Reinforcing structure of soft rock tunnel steel arch

Abstract

The invention discloses a reinforcing structure of a soft rock tunnel steel arch, and relates to the technical field of tunnel construction, the reinforcing structure comprises a bottom arch and a middle arch, one end of the bottom arch is welded with a connecting plate, and the connecting plate is provided with a threaded through hole; threaded through holes are formed in a web at the other end of the bottom arch frame and webs at the two ends of the middle arch frame. A reinforcing sleeve assembly is arranged at the joint of the bottom arch frame and the middle arch frame in a sleeved mode. The reinforcing sleeve assemblies are fixedly connected with the bottom arch frame and the middle arch frame through bolt assemblies. According to the reinforcing structure of the soft rock tunnel steel arch frame, the reinforcing sleeve assemblies are matched with the bolt assemblies, the bottom arch frame and the middle arch frame can be fixedly connected conveniently, reinforcing at the positions of the web and the lower flange plate is achieved, the upper flange plate is smooth, the number of primary support concrete is reduced, and the construction efficiency is improved. And the bottom arch frame and the middle arch frame are vibrated and compacted with the primarily sprayed concrete, so that cavities are avoided, and a good guarantee is provided for the next procedure.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and in particular to a reinforced structure for a steel arch frame in a soft rock tunnel. Background Technology

[0002] Currently, the mainstream principle for dealing with deformation in soft rock tunnel construction is a combination of "releasing and resisting." "Releasing" refers to increasing the allowable deformation to effectively release the pressure from loosening of the surrounding rock; "Resisting" refers to improving the stiffness of the initial support and enhancing its bearing capacity. Effectively improving the stiffness of the initial support involves strengthening the mechanical properties of the steel arch frame. Existing technologies often employ methods such as increasing the grade of steel and using double-layer arch frames. Both of these methods only improve the overall mechanical strength of the initial steel arch frame, failing to provide targeted reinforcement, and they have the following drawbacks.

[0003] The disadvantages of increasing the size of the steel grade to improve the mechanical properties of the arch frame are as follows: First, with larger steel grade arch frames, the arch frame flanges are also larger, making it easy for the steel frame and the initial shotcrete to become loose and voids to appear; Second, larger steel grade arch frames have a large weight per meter, making installation difficult and costly; Third, larger steel grade arch frames require higher quality cold bending machinery.

[0004] The disadvantages of using double-layer arch frames to improve the mechanical properties of the arch frame are: 1. The construction process of double-layer arch frames is complex and the construction efficiency is low; 2. The construction of double-layer arch frames will cause the amount of arch frame and initial support concrete to increase several times, resulting in poor economic benefits.

[0005] Developing a reinforced structure for steel arch frames in soft rock tunnels that is easy to process, reduces construction procedures and costs, and ensures the connection strength between arch frames has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a reinforced structure for steel arch frames in soft rock tunnels, thereby solving the problems listed in the background art.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: The present invention provides a reinforcing structure for a steel arch frame in a soft rock tunnel, comprising a bottom arch frame and a middle arch frame, wherein a connecting plate is welded to one end of the bottom arch frame, and the connecting plate is provided with a threaded through hole; Threaded through holes are provided on the other end web of the bottom arch and on both ends web of the middle arch. A reinforcing sleeve assembly is fitted at the joint between the bottom arch and the middle arch; The reinforcing sleeve assembly is fixedly connected to the bottom arch and the intermediate arch via bolt assemblies.

[0008] Preferably, a reinforcing steel plate is welded to the web of the bottom arch frame.

[0009] Preferably, the reinforcing sleeve assembly includes a lower flange abutment plate, and L-shaped plates are welded to both ends of the lower flange abutment plate; The L-shaped plate is welded to the reinforcing web plate; The reinforcing web is provided with threaded holes; The reinforcing web is fixedly connected to the bottom arch and the intermediate arch by bolts passing through the threaded holes.

[0010] Compared with the prior art, the beneficial technical effects of the present invention are as follows: This invention provides a reinforced structure for a steel arch frame in a soft rock tunnel. The reinforced sleeve assembly and bolt assembly work together to easily fix and connect the bottom arch frame and the middle arch frame, ensuring the connection strength between the bottom arch frame and the middle arch frame. This allows for reinforcement at the web and lower flange positions, making the upper flange plate smooth, reducing the amount of initial support concrete, and ensuring that the bottom arch frame and the middle arch frame are compacted with the initial shotcrete, thus avoiding voids. Monitoring data showed that adding reinforcing steel plates on both sides can effectively enhance the arch frame's resistance to rock convergence, alleviate the convergence of the initial support during construction, buy more time for subsequent construction processes, and provide a good guarantee for the next step of construction. Attached Figure Description

[0011] The present invention will be further described below with reference to the accompanying drawings.

[0012] Figure 1 This is a three-dimensional schematic diagram of a reinforced steel arch frame for soft rock tunnels according to the present invention; Figure 2 This is a front view schematic diagram of the reinforcing structure of a steel arch frame for a soft rock tunnel according to the present invention; Figure 3 This is a top view schematic diagram of the reinforcement structure of a steel arch frame for a soft rock tunnel according to the present invention; Figure 4 This is a front view schematic diagram of the connection state of the intermediate arch frame of the present invention; Figure 5 This is a three-dimensional schematic diagram of the connection state of the intermediate arch frame of the present invention; Figure 6 This is a three-dimensional schematic diagram of the reinforcing sleeve assembly of the present invention; Figure 7 This is a comparison table of test data from the construction of a soft rock tunnel on a plateau, which is part of the present invention.

