Method for protecting open TBM from tunneling through rock burst

Abstract

The application provides a protection method for open TBM to pass through a rock burst tunnel, and relates to the field of open TBM tunnel protection. The open TBM comprises a shield, an arch mounting device, a control room and a main control module. A strip groove is welded on the inner wall of the shield. The strip groove is upwardly open and is provided with an auxiliary movement module. A flexible foam plate is pasted on the upper part of a steel panel. The steel panel pasted with the flexible foam plate is placed on the auxiliary movement module. When passing through a section needing protection, the main control module controls the auxiliary movement module to draw out the steel panel pasted with the flexible foam plate. Meanwhile, the arch mounting device installs a steel arch. The steel panel pasted with the flexible foam plate is supported on the outside of the steel arch, so as to form a shed protection structure with outer flexibility and inner rigidity. When rock burst occurs, the flexible foam plate on the outside can buffer and release the kinetic energy of the ejected rock mass, so as to reduce the impact on the rigid structure, effectively protect the equipment and workers, ensure the safety of the tunnel construction and the chamber, and speed up the construction progress.

Description

Technical Field

[0001] This invention relates to the field of open-face TBM tunnel protection, and more particularly to a protection method for open-face TBMs traversing rockburst tunnels. Background Technology

[0002] With the rapid development of underground engineering construction technology, open-face TBMs are increasingly being used in tunnel construction. However, due to the exposed support construction space of open-face TBMs, during tunnel construction, sections with great burial depth, high ground stress, and good rock integrity are sometimes encountered, making rockbursts very likely to occur. Tunnel rockbursts are mainly concentrated within 120° of the top arch, and their main manifestations include spalling, detachment, and ejection. This not only seriously threatens the safety of construction personnel and equipment but also affects the construction progress and increases construction costs.

[0003] Therefore, the commonly used method is to protect the structure using steel arches and steel reinforcement bars. This method protects the safety of construction personnel and equipment to a certain extent. However, due to the 6-8cm gaps between the steel reinforcement bars, it is difficult to completely prevent the frequent falling of broken rock fragments, especially when the upper rock crater is deep, the steel reinforcement bars also suffer from insufficient rigidity and deformation into the tunnel. The utility model patent "A Shield Tail Support Structure for an Open-Type TBM" (ZL 2019 20231362.X) proposes an improvement. This improvement involves installing strip steel plates along the length of the "H"-shaped steel reinforcement bars at the top, and welding these strip steel plates to the steel reinforcement bars to form ribs. This creates a relatively closed canopy structure after the shield exits. This improvement increases the longitudinal support rigidity, reduces the exposed area of ​​the top rock surface, and solves the problem of excessive collapse load in the rock blast section causing deformation of the support structure and collapse of broken rock. However, due to limitations imposed by the open-type TBM rebar system, small gaps remain between the top ribs, making it difficult to completely prevent the sliding of rock debris and powder after a strong rockburst. Furthermore, the strip steel plates require manual placement inside the shield, increasing the workload for workers inside the tunnel and resulting in lower construction efficiency. Additionally, during strong rockbursts, especially those with delayed eruptions, the impact energy after the rock mass fractures is high, and the top crater is deep. This makes the structure susceptible to impact damage and prone to deformation into the tunnel due to insufficient support stiffness. Summary of the Invention

[0004] This invention provides a protection method for open-type TBMs traversing rockburst tunnels, to solve the problems of low rock surface sealing leading to excessive fine-grained rock debris and insufficient support rigidity in the prior art.

[0005] The technical solution adopted by the present invention to solve its technical problem is: the protection method of open TBM passing through rockburst tunnel according to the present invention, wherein the open TBM includes a shield, an arch frame installer, a control room, and a main control module. The inner wall of the shield is welded with strip channel steel on both sides, the channel steel openings upward and is provided with an auxiliary motion module, the main control module is located in the control room, and the main control module is electrically connected to the auxiliary motion module to control the auxiliary motion module;

[0006] The protection method includes the following steps:

[0007] (1) Preparation before installation: Before the open TBM is installed, the steel panel and steel arch frame are processed into arcs of corresponding size according to the diameter of the tunnel excavated by the open TBM, and flexible foam boards are pasted on the radial outer side of the steel panel to form an integrated structure.

