A tunnel double-side wall pilot pit support system and construction method

Abstract

The present invention relates to the technical field of tunnel support, and more specifically, it relates to a tunnel double-side wall pilot pit method support system and construction method, comprising two L-shaped support frames, the two L-shaped support frames are mirror-imaged in the pilot pit, the two L-shaped support frames respectively form a closed structure of tunnel cavern upper steps with the inner side wall and the top surface of the pilot pit, each L-shaped support frame comprises a longitudinal plate and a transverse plate connected to each other, the inner end of the longitudinal plate is telescopically provided with a bottom plate, the inner end of the transverse plate is telescopically provided with a side plate, the bottom plate of the L-shaped support frame and the inner side wall and the bottom surface of the pilot pit form a closed structure of tunnel cavern lower steps, the side plates of the L-shaped support frame and the top surface of the pilot pit form a closed structure of tunnel middle cavern upper steps, and the side plates of the L-shaped support frame and the bottom surface of the pilot pit form a closed structure of core soil. The present invention can solve the problems of excessive materials to be prepared and complicated construction steps in the forming process of the support system of the double-side wall pilot pit method.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel support, in particular to a tunnel double-side wall pilot pit support system and a construction method. Background Art

[0002] The double-side wall pilot method, also known as the double-side wall pilot tunnel method or the glasses method, is a branch of the New Austrian Tunneling Method (NATM), based on the basic principles of the New Austrian Tunneling Method (NATM). When excavating the pilot pit, the disturbance to the surrounding rock is minimized, and the temporary support of the pilot pit is mostly constructed by combining grid steel frame, hanging net and shotcrete, so that the section is closed as soon as possible, so as to make full use of the self-bearing capacity of the surrounding rock and control the deformation of the surrounding rock.

[0003] like Figure 1 According to the prior art shown, when excavating the pilot pit, the upper step of the right cavern of the tunnel is excavated first, and then I-beams are erected, anchor rods are inserted and concrete is sprayed to form the support of area 1. Similarly, the lower step of the right cavern of the tunnel (area 2), the upper step of the left cavern of the tunnel (area 3), the lower step of the left cavern of the tunnel (area 4), the upper step of the middle cavern of the tunnel (area 5) and the excavation and support of the core soil (area 6) are carried out in sequence. Finally, the support system in the pilot pit is used to effectively control the deformation of the surrounding rock. After that, the temporary support can be removed after the cavern structure of the pilot pit reaches a stable state.

[0004] However, in the above-mentioned prior art, each part of the support system needs to be formed after erecting I-beams, inserting anchor rods and spraying concrete in sequence, resulting in excessive preparation of materials and cumbersome construction steps. Further improvements are still needed to improve the construction convenience of the double-side wall pilot tunnel method. Summary of the invention

[0005] In order to solve the problem that too much material needs to be prepared during the forming process of the support system of the double-side wall pilot tunnel method and the construction steps are cumbersome, the present application provides a tunnel double-side wall pilot tunnel method support system and construction method.

[0006] In a first aspect, the present invention provides a tunnel double-side wall pilot pit support system, which adopts the following technical solution:

[0007] A tunnel double-side wall pilot pit support system includes two L-shaped support frames, which are mirror-arranged in the pilot pit. The right L-shaped support frame forms a closed structure of the upper step of the right cavern of the tunnel with the right inner wall and the top surface of the pilot pit, and the left L-shaped support frame forms a closed structure of the upper step of the left cavern of the tunnel with the left inner wall and the top surface of the pilot pit. Each L-shaped support frame includes a longitudinal plate and a transverse plate connected to each other, the inner end of the longitudinal plate is telescopically provided with a bottom plate, and the inner end of the transverse plate is telescopically provided with a side plate, the bottom plate of the right L-shaped support frame and the right inner wall and the bottom surface of the pilot pit form a closed structure of the lower step of the right cavern of the tunnel, the bottom plate of the left L-shaped support frame and the left inner wall and the bottom surface of the pilot pit form a closed structure of the lower step of the left cavern of the tunnel, the side plates of the two L-shaped support frames and the top surface of the pilot pit form a closed structure of the upper step of the middle cavern of the tunnel, and the side plates of the two L-shaped support frames and the bottom surface of the pilot pit form a closed structure of the core soil.

[0008] Preferably, the longitudinal plate of the L-shaped support frame is arched with respect to the bottom plate.

[0009] Preferably, the longitudinal plate and the bottom plate of the L-shaped support frame are parallel to the vertical direction.

