Steel pipe piece for open-type TBM construction and construction method

Abstract

The invention discloses an open type TBM (tunnel boring machine) construction steel pipe piece which comprises an arc-shaped back plate (1), movable steel frames and fixed steel frames are arranged on the arc-shaped inner wall of the arc-shaped back plate (1) in the annular direction of the arc-shaped back plate (1), the movable steel frames and the fixed steel frames are alternately arranged, and grouting holes (2) are formed in the arc-shaped back plate (1). According to the steel pipe piece for open-type TBM construction and the construction method, through the design that the steel pipe piece comprises the arc-shaped back plate, the movable steel frame and the fixed steel frame, the steps in the construction method are combined, surrounding rock can be effectively supported, and recoverability of part of assemblies is achieved; therefore, the problems of insufficient support strength, high steel consumption and difficulty in recovery in the prior art are solved, and the support has the advantages of providing reliable support strength, facilitating recovery of part of components, reducing surrounding rock disturbance and reducing construction cost.

Description

Technical Field

[0001] This invention relates to an open-type TBM construction support system, and more particularly to a steel pipe segment for open-type TBM construction and a construction method thereof. Background Technology

[0002] Currently, when constructing open-face TBMs in fault fracture zones and weak surrounding rock, frequent collapses and rockfalls occur due to the poor self-stabilizing ability of the surrounding rock, sometimes causing the machine to jam and severely restricting the TBM's tunneling speed. To solve this problem, traditional construction often uses a steel frame + rebar support system. However, this method cannot effectively prevent rockfalls, resulting in a large amount of manual cleaning work and low efficiency. At the same time, the steel frame + rebar support system suffers from insufficient support strength and steel frame deformation when dealing with soft rock deformation and strong rock bursts.

[0003] To address the aforementioned issues, engineers introduced steel pipe segments as an initial support measure for tunnels, effectively resolving problems such as tunnel collapse, debris spillage, and steel frame deformation. However, traditional steel pipe segments employ an integrated frame structure with a thick steel plate backing, resulting in a large amount of steel consumption and high construction costs.

[0004] Chinese patent application CN110939468A discloses an invention patent entitled "Prefabricated Support Steel Segments for Open-Type TBMs and a Combined Shotcrete and Anchor Support Method Thereof". This prefabricated annular steel segment is divided into multiple rings, each ring consisting of a ribbed steel shell structure. The annular steel segments are connected by bolts. Pre-drilled holes are provided on the steel segment panels and ribs, allowing for the placement of grouting holes, bolt holes, anchor bolt holes, drainage holes, etc. