Sandstone and mudstone large-section tunnel excavation support structure

Abstract

This invention belongs to the field of tunnel support technology, specifically a support structure for large-section tunnel excavation in sandstone and mudstone. It includes a pair of support plates, with an inflatable rubber plate fixedly connected to the top of each support plate. An elastic rubber plate is also fixedly connected to the top of the inflatable rubber plate. After installation inside the tunnel, gas is injected into the inflatable rubber plate, causing it to expand and compress the elastic rubber plate. This ensures the elastic rubber plate fits tightly against the tunnel's inner wall. Simultaneously, the elastic rubber plate undergoes elastic deformation, actively filling any voids and preventing gaps between the tunnel's inner wall and the elastic rubber plate. This achieves surface contact and even force transmission, significantly reducing stress concentration. Furthermore, the angle between the pair of support plates can be adjusted to accommodate tunnel inner walls of different shapes, making it widely applicable. When the ground subsides, the support columns can be moved upwards to ensure the elastic rubber plate remains in contact with the tunnel's inner wall, guaranteeing effective tunnel support.

Description

Technical Field

[0001] This invention belongs to the field of tunnel support technology, specifically a support structure for excavating large-section tunnels in sandstone and mudstone. Background Technology

[0002] In tunnel construction, especially in mountainous and hilly areas, geological conditions such as sandstone and mudstone are frequently encountered. These rock masses exhibit significant differences in strength; mudstone is prone to softening and disintegration when exposed to water, exhibiting poor self-stability; while sandstone layers are relatively hard but may contain joints and fissures. When excavating large-section tunnels to meet traffic demands, a huge free face is created, severely disrupting the original stress balance of the strata. This can easily lead to surrounding rock relaxation, deformation, rockfall, or even large-scale collapse, posing a serious threat to construction safety and project progress. Therefore, during tunnel excavation, support structures are used to support and protect the tunnel interior, improving the safety of workers and ensuring the smooth progress of tunnel excavation.

[0003] The existing steel arch frames in the support structures for large-section sandstone and mudstone tunnels are straight steel sections, while the excavation profile is an irregular curved surface. There are usually gaps between the two. Although concrete blocks are used to fill the gaps, the contact points are few and random, resulting in the inability to evenly transmit the surrounding rock pressure to the arch frames. This causes excessive local bending moments and torsional instability in the arch frames. The shotcrete layer is also prone to peeling and falling off due to uneven bonding with the surrounding rock. Therefore, the present invention provides a support structure for excavation of large-section tunnels in sandstone and mudstone. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0005] The technical solution adopted by the present invention to solve its technical problem is: the present invention provides a support structure for excavation of large-section tunnels in sandstone and mudstone, including a pair of support plates, the top of which is fixedly connected to a rubber inflatable plate, and the top of which is fixedly connected to an elastic rubber plate. The support plate is equipped with an air pump and a controller inside, and the air outlet of the air pump is connected to the rubber inflatable plate. The bottom of the support plate is fixedly connected to several connecting frames. Inside the connecting frames, a fixed plate is rotatably connected via a rotating block. The bottom of the fixed plate is fixedly connected to a support column, and a sleeve base is fitted onto the bottom end of the support column. A circular plate is fixedly fitted onto the surface of the support column. An air inlet pipe is fixedly connected between the bottom of the circular plate and the top of the sleeve base. An air inlet valve is installed on the air inlet pipe. An air pump and a controller are installed inside the circular plate. The socket base has a plug hole, and the socket base has an internal hole that communicates with the plug hole. The internal hole communicates with the plug hole, and a support plate is fixedly connected inside the internal hole. The support plate has an air inlet, and the bottom end of the air inlet pipe is located below the support plate. In the initial state, the bottom end of the support column abuts against the top of the support plate. A pair of arc-shaped grooves are provided on the circular plate, and an arc-shaped plate is movably inserted inside the arc-shaped grooves. A switch valve and a controller are provided on the arc-shaped grooves, and the air outlet of the second air pump is connected to the arc-shaped grooves.

[0006] Preferably, a limiting ring is fixedly sleeved on the outer side of the bottom end of the support column. The outer diameter of the limiting ring is larger than the diameter of the insertion hole. A sealing groove is opened on the outer side of the limiting ring. A sealing ring is fixedly connected inside the sealing groove. The outer side of the sealing ring abuts against the inside of the inner hole.

