Self-adaptive contraction grating arch frame structure

Abstract

The utility model discloses a self-adaptive contraction grating arch frame structure which comprises a plurality of grating arch frame rings which are evenly arranged in the longitudinal direction of a tunnel, each grating arch frame ring is formed by connecting a plurality of arch frame sections end to end, and every two adjacent arch frame sections are connected through a retractable resistance limiting device. The retractable resistance limiting device comprises an upper connecting plate and a lower connecting plate, the upper connecting plate is fixedly connected with the upper arch frame section, the lower connecting plate is fixedly connected with the lower arch frame section, the upper connecting plate and the lower connecting plate are connected through a fixing piece, and the upper connecting plate and the lower connecting plate slide relatively under the action of large external force. The retractable resistance limiting devices are arranged at the joints of the arch frame sections, so that energy release yielding of the grid arch frame structure is achieved, the stress condition of a primary supporting structure is improved, the problems that the sliding resistance of a traditional retractable arch frame is unstable and cannot be adjusted are solved, and the retractable arch frame has the advantages of being high in supporting strength, easy and convenient to install, capable of being self-adaptive to surrounding rock deformation and the like.

Description

Technical Field

[0001] The utility model belongs to the technical field of tunnel support, and in particular relates to a grid arch structure with adaptive contraction. Background Art

[0002] In the process of building mountain tunnels in southwest my country, various complex geological conditions such as high ground stress and weak and broken surrounding rocks are often encountered. After tunnel excavation, the surrounding rock deformation is often large, the deformation rate is fast, and the duration is long. As a result, the load acting on the initial support structure continues to increase. When it exceeds the structural bearing limit, it will cause engineering disasters such as steel frame failure, concrete spalling, and secondary lining cracking. This puts higher requirements on the support structure design of high ground stress soft rock tunnels. The use of arch frame structures with high bearing capacity and the ability to adapt to surrounding rock deformation has become an effective support measure to control the large deformation problem of high ground stress soft rock tunnels.

[0003] However, in engineering projects, the arch sections are generally connected by rigid connections such as angle steel and flange plates. The arch is not retractable and can only withstand the surrounding rock load. Once the load exceeds the bearing limit, the arch will be damaged, which may induce the instability and collapse of the tunnel support system. Therefore, in view of the high-stress soft rock geological conditions, it is necessary to design an arch structure with high bearing capacity and adaptive shrinkage with the deformation of the surrounding rock to solve the defect that the grid arch or steel arch cannot continue to bear the load after the tunnel deformation exceeds the limit. Utility Model Content

[0004] In view of the above-mentioned deficiencies in the prior art, the utility model provides a grid arch structure with strong contractibility, high support strength, easy installation, and the ability to effectively adapt to large deformations of surrounding rocks, so that it can deform under certain loads and avoid damage due to excessive loads.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A self-adaptive retractable grid arch structure comprises a plurality of grid arch rings evenly arranged along the longitudinal direction of a tunnel, wherein the grid arch rings are formed by a plurality of arch segments connected end to end, and adjacent arch segments are connected by a retractable resistance limiting device, and the retractable resistance limiting device comprises an upper connecting plate fixedly connected to the upper arch segment and a lower connecting plate fixedly connected to the lower arch segment, and the upper connecting plate and the lower connecting plate are connected by fixings, and under the action of a large external force, the upper connecting plate and the lower connecting plate slide relative to each other.

[0007] In a further solution, the upper connecting plate is provided with an upper slot along its length direction, and the lower connecting plate is provided with a lower slot along its length direction, and the fixing piece is passed through the upper slot and the lower slot to connect the upper connecting plate and the lower connecting plate.

[0008] In a further solution, the retractable resistance limiting device also includes pads, which are respectively located on the outer sides of the upper connecting plate and the lower connecting plate.

[0009] In a further solution, adjacent grid arch rings are connected via connecting pieces.

