifications. This not only causes material waste and construction delays, but also easily leads to local stress concentration or top voids due to insufficient fit between the support structure and the contour of the surrounding rock, reducing the support effect and increasing the risk of surrounding rock instability.

[0003] Therefore, there is an urgent need to develop a temporary support structure for water conveyance tunnels with variable cross-sections that can be flexibly adjusted and adapted to different cross-sectional dimensions. Summary of the Invention

[0004] The purpose of this invention is to provide an adaptive temporary support structure and its construction method for a variable cross-section water conveyance tunnel. The construction method adopts an integrated temporary support and achieves adaptive support for tunnels with different cross-sectional dimensions through an adjustable lever mechanism and an openable arch support. It features convenient installation, flexible adjustment, and strong adaptability.

[0005] The variable cross-section water conveyance tunnel adaptive adjustment temporary support structure and its construction method described in this invention are symmetrical structures, using integrated temporary supports. The temporary supports include columns, beams, and connecting beams. At least two columns are provided on each side of the temporary supports. The columns are arranged close to the tunnel sidewall and are used to provide bottom support for the entire temporary support structure.

[0006] The top of the column is connected to an upper fixed beam via a hinged support, and a lower fixed beam is fixedly connected to the middle of the column. The upper and lower fixed beams are arranged parallel to each other. An upper movable beam is slidably connected to the upper fixed beam, and an upper anchor block is fixedly installed at the end of the upper movable beam. A lower movable beam is slidably connected to the lower fixed beam, and a lower anchor block is fixedly installed at the end of the lower movable beam. The upper movable beam can slide relative to the upper fixed beam along its length, thus forming a beam body with a variable length when combined with the upper fixed beam. Similarly, the lower movable beam can slide relative to the lower fixed beam along its length, forming a beam body with a variable length when combined with the lower fixed beam. This variable-length beam structure provides a variable lever arm for subsequent adjustment lever action, providing a structural basis for adjusting the support height and angle. The upper fixed beam, upper movable beam, and upper anchor block are arranged vertically in correspondence with the lower fixed beam, lower movable beam, and lower anchor block, respectively. A tie rod is installed between the upper and lower anchor blocks. The tie rod can be powered by a jack. By adjusting the length of the tie rod, the end of the upper movable beam is pulled, and the hinged support is used as a fulcrum to move the end of the upper fixed beam away from the hinged support upward or downward, thereby achieving the adjustment of the support structure height as described later.

[0007] Each pair of horizontally opposite columns forms a group. The upper fixed beams on the two groups of horizontally opposite columns are respectively installed at the two bottom ends of an arched support. Therefore, the arched support includes at least a first support and a second support. Both the first and second supports are components of the arched support, named only based on their different installation positions. The arched support and the upper fixed beam are connected by a hinged end. The specific connection method is as follows: an upper hinge plate is fixedly installed at the bottom end of the arched support, and a lower hinge plate is fixedly installed at the upper end of the upper fixed beam. One end of the upper hinge plate and the lower hinge plate are hinged together by a hinge shaft, allowing the connecting end of the upper and lower hinge plates to rotate relative to each other around the hinge shaft, providing room for adjustment of the arched support angle.

[0008] Anchor sleeves and anchor plates are spaced apart on both the first and second supports. Several cables connect the first and second supports, with the ends of the cables correspondingly installed on the anchor sleeves and anchor plates. The opening degree of the first and second supports can be changed by extending or retracting the length of the cables. During adjustment, the upper hinge plates at the bottom of the first and second supports can rotate relative to each other around the lower hinge plate on the upper fixed beam. In state one, the angle between the central axis of the first support and the horizontal line is α, corresponding to a support height of h1. In state two, the angle between the central axis of the first support and the horizontal line is β, corresponding to a support height of h2. By adjusting these angles and heights, adaptive support for tunnel arch heights of different cross-sectional dimensions can be achieved.

[0009] To further improve the tightness of the contact between the temporary support structure and the surrounding rock of the tunnel, the length of the tie rod can be adjusted to move the end of the upper fixed beam away from the hinged support upward, thereby moving the end of the arch support upward synchronously, achieving fine adjustment of the height of the arch support and ensuring that the arch support is in close contact with the surrounding rock.

