Independent double-hole straight middle wall multi-arch tunnel

Abstract

The utility model provides an independent double-hole straight middle wall multi-arch tunnel, which relates to the technical field of tunnel construction, and comprises a front hole and a rear hole which are arranged in parallel, a straight middle wall is arranged between the front hole and the rear hole, and common hollow grouting anchor rods and lengthened hollow grouting anchor rods are arranged in surrounding rock surrounding the front hole and the rear hole at intervals. The first hole and the second hole are sequentially provided with a second lining and a primary support from inside to outside, an expanding excavation replacement filling area is arranged on the side, close to the straight middle wall, of the first hole, a plurality of vertical I-shaped steel is arranged in the expanding excavation replacement filling area at intervals in the length direction of the first hole, and the vertical I-shaped steel is arranged close to the side, away from the first hole, of the expanding excavation replacement filling area. The outer side of the I-shaped steel is wrapped with sprayed concrete. The stress form of the tunnel structure is improved, and the tunnel structure is more suitable for the working condition that the middle line distance of the straight middle wall multi-arch tunnel is large.

Description

Technical Field

[0001] This utility model relates to the field of tunnel construction technology, and in particular to an independent twin-bore straight-center-walled arch tunnel. Background Technology

[0002] In cases where tunnels connect to large bridges, a twin-arch tunnel structure is typically constructed at the tunnel entrance to ensure smooth alignment. Twin-arch tunnels are mainly classified into two categories based on their structural characteristics: straight-center-wall twin-arch tunnels and curved-center-wall twin-arch tunnels. For these types of tunnels, the three-pilot tunnel method is widely used for construction. The specific steps include: first, excavating the central pilot tunnel and simultaneously implementing initial support; then, constructing the central partition wall; next, ensuring that the pilot tunnel and the subsequent tunnel are staggered and parallel, carrying out excavation and support work; and finally, before constructing the secondary lining of the subsequent tunnels, the temporary support structure of the central pilot tunnel must be removed. However, the three-tunnel construction method also has several shortcomings: First, the construction of the main tunnel starts relatively late, the construction process is complex, and the overall construction period is long; second, the temporary support structure of the middle tunnel needs to be dismantled later, which not only consumes a lot of materials but also increases construction costs; third, the joint between the top of the partition wall and the lining of the main tunnel in the straight central wall arch tunnel is prone to form a construction joint, which poses a potential risk of water leakage, thus posing a challenge to the construction quality and making it difficult to ensure that the high standards of construction quality are achieved. Utility Model Content

[0003] This utility model provides an independent double-bore straight central wall arch tunnel, the purpose of which is to solve at least one of the technical problems existing in the prior art mentioned in the background art.

[0004] This utility model provides the following technical solution to achieve the above objectives:

[0005] An independent twin-tunnel straight-center-wall arch tunnel includes a pilot tunnel and a rear tunnel arranged in parallel. A straight-center wall is set between the pilot tunnel and the rear tunnel. Ordinary hollow grouting anchors and extended hollow grouting anchors are set at intervals in the surrounding rock surrounding the pilot tunnel and the rear tunnel. The pilot tunnel and the rear tunnel are arranged sequentially from the inside to the outside with secondary lining, steel arch frame and primary support. An excavation and replacement zone is set on the side of the pilot tunnel near the straight-center wall. Several vertical I-beams are set at intervals along the length of the pilot tunnel in the excavation and replacement zone. The vertical I-beams are set on the side of the excavation and replacement zone away from the pilot tunnel. The outside of the vertical I-beams is wrapped with shotcrete.

[0006] Furthermore, the excavation and backfilling area includes a vertical section set within the straight central wall and an arc-shaped section at the top, with the arc-shaped section facing the direction of the pilot tunnel.

[0007] Furthermore, the vertical I-beams are connected to the steel arch frame of the pilot tunnel via horizontal I-beams.

[0008] Furthermore, the horizontal I-beams are arranged at equal intervals along the height direction of the vertical I-beams.

[0009] Furthermore, the spacing of the vertical I-beams is consistent with the spacing of the pre-existing tunnel-shaped steel arch frame.

