Tunnel primary support steel arch inverted arch adjusting structure and mounting method

Abstract

The invention discloses a tunnel primary support steel arch inverted arch adjusting structure, which belongs to the technical field of tunnel primary support construction, and comprises an inverted arch unit, the inverted arch unit is composed of a middle section and outer side sections positioned at two ends of the middle section, one end of the middle section is provided with a connecting flange, and the other end of the middle section is reserved with an on-site to-be-cut end; a length dynamic adjusting structure is formed; and connecting flanges are respectively arranged at two ends of the two outer side sections. Through the application of the inverted arch adjusting structure, the installation accuracy of the inverted arch unit of the primary support steel arch frame is improved, the installation quality of the steel arch frame is greatly improved, and the inverted arch adjusting structure can be flexibly suitable for field actual changes and is high in error-tolerant rate. The invention further discloses a mounting method for the inverted arch of the tunnel primary support steel arch.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel initial support construction, and provides a tunnel initial support steel arch frame invert arch adjustment structure and an installation method. Background Art

[0002] At present, tunnel and underground engineering usually uses the "New Austrian Tunneling Method" as the theoretical basis to guide the support design and on-site construction of tunnel engineering, that is, to give full play to the self-bearing capacity of the surrounding rock, on the one hand, allow the surrounding rock to deform for stress release, and on the other hand, use anchor rods and shotcrete as the initial support structure to limit the surrounding rock from excessive deformation. In summary, the initial support and surrounding rock bear the load together, such as Figure 1 As shown, the full-ring grid steel arch frame (100) for initial tunnel support includes: a crown unit (40), two side wall units (30), two transition units (20) and an invert unit (10).

[0003] However, during the excavation of the tunnel invert, due to factors such as geological differences and blasting construction technology, it is very easy for the invert to be over-excavated or partially under-excavated, which in turn affects the curvature of the invert base, resulting in a deviation between the actual curvature of the invert and the designed curvature, which indirectly affects the installation quality of the initial support steel arch frame. The following problems often occur during the installation process: 1) The installation sequence from one end to the other end, that is, a side wall unit → a transition unit → an invert unit → another transition unit → another side wall unit. In this way, the connection plate at one end is tightly connected to the side wall unit and the bolts are installed in place. However, due to the deviation between the actual curvature of the invert and the designed curvature of the other end, the connection quality between the later installed end and the other side wall unit is further affected, resulting in the situation that the connecting steel plate is misaligned and cannot be installed; 2) The installation sequence from both ends to the middle is: that is, a side wall unit → a transition unit → an invert unit ← another transition unit ← another side wall unit. In this way, the two transition units are first installed in place with the two side wall units respectively, and then the invert unit is assembled. It is easy to have an inappropriate arch frame length, which leads to a situation that it cannot be closed, and the connection will also be affected.

[0004] Therefore, if the initial support of the tunnel cannot be closed to form a complete force system and effectively withstand the surrounding rock pressure, it will cause settlement of the initial support and the secondary lining, leading to cracks in the secondary lining, water seepage and other quality and safety problems. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a tunnel primary support steel arch frame back arch adjustment structure and installation method, aiming to improve the accuracy of the installation of the tunnel primary support steel arch frame back arch, greatly improve the installation quality of the steel arch frame, and flexibly adapt to actual changes on site with high fault tolerance, thereby ensuring the overall stability and reliability of the steel arch frame system.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a tunnel primary support steel arch frame inverted arch adjustment structure, comprising an inverted arch unit, the inverted arch unit is composed of a middle section and outer sections located at both ends of the middle section, a connecting flange is arranged at one end of the middle section, and an end to be cut off on site is reserved at the other end to form a length dynamic adjustment structure; connecting flanges are arranged at both ends of the two outer sections. By adopting the above scheme, the tunnel primary support steel arch frame inverted arch adjustment structure optimizes the efficiency and safety of tunnel construction through flexible connection and adjustment methods, and provides effective technical support for modern tunnel engineering.

[0008] Optionally, the middle section and the outer section are all prefabricated in the factory, which not only improves the overall performance of the structure, but also optimizes the construction process, providing a strong guarantee for the smooth progress of the tunnel project.

[0009] Optionally, the length L1 of the end to be cut off on the site reserved on the middle section is dynamically adjusted according to the designed arc length L of the inverted arch unit of the tunnel primary support steel arch frame, and satisfies L1=L+(15-40)cm. This design improves the construction adaptability and safety of the tunnel primary support steel arch frame through reasonable reserved length and dynamic adjustment mechanism, and provides guarantee for the successful implementation of tunnel engineering.