[0010] Furthermore, by cooperating with the connecting beams and connecting rods, two sets of temporary supports, namely the first unit and the second unit, can be spliced ​​together to form a combined support. By splicing two or more sets of units, continuous support for tunnels of different lengths can be achieved, adapting to the support requirements of tunnels of different lengths.

[0011] The temporary supports described in this invention are flexible in their application. They can be applied directly to the surrounding rock of tunnels, or protective plates can be laid on top of the arched supports to provide comprehensive support to the surrounding rock. Furthermore, the temporary supports can also be used in the initial support structure of tunnels. In summary, the application scenarios of temporary supports are not limited to those described in this specification; appropriate matching and adaptation can be carried out according to different actual construction scenarios.

[0012] To make the objectives, technical solutions, and advantages of this invention clearer, the construction steps of this invention will be described in detail below. The variable cross-section water conveyance tunnel adaptive adjustment temporary support structure and its construction method according to this invention include the assembly, placement, and adjustment of the temporary support. The construction steps are as follows:

[0013] Step 1: Pre-construction preparation

[0014] Based on the tunnel design drawings and the actual excavation cross-section, surveying and setting out are carried out to determine the installation positions of temporary supports; the temporary support components required for construction are inspected and prepared, including columns, beams, connecting beams, upper fixed beams, lower fixed beams, upper movable beams, lower movable beams, upper anchor blocks, lower anchor blocks, tie rods, first supports, second supports, upper hinge plates, lower hinge plates, hinge shafts, anchor sleeves, anchor plates, cables, hinge supports, protective plates, and connecting rods; the components are inspected for quality to ensure that all parts are intact, sliding connections are well lubricated, and hinged parts rotate flexibly.

[0015] Step 2: Pre-assembly of temporary supports

[0016] S21. Assembly of Columns and Beams: Connect the columns, beams, and connecting beams to form a single-sided support frame. Install a hinged support at the top of each column and install the upper fixed beam on the hinged support; fix the lower fixed beam in the middle of the column, ensuring that the upper and lower fixed beams are parallel to each other.

[0017] S22. Installation of the movable beam: Slide the upper movable beam onto the groove or guide rail of the upper fixed beam, and slide the lower movable beam onto the groove or guide rail of the lower fixed beam. Fix the upper anchor block at the end of the upper movable beam and the lower anchor block at the end of the lower movable beam, ensuring that the upper and lower anchor blocks are vertically aligned.

[0018] S23. Tie rod system installation: Install the tie rod between the upper and lower anchor blocks, and connect the jack to the tie rod to form an adjustable tie rod power system.

[0019] S24. Arch Support Installation: The first and second supports are hoisted into place, with each pair of laterally opposite columns forming a group. The upper hinge plates at the bottom of the first and second supports are aligned with the lower hinge plates on the corresponding upper fixed beams, and hinge pins are inserted to complete the hinge connection. Anchor sleeves and anchor plates are installed at intervals on the first and second supports. Several cables are connected between the first and second supports, with the ends of the cables correspondingly installed on the anchor sleeves and anchor plates on the first and second supports. By extending and retracting the length of the cables, the opening and closing degree of the first and second supports is changed. During the adjustment process, the upper hinge plates at the bottom of the first and second supports rotate relative to each other around the lower hinge plates on the upper fixed beam.

[0020] Step 3: Temporary support in place

[0021] The assembled temporary supports are transported to the section of the tunnel awaiting support, with the columns positioned close to the tunnel sidewalls, at least two columns on each side. The columns are then temporarily fixed after their verticality and elevation are adjusted.

[0022] Step 4: Adjusting the opening and closing degree of the arch support

[0023] Based on the tunnel cross-sectional dimensions, the relative opening and closing degree of the two supports is adjusted by extending the length of several cables connecting the first and second supports. During adjustment, the upper hinge plates at the bottom of the first and second supports rotate around the lower hinge plates, so that the central axis of the first support forms a designed angle α with the horizontal line, corresponding to a support height h1; or it is adjusted to an angle β, corresponding to a support height h2. Through the above-mentioned corresponding changes in angle and height, the arch support is adapted to the arch height of tunnels with different cross-sections.