[0008] (2) Installation inside the tunnel: The two ends of the steel panel and the flexible foam board, which form an integral structure, are set above the auxiliary motion module of the strip channel steel. The main control module sends control signals to the auxiliary motion module according to the tunneling direction of the open TBM. The movement direction of the auxiliary motion module is opposite to the tunneling direction, and the speed of the auxiliary motion module is adaptively adjusted according to the tunneling speed. As the open TBM tunnels forward, the steel panel and the flexible foam board are pulled out from the inside of the shield of the open TBM along the auxiliary motion module in the channel steel. At the same time, the arch frame installer of the open TBM simultaneously grabs and assembles the steel arch frame to form a circular structure that supports the inner side of the arc-shaped steel panel. The steel panel and the flexible foam board are fixed to the rock wall. After the upper rock wall exits the shield, it is closed by the arc-shaped steel panel and the flexible foam board within the arch range to form a canopy structure that is flexible on the outside and rigid on the inside.

[0009] The steel panel can be made of Q235 steel or Q355 steel, with a radius smaller than the tunnel radius, an angle of 120°~180°, a length direction of the tunnel axis and set to 0.3~0.8m according to support requirements, and a thickness of 0.3~1.0cm according to support rigidity requirements. The steel panel is processed outside the tunnel and then transported to the tunnel for use.

[0010] The auxiliary motion module includes an electric conveyor belt fixed on the channel steel by a frame. The electric conveyor belt runs around a pulley one driven by a drive motor and a pulley two that can rotate around an axis. With the help of the electric conveyor belt, the integrated structure formed by the steel panel and the flexible foam board is driven to maintain linear motion.

[0011] The first pulley and the second pulley are located at both ends of the channel steel. The width of the electric conveyor belt is the same as the opening width of the channel steel. The length of the steel panel and the flexible foam board is the same as or greater than the length of the channel steel. The sum of the thicknesses of the steel panel and the flexible foam board is less than the opening width of the channel steel.

[0012] The electric conveyor belt is made of high-strength and wear-resistant rubber material, and the frame is made of metal or high-strength synthetic material to support and maintain the shape stability of the electric conveyor belt.

[0013] The auxiliary motion module includes an electric conveyor chain fixedly mounted on the channel steel by a frame. The electric conveyor chain runs around a sprocket driven by a drive motor and a sprocket that can rotate around an axis. With the help of the electric conveyor chain, the integrated structure formed by the steel panel and the flexible foam board is driven to maintain linear motion.

[0014] The first sprocket and the second sprocket are disposed at both ends of the channel steel. The width of the electric conveyor chain is the same as the opening width of the channel steel. The length of the steel panel and the flexible foam board is the same as or greater than the length of the channel steel. The sum of the thicknesses of the steel panel and the flexible foam board is less than the opening width of the channel steel.

[0015] The electric conveyor chain is made of high-strength alloy material, and the frame is made of metal or high-strength synthetic material to support and maintain the shape stability of the electric conveyor chain.

[0016] The flexible foam board is a polyethylene board, polyurethane board, or aluminum foam board, with a thickness of 2-5 cm, a density of 70-500 kg / m³, an elastic modulus of 100-1000 MPa, a compressive strength of 0.5-5 MPa, and a compressibility of 30%-70%.

[0017] The steel arch frame is made of H-beams or I-beams bent into an arc shape, with a radius smaller than that of the steel panel.

[0018] The beneficial effects of this invention are:

[0019] 1. It forms a canopy structure that is flexible on the outside and rigid on the inside, which improves the protective rigidity of the tunnel roof, provides better protection for construction personnel and equipment, and avoids the problem of cleaning up debris from the roof after a rock burst.