[0010] In a further solution, end plates are vertically fixed at both ends of the lower connecting plate, and connecting holes are opened on the end plates; the connecting member is a U-shaped structure, and its two ends are respectively connected to the connecting holes on the adjacent retractable resistance limiting device.

[0011] In a further solution, the arch frame segment includes four main limb steel pipes, the four main limb steel pipes are connected by evenly arranged reinforcing ribs, and stirrups are welded on the outer periphery of the four main limb steel pipes.

[0012] In a further embodiment, the reinforcing ribs are U-shaped ribs, Π-shaped ribs, 8-shaped ribs or Z-shaped ribs; the main limb steel pipes are smooth steel pipes, corrugated steel pipes or ribbed steel pipes.

[0013] A further solution further comprises a concrete layer, wherein the arch frame segments are built inside the concrete layer.

[0014] In the present application, the retractable resistance device is arranged between adjacent arch frame segments to connect the arch frame segments into a whole. The expansion and contraction amount of the retractable resistance device can be designed according to the deformation of the surrounding rock, and the load required for the sliding of the retractable resistance device can be calculated by the bolt tightening force.

[0015] Compared with the prior art, the beneficial effects of the utility model are:

[0016] (1) The utility model provides a retractable limiting device at the connection of the arch frame segments. When the grid arch frame structure is subjected to a force exceeding a certain limit value, the retractable limiting device will be pressurized, so that the upper and lower connecting plates in the retractable limiting device will slide relative to each other, thereby achieving shrinkage deformation and moderate pressure relief, effectively reducing the surrounding rock pressure acting on the initial support, and preventing the support structure from being damaged due to excessive load.

[0017] (2) The retractable limiting device in the utility model has good compression performance. Compared with the traditional rigid joint, the retractable limiting device has a higher early support force. When the surrounding rock load increases to a certain extent, it will produce compression shrinkage and then reach a new stable state, so that the grid arch structure has a higher safety redundancy.

[0018] (3) The utility model can adjust the fastening force and model of the fixing parts (bolts), the size of the main limb steel pipe in the arch frame segment, and the arrangement spacing of the reinforcing ribs according to the needs of different projects, so that the grid arch frame structure can achieve the best support state, and can realize dynamic adjustment, with a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0020] Figure 1 It is a schematic diagram of the structure of this application;

[0021] Figure 2 It is a structural schematic diagram of the arch frame segment in this application;

[0022] Figure 3 It is a schematic diagram of the structure of the retractable resistance limiting device in the present application;

[0023] Figure 4 It is a schematic diagram of the structure of the lower connecting plate in this application;

[0024] Figure 5 It is a structural schematic diagram of the upper connecting plate in this application;

[0025] Figure 6 This is a schematic diagram of the retractable resistance limiting device in the present application before compression and deformation;

[0026] Figure 7 It is a schematic diagram of the retractable resistance limiting device after compression deformation in the present application.

[0027] Description of the markings in the figure:

[0028] 1-arch frame segment, 11-main limb steel pipe, 12-reinforcement ribs, 13-stirrups;

[0029] 2-retractable resistance limiting device, 21-lower connecting plate, 211-connecting hole, 212-lower notch, 213-end plate, 22-upper connecting plate, 221-upper notch, 23-pad, 24-fixing piece;

[0030] 3-Connectors, 4-Concrete layer. DETAILED DESCRIPTION

[0031] In order to make the technical scheme of the present application better understood by the persons skilled in the art, the technical scheme in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field belong to the scope of protection of the present application.

[0032] The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0033] See also Figure 1-7 A self-adaptive shrinkage grid arch structure comprises a plurality of grid arch rings uniformly arranged along the longitudinal direction of a tunnel, wherein the grid arch rings are formed by connecting a plurality of arch segments 1 end to end, and adjacent arch segments 1 are connected by a retractable resistance limiting device 2, wherein the retractable resistance limiting device 2 comprises an upper connecting plate 22 fixedly connected to an upper arch segment and a lower connecting plate 21 fixedly connected to a lower arch segment, wherein the upper connecting plate 22 and the lower connecting plate 21 are connected by a fixing member 24, and under the action of a large external force, the upper connecting plate 22 and the lower connecting plate 21 slide relative to each other.