[0010] Preferably, a first cavity for accommodating the bottom plate is opened in the longitudinal plate, a first material port connected to the first cavity is opened in the longitudinal plate, and after the bottom plate is extended, the first cavity is filled with filler through the first material port; a second cavity for accommodating the side plate is opened in the transverse plate, and a second material port connected to the second cavity is provided in the transverse plate, and after the side plate is extended, the second cavity is filled with filler through the second material port.

[0011] Preferably, the material injected into the first cavity and the second cavity is liquid.

[0012] Preferably, the inner ends of the bottom plate and the side plates are both provided with sealing rings on their side walls.

[0013] Preferably, an avoidance hole is provided at the inner end of the bottom plate along the extension and contraction direction of the side plate.

[0014] Preferably, the L-shaped support frame is a steel structure.

[0015] Preferably, the outer ends of the longitudinal plate and the transverse plate of the L-shaped support frame are fixedly connected to the inner wall of the guide pit, the longitudinal plate and the bottom plate of the L-shaped support frame are fixedly connected after completion of extension, the transverse plate and the side plate of the L-shaped support frame are fixedly connected after completion of extension, and the side plates between the two L-shaped support frames are fixedly connected, and the above connections of the support system are all bolted connections.

[0016] In a second aspect, the present invention provides a construction method for a tunnel double-side wall pilot pit support system, which adopts the following technical solution:

[0017] A construction method of a tunnel double-side wall pilot pit support system, comprising the following steps:

[0018] S1: excavate the upper step of the right cavern of the tunnel, set up I-beams on the right wall and top surface of the cavern, insert anchor rods and spray concrete, and after forming, install one of the L-shaped support frames into the cavern and connect it to the inner wall and top surface of the pilot pit;

[0019] S2: excavate the lower step of the right cavern of the tunnel, set up I-beams on the right wall and bottom of the cavern, insert anchor rods and spray concrete, and after forming, pull out the bottom plate in the longitudinal plate of the L-shaped support frame above it, then fix the bottom plate with the longitudinal plate, connect the bottom plate with the bottom surface of the pilot pit, and fill the first cavity in the longitudinal plate with filler;

[0020] S3: excavate the upper step of the left cavern of the tunnel, set up I-beams on the left wall and top surface of the cavern, insert anchor rods and spray concrete, and after forming, install another L-shaped support frame into the cavern and connect it to the inner wall and top surface of the pilot pit;

[0021] S4: excavate the lower step of the left cavern of the tunnel, set up I-beams on the left wall and bottom of the cavern, insert anchor rods and spray concrete, and after forming, pull out the bottom plate in the longitudinal plate of the L-shaped support frame above it, then fix the bottom plate with the longitudinal plate, connect the bottom plate with the bottom surface of the pilot pit, and fill the first cavity in the longitudinal plate with filler;

[0022] S5: excavating the upper step of the middle cavern, setting up I-beams on the top surface of the cavern, inserting anchors and spraying concrete, and after forming, pulling out the side plates in the transverse plates of the two L-shaped support frames, and then fixing the side plates with the transverse plates, and fixing the two side plates, and filling the second cavity in the transverse plates with fillers;

[0023] S6: Excavate the core soil, set up I-beams on the bottom of the cavern, insert anchors and spray concrete to complete the construction of pilot pit excavation using the support system.

[0024] The beneficial effects of the present invention are:

[0025] By adopting the tunnel double-side wall pilot pit support system and construction method of the present invention, only the inner wall of the pilot pit needs to be equipped with I-beams, anchor rods inserted and concrete sprayed, and the support system is composed of two movable and deformable L-shaped support frames. Compared with the prior art, there is no need to prepare too much material and the construction steps are effectively simplified. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a plan view of a tunnel double side wall pilot tunnel support system in the background technology;

[0027] Figure 2 It is a plan view of the tunnel double side wall pilot pit method support system in the embodiment of the present application;

[0028] Figure 3 is a plan view of a tunnel double side wall pilot pit method support system in other embodiments;

[0029] Figure 4 is a cross-sectional view of a tunnel double-side wall pilot pit support system in an embodiment of the present application;

[0030] Explanation of the accompanying drawings: 11. L-shaped support frame; 12. Longitudinal plate; 13. Transverse plate; 14. Bottom plate; 15. Side plate; 16. First cavity; 17. First material opening; 18. Second cavity; 19. Second material opening; 20. Avoidance hole. DETAILED DESCRIPTION

[0031] The following will be combined with the attached Figure 2 -Attached Figure 4 The present invention is further illustrated by the following embodiments.

[0032] This embodiment discloses a tunnel double-side wall pilot pit support system.

[0033] Reference Figure 2 The tunnel double-side wall pilot pit support system includes two L-shaped support frames 11, which are mirror-imaged in the pilot pit. The right L-shaped support frame 11 forms a closed structure of the upper step (area 1) of the right cavern of the tunnel with the right inner wall and top surface of the pilot pit, and the left L-shaped support frame 11 forms a closed structure of the upper step (area 3) of the left cavern of the tunnel with the left inner wall and top surface of the pilot pit. Further, each L-shaped support frame 11 includes a longitudinal plate 12 and a transverse plate 13 connected to each other, the longitudinal plate 12 is biased in the vertical direction, and the transverse plate 13 is biased in the horizontal direction. The end where the longitudinal plate 12 and the transverse plate 13 are connected to the inner wall of the pilot pit is the outer end, and the end where the longitudinal plate 12 and the transverse plate 13 are connected to each other is the inner end. The inner end of the longitudinal plate 12 is telescopically provided with a bottom plate 14, and the inner end of the transverse plate 13 is telescopically provided with a side plate 15, wherein the bottom plate 14 of the right L-shaped support frame 11 and the side plate 15 are telescopically provided. The right inner wall and bottom surface of the pilot pit form a closed structure of the lower step of the right chamber of the tunnel (area 2), the bottom plate 14 of the left L-shaped support frame 11 and the left inner wall and bottom surface of the pilot pit form a closed structure of the lower step of the left chamber of the tunnel (area 4), the side plates 15 of the two L-shaped support frames 11 and the top surface of the pilot pit form a closed structure of the upper step of the middle chamber of the tunnel (area 5), ​​and the side plates 15 of the two L-shaped support frames 11 and the bottom surface of the pilot pit form a closed structure of the core soil (area 6).

[0034] Reference Figure 2In the present invention, the L-shaped support frame 11 is a steel structure and is prefabricated in the factory to achieve the effect of convenient processing and to facilitate the formation of a telescopic structure, while the inner wall of the guide pit is still formed by the steps of erecting I-beams, inserting anchor rods and spraying concrete. In order to achieve stable support of the support system, it is necessary to connect multiple key positions of the support system, wherein the outer ends of the longitudinal plate 12 and the transverse plate 13 of the L-shaped support frame 11 are fixedly connected to the inner wall of the guide pit, the longitudinal plate 12 of the L-shaped support frame 11 is fixedly connected to the bottom plate 14 after the elongation is completed, the transverse plate 13 of the L-shaped support frame 11 is fixedly connected to the side plate 15 after the elongation is completed, and the side plates 15 between the two L-shaped support frames 11 are fixedly connected. In this embodiment, the above multiple key positions of the support system are all connected by bolts. When the temporary support needs to be removed after the excavation of the cavern of the guide pit is completed, the bolt connection method of the support system has the effect of facilitating removal. In other embodiments, embedded connection, adhesive connection and other methods can also be used, as long as a fixed connection can be achieved.

[0035] Reference Figure 2 and Figure 3 In this embodiment, the longitudinal plate 12 of the L-shaped support frame 11 and the bottom plate 14 are arched, and the arched structure makes the stress distribution of the entire support system more uniform, reducing local stress concentration. In other embodiments, the longitudinal plate 12 of the L-shaped support frame 11 and the bottom plate 14 are parallel to the vertical direction, which can further simplify the construction and design, and can also simplify the management of the support system.

[0036] Reference Figure 2 and Figure 4After the bottom plate 14 extends out from the longitudinal plate 12, a first cavity 16 is formed in the longitudinal plate 12, and after the side plate 15 extends out from the transverse plate 13, a second cavity 18 is formed in the transverse plate 13. The longitudinal plate 12 and the transverse plate 13 are respectively provided with a first material port 17 connected to the first cavity 16 and a second material port 19 connected to the second cavity 18. Further, after the bottom plate 14 is extended and fixed, the first cavity 16 is filled with filling material through the first material port 17, and after the side plate 15 is extended and fixed, the second cavity 18 is filled with filling material through the second material port 19, so as to respectively improve the structural strength of the L-shaped support frame 11 at this time to provide a stable support effect. In this embodiment, the material injected into the first cavity 16 and the second cavity 18 is liquid, which is convenient for injection and discharge, and is convenient for repeated use of the L-shaped support frame 11. In addition, the inner ends of the bottom plate 14 and the side plates 15 are sleeved with sealing rings on their side walls. The sealing ring of the bottom plate 14 is used to maintain the sealing performance of the first cavity 16, and the sealing ring of the side plate 15 is used to maintain the sealing performance of the second cavity 18. The first material port 17 and the second material port 19 are both provided with screw caps. In the support stage, the screw caps can be opened to inject fillers into the first cavity 16 and the second cavity 18. In the removal stage, the screw caps can be opened to discharge the fillers in the first cavity 16 and the second cavity 18.