[0024] Step 5: Fine adjustment of support height

[0025] Activate the jack connected to the tie rod, and by changing the length of the tie rod, drive the upper movable beam to slide along the upper fixed beam. The sliding of the upper movable beam causes the upper anchor block to move, and with the hinged support as the fulcrum, raises or lowers the end of the upper fixed beam away from the hinged support. This action simultaneously drives the end of the arched support hinged to the upper fixed beam to move, achieving fine adjustment of the overall height of the arched support until the arched support is in close contact with the tunnel surrounding rock surface.

[0026] Step Six: Laying and Supporting the Protective Panels

[0027] Choose one of the following three usage methods based on construction needs:

[0028] Method 1: Temporary supports act directly on the surrounding rock of the tunnel, so that the arched supports are in direct contact with the surrounding rock to provide support;

[0029] Method 2: Lay a protective plate on the upper part of the arch support and fix the protective plate firmly to the arch support to achieve full support for the surrounding rock.

[0030] Method 3: The temporary supports are installed in accordance with the initial support structure of the tunnel, and the connection nodes are tightened to achieve auxiliary support.

[0031] It can be flexibly adapted to the actual scenario and is not limited to a single construction method.

[0032] Step 7: Construction of Multi-Unit Continuous Support

[0033] For long tunnel sections requiring continuous support, repeat steps two through six to complete the assembly and placement of the second unit of temporary supports. Adjacent temporary supports of the first and second units are longitudinally spliced ​​together using connecting beams and rods to form a combined support system.

[0034] The beneficial effects of this invention are as follows:

[0035] (1) By setting up an arch support composed of a first support and a second support, and by using cables to adjust the opening and closing degree of the two, the present invention can realize the continuous change of the angle between the central axis of the arch support and the horizontal line, and adjust the support height accordingly, thereby accurately adapting to the tunnel arch height requirements of different cross-sectional dimensions, and solving the problem that traditional fixed arch frames are difficult to adapt to tunnels with variable cross-sections.

[0036] (2) The present invention drives the upper movable beam to slide on the upper fixed beam by means of a tie rod, and forms a lever mechanism with the hinged support as the fulcrum. This allows for fine adjustment of the overall height of the arch support, so that the arch support is in close contact with the tunnel surrounding rock surface, which improves the contact tightness between the support structure and the surrounding rock, and enhances the support effect and construction safety.

[0037] (3) The present invention adopts an integrated temporary support design, and the main components can be pre-assembled on the ground and then transported to the tunnel as a whole, reducing the amount of high-altitude work and on-site modification work inside the tunnel. At the same time, the support height and angle can be quickly adjusted by tie rods and cables, which is simple and quick to operate and improves construction efficiency.

[0038] (4) The present invention can longitudinally splice multiple temporary support units (first unit and second unit) through connecting beams and connecting rods to form a combined support system, which can flexibly adapt to the continuous support requirements of tunnel sections of different lengths.

[0039] (5) This invention can be used directly to provide support to the surrounding rock, or to lay protective plates on top of it to form comprehensive protection. It can also be used to reinforce the initial support structure of the tunnel. It is flexible and diverse in its use, and can be used in conjunction with different geological conditions and construction techniques. It has a wide range of applications.

[0040] (6) The present invention forms a stable support frame through columns, beams and connecting beams, and achieves effective force transmission through hinged ends, sliding connections and other structures. The structure has clear stress and high overall stability and safety reliability. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of a temporary support structure;

[0042] Figure 2 for Figure 1 Enlarged view of node A;

[0043] Figure 3 Right view of the temporary support configuration;

[0044] Figure 4 Right view of temporary support state two;

[0045] Figure 5 This is a diagram illustrating the temporary support in a supported state.

[0046] Figure 6 This is a schematic diagram of the connection between two sets of temporary supports.

[0047] The attached diagram lists the components represented by each number as follows:

[0048] In the diagram: 1. Surrounding rock; 2. Temporary support; 3. Column; 4. Horizontal beam; 5. Connecting beam; 6. First support; 7. Second support; 8. Cable; 9. Anchor plate; 10. Tie rod; 11. Hinge end; 12. Upper fixed beam; 13. Upper movable beam; 14. Upper anchor block; 15. Lower fixed beam; 16. Lower movable beam; 17. Lower anchor block; 18. Hinge support; 19. Upper hinge plate; 20. Lower hinge plate; 21. Hinge shaft; 22. Anchor sleeve; 23. First unit; 24. Second unit; 25. Connecting rod; 26. Arch support. Detailed Implementation

[0049] The following provides a detailed description of the specific implementation of the adaptive and adjustable temporary support structure for water conveyance tunnels and its construction method according to the present invention. Those skilled in the art can understand and implement this technical solution based on this description, but the scope of protection of the present invention is not limited to this specific embodiment.