[0010] Optionally, a tensioning assembly is provided between the middle section and the connection parts with the outer sections at both ends thereof. The tensioning assembly comprises a screw rod penetrating the connecting flange and anti-loosening nuts mounted on both ends of the screw rod and resting on the outer side of the connecting flange. This not only improves the safety and stability of the structure, but also enhances the flexibility and convenience of maintenance during the construction process, and provides strong support for the overall performance of the primary supporting steel arch frame of the tunnel.

[0011] Optionally, the connecting flanges of the middle section and the outer sections connected to the two ends are provided with corresponding elliptical holes or strip holes for the screw to pass through. This design provides greater installation flexibility, can adapt to different installation angles and position deviations, and improves the convenience of construction.

[0012] The present invention is also based on the above-mentioned method for installing the tunnel primary support steel arch frame invert arch adjustment structure, and the installation method comprises:

[0013] a) Prefabricate two outer sections with fixed lengths and a middle section with adjustable length, and both ends of the two outer sections have connecting flanges, while one end of the middle section has a connecting flange and the other end is reserved for on-site cutting;

[0014] b) The order of installation of the inverted arch unit from both ends to the middle, that is, first wait for the two outer sections to be connected to the transition units on both sides of the tunnel primary support steel arch frame respectively, then cut the on-site end of the middle section to be cut off according to the measured distance between the two outer sections after they are installed and fixed, and weld the matching connection flange after cutting;

[0015] c) Connect the two ends of the middle section 1 to the two outer sections by means of bolt assemblies.

[0016] In this way, the installation method can effectively realize the rapid and accurate installation of the tunnel primary support steel arch frame and the invert arch adjustment structure. The design and implementation of each link ensures the safety and adaptability of the structure, while providing flexibility and adjustment convenience during the construction process, providing a guarantee for the smooth progress of the tunnel project.

[0017] Preferably, after step c), a reinforcing structure is formed between the middle section and the outer sections at both ends thereof by using a reinforcing assembly.

[0018] The beneficial effects of the present invention are as follows: the tunnel primary support steel arch frame back arch adjustment structure and installation method of the present invention, through its application, help to improve the accuracy of the installation of the tunnel primary support steel arch frame back arch unit, greatly improve the installation quality of the steel arch frame, and can flexibly adapt to actual changes on site with a high fault tolerance rate.

[0019] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0021] Figure 1 It is a structural schematic diagram of the tunnel primary support steel arch frame in the prior art;

[0022] Figure 2 It is a schematic diagram of the tunnel primary support steel arch frame invert arch adjustment structure before construction of the present invention;

[0023] Figure 3 It is a schematic diagram of the construction of the inverted arch adjustment structure of the primary support steel arch frame of the tunnel of the present invention;

[0024] Figure 4 It is a schematic diagram of the tunnel primary support steel arch frame invert arch adjustment structure after construction of the present invention;

[0025] Figure 5 for Figure 4 A schematic diagram of a reinforcement assembly is added;

[0026] Figure numerals: 100-steel arch frame; 10-inverted arch unit, 20-transition unit, 30-side wall unit, 40-vault unit; 1-middle section, 2-outer section, 3-connecting flange, 4-end to be cut off on site, 5-screw, 6-locking nut. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with specific implementation methods. The accompanying drawings are only used for exemplary descriptions and are only schematic diagrams, not actual drawings, and cannot be understood as limiting this patent; in order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the accompanying drawings may be omitted.

[0028] like Figure 2 As shown, the tunnel primary support steel arch frame inverted arch adjustment structure mentioned in this embodiment is mainly to meet the dynamic adjustment requirements in tunnel construction, including an inverted arch unit 10, which is composed of a middle section 1 and outer sections 2 located at both ends of the middle section 1. The design of the middle section 1 takes into account the flexibility during the construction process. The connecting flange 3 at one end is used to connect with the adjacent outer section 2 to ensure the stability and safety of the structure; and the end 4 to be cut off at the other end is reserved to allow the length to be dynamically adjusted at the construction site to adapt to different construction conditions and requirements, thereby forming a length dynamic adjustment structure; the two ends of the two outer sections 2 are also equipped with connecting flanges 3, so that the entire inverted arch unit 10 can be effectively connected with other supporting structures, thereby enhancing the overall bearing capacity and stability. This design not only improves the flexibility of construction, but also can cope with the challenges brought by factors such as geological changes and construction errors during tunnel construction.