[0037] Reference Figure 2 and Figure 4 The inner end of the bottom plate 14 is provided with an avoidance hole 20 along the extension direction of the side plate 15. On the one hand, after the bottom plate 14 is extended, its inner end can avoid the extension and contraction of the side plate 15. On the other hand, after the side plate 15 passes through the bottom plate 14 during the extension process, the side plate 15 and the bottom plate 14 can achieve a mutual limiting effect, thereby improving the structural stability.

[0038] This embodiment also discloses a construction method of a tunnel double-side wall pilot pit support system.

[0039] Reference Figures 2 to 4 The construction method of the tunnel double side wall pilot tunnel support system includes the following steps:

[0040] S1: excavate the upper step of the right cavern of the tunnel (area 1), set up I-beams on the right wall and top surface of the cavern, insert anchor rods and spray concrete, and after forming, install one of the L-shaped support frames 11 into the cavern and connect it to the inner wall and top surface of the pilot pit;

[0041] S2: excavate the lower step of the right cavern of the tunnel (area 2), set up I-beams on the right side wall and bottom surface of the cavern, insert anchor rods and spray concrete, and after forming, pull out the bottom plate 14 in the longitudinal plate 12 of the upper L-shaped support frame 11, then fix the bottom plate 14 with the longitudinal plate 12, connect the bottom plate 14 with the bottom surface of the pilot pit, and fill the first cavity 16 in the longitudinal plate 12 with filler;

[0042] S3: excavate the upper step of the left cavern of the tunnel (area 3), set up I-beams on the left wall and top surface of the cavern, insert anchor rods and spray concrete, and after forming, install another L-shaped support frame 11 into the cavern and connect it to the inner wall and top surface of the pilot pit;

[0043] S4: excavate the lower step of the left tunnel chamber (area 4), set up I-beams on the left side wall and bottom surface of the tunnel chamber, insert anchor rods and spray concrete, and after forming, pull out the bottom plate 14 in the longitudinal plate 12 of the upper L-shaped support frame 11, then fix the bottom plate 14 with the longitudinal plate 12, connect the bottom plate 14 with the bottom surface of the pilot pit, and fill the first cavity 16 in the longitudinal plate 12 with filler;

[0044] S5: excavating the upper step of the middle cavern (area 5), ​​setting up I-beams on the top surface of the cavern, inserting anchors and spraying concrete, and after forming, pulling out the side plates 15 in the transverse plates 13 of the two L-shaped support frames 11, and then fixing the side plates 15 to the transverse plates 13, and fixing the two side plates 15, and filling the second cavity 18 in the transverse plates 13 with fillers;

[0045] S6: Excavate the core soil (area 6), set up I-beams on the bottom of the cavern, insert anchors and spray concrete to complete the construction of the pilot pit excavation using the support system.

[0046] To sum up, with the tunnel double-side wall pilot pit support system and construction method of the present invention, only the inner wall of the pilot pit needs to be equipped with I-beams, anchor rods inserted and concrete sprayed, and the support system is composed of two movable and deformable L-shaped support frames 11. Compared with the prior art, there is no need to prepare too much material and the construction steps are effectively simplified.