[0020] 2. The integrated steel panel and flexible foam board can be transported automatically inside the shield of the open TBM, reducing manual intervention and improving the efficiency of building protective measures inside the tunnel. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of the steel panel of the present invention, after a flexible foam board is attached to the radially outer side to form an integral structure, placed inside an open TBM shield.

[0022] Figure 2 This is a cross-sectional schematic diagram of the steel panel and flexible foam board of the integrated structure installed after the open-type TBM shield of the present invention is extracted.

[0023] Figure 3 This is a schematic diagram of the overall installation of the protective structure of the present invention.

[0024] Reference numerals: 1. Shield; 2. Channel steel; 3. Auxiliary motion module; 4. Flexible foam board; 5. Steel panel; 6. Steel arch frame. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0026] First Embodiment

[0027] Figures 1 to 3 As shown, this embodiment provides a protection method for an open-face TBM traversing a rockburst tunnel. The open-face TBM includes a shield 1, an arch frame installer, a control room, and a main control module. The shield 1 is the tail shield of the open-face TBM, and its main function is to support and protect the tunnel wall. During TBM excavation, it ensures the stability and safety of the tunnel wall by providing support and protecting the tunnel wall. The main control module is the core component of the TBM system, undertaking the important task of controlling and monitoring the entire TBM system. The main control module can start and stop the TBM, adjust the speed and direction of the cutterhead, control the forward and backward movement of the propulsion system, and control the material feeding and discharging of the protection system and the arch frame installer.

[0028] The open-type TBM shield 1 has strip-shaped channel steel 2 welded to both sides along the tunnel axis. The channel steel 2 has an opening facing upward and is equipped with an auxiliary motion module 3. The main control module is located in the control room and is electrically connected to the auxiliary motion module to control the auxiliary motion module. The auxiliary motion module 3 includes an electric conveyor belt made of high-strength, wear-resistant rubber material with good elasticity and wear resistance, a frame made of metal or high-strength synthetic material to support and maintain the shape stability of the electric conveyor belt, and a drive motor to drive the electric conveyor belt.

[0029] The protection method includes the following steps:

[0030] (1) Preparation before installation: Before the open TBM is installed, the steel panel 5 and the steel arch frame 6 are processed into arcs of corresponding sizes according to the diameter of the tunnel excavated by the open TBM, and flexible foam board 4 is pasted on the radial outside of the steel panel 5 to form an integrated structure.

[0031] (2) Installation inside the tunnel: The two ends of the steel panel 5 and the flexible foam board 4, forming an integrated structure, are positioned above the auxiliary motion module of the strip channel steel 2. The main control module sends a control signal to the auxiliary motion module. After receiving the signal from the main control module, the auxiliary motion module controls the rotation direction of the drive motor to be the same as the tunneling direction. At this time, one end of the steel panel 5 and the flexible foam board 4, forming an integrated structure, is placed on the electric conveyor belt. Friction is generated between the surface layer of the electric conveyor belt and the steel panel 5 and the flexible foam board 4, forming an integrated structure, to ensure that they can be firmly brought into the shield 1. When the entire steel panel 5 and the flexible foam board 4 forming an integrated structure are completely inside the shield 1, the main control module sends a stop signal to the auxiliary motion module. After receiving the stop signal, the auxiliary motion module stops the electric conveyor belt, completing the feeding task.

[0032] During this process, the main control module sends control signals and stop commands. The auxiliary motion module receives signals and controls the rotation direction of the drive motor, allowing the steel panel 5 and flexible foam board 4 to be carried onto the electric conveyor belt and into the shield 1. The entire process is carried out under the control of the main control module to complete the feeding task.