[0050] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. To keep the following description of the embodiments of the present invention clear and concise, detailed descriptions of known functions and components are omitted.

[0051] Example 1: Temporary support for a single-section variable cross-section tunnel

[0052] like Figures 1 to 5 As shown in the figure, this embodiment provides an adaptive and adjustable temporary support structure for a variable cross-section water conveyance tunnel, used for temporary support of the excavation face of a variable cross-section water conveyance tunnel. The cross-sectional dimensions of the section of the tunnel to be supported vary, and the arch height design requires adjustment between h1 and h2.

[0053] The temporary support structure is a symmetrical structure, employing an integrated temporary support 2. The temporary support 2 includes columns 3, beams 4, and connecting beams 5. Based on the tunnel span, in this embodiment, two columns 3 are installed on each side of the temporary support 2. The columns 3 are arranged adjacent to the surrounding rock 1 of the tunnel sidewall, providing bottom support for the entire temporary support structure.

[0054] The top of the column 3 is connected to an upper fixed beam 12 via a hinged support 18, and a lower fixed beam 15 is fixedly connected to the middle of the column 3. The upper fixed beam 12 and the lower fixed beam 15 are arranged in parallel. An upper movable beam 13 is slidably connected to the upper fixed beam 12, and an upper anchor block 14 is fixedly installed at the end of the upper movable beam 13. A lower movable beam 16 is slidably connected to the lower fixed beam 15, and a lower anchor block 17 is fixedly installed at the end of the lower movable beam 16. The upper movable beam 13 can slide relative to the upper fixed beam 12 along its length, so that the upper movable beam 13 and the upper fixed beam 12 combine to form a beam with a variable length. The lower movable beam 16 can slide relative to the lower fixed beam 15 along its length, so that the lower movable beam 16 and the lower fixed beam 15 combine to form a beam with a variable length. The upper fixed beam 12, upper movable beam 13, and upper anchor block 14 are arranged vertically in correspondence with the lower fixed beam 15, lower movable beam 16, and lower anchor block 17, respectively. A tie rod 10 is installed between the upper anchor block 14 and the lower anchor block 17. The tie rod 10 uses a jack as its power source.

[0055] Each pair of horizontally opposite columns 3 forms a group, and the upper fixed beams 12 on the two groups of horizontally opposite columns 3 are respectively installed at the two bottom ends of an arched support 26. The arched support 26 includes a first support 6 and a second support 7. The arched support 26 and the upper fixed beam 12 are connected by a hinged end 11. Specifically, an upper hinge plate 19 is fixedly installed at the bottom end of the arched support 26, and a lower hinge plate 20 is fixedly installed at the upper end of the upper fixed beam 12. One end of the upper hinge plate 19 and the lower hinge plate 20 are hinged together by a hinge shaft 21, so that the connecting end of the upper hinge plate 19 and the lower hinge plate 20 can rotate relative to each other around the hinge shaft 21.

[0056] Anchor sleeves 22 and anchor plates 9 are distributed at intervals on the first support 6 and the second support 7. Several cables 8 are connected between the first support 6 and the second support 7, and the ends of the cables 8 are respectively installed on the anchor sleeves 22 and the anchor plates 9.

[0057] The construction process in this embodiment is as follows:

[0058] First, the temporary support 2 is pre-assembled outside the tunnel. The columns 3 are connected to the crossbeams 4 and connecting beams 5 to form a single-sided support frame. A hinged support 18 is installed at the top of each column 3 and connected to the upper fixed beam 12, while a lower fixed beam 15 is fixedly installed in the middle. The upper movable beam 13 is slidably installed onto the upper fixed beam 12, and the lower movable beam 16 is slidably installed onto the lower fixed beam 15. An upper anchor block 14 is installed at the end of the upper movable beam 13, and a lower anchor block 17 is installed at the end of the lower movable beam 16. A tie rod 10 is installed between the upper anchor block 14 and the lower anchor block 17, and a jack is connected. Taking two horizontally opposite columns 3 as a group, the upper hinge plate 19 at the bottom of the first support 6 and the upper hinge plate 19 at the bottom of the second support 7 are aligned with the lower hinge plate 20 on the corresponding side upper fixed beam 12, and the hinge shaft 21 is inserted to complete the hinge connection. Anchor sleeves 22 and anchor plates 9 are installed on the first support 6 and the second support 7, and cables 8 are connected.

