A tunnel support structure with a honeycomb energy absorption device and its construction method

Abstract

The present invention discloses a tunnel support structure with a honeycomb energy absorption device, which includes a primary support steel arch, a primary support shotcrete layer, and a secondary lining layer. The primary support steel arch is mainly composed of multiple sections of H-shaped steel, and a honeycomb energy absorption device is provided at the joint of the H-shaped steel combination. The primary support steel arch and the honeycomb energy absorption device are arranged in the primary support shotcrete layer. The present invention also provides a construction method for the tunnel support structure with a honeycomb energy absorption device. In the tunnel support structure of the present invention, a honeycomb energy absorption device is preset. The honeycomb energy absorption device releases the energy of the surrounding rock through compression deformation, which can effectively solve the problem that the primary support of a large-deformation tunnel is prone to deformation and damage. Moreover, the structure of the honeycomb energy absorption device itself has a certain strength and can maintain stability during installation. The adoption of the above honeycomb energy absorption device can avoid multiple arch replacements, accelerate the construction progress, and have higher construction safety.

Description

Technical Field

[0001] The present invention belongs to the field of tunnel engineering, and particularly relates to a tunnel support structure and a construction method thereof. Background Technique

[0002] In recent years, the infrastructure construction in China has been booming, and the scale of tunnel construction is unprecedented. Inevitably, tunnels need to be built in an environment with extremely poor formation conditions. When a tunnel passes through high in-situ stress or soft and fractured strata, the surrounding rock of the cavern is prone to large deformations, which will in turn cause the initial support steel frame to be distorted and deformed, and the concrete to be crushed and fall off. In severe cases, it will induce the collapse of the tunnel. If the high in-situ stress is not properly released, it is easy to cause the secondary lining to crack and deform in the later stage.

[0003] In the past, the principle of "strong support" was adopted in the design and construction of large-deformation tunnels. Common measures included increasing the thickness of the concrete layer, setting double-layer initial support, etc. However, in most cases, the large-deformation problem could not be effectively solved. During the construction period, the deformation of the surrounding rock was serious, and arch replacement was required multiple times, which seriously affected the construction progress and endangered the construction safety. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technique, and provide a tunnel support structure with a honeycomb energy-absorbing device and a construction method thereof, which have good stability and a simple structure, and are particularly suitable for the construction of large-deformation tunnels. To solve the above technical problem, the technical solution proposed by the present invention is as follows:

[0005] A tunnel support structure with a honeycomb energy-absorbing device includes an initial support steel arch, an initial support shotcrete layer, and a secondary lining layer. The initial support steel arch is mainly composed of multiple sections of H-shaped steel. A honeycomb energy-absorbing device is provided at the joint of the H-shaped steel combination. The initial support steel arch and the honeycomb energy-absorbing device are arranged in the initial support shotcrete layer. Generally, multiple honeycomb energy-absorbing devices are provided in one initial support steel arch.

[0006] In the above tunnel support structure with a honeycomb energy-absorbing device, preferably, the honeycomb energy-absorbing device includes a connector (plate-shaped) and a honeycomb energy-absorbing layer. The honeycomb energy-absorbing layer is clamped between the connectors. The H-shaped steel is connected to the honeycomb energy-absorbing device through the connector. Each honeycomb energy-absorbing device is provided with two connectors, which are respectively used to connect the H-shaped steel above and below the honeycomb energy-absorbing device.

[0007] In the above tunnel support structure with a honeycomb energy-absorbing device, preferably, the connector is provided with a preset bolt, and the end head of the H-shaped steel is provided with a connecting plate. Bolt holes for cooperating with the preset bolt are formed in the connecting plate. After the above preset bolt passes through the bolt hole, the connecting plate and the connector are fixed by a nut to fix the honeycomb energy-absorbing device to the H-shaped steel.

[0008] In the above tunnel support structure with a honeycomb energy absorption device, preferably, the honeycomb energy absorption layer includes a plurality of honeycomb cells. The honeycomb cells are of a hollow structure, and the cross-section of the honeycomb cells is a regular hexagon. The openings of the honeycomb cells face the center of the tunnel. The above honeycomb cells have excellent geometric and mechanical properties, and the above opening direction is conducive to injecting concrete into the honeycomb cells subsequently.