[0029] In this embodiment, the middle section 1 and the outer section 2 are all factory prefabricated parts. The production of factory prefabricated parts can be carried out in a controlled environment to ensure the quality of materials and processing accuracy. Such high-quality prefabricated components can reduce the error of on-site construction and improve the stability and safety of the overall structure. At the same time, the use of prefabricated parts can significantly shorten the on-site construction time. Since the middle section 1 and the outer section 2 have been processed and treated in the factory, the construction personnel only need to assemble and connect them on site, which greatly improves the construction efficiency. In addition, the standardized production of prefabricated parts can also reduce construction costs and reduce the complexity of on-site construction. The construction team can adapt to different construction environments and conditions more quickly and make adjustments flexibly. Finally, the transportation and stacking of prefabricated parts are also relatively easy, which helps to improve the management efficiency of the construction site and reduce the clutter during the construction process.

[0030] In this embodiment, the length L1 of the reserved end 4 to be cut off on the site of the middle section 1 is dynamically adjusted according to the design arc length L of the inverted arch unit 10 of the tunnel primary support steel arch frame 100, satisfying L1=L+(15-40) cm. That is, the length L1 of the reserved end 4 to be cut off should be greater than the design arc length L of the inverted arch unit 10, plus a range of 15 to 40 cm. Such a design takes into account the following aspects: flexibility. In actual construction, due to factors such as the geological conditions of the tunnel and construction errors, it may be necessary to fine-tune the length of the steel arch frame. By reserving a certain length, necessary adjustments can be made without affecting the safety of the overall structure. Adaptability. Different tunnel designs and construction conditions may require different arc lengths. By dynamically adjusting the length of the end to be cut off, these changes can be better adapted to ensure the effectiveness and safety of the tunnel primary support steel arch frame. Safety. The added length of 15 to 40 cm provides an additional safety margin for construction, avoiding structural instability or safety hazards caused by insufficient length.

[0031] For example Figure 5 As shown, in another embodiment, a tie-fastening assembly is provided between the middle section 1 and the outer sections 2 at both ends thereof to enhance the stability and bearing capacity of the overall structure. The tie-fastening assembly includes a screw rod 5 that runs through the connection flange 3 and a locking nut 6 that is sleeved on both ends of the screw rod 5 and abuts against the outer side of the connection flange 3. The screw rod 5 serves to connect and fix the middle section 1 and the outer section 2. The strength and material selection of the screw rod 5 are crucial to ensure that it can withstand various forces and pressures during the construction process. The locking nut 6 mainly functions to achieve the fastening between the middle section 1 and the outer section 2 by adjusting the position and tightening degree of the nut. This design allows for convenient adjustment and maintenance when necessary. With the above scheme, the design of the tie-fastening assembly ensures that the connection between the middle section 1 and the outer section 2 is tighter, reduces the relative displacement caused during construction and use, and enhances the overall structural stability. And through the locking nut, the tightness of the connection can be easily adjusted to adapt to different construction conditions and environmental requirements. This flexibility allows for rapid response to changes during construction and avoids safety hazards caused by improper fixing. The reinforcement components can also effectively transfer the forces between the various parts, ensuring that the entire steel arch frame maintains good mechanical properties during construction and use.

[0032] In this embodiment, the middle section 1 and the connecting flanges 3 of the outer sections 2 connected to the middle section 1 and ...

[0033] Combination Figure 2-4As shown, this embodiment also mentions a method for installing a tunnel primary steel arch frame inverted arch, which is based on the above-mentioned tunnel primary steel arch frame inverted arch adjustment structure. The installation method includes: first, prefabricating two outer sections 2 with fixed lengths and a middle section 1 with adjustable length, and both ends of the two outer sections 2 have connecting flanges 3, and one end of the middle section 1 has a connecting flange 3, and the other end is reserved for an on-site end 4 to be cut off; then, the inverted arch unit 10 is installed in a closed order from both ends to the middle, first the two outer sections 2 are welded and connected to the transition units 20 on both sides of the tunnel primary steel arch frame 100 respectively, and then the on-site end 4 to be cut off of the middle section 1 is cut to the target length according to the measured spacing between the two outer sections 2 after the two sections are installed and fixed, and a matching connecting flange 3 is welded on one end after cutting; finally, the two ends of the middle section 1 are connected to the two outer sections 2 in three sections through the connecting flange 3 and the bolt assembly to form a closed inverted arch structure of the tunnel primary steel arch frame.