[0010] Furthermore, a connecting plate is provided between the horizontal I-beam and the vertical I-beam.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] 1. This utility model provides an independent double-bore straight-center-wall arch tunnel, which improves the stress form of the tunnel structure and is more suitable for structural and process optimization in the case of a large center-to-center spacing of straight-center-wall arch tunnels. Compared with the prior art, it has the advantages of simple construction, short construction period, low cost and improved quality.

[0013] 2. Compared with the conventional three-tunnel method, this utility model eliminates the middle tunnel and the middle partition wall, optimizes the construction process by constructing the front and rear tunnels in parallel, improves construction efficiency, shortens the construction period, and saves materials and construction costs; the drainage system and lining of the front and rear tunnels are arranged and constructed independently, which solves the problem of water leakage in straight central wall arch tunnels and ensures construction quality. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0016] Figure 2 This is a schematic diagram of the detailed structure of the excavation and replacement area of ​​this utility model;

[0017] Attached reference numerals: 1-Preliminary tunnel; 2-Subsequent tunnel; 3-Foam vibration isolation plate; 4-Expanded excavation and backfill area; 5-Vertical I-beam; 6-Horizontal I-beam; A-Steel arch frame.

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0020] Figure 2 This is a schematic diagram of the detailed structure of the excavation and replacement area of ​​this utility model;

[0021] Attached reference numerals: 1-Preliminary tunnel; 2-Subsequent tunnel; 3-Foam vibration isolation plate; 4-Expanded excavation and backfill area; 5-Vertical I-beam; 6-Horizontal I-beam; A-Steel arch frame. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0023] It should be noted that in this utility model: the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices; the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," "longitudinal," etc., indicate orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings. The terminology used is primarily for the purpose of better describing this utility model and its embodiments, and is not intended to limit the indicated devices, elements, or components to having a specific orientation, or to construct and operate in a specific orientation. Terms such as "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Terms such as "installed," "set," "equipped with," "connected," "linked," "socketed," etc., should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, elements, or components. Furthermore, some terms, in addition to indicating orientation or positional relationships, may also have other meanings; for example, the term "above" may, in some cases, indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this utility model according to the specific circumstances.

[0024] Example. An independent twin-tunnel straight-center-wall arch tunnel, structurally as described in 1 to 2, includes a first tunnel 1 and a second tunnel 2 arranged side by side. A straight-center wall is provided between the first tunnel 1 and the second tunnel 2. Ordinary hollow grouting anchors and extended hollow grouting anchors are spaced apart in the surrounding rock surrounding the first tunnel 1 and the second tunnel 2. The extended hollow grouting anchors are located near the center of the two tunnels. The first tunnel 1 and the second tunnel 2 are arranged sequentially from the inside out with secondary lining and primary support (a steel arch frame is installed in the primary support). An excavation and replacement zone 4 is set on the side of the first tunnel 1 near the straight-center wall. Several vertical I-beams 5 are spaced apart along the length of the first tunnel 1 in the excavation and replacement zone 4. The vertical I-beams 5 are located adjacent to the side of the excavation and replacement zone 4 away from the first tunnel 1, and the outside of the vertical I-beams 5 is wrapped with shotcrete. The excavation and replacement zone 4 includes a vertical part set in the straight-center wall and an arc-shaped part at the top, with the arc-shaped part facing the direction of the first tunnel 1.

[0025] The vertical H-beams 5 are connected to the steel arch frame of the pilot tunnel 1 via horizontal H-beams 6. Three horizontal H-beams 6 are arranged at equal intervals along the height of the vertical H-beams 5. The longitudinal spacing of the vertical H-beams 5 is consistent with the spacing of the steel arch frame of the pilot tunnel 1. Connecting plates are installed between the horizontal H-beams 6, the vertical H-beams 5, and the steel arch frame of the pilot tunnel 1. The arrangement of horizontal H-beams 6 strengthens the connection between the vertical H-beams 5 and the steel arch frame of the pilot tunnel 1, improving the overall structural strength and the stress distribution of the tunnel structure. The connecting plates employ a combination of welding and bolting to fully ensure the connection strength at the joints. The vertical H-beams (5) are made of I14 H-beams.