[0009] In the above tunnel support structure with a honeycomb energy absorption device, preferably, the minimum total thickness of the honeycomb energy absorption device is n×h, where h is calculated by the following formula:

[0010]

[0011] Where n is the number of honeycomb energy absorption devices, h is the thickness of a single honeycomb energy absorption device, t is the wall thickness of the honeycomb cell, a is the length of the honeycomb cell, and s is the value of the initial observed or predicted tunnel clearance convergence. Through the above calculation method, the number and thickness of the honeycomb energy absorption devices required in the tunnel support structure can be determined, and it can be ensured that the honeycomb energy absorption devices meet the requirements of compression deformation.

[0012] In the above tunnel support structure with a honeycomb energy absorption device, preferably, the length L of the honeycomb energy absorption device is equal to the spacing k between two adjacent primary support steel arch frames, and the honeycomb energy absorption devices at the same height of two adjacent primary support steel arch frames are connected to each other. The above setting can enhance the integrity of the primary support steel arch frame, have a certain self-stabilizing ability before the shotcrete is applied, and at the same time ensure that the honeycomb energy absorption device penetrates through the tunnel primary support structure to enhance its effect.

[0013] In the above tunnel support structure with a honeycomb energy absorption device, preferably, the width b of the honeycomb energy absorption device is equal to the thickness of the primary support shotcrete layer. The above setting can make the overall thickness of the primary support structure consistent, ensure the flatness of the primary support surface after construction, and eliminate the quality hidden danger of the void behind the secondary lining caused by the uneven surface of the shotcrete.

[0014] In the above tunnel support structure with a honeycomb energy absorption device, preferably, the tunnel support structure includes a waterproof layer and locking foot bolts. The waterproof layer is located at the bottom layer of the primary support shotcrete layer, and the locking foot bolts are connected to the primary support steel arch frame.

[0015] As a general technical concept, the present invention also provides a construction method for a tunnel support structure with a honeycomb energy absorption device, including the following steps:

[0016] S1: Excavate the tunnel by the method of multi-step reserved core soil. After the excavation of the topmost circular part is completed, construct the waterproof layer, then erect the primary support steel arch frame and the locking foot bolts. Install the honeycomb energy absorption device synchronously when erecting the primary support steel arch frame, and then spray the primary support shotcrete layer;

[0017] S2: Continue to excavate and construct downward according to the construction method of S1 to complete the construction of the primary support steel arch and the primary support shotcrete layer of the next bench.

[0018] S3: Repeat S2 until the construction of all the primary support steel arches and the primary support shotcrete layers is completed, and then complete the construction of the invert part.

[0019] S4: The honeycomb energy absorption device undergoes extrusion deformation under the action of surrounding rock stress. After the deformation of the honeycomb energy absorption device is stable, the secondary lining layer is constructed, that is, the construction of the tunnel support structure is completed.

[0020] In the above construction method, preferably, when spraying the primary support shotcrete layer, a rubber sealing layer is detachably provided at the opening of the honeycomb cells of the honeycomb energy absorption device. After the deformation of the honeycomb energy absorption device is stable, the rubber sealing layer is removed, and the honeycomb cells are filled with shotcrete, and then the secondary lining layer is constructed. The rubber sealing layer prevents the primary support shotcrete layer from entering the honeycomb cells before the deformation is stable, so as not to affect the compression deformation of the honeycomb energy absorption device. When the deformation is stable, the rubber sealing layer is removed and then concrete is sprayed into the honeycomb cells to make the structure of the honeycomb energy absorption device more stable and the overall stability of the entire tunnel support structure higher.

[0021] Compared with the prior art, the advantages of the present invention are as follows:

[0022] 1. The honeycomb energy absorption device is preset in the tunnel support structure of the present invention. Through compression deformation, the energy of the surrounding rock can be released, which can effectively solve the problem that the initial support of large-deformation tunnels is prone to deformation and damage. Moreover, the structure of the honeycomb energy absorption device itself has a certain strength and can maintain stability during installation. The adoption of the above honeycomb energy absorption device can avoid multiple arch replacements, accelerate the construction progress, and the construction safety is higher.

[0023] 2. The honeycomb energy absorption device of the present invention is a part of the tunnel structure. It not only utilizes the characteristics of the honeycomb device to absorb energy through deformation, but also utilizes the characteristics of the porous honeycomb structure after the primary support deformation is basically stable. Concrete is sprayed into the honeycomb cavity to make the structure completely stable and avoid the secondary lining layer from being subjected to a large load.

[0024] 3. The honeycomb energy absorption device in the present invention is a prefabricated component, which is simple to manufacture and convenient to install on site.

[0025] 4. The construction method of the present invention is simple, has a high degree of matching with the existing method, and the equipment and instruments used in the construction process can be universal, without the need to add other equipment, and the construction cost is low.

[0026] 5. The present invention releases the surrounding rock pressure through the compression deformation of the honeycomb energy absorption device. After the energy of the tunnel surrounding rock is released, the pressure applied to the tunnel structure is reduced, and there is no need to greatly strengthen the support parameters, which improves the economy. Brief Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 It is a schematic structural diagram of the tunnel support structure of the present invention.

[0029] Figure 2 It is a schematic structural diagram of the honeycomb energy absorption device of the present invention.

[0030] Figure 3 It is a schematic connection structure diagram between the honeycomb energy absorption device and the H-shaped steel of the present invention.

[0031] Figure 4 It is Figure 3 The structural schematic diagram after the initial shotcrete layer is sprayed in

[0032] Figure 5 It is a schematic dimension diagram of the honeycomb energy absorption layer in the present invention.

[0033] Figure 6 It is a schematic construction method diagram in Embodiment 1.

[0034] Figure 7 It is a schematic construction method diagram in Embodiment 2.

[0035] Legend Explanation:

[0036] 1. Initial support steel arch; 11. H-shaped steel; 12. Connecting plate; 2. Initial shotcrete layer; 3. Secondary lining layer; 4. Honeycomb energy absorption device; 41. Connector; 42. Honeycomb energy absorption layer; 43. Preset bolt; 5. Waterproof layer; 6. Locking foot bolt; 7. Rubber sealing layer. Detailed Embodiments

[0037] For the convenience of understanding the present invention, the following will describe the present invention more comprehensively and in detail in combination with the specification drawings and preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0038] Unless otherwise defined, all the technical terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention.

[0039] Embodiment 1:

[0040] As Figures 1 - 5 shown, the tunnel support structure with a honeycomb energy absorption device in this embodiment includes a primary support steel arch 1, a primary support shotcrete layer 2, and a secondary lining layer 3. The primary support steel arch 1 is mainly composed of multiple sections of H-shaped steel 11. A honeycomb energy absorption device 4 is provided at the joint of the combination of H-shaped steel 11. The primary support steel arch 1 and the honeycomb energy absorption device 4 are arranged in the primary support shotcrete layer 2.

[0041] In this embodiment, the honeycomb energy absorption device 4 includes a connector 41 and a honeycomb energy absorption layer 42. The honeycomb energy absorption layer 42 is sandwiched between the connectors 41. The H-shaped steel 11 is connected to the honeycomb energy absorption device 4 through the connector 41.

[0042] In this embodiment, a preset bolt 43 is provided on the connector 41. A connecting plate 12 is provided at the end of the H-shaped steel 11. A bolt hole for cooperating with the preset bolt 43 is opened on the connecting plate 12. After the preset bolt 43 passes through the bolt hole, it is fixed by a nut.

[0043] In this embodiment, the honeycomb energy absorption layer 42 includes a plurality of honeycomb cells. The honeycomb cells are hollow structures, and the cross-section of the honeycomb cells is a regular hexagon. The openings of the honeycomb cells face the tunnel center.

[0044] In this embodiment, the length L of the honeycomb energy absorption device 4 is equal to the distance k between two adjacent primary support steel arches 1. The honeycomb energy absorption devices 4 at the same height of two adjacent primary support steel arches 1 are connected to each other.

[0045] In this embodiment, the width b of the honeycomb energy absorption device 4 is equal to the thickness of the primary support shotcrete layer 2.

[0046] In this embodiment, the tunnel support structure includes a waterproof layer 5 and a locking foot bolt 6. The waterproof layer 5 is located at the bottom of the primary support shotcrete layer 2. The locking foot bolt 6 is connected to the primary support steel arch 1.