[0059] Subsequently, the assembled temporary support 2 was transported to the tunnel support section and positioned so that the column 3 was placed close to the surrounding rock 1 of the tunnel sidewall. After adjusting the verticality and elevation, it was temporarily fixed.

[0060] Adjustments are made according to the actual cross-sectional dimensions of the tunnel. First, the opening and closing degree of the arch support is adjusted: the relative opening degree of the first support 6 and the second support 7 is changed by extending the length of the telescopic cable 8. During the adjustment process, the upper hinge plate 19 at the bottom of the first support 6 and the second support 7 rotates around the lower hinge plate 20. For example... Figure 3 As shown in state one, when a smaller support height is required, the angle between the central axis of the first support 6 and the horizontal line is adjusted to α, corresponding to a support height of h1; as Figure 4As shown in state two, when a larger support height is required, the included angle is adjusted to β, corresponding to a support height of h2. Through the above adjustment, the arch support 26 is adapted to the tunnel arch height of the current section.

[0061] Then, fine-tuning of the support height is performed: The jacks are activated, and the upper movable beam 13 is driven to slide along the upper fixed beam 12 by changing the length of the tie rod 10. The sliding of the upper movable beam 13 causes the upper anchor block 14 to move, and with the hinged support 18 as the fulcrum, the end of the upper fixed beam 12 away from the hinged support 18 is lifted upwards. This action simultaneously causes the end of the arched support 26, which is hinged to the upper fixed beam 12, to move upwards until the arched support 26 is tightly fitted against the surface of the tunnel surrounding rock 1, such as... Figure 5 As shown.

[0062] Finally, according to construction needs, a protective plate is laid on the upper part of the arch support 26 to achieve full support for the surrounding rock 1.

[0063] Example 2: Multi-unit continuous support

[0064] like Figure 6 As shown, this embodiment is basically the same as embodiment one, except that multiple temporary support units are set up for long tunnels that require continuous support.

[0065] During actual construction, the steps in Example 1 are repeated to complete the assembly, positioning, and adjustment of the temporary supports of the first unit 23 and the second unit 24. Subsequently, the adjacent temporary supports 2 of the first unit 23 and the second unit 24 are longitudinally spliced ​​together by the connecting beam 5 and the connecting rod 25 to form a combined support system, thereby achieving continuous support for tunnels of different lengths.

[0066] Example 3: Support in different application scenarios

[0067] This embodiment is basically the same as Embodiment 1, except that the temporary support is used differently.

[0068] Depending on the actual construction scenario, one of the following three usage methods can be selected:

[0069] Method 1: Temporary supports are applied directly to the surrounding rock 1 of the tunnel, so that the arch support 26 is in direct contact with the surrounding rock 1 to provide support.

[0070] Method 2: Lay a protective plate on the upper part of the arch support 26 and fix the protective plate to the arch support 26 securely. The protective plate provides full support for the surrounding rock 1 (as shown in Example 1).

[0071] Method 3: The temporary supports are installed in accordance with the initial support structure of the tunnel, and the connection nodes are tightened to achieve auxiliary support.