[0013] Explanation of reference numerals in the attached drawings: 1. Connecting plate; 2. Bottom arch frame; 3. Reinforcing sleeve assembly; 301. Reinforcing web plate; 302. Threaded hole; 303. L-shaped plate; 304. Lower flange abutment plate; 4. Bolt assembly; 5. Intermediate arch frame; 6. Reinforcing steel plate. Detailed Implementation

[0014] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0015] like Figure 1-7 As shown, a reinforced structure for a steel arch frame in a soft rock tunnel includes a bottom arch frame 2 and a middle arch frame 5. The bottom arch frame 2 and the middle arch frame 5 are bent to the design radius by an arch frame bending machine, and the bent steel arch frame should be arc-shaped. A connecting plate 1 is welded to one end of the bottom arch frame 2. The verticality should be guaranteed to meet the design requirements during the welding process. The connecting plate 1 has a threaded through hole. Furthermore, the connecting plate is made of Q235B plate and is cut into shape by CNC laser machine. Threaded through holes are provided on the other end web of the bottom arch 2 and on both ends web of the middle arch 5. A reinforcing sleeve assembly 3 is fitted at the joint between the bottom arch frame 2 and the middle arch frame 5; The reinforcing sleeve assembly 3 is fixedly connected to the bottom arch frame 2 and the intermediate arch frame 5 by bolt assembly 4, together forming the initial support steel arch frame.

[0016] Specifically, a reinforcing steel plate 6 is welded to the web of the bottom arch frame 2, with the reinforcing steel plate being preferred to locally strengthen the bottom arch frame; The reinforcing steel plate is partially circular, and the inner and outer arc radii should be designed to ensure close contact with the bottom arch flange plate, so that the stress on the flange plate can be shared by the reinforcing steel plate. Intermittent welding is used to connect the reinforcing steel plate and the flange plate to reduce the deformation of the bottom arch frame caused by welding stress; furthermore, the reinforcing steel plates are set opposite to each other on both sides of the bottom arch frame to ensure uniform stress distribution. Meanwhile, the relative position of the reinforcing steel plate and the bottom arch frame should be determined by on-site deformation monitoring data, and the reinforcing steel plate should be used to locally reinforce areas with high deformation rates.

[0017] Specifically, the reinforcing sleeve assembly 3 includes a lower flange abutment plate 304, and L-shaped plates 303 are welded to both ends of the lower flange abutment plate 304; The L-shaped plate 303 is welded to the reinforcing web plate 301; The reinforcing web 301 is provided with a threaded hole 302; The reinforcing web 301 is fixedly connected to the bottom arch 2 and the intermediate arch 5 through the threaded hole 302 via the bolt assembly 4; In use, the lower flange abutment plate and L-shaped plate welding can wrap the lower flange plate, and the reinforced web plate can reinforce the web plate. Furthermore, the bottom arch frame and the middle arch frame are reinforced at the position of the web plate and the lower flange plate, so that the upper flange plate is smooth, reducing the amount of initial support concrete, and ensuring that the bottom arch frame and the middle arch frame are vibrated and compacted with the initial shotcrete to avoid voids. The reinforcing sleeve assembly 3 and the bolt assembly 4 work together to facilitate the fixed connection between the bottom arch frame and the middle arch frame, and to ensure the connection strength between the bottom arch frame and the middle arch frame.

[0018] like Figure 7 As shown in the monitoring data, adding reinforcing steel plates on both sides of the arch frame can effectively enhance the arch frame's resistance to rock convergence, alleviate the convergence of the initial support during construction, buy more time for subsequent construction procedures, and provide a good guarantee for the next step of construction.

[0019] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0020] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A reinforcing structure for a steel arch frame in a soft rock tunnel, characterized in that: It includes a bottom arch frame (2) and a middle arch frame (5). One end of the bottom arch frame (2) is welded with a connecting plate (1), and the connecting plate (1) has a threaded through hole. The other end web of the bottom arch (2) and both ends web of the middle arch (5) are provided with threaded through holes; A reinforcing sleeve assembly (3) is fitted at the joint between the bottom arch frame (2) and the middle arch frame (5). The reinforcing sleeve assembly (3) is fixedly connected to the bottom arch frame (2) and the intermediate arch frame (5) by bolt assembly (4).

2. The reinforcing structure of a steel arch frame for a soft rock tunnel according to claim 1, characterized in that: A reinforcing steel plate (6) is welded to the web of the bottom arch (2).

3. The reinforcing structure of a steel arch frame for a soft rock tunnel according to claim 1, characterized in that: The reinforcing sleeve assembly (3) includes a lower flange abutment plate (304), and L-shaped plates (303) are welded to both ends of the lower flange abutment plate (304). The L-shaped plate (303) is welded to the reinforcing web plate (301); The reinforcing web (301) is provided with a threaded hole (302); The reinforcing web (301) is fixedly connected to the bottom arch (2) and the intermediate arch (5) through the threaded hole (302) by the bolt assembly (4).

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