[0047] As Figure 6 shown, this embodiment also provides a construction method for a tunnel support structure with a honeycomb energy absorption device, including the following steps:

[0048] S1: The tunnel is excavated by the method of leaving the core soil in two benches. A total of 6 honeycomb energy absorption devices 4 are set. Among them, 4 are located between each section of H-shaped steel 11 of the primary support steel arch 1 on the upper bench, and 2 are located between the primary support steel arch 1 on the upper bench and the primary support steel arch 1 on the lower bench;

[0049] S2: After the excavation of the upper bench annular part is completed, the waterproof layer 5 is constructed. Then, the primary support steel arch 1 and the locking foot bolt 6 are erected. When erecting the primary support steel arch 1, the honeycomb energy absorption device 4 is installed synchronously. Then, the primary support shotcrete layer 2 is sprayed; when spraying the primary support shotcrete layer 2, a rubber sealing layer 7 is provided at the opening of the honeycomb cell of the honeycomb energy absorption device 4;

[0050] S3: Excavate the reserved core soil part;

[0051] S4: After the lower bench excavation, construct the other primary support steel arch 1 and the primary support shotcrete layer 2 according to the method of S2;

[0052] S5: Complete the construction of the invert part;

[0053] S6: The honeycomb energy absorption device 4 is extruded and deformed under the action of the surrounding rock stress. After the deformation of the honeycomb energy absorption device 4 is stable, remove the rubber sealing layer 7, fill the honeycomb cells with shotcrete, and then construct the secondary lining layer 3, that is, complete the construction of the tunnel support structure.

[0054] In this embodiment, the minimum thickness h1 of the honeycomb energy absorption device 4 between each section of H-shaped steel 11 of the single upper bench primary support steel arch 1 is calculated by the following formula:

[0055]

[0056] The minimum thickness h2 of the honeycomb energy absorption device 4 between the single upper bench primary support steel arch 1 and the lower bench primary support steel arch 1 is calculated by the following formula:

[0057]

[0058] Wherein, t is the wall thickness of the honeycomb cell, a is the length of the honeycomb cell, and s is the pre-observed or predicted tunnel clearance convergence value.

[0059] The total thickness setting of the above honeycomb energy absorption device 4 considers the compression deformation amount and the axial force distribution characteristics of the tunnel structure. The above total thickness can meet the requirements of the compression deformation amount. The axial force distribution characteristics of the tunnel structure are that the axial force is larger near the arch foot and smaller at the crown. Considering this characteristic, the thickness of the honeycomb energy absorption device 4 near the arch foot is twice that of other parts.

[0060] Example 2:

[0061] The tunnel support structure with a honeycomb energy absorption device in this embodiment is similar to that in Example 1.

[0062] As Figure 7 shown, the construction method of the tunnel support structure with a honeycomb energy absorption device in this embodiment includes the following steps:

[0063] S1: Excavate the tunnel in the way of three benches with reserved core soil, and a total of 6 honeycomb energy absorption devices 4 are set, of which 2 are located between each section of H-shaped steel 11 of the upper bench primary support steel arch 1, 2 are located between the upper bench primary support steel arch 1 and the middle bench primary support steel arch 1, and 2 are located between the middle bench primary support steel arch 1 and the lower bench primary support steel arch 1;

[0064] S2: After the excavation of the upper bench annular part is completed, apply the waterproof layer 5, then install the primary support steel arch 1 and the locking foot bolts 6. When installing the primary support steel arch 1, synchronously install the honeycomb energy absorption device 4, and then spray the primary support shotcrete layer 2; when spraying the primary support shotcrete layer 2, a rubber sealing layer 7 is provided at the opening of the honeycomb cells of the honeycomb energy absorption device 4;

[0065] S3: After the excavation of the left and right sides of the middle bench part is completed, construct the primary support steel arch 1 and the primary support shotcrete layer 2 according to the method of S2;

[0066] S4: Excavate the reserved core soil part of the upper bench;

[0067] S5: After the excavation of the left and right sides of the lower bench part is completed, construct the primary support steel arch 1 and the primary support shotcrete layer 2 according to the method of S2;

[0068] S6: Excavate the reserved core soil part of the middle bench;

[0069] S7: Excavate the reserved core soil part of the lower bench and complete the construction of the invert part;

[0070] S8: The honeycomb energy absorption device 4 is compressed and deformed under the action of the surrounding rock stress. After the deformation of the honeycomb energy absorption device 4 is stable, remove the rubber sealing layer 7, fill the honeycomb cells with shotcrete, and then construct the secondary lining layer 3, that is, complete the construction of the tunnel support structure.