[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A temporary support structure for a variable cross-section water conveyance tunnel that adapts and adjusts, characterized in that: The temporary support structure is a symmetrical structure, using an integrated temporary support (2). The temporary support (2) includes columns (3), beams (4), and connecting beams (5). At least two columns (3) are provided on each side of the temporary support (2), and the columns (3) are arranged close to the tunnel sidewall. The top of the column (3) is connected to an upper fixed beam (12) via a hinged support (18), and the middle of the column (3) is fixedly connected to a lower fixed beam (15). The upper fixed beam (12) and the lower fixed beam (15) are arranged in parallel. The upper fixed beam (12) is slidably connected to an upper movable beam (13), and an upper anchor block (14) is fixedly installed at the end of the upper movable beam (13); the lower fixed beam (15) is slidably connected to a lower movable beam (16), and a lower anchor block (17) is fixedly installed at the end of the lower movable beam (16); the upper movable beam (13) can slide relative to the upper fixed beam (12) along the length direction, so that the upper movable beam (13) and the upper fixed beam (12) are combined to form a beam body with variable length; the lower movable beam (16) can slide relative to the lower fixed beam (15) along the length direction, so that the lower movable beam (16) and the lower fixed beam (15) are combined to form a beam body with variable length; The upper fixed beam (12), upper movable beam (13), and upper anchor block (14) are respectively arranged vertically and vertically with the lower fixed beam (15), lower movable beam (16), and lower anchor block (17). A tie rod (10) is installed between the upper anchor block (14) and the lower anchor block (17). The tie rod (10) uses a jack as a power source. By adjusting the length of the tie rod (10), the end of the upper movable beam (13) is pulled, and the hinge support (18) is used as a fulcrum to drive the upper fixed beam (12) away from the hinge support (18) to rise and fall, thereby realizing the adjustment of the height of the support structure. Each pair of horizontally opposite columns (3) forms a group. The upper fixed beams (12) on the two groups of horizontally opposite columns (3) are respectively installed at the two bottom ends of an arched support (26). The arched support (26) includes at least a first support (6) and a second support (7). The arch support (26) and the upper fixed beam (12) are connected by a hinge end (11). The specific connection method is as follows: an upper hinge plate (19) is fixedly installed at the bottom end of the arch support (26), and a lower hinge plate (20) is fixedly installed at the upper end of the upper fixed beam (12). One end of the upper hinge plate (19) and the lower hinge plate (20) are hinged together by a hinge shaft (21), so that the connection end of the upper hinge plate (19) and the lower hinge plate (20) can rotate relative to each other around the hinge shaft (21). Anchor sleeves (22) and anchor plates (9) are distributed at intervals on the first support (6) and the second support (7). Several cables (8) are connected between the first support (6) and the second support (7). The ends of the cables (8) are installed on the anchor sleeves (22) and the anchor plates (9). By extending and retracting the length of the cables (8), the relative opening and closing degree of the first support (6) and the second support (7) is changed. During the opening and closing adjustment process, the upper hinge plate (19) at the bottom of the first support (6) and the second support (7) rotates relative to the lower hinge plate (20) on the upper fixed beam (12). By adjusting the angle and height, the adaptive support for tunnel arch height with different cross-sectional dimensions can be achieved.

2. The adaptive and adjustable temporary support structure for a variable cross-section water conveyance tunnel according to claim 1, characterized in that: The adjustment of the tie rod (10) is used to make the top of the arch support (26) fit tightly against the surrounding rock (1) of the tunnel.

3. The adaptive and adjustable temporary support structure for a variable cross-section water conveyance tunnel according to claim 1, characterized in that: By cooperating with the connecting beam (5) and the connecting rod (25), the two sets of temporary supports, namely the first unit (23) and the second unit (24), are spliced ​​together to form a combined support, thereby achieving continuous support for tunnels of different lengths.

4. The adaptive and adjustable temporary support structure for a variable cross-section water conveyance tunnel according to claim 1, characterized in that: The temporary support acts directly on the surrounding rock (1) of the tunnel, or a protective plate is laid on the upper part of the arch support (26) to achieve full support for the surrounding rock (1) through the protective plate, or it is laid in line with the initial support structure of the tunnel.