[0033] When an open-face TBM encounters a tunnel section with great burial depth, high ground stress, and good rock integrity, to prevent rock bursts from threatening equipment and personnel, the main control module sends a control signal to the auxiliary motion module to control the electric conveyor belt to move in the opposite direction to the tunneling direction. The speed of the electric conveyor belt is also adaptively adjusted according to the tunneling speed. As the open-face TBM advances, the steel panel 5 and the flexible foam board 4 are pulled out from both sides of the shield 1 inside the open-face TBM along the electric conveyor belt in the channel steel 2. Simultaneously, the arch frame installer of the open-face TBM simultaneously grabs and assembles the steel arch frame 6, forming a circular structure that supports the inner side of the arc-shaped steel panel 5. The steel panel 5 and the flexible foam board 4 are fixed to the rock wall. After the upper rock wall exits the shield 1, it is sealed by the arc-shaped steel panel 5 and flexible foam board 4 within the arch area, forming a flexible outer and rigid inner protective structure.

[0034] The auxiliary motion module includes an electric conveyor belt fixed on the channel steel 2 by a frame. The electric conveyor belt runs around a pulley 1 driven by a drive motor and a pulley 2 that can rotate around an axis. With the help of the electric conveyor belt, the integrated structure formed by the steel panel 5 and the flexible foam board 4 is driven to maintain linear motion.

[0035] The first pulley and the second pulley are located at both ends of the channel steel 2. The width of the electric conveyor belt is the same as the opening width of the channel steel 2. The length of the steel panel 5 and the flexible foam board 4 is the same as or greater than the length of the channel steel 2. The sum of the thicknesses of the steel panel 5 and the flexible foam board 4 is less than the opening width of the channel steel 2.

[0036] The flexible foam board 4 is a polyethylene board, polyurethane board, or aluminum foam board, with a thickness of 2-5 cm, a density of 70-500 kg / m³, an elastic modulus of 100-1000 MPa, a compressive strength of 0.5-5 MPa, and a compressibility of 30%-70%.

[0037] The steel arch frame 6 is made of H-beams or I-beams bent into an arc shape, with a radius smaller than that of the steel panel 5.

[0038] Second Embodiment

[0039] Figures 1 to 3 As shown, this embodiment provides a protection method for an open-face TBM traversing a rockburst tunnel. The open-face TBM includes a shield 1, an arch frame installer, a control room, and a main control module. The open-face TBM shield 1 is the tail shield portion of the open-face TBM, and its main function is to support and protect the tunnel wall. During TBM excavation, it ensures the stability and safety of the tunnel wall by providing support and protecting the wall surface. The main control module is the core component of the TBM system, undertaking the important task of controlling and monitoring the entire TBM system. The main control module can start and stop the TBM's operation, adjust the speed and direction of the cutterhead, control the forward and backward movement of the propulsion system, and control the material feeding and discharging of the protection system and the arch frame installer.

[0040] The open-type TBM shield 1 has strip-shaped channel steel 2 welded to both sides along the tunnel axis. The channel steel 2 has an upward opening and is equipped with an auxiliary motion module. The main control module is located in the control room and is electrically connected to the auxiliary motion module to control the auxiliary motion module. The auxiliary motion module includes an electric conveyor chain made of high-strength alloy, a frame made of metal or high-strength synthetic material to support and maintain the shape stability of the electric conveyor chain, and a drive motor to drive the electric conveyor chain.

[0041] The protection method includes the following steps:

[0042] (1) Preparation before installation: Before the open TBM is installed, the steel panel 5 and the steel arch frame 6 are processed into arcs of corresponding sizes according to the diameter of the tunnel excavated by the open TBM, and flexible foam board 4 is pasted on the radial outside of the steel panel 5 to form an integrated structure.

[0043] (2) Installation inside the tunnel: The two ends of the steel panel 5 and the flexible foam board 4, which form an integrated structure, are positioned above the auxiliary motion module of the strip channel steel 2. The main control module sends a control signal to the auxiliary motion module. After receiving the signal from the main control module, the auxiliary motion module controls the rotation direction of the drive motor to be the same as the tunneling direction. At this time, one end of the steel panel 5 and the flexible foam board 4, which form an integrated structure, is placed on the electric conveyor chain. Friction is generated between the surface layer of the electric conveyor chain and the steel panel 5 and the flexible foam board 4, which form an integrated structure, to ensure that they can be firmly brought into the shield 1. When the entire steel panel 5 and the flexible foam board 4, which form an integrated structure, are completely inside the shield 1, the main control module sends a stop signal to the auxiliary motion module. After receiving the stop signal, the auxiliary motion module stops the electric conveyor chain, completing the feeding task.