[0007] Preferably, a protective cover is fitted to the outside of the support column, the protective cover is sleeved on the outside of the air intake pipe, the top of the protective cover abuts against the bottom wall of the circular plate, the bottom of the protective cover abuts against the top of the sleeve base, a plug-in plate is fixedly connected to the bottom of the protective cover, and the top of the sleeve base is provided with an installation groove that matches the plug-in plate.

[0008] Preferably, the inner wall of the mounting groove is coated with a magnetic coating first, and both sides of the plug plate are coated with a magnetic coating second that is magnetically connected to the magnetic coating first.

[0009] Preferably, a first sensor and a controller are provided on the inner wall of the protective cover, and a leakage warning light is provided on the outer side of the protective cover.

[0010] Preferably, a connecting block is fixedly connected to the top of the fixing plate, an electric push rod is fixedly connected to each of the two sides of the connecting block, a reinforcing block is fixedly connected to the telescopic end of the electric push rod, and a reinforcing hole adapted to the reinforcing block is opened on each of the two inner sidewalls of the connecting frame.

[0011] Preferably, the elastic rubber plate is equipped with a controller and a second sensor, and the bottom of the support plate is fixedly connected with several equally spaced indicator lights. The second sensor and the indicator lights are electrically connected to the controller through wires.

[0012] Preferably, a vertical block is fixedly connected to the bottom of the support plate, and an electric push rod two is fixedly connected to the side of the vertical block. A scraper is fixedly connected to the telescopic end of the electric push rod two, and the conical side of the scraper abuts against the bottom of the support plate.

[0013] Preferably, each of the two inner sidewalls of the arc-shaped groove is provided with a sliding groove, and each of the two sidewalls of the arc-shaped plate is fixedly connected with a slider that matches the sliding groove.

[0014] Preferably, a rectangular groove is provided on one side of each pair of support plates that are close to each other. A telescopic airbag plate is slidably and sealed inside the rectangular groove. Several springs are fixedly connected between the telescopic airbag plate and the rectangular groove. A telescopic rubber frame is fixedly connected to the outside of the telescopic airbag plate. An air pump and controller are provided inside the telescopic airbag plate. The air outlet of the air pump is connected to the telescopic airbag plate. In the initial state, the springs are in a contracted state. A side wall groove is provided on one pair of inner side walls of the rectangular groove. A movable block adapted to the side wall groove is fixedly connected to one pair of side sides of the telescopic rubber frame.

[0015] The beneficial effects of this invention are as follows: 1. The present invention relates to a support structure for large-section tunnel excavation in sandstone and mudstone. After the present invention is installed inside the tunnel, gas is injected into the rubber inflatable plate to expand and compress the elastic rubber plate, so that the elastic rubber plate fits tightly against the tunnel ceiling. At the same time, the elastic rubber plate will undergo elastic deformation to actively fill the voids and prevent gaps from forming between the tunnel ceiling and the elastic rubber plate. This achieves surface contact and uniform force transmission, greatly reducing stress concentration. Furthermore, by adjusting the included angle between a pair of support plates, it can be made to abut against tunnel ceilings of different shapes, thus having a wide range of applications. When the ground subsides, the support columns can be moved upward to ensure that the elastic rubber plate always abuts against the tunnel ceiling, guaranteeing the support effect for the tunnel.

[0016] 2. The sandstone and mudstone large-section tunnel excavation support structure of the present invention involves adjusting the included angle between a pair of support plates so that they abut against the tunnel inner wall of different shapes. Under the action of spring thrust, the telescopic airbag plate and the telescopic rubber frame are moved together to the outside of the rectangular groove, so that the sides of the pair of opposing telescopic rubber frames abut against each other. Then, the air pump is started to inject air into the telescopic airbag plate, causing it to expand and push the telescopic rubber frame, so that the side of the telescopic rubber frame fits tightly against the tunnel inner wall. This ensures the support effect on the tunnel inner wall after the position of the support plates is adjusted, and prevents soil and rocks from falling between the pair of support plates. Attached Figure Description

[0017] The invention will now be further described with reference to the accompanying drawings.

[0018] Figure 1 This is a perspective view of the present invention; Figure 2 This is a schematic diagram of the protective cover in this invention; Figure 3 This is an enlarged view of point A in this invention; Figure 4 This is a schematic diagram of the arc-shaped plate in this invention; Figure 5 This is an enlarged view of point B in this invention; Figure 6 This is a schematic diagram of the bottom of the support plate in this invention; Figure 7 This is a schematic diagram of the socket base in this invention; Figure 8 This is a schematic diagram of the telescopic rubber frame in this invention; Figure 9 This is a schematic diagram of the interior of the rectangular groove in this invention.

[0019] In the diagram: 1. Support plate; 2. Rubber inflatable plate; 3. Elastic rubber plate; 4. Rotating block; 5. Fixing plate; 6. Support column; 7. Sleeve base; 8. Circular plate; 9. Air inlet pipe; 10. Insertion hole; 11. Internal hole; 12. Support plate; 13. Air inlet; 14. Limiting ring; 15. Sealing ring; 16. Protective cover; 17. Insertion plate; 18. Mounting groove; 19. Magnetic coating one; 20. Magnetic coating two; 1. Connecting block; 22. Electric push rod one; 23. Reinforcing block; 24. Reinforcing hole; 25. Arc groove; 26. Arc plate; 27. Vertical block; 28. Electric push rod two; 29. ​​Scraper; 30. Indicator light; 31. Slide groove; 32. Slider; 33. Rectangular groove; 34. Telescopic airbag plate; 35. Telescopic rubber frame; 36. Spring; 37. Side wall groove; 38. Moving block; 39. Connecting frame; 40. Air leakage warning light. Detailed Implementation

[0020] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0021] Example 1: As Figures 1 to 5 As shown in the embodiment of the present invention, a support structure for excavation of a large-section tunnel in sandstone and mudstone includes a pair of support plates 1, with a rubber inflatable plate 2 fixedly connected to the top of the support plate 1, and an elastic rubber plate 3 fixedly connected to the top of the rubber inflatable plate 2. The support plate 1 is equipped with an air pump and a controller. The air outlet of the air pump is connected to the rubber inflatable plate 2. The bottom of the support plate 1 is fixedly connected to several connecting frames 39. The inside of the connecting frame 39 is rotatably connected to a fixed plate 5 through a rotating block 4. The bottom of the fixed plate 5 is fixedly connected to a support column 6. The bottom end of the support column 6 is fitted with a sleeve base 7. A circular plate 8 is fixedly sleeved on the surface of the support column 6. An air inlet pipe 9 is fixedly connected between the bottom of the circular plate 8 and the top of the sleeve base 7. An air inlet valve is provided on the air inlet pipe 9. An air pump and a controller are provided inside the circular plate 8. The socket base 7 has a plug hole 10, and the socket base 7 has an internal hole 11 that communicates with the plug hole 10. The internal hole 11 communicates with the plug hole 10, and a support plate 12 is fixedly connected inside the internal hole 11. The support plate 12 has an air inlet 13, and the bottom end of the air inlet pipe 9 is located below the support plate 12. In the initial state, the bottom end of the support column 6 abuts against the top of the support plate 12. A pair of arc-shaped grooves 25 are provided on the circular plate 8. An arc-shaped plate 26 is movably inserted inside the arc-shaped grooves 25. A switch valve and a controller are provided on the arc-shaped grooves 25. The air outlet of the second air pump is connected to the arc-shaped grooves 25.

[0022] In the existing technology, the steel arch frame on the existing sandstone and mudstone large-section tunnel excavation support structure is a straight steel section, while the excavation profile is an irregular curved surface. There is usually a gap between the two. Although concrete blocks are filled, the contact points are few and random, which makes it impossible to evenly transmit the surrounding rock pressure to the arch frame. This results in excessive local bending moment and torsional instability of the arch frame. The shotcrete layer is also prone to peeling and falling off due to uneven bonding with the surrounding rock. The present invention is used in the following steps: Step 1: When supporting the tunnel ceiling, the elastic rubber plate 3 needs to be moved so that its top is against the tunnel ceiling, and the socket base 7 is placed on the ground. The bottom end of the support column 6 is inserted into the insertion hole 10, and the support column 6 is used to support the support plate 1 and all the mechanisms on it. Start the air pump 1 to inject air into the rubber air plate 2, causing it to expand and push the elastic rubber plate 3 to fit tightly against the tunnel ceiling. At the same time, the elastic rubber plate 3 will deform under pressure to actively fill the tunnel cavities, making it difficult for soil and rocks on the tunnel ceiling to fall and optimizing the support effect. Step 2: When the shape of the tunnel ceiling is concave or convex, the side of the pair of support plates 1 that is close to each other should be rotated upwards, or the side of the pair of support plates 1 that is close to each other should be rotated downwards, in order to adjust the angle formed between the pair of support plates 1 until the side of the elastic rubber plate 3 away from the rubber inflatable plate 2 is in contact with the tunnel ceiling. Then repeat the operation in Step 1 to make the rubber inflatable plate 2 deform under pressure, so as to actively fill the tunnel cavity. When the support plate 1 rotates up and down, it will drive the connecting frame 39 to rotate on the fixed plate 5. After adjusting the angle of the support plate 1, the second air pump is started to fill one of the arc grooves 25 with air, which pushes the arc plate 26 upward and gradually approaches the connecting frame 39 until the top of the arc plate 26 abuts against the connecting frame 39, so as to use the arc plate 26 to support the connecting frame 39 and improve the stability of the support plate 1. While keeping the included angle between a pair of support plates 1 constant, the distance between a pair of support columns 6 can be changed by adjusting the inclination of the pair of support columns 6 so that equipment of different sizes can pass between the pair of support columns 6. Step 3: When the entire invention moves down due to ground subsidence, the second air pump needs to be started to inject gas into the sleeve base 7 through the air inlet pipe 9. Then, under the action of gas thrust, the support column 6 and all the mechanisms on it will move up together until the elastic rubber plate 3 is tightly attached to the tunnel ceiling.