[0071] In this embodiment, the minimum thickness h1 of the honeycomb energy absorption device 4 between each H-shaped steel 11 of a single primary support steel arch 1 of the upper bench is calculated by the following formula:

[0072]

[0073] The minimum thickness h2 of the honeycomb energy absorption device 4 between a single primary support steel arch 1 of the upper bench and the primary support steel arch 1 of the middle bench is calculated by the following formula:

[0074]

[0075] The minimum thickness h3 of the honeycomb energy absorption device 4 between a single primary support steel arch 1 of the middle bench and the primary support steel arch 1 of the lower bench is calculated by the following formula:

[0076]

[0077] Where t is the wall thickness of the honeycomb cell, a is the length of the honeycomb cell, and s is the pre-observed or predicted tunnel clearance convergence value.

Claims

1. A tunnel support structure with a honeycomb energy absorption device, comprising a primary support steel arch (1), a primary support shotcrete layer (2), and a secondary lining layer (3), characterized in that, The primary support steel arch (1) is mainly composed of multiple sections of H-shaped steel (11). A honeycomb energy absorption device (4) is provided at the joint of the combination of the H-shaped steel (11). The primary support steel arch (1) and the honeycomb energy absorption device (4) are arranged in the primary support shotcrete layer (2); The honeycomb energy absorption device (4) includes a connector (41) and a honeycomb energy absorption layer (42). The honeycomb energy absorption layer (42) is clamped between the connectors (41). The H-shaped steel (11) is connected to the honeycomb energy absorption device (4) through the connector (41); The honeycomb energy absorption layer (42) includes a plurality of honeycomb cells. The honeycomb cells are hollow structures, and the cross-section of the honeycomb cells is a regular hexagon. The openings of the honeycomb cells face the center of the tunnel; The minimum total thickness of the honeycomb energy absorption device (4) is n×h, and h is calculated by the following formula: ； where n is the number of honeycomb energy absorption devices (4), h is the thickness of a single honeycomb energy absorption device (4), t is the wall thickness of the honeycomb cell, a is the length of the honeycomb cell, and s is the previously observed or predicted tunnel clearance convergence value; The length L of the honeycomb energy absorption device (4) is equal to the spacing k between two adjacent primary support steel arches (1). The honeycomb energy absorption devices (4) at the same height of two adjacent primary support steel arches (1) are connected to each other. The width b of the honeycomb energy absorption device (4) is equal to the thickness of the primary support shotcrete layer (2).

2. The tunnel support structure with a honeycomb energy absorption device according to claim 1, characterized in that, A preset bolt (43) is provided on the connector (41). A connecting plate (12) is provided at the end of the H-shaped steel (11). A bolt hole for cooperating with the preset bolt (43) is opened on the connecting plate (12).

3. The tunnel support structure with a honeycomb energy absorption device according to claim 1 or 2, characterized in that, The tunnel support structure includes a waterproof layer (5) and a foot-locking bolt (6). The waterproof layer (5) is located at the bottom layer of the primary support shotcrete layer (2). The foot-locking bolt (6) is connected to the primary support steel arch (1).

4. A construction method of a tunnel support structure with a honeycomb energy absorption device according to any one of claims 1 - 3, characterized in that, It includes the following steps: S1: The tunnel is excavated by the method of multi-step reserved core soil. After the excavation of the topmost annular part is completed, the waterproof layer (5) is constructed. Then, the primary support steel arch (1) and the foot-locking bolt (6) are erected. When the primary support steel arch (1) is erected, the honeycomb energy absorption device (4) is installed synchronously. Then, the primary support shotcrete layer (2) is sprayed; S2: Continue to excavate and construct downward according to the construction method of S1 to complete the construction of the primary support steel arch (1) and the primary support shotcrete layer (2) of the next step; S3: Repeat S2 until the construction of all the primary support steel arches (1) and the primary support shotcrete layer (2) is completed, and then complete the construction of the invert part; S4: The honeycomb energy absorption device (4) undergoes extrusion deformation under the action of surrounding rock stress. After the deformation of the honeycomb energy absorption device (4) is stable, the secondary lining layer (3) is constructed, that is, the construction of the tunnel support structure is completed.

5. The construction method according to claim 4, characterized in that, When spraying the primary support shotcrete layer (2), a rubber sealing layer (7) is provided at the opening of the honeycomb cell of the honeycomb energy absorption device (4). After the deformation of the honeycomb energy absorption device (4) is stable, the rubber sealing layer (7) is removed, and the honeycomb cell is filled with shotcrete, and then the secondary lining layer (3) is constructed.

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