[0044] During this process, the main control module sends control signals and stop commands. The auxiliary motion module receives signals and controls the rotation direction of the motor, allowing the steel panel 5 and flexible foam board 4 to be carried into the electric conveyor chain and into the shield 1. The entire process is carried out under the control of the main control module to complete the feeding task.

[0045] When an open-face TBM encounters a tunnel section with great burial depth, high ground stress, and good rock integrity, to prevent rock bursts from threatening equipment and personnel, the main control module sends a control signal to the auxiliary motion module to control the electric conveyor chain to move in the opposite direction to the tunneling direction. The speed of the electric conveyor chain is also adaptively adjusted according to the tunneling speed. As the open-face TBM advances, the steel panel 5 and the flexible foam board 4 are pulled out from both sides inside the shield 1 of the open-face TBM along the electric conveyor chain in the channel steel 2. Simultaneously, the arch frame installer of the open-face TBM simultaneously grabs and assembles the steel arch frame 6, forming a circular structure that supports the inner side of the arc-shaped steel panel 5. The steel panel 5 and the flexible foam board 4 are fixed to the rock wall. After the upper rock wall exits the shield 1, it is sealed by the arc-shaped steel panel 5 and flexible foam board 4 within the arch area, forming a flexible outer and rigid inner protective structure.

[0046] The auxiliary motion module includes an electric conveyor chain fixedly mounted on the channel steel 2 by a frame. The electric conveyor chain runs around a sprocket driven by a drive motor and a sprocket that can rotate around an axis. With the help of the electric conveyor chain, the integrated structure formed by the steel panel 5 and the flexible foam board 4 is driven to maintain linear motion.

[0047] The first sprocket and the second sprocket are disposed at both ends of the channel steel 2. The width of the electric conveyor chain is the same as the opening width of the channel steel 2. The length of the steel panel 5 and the flexible foam board 4 is the same as or greater than the length of the channel steel 2. The sum of the thicknesses of the steel panel 5 and the flexible foam board 4 is less than the opening width of the channel steel 2.

[0048] The flexible foam board 4 is a polyethylene board, polyurethane board, or aluminum foam board, with a thickness of 2-5 cm, a density of 70-500 kg / m³, an elastic modulus of 100-1000 MPa, a compressive strength of 0.5-5 MPa, and a compressibility of 30%-70%. The steel arch frame 6 is made of H-beams or I-beams bent into an arc shape, with a radius smaller than that of the steel panel 5.

[0049] The method in this embodiment is roughly the same as the protection method for an open TBM traversing a rockburst tunnel in the first embodiment. The difference is that the transmission device of the auxiliary motion module in the second embodiment is changed to an electric conveyor chain. The electric conveyor chain has a higher load capacity and is more suitable for conveying the large-sized and thick steel panel 5 and the flexible foam board 4 that form an integrated structure. It provides a larger protection area for the top and better protection for construction personnel and their equipment.

[0050] The above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

[0051] While the specific embodiments of this disclosure have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of this disclosure. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of this disclosure are still within the scope of protection of this disclosure.