[0026] The installation method of this utility model is as follows: First, construct the pilot tunnel 1. During construction, excavate towards the rear tunnel 2 to create an excavation and backfilling zone 4. Install foam vibration isolation plates 3 on the side of the excavation and backfilling zone 4 near the rear tunnel 2. Apply initial shotcrete along the outline of the expanded pilot tunnel 1. Then, erect vertical H-beams 5 and the steel arch frame of the pilot tunnel 1. Connect the vertical H-beams 5, the steel arch frame of the pilot tunnel 1, and the horizontal H-beams 6 using bolted and welded connections. Apply shotcrete in layers until it covers the vertical H-beams 5 and the horizontal H-beams 6 and is flush with the designed excavation surface before the expansion of the pilot tunnel 1. Subsequently, construct the initial support and drainage system for the pilot tunnel 1. After the lining structure of the pilot tunnel 1 reaches its design strength, the pilot tunnel 2 is constructed at a distance from the secondary tunnel 2. Appropriate methods are used to excavate the secondary tunnel 2 according to the surrounding rock conditions. During excavation, the side furthest from the pilot tunnel 1 is excavated first, followed by the side closer to the pilot tunnel 1. Excavation stops when the foam vibration isolation plate 3 is installed. The foam vibration isolation plate 3 is removed, and the initial support, drainage system, and lining structure of the secondary tunnel 2 are constructed. The aforementioned steps are repeated until the tunnel construction is completed. The parallel construction of the pilot tunnel 1 and the secondary tunnel 2 is achieved through these steps, which improves construction efficiency compared to the three-pilot tunnel method.

[0027] This utility model has been implemented in a bifurcation tunnel in Guizhou Province. A test section was set up to verify the structure and installation method described in the utility model. The test section was a two-lane tunnel with poor surrounding rock (Class IV). The test section was 36m long. Compared with the conventional three-tunnel method, the construction period was shortened by approximately 33 days, and the cost was reduced by approximately 1.186 million yuan.

[0028] Obviously, the above description is only a part of the embodiments of this utility model, and not all of them. The above embodiments are not intended to limit this utility model, and various modifications and variations can be made to this utility model by those skilled in the art. Any combination, modification, equivalent substitution, improvement, and all other embodiments that can be made by those skilled in the art within the spirit and principles of this utility model should be within the protection scope of this utility model.

Claims

1. An independent twin-tunnel straight-center wall arch tunnel, comprising a pilot tunnel (1) and a follower tunnel (2) arranged in parallel, a straight-center wall between the pilot tunnel (1) and the follower tunnel (2), ordinary hollow grouting anchors and extended hollow grouting anchors being spaced apart in the surrounding rock surrounding the pilot tunnel (1) and the follower tunnel (2), and secondary lining and primary support being arranged sequentially from the inside to the outside of the pilot tunnel (1) and the follower tunnel (2), characterized in that: An excavation and backfilling zone (4) is set up on the side of the pilot tunnel (1) near the straight central wall. Several vertical I-beams (5) are set up at intervals along the length of the pilot tunnel (1) in the excavation and backfilling zone (4). The vertical I-beams (5) are set up on the side of the excavation and backfilling zone (4) away from the pilot tunnel (1). The outside of the vertical I-beams (5) is wrapped with shotcrete.

2. The independent twin-tunnel straight-center-walled arch tunnel according to claim 1, characterized in that: The excavation and replacement zone (4) includes a vertical section set in the straight central wall and an arc-shaped section at the top, with the arc-shaped section facing the direction of the pilot tunnel (1).

3. The independent twin-tunnel straight-center-walled arch tunnel according to claim 1, characterized in that: The vertical I-beam (5) is connected to the steel arch frame of the pilot tunnel (1) by the horizontal I-beam (6).

4. The independent twin-tunnel straight-center-walled arch tunnel according to claim 3, characterized in that: The horizontal I-beam (6) is arranged in three equal intervals along the height direction of the vertical I-beam (5).

5. The independent twin-tunnel straight-center-walled arch tunnel according to claim 4, characterized in that: The longitudinal spacing of the vertical I-beams (5) is consistent with the spacing of the steel arch frame of the pre-tunnel (1).

6. The independent twin-tunnel straight-center-wall arch tunnel according to claim 4, characterized in that: A connecting plate is provided between the horizontal I-beam (6), the vertical I-beam (5), and the steel arch frame of the pilot hole (1).

7. The independent twin-tunnel straight-center-walled arch tunnel according to claim 1, characterized in that: The vertical I-beam (5) is made of I14 I-beam.

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