[0047] The above are all preferred embodiments of the present invention, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A construction method of a tunnel double-side wall pilot pit support system, characterized in that: The tunnel double-side wall pilot pit support system comprises two L-shaped support frames (11), the two L-shaped support frames (11) are arranged in a pilot pit in a mirror image, the right L-shaped support frame (11) and the right inner wall and top surface of the pilot pit form a closed structure of steps on the right cavern of the tunnel, and the left L-shaped support frame (11) and the left inner wall and top surface of the pilot pit form a closed structure of steps on the left cavern of the tunnel, the L-shaped support frame (11) comprises a longitudinal plate (12) and a transverse plate (13) connected to each other, the inner end of the longitudinal plate (12) is telescopically provided with a bottom plate (14), and the inner end of the transverse plate (13) is A side plate (15) is telescopically provided, the bottom plate (14) of the right L-shaped support frame (11) and the right inner wall and bottom surface of the pilot pit form a closed structure of the lower step of the right cavern of the tunnel, the bottom plate (14) of the left L-shaped support frame (11) and the left inner wall and bottom surface of the pilot pit form a closed structure of the lower step of the left cavern of the tunnel, the side plates (15) of the two L-shaped support frames (11) and the top surface of the pilot pit form a closed structure of the upper step of the middle cavern of the tunnel, and the side plates (15) of the two L-shaped support frames (11) and the bottom surface of the pilot pit form a closed structure of the core soil; A first cavity (16) for accommodating the bottom plate (14) is provided in the longitudinal plate (12), a first material opening (17) communicating with the first cavity (16) is provided in the longitudinal plate (12), and after the bottom plate (14) is extended, the first cavity (16) is filled with filler through the first material opening (17), a second cavity (18) for accommodating the side plate (15) is provided in the transverse plate (13), and a second material opening (19) communicating with the second cavity (18) is provided in the transverse plate (13), and after the side plate (15) is extended, the second cavity (18) is filled with filler through the second material opening (19); The following steps are involved: S1: excavating the upper step of the right cavern of the tunnel, erecting I-beams on the right side wall and top surface of the cavern, inserting anchor rods and spraying concrete, and after forming, installing one of the L-shaped support frames (11) into the cavern and connecting it to the inner side wall and top surface of the pilot pit; S2: excavating the lower step of the right cavern of the tunnel, erecting I-beams on the right side wall and bottom surface of the cavern, inserting anchor rods and spraying concrete, and after forming, pulling out the bottom plate (14) in the longitudinal plate (12) of the L-shaped support frame (11) above it, and then fixing the bottom plate (14) to the longitudinal plate (12), and connecting the bottom plate (14) to the bottom surface of the pilot pit, and filling the first cavity (16) in the longitudinal plate (12) with filler; S3: excavating the upper step of the left cavern of the tunnel, erecting I-beams on the left side wall and top surface of the cavern, inserting anchor rods and spraying concrete, and after forming, installing another L-shaped support frame (11) into the cavern and connecting it to the inner side wall and top surface of the pilot pit; S4: excavating the lower step of the left cavern of the tunnel, erecting I-beams on the left side wall and bottom surface of the cavern, inserting anchor rods and spraying concrete, and after forming, pulling out the bottom plate (14) in the longitudinal plate (12) of the L-shaped support frame (11) above it, and then fixing the bottom plate (14) to the longitudinal plate (12), and connecting the bottom plate (14) to the bottom surface of the pilot pit, and filling the first cavity (16) in the longitudinal plate (12) with filler; S5: excavating the upper steps of the middle cavern, erecting I-beams on the top surface of the cavern, inserting anchor rods and spraying concrete, and after forming, pulling out the side panels (15) in the transverse panels (13) of the two L-shaped support frames (11), and then fixing the side panels (15) to the transverse panels (13), and fixing the two side panels (15) to each other, and filling the second cavity (18) in the transverse panel (13) with fillers; S6: excavating core soil, setting up I-beams on the bottom surface of the cavern, inserting anchor rods and spraying concrete, and completing the construction of the pilot pit excavation using the support system.

2. The construction method of a tunnel double-side wall pilot pit support system according to claim 1 is characterized in that: The longitudinal plate (12) and the bottom plate (14) of the L-shaped support frame (11) are in an arch shape.

3. The construction method of a tunnel double-side wall pilot pit support system according to claim 1 is characterized in that: The longitudinal plate (12) and the bottom plate (14) of the L-shaped support frame (11) are both parallel to the vertical direction.

4. The construction method of a tunnel double-side wall pilot pit support system according to claim 1 is characterized in that: The material injected into the first cavity (16) and the second cavity (18) is liquid.

5. The construction method of a tunnel double-side wall pilot pit support system according to claim 4 is characterized in that: The inner end of the bottom plate (14) and the inner end of the side plate (15) are both sleeved with sealing rings on their side walls.

6. The construction method of a tunnel double-side wall pilot pit support system according to claim 1, characterized in that: An avoidance hole (20) is provided at the inner end of the bottom plate (14) along the telescopic direction of the side plate (15).

7. The construction method of a tunnel double-side wall pilot pit support system according to claim 1, characterized in that: The L-shaped support frame (11) is a steel structure.

8. The construction method of a tunnel double-side wall pilot pit support system according to claim 1, characterized in that: The outer ends of the longitudinal plate (12) and the transverse plate (13) of the L-shaped support frame (11) are fixedly connected to the inner wall of the guide pit; the longitudinal plate (12) of the L-shaped support frame (11) is fixedly connected to the bottom plate (14) after completion of extension; the transverse plate (13) of the L-shaped support frame (11) is fixedly connected to the side plate (15) after completion of extension; the side plates (15) between the two L-shaped support frames (11) are fixedly connected to each other; and the above connections of the support system are all bolted connections.

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