5. A construction method for an adaptive and adjustable temporary support structure for a variable cross-section water conveyance tunnel, comprising the adaptive and adjustable temporary support structure for a variable cross-section water conveyance tunnel as described in any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Pre-construction preparation Based on the tunnel design drawings and the actual excavation section, conduct surveying and setting out to determine the installation position of temporary supports; inspect and prepare the temporary support components required for construction, including columns (3), beams (4), connecting beams (5), upper fixed beams (12), lower fixed beams (15), upper movable beams (13), lower movable beams (16), upper anchor blocks (14), lower anchor blocks (17), tie rods (10), first supports (6), second supports (7), upper hinge plates (19), lower hinge plates (20), hinge shafts (21), anchor sleeves (22), anchor plates (9), cables (8), hinge supports (18), protective plates, and connecting rods (25); conduct quality inspections on the components to ensure that each part is intact, the sliding connection parts are well lubricated, and the hinge parts rotate flexibly; Step 2: Pre-assembly of temporary supports S21. Assembly of column (3) and beam: Connect column (3) with crossbeam (4) and connecting beam (5) to form a single-sided support frame; install hinge support (18) at the top of each column (3) and install upper fixed beam (12) on hinge support (18); fix lower fixed beam (15) in the middle of column (3) to ensure that upper fixed beam (12) and lower fixed beam (15) are parallel to each other; S22. Installation of movable beam: Slide the upper movable beam (13) onto the groove or guide rail of the upper fixed beam (12), and slide the lower movable beam (16) onto the groove or guide rail of the lower fixed beam (15); fix the upper anchor block (14) at the end of the upper movable beam (13), and fix the lower anchor block (17) at the end of the lower movable beam (16), ensuring that the upper anchor block (14) and the lower anchor block (17) are vertically aligned. S23. Installation of the tie rod system: Install the tie rod (10) between the upper anchor block (14) and the lower anchor block (17), and connect the jack to the tie rod (10) to form an adjustable tie rod power system; S24. Installation of arch support (26): Take two horizontally opposite columns (3) as a group and hoist the first support (6) and the second support (7) into place; align the upper hinge plate (19) at the bottom of the first support (6) and the upper hinge plate (19) at the bottom of the second support (7) with the lower hinge plate (20) on the corresponding side upper fixed beam (12) and insert the hinge shaft (21) to complete the hinge connection; install anchor sleeves (22) and anchor plates (9) at intervals on the first support (6) and the second support (7); connect several cables (8) between the first support (6) and the second support (7) and install the ends of the cables (8) on the anchor sleeves (22) and anchor plates (9) on the first support (6) and the second support (7) respectively; By adjusting the length of the telescopic cable (8), the opening and closing degree of the first support (6) and the second support (7) can be changed. During the opening and closing adjustment process, the upper hinge plate (19) at the bottom of the first support (6) and the second support (7) rotates relative to each other around the lower hinge plate (20) on the upper fixed beam (12). Step 3: Temporary support in place The assembled temporary supports are transported to the section of the tunnel to be supported, and the columns (3) are arranged close to the tunnel sidewalls, with at least two columns (3) on each side; the verticality and elevation of the columns (3) are adjusted and then temporarily fixed. Step 4: Adjusting the opening and closing degree of the arch support (26) According to the tunnel cross-section dimensions, the relative opening and closing degree of the two supports is adjusted by extending and retracting the length of several cables (8) connected between the first support (6) and the second support (7); during the adjustment process, the upper hinge plate (19) at the bottom of the first support (6) and the second support (7) rotates around the lower hinge plate (20) so that the central axis of the first support (6) forms a design angle α with the horizontal line, corresponding to the support height h1; or it is adjusted to an angle β, corresponding to the support height h2; through the above-mentioned corresponding changes in angle and height, the arch support (26) is adapted to the tunnel arch height of different cross-sections; Step 5: Fine adjustment of support height Start the jack connected to the tie rod (10), and drive the upper movable beam (13) to slide along the upper fixed beam (12) by changing the length of the tie rod (10); the sliding of the upper movable beam (13) drives the upper anchor block (14) to move, and with the hinge support (18) as the fulcrum, the end of the upper fixed beam (12) away from the hinge support (18) is raised or lowered; this action simultaneously drives the end of the arch support (26) hinged to the upper fixed beam (12) to move, so as to achieve a fine adjustment of the overall height of the arch support (26) until the arch support (26) is tightly attached to the surface of the tunnel surrounding rock (1); Step Six: Laying and Supporting the Protective Panels Choose one of the following three usage methods based on construction needs: Method 1: Temporary support is applied directly to the surrounding rock of the tunnel (1), so that the arch support (26) is in direct contact with the surrounding rock (1) to provide support; Method 2: Lay a protective plate on the upper part of the arch support (26) and fix the protective plate to the arch support (26) securely to achieve full support for the surrounding rock (1) through the protective plate; Method 3: The temporary supports are laid out in accordance with the initial support structure of the tunnel, and the connection nodes are tightened to achieve auxiliary support; Step 7: Construction of Multi-Unit Continuous Support For long tunnels that require continuous support, repeat steps two to six to complete the assembly and placement of the temporary support of the second unit (24); use connecting beams (5) and connecting rods (25) to longitudinally splice the adjacent temporary supports of the first unit (23) and the second unit (24) to form a combined support system.

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