[0023] In summary, after the present invention is installed inside the tunnel, gas is injected into the rubber inflatable plate 2 to expand and compress the elastic rubber plate 3, so that the elastic rubber plate 3 fits tightly against the tunnel ceiling. At the same time, the elastic rubber plate 3 will undergo elastic deformation to actively fill the voids and prevent gaps from forming between the tunnel ceiling and the elastic rubber plate 3, thereby achieving surface contact and uniform force transmission, greatly reducing stress concentration. Moreover, by adjusting the included angle between a pair of support plates 1, it can be made to abut against tunnel ceilings of different shapes, making it widely applicable. When the ground sinks, the support column 6 is moved upward to ensure that the elastic rubber plate 3 always abuts against the tunnel ceiling, ensuring the support effect for the tunnel.

[0024] like Figure 7 As shown, a limiting ring 14 is fixedly sleeved on the outer side of the bottom end of the support column 6. The outer diameter of the limiting ring 14 is larger than the diameter of the insertion hole 10. A sealing groove is opened on the outer side of the limiting ring 14. A sealing ring 15 is fixedly connected inside the sealing groove. The outer side of the sealing ring 15 abuts against the inside of the inner hole 11. When the support column 6 moves upward, it will drive the limiting ring 14, causing the limiting ring 14 to move within the internal hole 11. The limiting ring 14 can prevent the support column 6 from separating from the sleeve base 7.

[0025] like Figure 2 As shown, a protective cover 16 is placed on the outer side of the support column 6. The protective cover 16 is sleeved on the outer side of the air intake pipe 9. The top of the protective cover 16 abuts against the bottom wall of the circular plate 8, and the bottom of the protective cover 16 abuts against the top of the sleeve base 7. A plug-in plate 17 is fixedly connected to the bottom of the protective cover 16. The top of the sleeve base 7 is provided with an installation groove 18 that matches the plug-in plate 17. The connector plate 17 needs to be inserted into the mounting slot 18 to install the protective cover 16 on the socket base 7. The protective cover 16 is used to protect the air intake pipe 9 so that it is not easily pulled or broken by foreign objects.

[0026] like Figure 2 and Figure 7As shown, the inner wall of the mounting groove 18 is coated with a magnetic coating 19, and a pair of sides of the plug-in plate 17 are coated with a magnetic coating 20 that is magnetically connected to the magnetic coating 19. After the plug plate 17 is inserted into the mounting slot 18, the magnetic coating 19 will be magnetically connected to the magnetic coating 20, thereby improving the stability of the plug plate 17 in the mounting slot 18, and consequently improving the stability of the protective cover 16 outside the air intake pipe 9.

[0027] like Figure 2 As shown, a first sensor and a controller are provided on the inner wall of the protective cover 16, and a leak warning light 40 is provided on the outer side of the protective cover 16. The first sensor is used to detect whether the air intake pipe 9 is damaged and leaking. If a leak occurs, the leak warning light 40 will light up to remind personnel to carry out maintenance.

[0028] like Figure 3 and Figure 4 As shown, a connecting block 21 is fixedly connected to the top of the fixed plate 5. An electric push rod 22 is fixedly connected to a pair of sides of the connecting block 21. A reinforcing block 23 is fixedly connected to the telescopic end of the electric push rod 22. A reinforcing hole 24 adapted to the reinforcing block 23 is opened on a pair of inner side walls of the connecting frame 39. After the support plate 1 is installed, the electric push rod 22 is activated to push one side of the reinforcing block 23 into the reinforcing hole 24 to improve the stability of the connecting frame 39 and all its mechanisms.