[0034] like Figure 1 As shown, this embodiment is explained by taking two local grid arch frame rings as an example. Two adjacent arch frame segments 1 in the same grid arch frame ring are connected by a retractable limiting device 2. Since the upper connecting plate 22 in the retractable limiting device 2 is connected to the upper arch frame segment and the lower connecting plate 21 is connected to the lower arch frame segment, when subjected to surrounding rock load and exceeding a certain value, it will drive the upper connecting plate 22 and the lower connecting plate 21 to slide relative to each other, thereby achieving shrinkage deformation, moderate pressure release, and effectively reducing the surrounding rock pressure acting on the initial support, thereby preventing the support structure from being subjected to excessive load and failing.

[0035] Specifically, Figure 3-5 As shown, two rows of upper notches 221 are formed on the upper connecting plate 22 along its length direction, and two rows of lower notches 212 are formed on the lower connecting plate 21 along its length direction, and the fixing member 24 is inserted through the upper notches 221 and the lower notches 212 to connect the upper connecting plate 22 and the lower connecting plate 21. In this embodiment, the fixing member 24 can be a high-strength bolt. When the force is large, the upper connecting plate 22 and the upper arch frame segment as a whole, and the lower connecting plate 21 and the lower arch frame segment as a whole move relative to each other to achieve shrinkage deformation.

[0036] In order to increase the friction resistance, the retractable resistance limiting device 2 further includes a pad 23, which is respectively located on the outer side of the upper connecting plate 22 and the lower connecting plate 21. The fixing member 24 connects it with the upper connecting plate 22 and the lower connecting plate 21, and the support resistance of the retractable resistance limiting device 2 can be adjusted by controlling the tightening degree of the fixing member 24.

[0037] In addition, in order to strengthen the overall support strength of the grid arch structure, the adjacent sides of the retractable blocking devices 2 on two adjacent grid arch rings are connected into a whole through a connecting piece 3. Specifically, end plates 213 are vertically fixed at both ends of the lower connecting plate 21, and the end plates 213 are provided with connecting holes 211; the connecting piece 3 is a U-shaped structure, and its two ends are respectively connected to the connecting holes 211 on the adjacent retractable blocking devices 2.

[0038] like Figure 2 As shown, the arch frame segment 1 includes four main limb steel pipes 11 as main load-bearing members. The four main limb steel pipes 11 are connected by evenly arranged reinforcing ribs 12 , and stirrups 13 are welded on the outer periphery of the four main limb steel pipes 11 .

[0039] The reinforcing ribs 12 are U-shaped ribs, Π-shaped ribs, 8-shaped ribs or Z-shaped ribs; U-shaped ribs and Π-shaped ribs can be used for connection at the same time, and the U-shaped ribs, Π-shaped ribs and stirrups 13 are arranged at a certain distance according to design requirements.

[0040] The main limb steel pipe 11 is a smooth steel pipe, a corrugated steel pipe or a ribbed steel pipe.

[0041] In another embodiment, the retractable limiting device is generally arranged at the top arch and the waist of the arch, and the arch frame segment 1 is built inside the concrete layer 4 to further form a stable primary support bearing system. No concrete is sprayed at the retractable limiting device 2.

[0042] The adaptively shrinkable grid arch structure provided in the embodiment of the present application is used to control the large deformation problem of high ground stress soft rock tunnels and realize adaptive support.