Claims

1. A protection method for an open-type TBM traversing a rockburst tunnel, wherein the open-type TBM includes a shield (1), an arch frame installer, a control room, and a main control module, wherein the main control module is located in the control room, characterized in that, The shield (1) has two strip-shaped channel steels (2) welded on both sides of the inner wall along the tunnel direction. The channel steels (2) have an opening facing upward and are equipped with an auxiliary motion module (3). The auxiliary motion module (3) is electrically connected to the main control module. The main control module is used to control the auxiliary motion module (3). The protection method includes the following steps: Step S1, Pre-installation preparation: Before the open-type TBM is installed, according to the diameter of the tunnel excavated by the open-type TBM, the steel panel (5) and steel arch frame (6) are processed into an arc-shaped structure corresponding to the inner wall size of the tunnel, and a flexible foam board (4) is pasted on the radial outer side of the steel panel (5) to form an integrated structure. Step S2, installation inside the tunnel: The two ends of the integrated structure formed by the steel panel (5) and the flexible foam board (4) are respectively placed above the auxiliary motion modules (3) of the two strip channel steels (2). The main control module controls the movement direction of the auxiliary motion module (3) to be opposite to the tunneling direction of the open TBM, and the speed of the auxiliary motion module (3) is adaptively adjusted according to the tunneling speed. As the open TBM tunnels forward, the steel panel (5) and the flexible foam board (4) move along the channel steel. (2) The auxiliary motion module (3) is pulled out from between the two channel steels inside the shield (1) of the open TBM. At the same time, the arch frame installer of the open TBM simultaneously grabs and assembles the steel arch frame (6) to form a circular structure that supports the inside of the arc-shaped steel panel (5). The steel panel (5) and the flexible foam board (4) are fixed to the rock wall. When the upper rock wall is detached from the support of the shield (1), the steel panel (5) and the flexible foam board (4) will close and support the arch area.

2. The protection method for an open-type TBM traversing a rockburst tunnel according to claim 1, characterized in that, The steel panel (5) is made of either Q235 steel or Q355 steel, and its radius is smaller than that of the tunnel. Its angle range is 120°~180°, its length is distributed along the tunnel direction, and its length is set to 0.3~0.8m according to the support and protection requirements. Its thickness is set to 0.3~1.0cm according to the support stiffness requirements. The steel panel (5) is processed outside the tunnel and then transported to the tunnel for use.

3. The protection method for an open-type TBM traversing a rockburst tunnel according to claim 1, characterized in that, The auxiliary motion module (3) includes an electric conveyor belt fixed on the channel steel (2) by a frame. The electric conveyor belt runs around a pulley one driven by a drive motor and a pulley two that can rotate around an axis. The electric conveyor belt drives the integrated structure formed by the steel panel (5) and the flexible foam board (4) to maintain linear motion.

4. The protection method for an open-type TBM traversing a rockburst tunnel according to claim 3, characterized in that, The first pulley and the second pulley are located at both ends of the channel steel (2). The width of the electric conveyor belt is the same as the opening width of the channel steel (2). The length of the steel panel (5) and the flexible foam board (4) is the same as or greater than the length of the channel steel (2). The sum of the thicknesses of the steel panel (5) and the flexible foam board (4) is less than the opening width of the channel steel (2).

5. The protection method for an open-type TBM traversing a rockburst tunnel according to claim 1, characterized in that, The auxiliary motion module (3) includes an electric conveyor chain fixed on the channel steel (2) by a frame. The electric conveyor chain runs around a sprocket driven by a drive motor and a sprocket that can rotate around an axis. The electric conveyor chain drives the integrated structure formed by the steel panel (5) and the flexible foam board (4) to maintain linear motion.

6. The protection method for an open-type TBM traversing a rockburst tunnel according to claim 5, characterized in that, The first sprocket and the second sprocket are disposed at both ends of the channel steel (2). The width of the electric conveyor chain is the same as the opening width of the channel steel (2). The length of the steel panel (5) and the flexible foam board (4) is the same as or greater than the length of the channel steel (2). The sum of the thicknesses of the steel panel (5) and the flexible foam board (4) is less than the opening width of the channel steel (2).

7. The protection method for an open-type TBM traversing a rockburst tunnel according to claim 1, characterized in that, The flexible foam board (4) is any one of polyethylene board, polyurethane board or aluminum foam board, with a thickness of 2~5cm, a density of 70~500kg / m³, an elastic modulus of 100~1000MPa, a compressive strength of 0.5~5MPa, and a compressibility of 30%~70%.

8. The protection method for an open-type TBM traversing a rockburst tunnel according to claim 1, characterized in that, The steel arch frame (6) is made of H-beams or I-beams bent into an arc shape with a radius smaller than that of the steel panel (5).

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