[0034] Among them, the measurement of spacing needs to be combined with the surrounding rock deformation monitoring data, and the reinforcement components can also be used to form a reinforcement structure between the middle section 1 and the outer sections 2 at both ends. Alternatively, a locking anchor pipe (Φ50×4mm, 2-4m long) is added to the middle section 1, and the anchor pipe is welded and fixed to the middle section steel frame, and the surrounding rock contact surface is reinforced with grouting.

[0035] The above solution has the following advantages:

[0036] Structural optimization: Combining factory prefabrication with on-site cutting, dynamically adjusting the length of the middle section to cope with complex geological conditions (such as alternation of hard and soft rocks, deformation of the biased section).

[0037] Connection enhancement: The introduction of tie-stiffening components and elliptical hole design can improve the node stiffness and avoid overall instability caused by loose steel frame connections.

[0038] Installation optimization: Emphasis on dynamic measurement and reserved cutting allowance to meet the technical requirements of timely and effective closure of the invert construction.

[0039] Note: The inverted arch unit of the primary steel arch frame of the tunnel should be constructed strictly in accordance with the above requirements. It is strictly forbidden to cut the steel frame in other sections; it is strictly forbidden to directly weld without using node plate bolts after cutting; it is strictly forbidden to weld the "big arm node plate" at the connection between the arch wall and the inverted arch steel frame on site instead of welding in the steel bar processing plant; it is strictly forbidden to use short steel frame connections to weaken the overall supporting capacity of the steel frame.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A tunnel primary support steel arch frame inverted arch adjustment structure, comprising an inverted arch unit (10), characterized in that: The inverted arch unit (10) is composed of a middle section (1) and outer sections (2) located at both ends of the middle section (1); a connecting flange (3) is provided at one end of the middle section (1) and an end (4) to be cut off on site is reserved at the other end to form a dynamic length adjustment structure; the two outer sections (2) are provided with the connecting flanges (3) at both ends.

2. The tunnel primary support steel arch frame invert arch adjustment structure according to claim 1 is characterized in that: The middle section (1) and the outer section (2) are both factory prefabricated parts.

3. The tunnel primary support steel arch frame invert arch adjustment structure according to claim 1 is characterized in that: The length L1 of the end (4) to be cut off on site reserved on the middle section (1) is dynamically adjusted according to the designed arc length L of the inverted arch unit (10) of the tunnel primary supporting steel arch frame (100), satisfying L1=L+(15-40) cm.

4. The tunnel primary support steel arch frame invert arch adjustment structure according to claim 1, characterized in that: A tightening assembly is provided between the middle section (1) and the outer sections (2) at both ends thereof, and the tightening assembly comprises a screw rod (5) penetrating the connecting flange (3) and a locking nut (6) mounted on both ends of the screw rod (5) and abutting against the outer side of the connecting flange (3).

5. The tunnel primary support steel arch frame invert arch adjustment structure according to claim 4 is characterized in that: The middle section (1) and the connecting flanges (3) of the outer sections (2) connected to the middle section (1) at both ends are provided with corresponding elliptical holes or strip holes for the screw rod (5) to pass through.

6. The method for installing the tunnel primary support steel arch frame inverted arch adjustment structure according to any one of claims 1 to 5, characterized in that: The installation method comprises: a) prefabricating two outer sections (2) with fixed lengths and a middle section (1) with adjustable length, wherein both ends of the two outer sections (2) are provided with connecting flanges (3), and one end of the middle section (1) is provided with a connecting flange (3) and the other end is reserved for an end (4) to be cut off on site; b) The order of closing the arch unit (10) from both ends to the middle, that is, first, the two outer sections (2) are connected to the transition units (20) on both sides of the tunnel primary support steel arch frame (100), and then the on-site end (4) of the middle section (1) to be cut off is cut according to the measured distance between the two outer sections (2) after they are installed and fixed, and the matching connection flange (3) is welded after cutting; c) Connecting the two ends of the middle section (1) to the two outer sections (2) by means of bolt assemblies.

7. The installation method according to claim 6, characterized in that: After step c), a reinforcing structure is formed between the middle section (1) and the outer sections (2) at both ends thereof by using a reinforcing assembly.

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