[0029] like Figure 6 As shown, the elastic rubber plate 3 is equipped with a controller and a second sensor inside. Several equally spaced indicator lights 30 are fixedly connected to the bottom of the support plate 1. The second sensor and the indicator lights 30 are electrically connected to the controller through wires. When the elastic rubber plate 3 is damaged and does not adhere to the tunnel ceiling, the indicator lights 30 will light up to give a visual signal to remind personnel and to help personnel determine the abnormal location.

[0030] like Figure 6 As shown, a vertical block 27 is fixedly connected to the bottom of the support plate 1, and an electric push rod 28 is fixedly connected to the side of the vertical block 27. A scraper 29 is fixedly connected to the telescopic end of the electric push rod 28. The conical side of the scraper 29 abuts against the bottom of the support plate 1. During use, the electric push rod 28 needs to be activated periodically to push the scraper 29 to move at the bottom of the support plate 1, so as to scrape off the dust and foreign matter adhering to the indicator light 30 and improve the cleanliness of the indicator light 30.

[0031] like Figure 4As shown, a sliding groove 31 is provided on each of the two inner sidewalls of the arc groove 25, and a slider 32 adapted to the sliding groove 31 is fixedly connected to each of the two sidewalls of the arc plate 26. The slider 32 can prevent the arc plate 26 from separating from the arc groove 25.

[0032] Example 2: Figure 8 and Figure 9 As shown in the comparative embodiment one, another embodiment of the present invention is as follows: a rectangular groove 33 is provided on one side of each pair of support plates 1 that are close to each other. A telescopic airbag plate 34 is slidably and sealed inside the rectangular groove 33. A plurality of springs 36 are fixedly connected between the telescopic airbag plate 34 and the rectangular groove 33. A telescopic rubber frame 35 is fixedly connected to the outside of the telescopic airbag plate 34. An air pump 3 and a controller are provided inside the telescopic airbag plate 34. The air outlet of the air pump 3 is connected to the telescopic airbag plate 34. In the initial state, the springs 36 are in a contracted state. A side wall groove 37 is provided on one pair of inner side walls of the rectangular groove 33. A movable block 38 adapted to the side wall groove 37 is fixedly connected to one pair of side sides of the telescopic rubber frame 35. The movable block 38 can prevent the telescopic rubber frame 35 from separating from the rectangular groove 33.

[0033] In use, the present invention adjusts the included angle between a pair of support plates 1 so that they abut against the tunnel ceiling of different shapes. Under the action of the spring 36, the telescopic airbag plate 34 and the telescopic rubber frame 35 are pushed together to move outward of the rectangular groove 33, so that the sides of the pair of opposing telescopic rubber frames 35 abut against each other. Then, the air pump 3 is started to inject air into the telescopic airbag plate 34 to make it expand and push the telescopic rubber frame 35 so that the side of the telescopic rubber frame 35 fits tightly against the tunnel ceiling. This ensures the support effect on the tunnel ceiling after the position of the support plates 1 is adjusted, and prevents soil and rocks from falling between the pair of support plates 1.

[0034] The terms "front," "back," "left," "right," "top," and "bottom" all refer to the figures in the accompanying drawings. Figure 1 Based on the perspective of the observer, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0035] In the description of this invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0036] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A support structure for excavating large-section tunnels in sandstone and mudstone, characterized in that: It includes a pair of support plates (1), the top of which is fixedly connected to a rubber inflatable plate (2), and the top of which is fixedly connected to an elastic rubber plate (3). The support plate (1) is equipped with an air pump and a controller. The air outlet of the air pump is connected to the rubber inflatable plate (2). The bottom of the support plate (1) is fixedly connected to several connecting frames (39). The inside of the connecting frame (39) is rotatably connected to a fixed plate (5) through a rotating block (4). The bottom of the fixed plate (5) is fixedly connected to a support column (6). The bottom end of the support column (6) is fitted with a sleeve base (7). A circular plate (8) is fixedly fitted on the surface of the support column (6). An air inlet pipe (9) is fixedly connected between the bottom of the circular plate (8) and the top of the sleeve base (7). An air inlet valve is provided on the air inlet pipe (9). An air pump and a controller are provided inside the circular plate (8). The socket base (7) is provided with a plug hole (10), and the socket base (7) is provided with an internal hole (11) that communicates with the plug hole (10). The internal hole (11) communicates with the plug hole (10). A support plate (12) is fixedly connected inside the internal hole (11). An air inlet (13) is provided on the support plate (12). The bottom end of the air inlet pipe (9) is located below the support plate (12). In the initial state, the bottom end of the support column (6) abuts against the top of the support plate (12). A pair of arc-shaped grooves (25) are provided on the circular plate (8). An arc-shaped plate (26) is movably inserted inside the arc-shaped groove (25). A switch valve and a controller are provided on the arc-shaped groove (25). The air outlet of the second air pump is connected to the arc-shaped groove (25).