[0043] like Figure 6-7 The figure shows the state of the retractable resistance limiting device 2 before and after compression deformation. The upper connecting plate 22 in the retractable resistance limiting device 2 is welded and fixed to the end of the main limb steel pipe 11 in the upper arch frame segment, and the lower connecting plate 21 in the retractable resistance limiting device 2 is welded and fixed to the end of the main limb steel pipe 11 in the lower arch frame segment; then the fixing piece 24 is used to pass through the upper notch 221 and the lower notch 212 to connect the upper connecting plate 22 and the lower connecting plate 21. In the implementation operation, the upper connecting plate 22 is located on the inner side of the four main limb steel pipes 11, and the lower connecting plate 21 is located on the outer side thereof. In order to facilitate the connection with the adjacent grid arch frame ring, a U-shaped connecting piece 3 is used for connection.

[0044] When the force does not exceed the friction resistance required for sliding, the grid arch structure is in a stable state (such as Figure 6 As the external load gradually increases, the upper connecting plate 22 and the lower connecting plate 21 in the retractable resistance limiting device 2 will slide relative to each other, that is, they will be compressed and deformed by the force (such as Figure 7 As shown in the figure, the surrounding rock load can be released to release the pressure, and then a new stable state can be reached. The retractable height can be designed according to the support needs, and the size of the sliding friction resistance can be adjusted by controlling the tightening degree of the fixings.

[0045] It should be understood that the above description is merely exemplary and the embodiments of the present application do not limit this.

[0046] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application are within the scope of protection of the pending claims of the present application.

[0047] In the description of the present application, terms such as "longitudinal", "circumferential", "left", "right", "up", "down", "inside", and "outside" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present application, and do not require that the present application must be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present application.

[0048] In addition, the terms "install", "set", "connect", and "fixed connection" used in this application should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate component. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

Claims

1. An adaptively shrinkable grid arch structure, comprising a plurality of grid arch rings uniformly arranged along the longitudinal direction of a tunnel, wherein the grid arch rings are formed by connecting a plurality of arch segments (1) end to end, characterized in that: Adjacent arch frame segments (1) are connected via a retractable resistance limiting device (2), the retractable resistance limiting device (2) comprising an upper connecting plate (22) fixedly connected to an upper arch frame segment, and a lower connecting plate (21) fixedly connected to a lower arch frame segment, the upper connecting plate (22) and the lower connecting plate (21) being connected via a fixing member (24), and under the action of a relatively large external force, the upper connecting plate (22) and the lower connecting plate (21) slide relative to each other.

2. The grid arch structure according to claim 1, characterized in that: An upper notch (221) is provided on the upper connecting plate (22) along its length direction, and a lower notch (212) is provided on the lower connecting plate (21) along its length direction. The fixing member (24) is inserted into the upper notch (221) and the lower notch (212) to connect the upper connecting plate (22) and the lower connecting plate (21).

3. The grid arch structure according to claim 1, characterized in that: The retractable resistance limiting device (2) further comprises a cushion block (23), wherein the cushion block (23) is respectively located on the outer side surfaces of the upper connecting plate (22) and the lower connecting plate (21).

4. The grid arch structure according to claim 1, characterized in that: Adjacent grid arch rings are connected via connecting pieces (3).

5. The grid arch structure according to claim 4, characterized in that: End plates (213) are vertically fixed at both ends of the lower connecting plate (21), and connecting holes (211) are provided on the end plates (213); the connecting member (3) is a U-shaped structure, and its two ends are respectively connected to the connecting holes (211) on the adjacent retractable resistance limiting device (2).

6. The grid arch structure according to claim 1, characterized in that: The arch frame segment (1) comprises four main limb steel pipes (11), the four main limb steel pipes (11) are connected by evenly arranged reinforcing ribs (12), and stirrups (13) are welded to the outer peripheries of the four main limb steel pipes (11).

7. The grid arch structure according to claim 6, characterized in that: The reinforcing ribs (12) are U-shaped ribs, Π-shaped ribs, 8-shaped ribs or Z-shaped ribs; the main limb steel pipe (11) is a smooth steel pipe, a corrugated steel pipe or a ribbed steel pipe.

8. The grid arch structure according to claim 1, characterized in that: It also comprises a concrete layer (4), wherein the arch frame segment (1) is built inside the concrete layer (4).

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