2. The support structure for excavation of large-section tunnels in sandstone and mudstone as described in claim 1, characterized in that: A limiting ring (14) is fixedly sleeved on the outer side of the bottom end of the support column (6). The outer diameter of the limiting ring (14) is larger than the diameter of the insertion hole (10). A sealing groove is opened on the outer side of the limiting ring (14). A sealing ring (15) is fixedly connected inside the sealing groove. The outer side of the sealing ring (15) abuts against the inside of the inner hole (11).

3. The support structure for excavation of large-section tunnels in sandstone and mudstone as described in claim 1, characterized in that: A protective cover (16) is placed on the outside of the support column (6). The protective cover (16) is sleeved on the outside of the air intake pipe (9). The top of the protective cover (16) abuts against the bottom wall of the circular plate (8). The bottom of the protective cover (16) abuts against the top of the sleeve base (7). A plug plate (17) is fixedly connected to the bottom of the protective cover (16). The top of the sleeve base (7) is provided with an installation groove (18) that matches the plug plate (17).

4. The support structure for excavation of large-section tunnels in sandstone and mudstone as described in claim 3, characterized in that: The inner wall of the mounting groove (18) is coated with a magnetic coating first (19), and the two sides of the plug plate (17) are coated with a magnetic coating second (20) that is magnetically connected to the magnetic coating first (19).

5. The support structure for excavation of large-section tunnels in sandstone and mudstone as described in claim 3, characterized in that: The inner wall of the protective cover (16) is provided with a first sensor and a controller, and the outer side of the protective cover (16) is provided with a leakage warning light (40).

6. The support structure for excavation of large-section tunnels in sandstone and mudstone as described in claim 1, characterized in that: The top of the fixed plate (5) is fixedly connected to a connecting block (21), and a pair of electric push rods (22) are fixedly connected to each of the two sides of the connecting block (21). A reinforcing block (23) is fixedly connected to the telescopic end of the electric push rod (22). A reinforcing hole (24) that matches the reinforcing block (23) is opened on each of the two inner sidewalls of the connecting frame (39).

7. The support structure for excavation of large-section tunnels in sandstone and mudstone as described in claim 1, characterized in that: The elastic rubber plate (3) is equipped with a controller and a second sensor. The bottom of the support plate (1) is fixedly connected with several equally spaced indicator lights (30). The second sensor and the indicator lights (30) are electrically connected to the controller through wires.

8. The support structure for excavation of large-section tunnels in sandstone and mudstone as described in claim 1, characterized in that: A vertical block (27) is fixedly connected to the bottom of the support plate (1), and an electric push rod (28) is fixedly connected to the side of the vertical block (27). A scraper (29) is fixedly connected to the telescopic end of the electric push rod (28), and the conical side of the scraper (29) abuts against the bottom of the support plate (1).

9. The support structure for excavation of large-section tunnels in sandstone and mudstone as described in claim 1, characterized in that: The arc groove (25) has a sliding groove (31) on each of its two inner sidewalls, and the arc plate (26) has a slider (32) that is compatible with the sliding groove (31) fixedly connected to each of its two sidewalls.

10. The support structure for excavation of large-section tunnels in sandstone and mudstone as described in claim 1, characterized in that: A rectangular groove (33) is provided on one side of each of the two support plates (1) that are close to each other. A telescopic airbag plate (34) is slidably and sealed inside the rectangular groove (33). Several springs (36) are fixedly connected between the telescopic airbag plate (34) and the rectangular groove (33). A telescopic rubber frame (35) is fixedly connected to the outside of the telescopic airbag plate (34). An air pump and a controller are provided inside the telescopic airbag plate (34). The air outlet of the air pump is connected to the telescopic airbag plate (34). In the initial state, the springs (36) are in a contracted state. A side wall groove (37) is provided on one of the two inner side walls of the rectangular groove (33). A moving block (38) that matches the side wall groove (37) is fixedly connected to one of the two sides of the telescopic rubber frame (35).

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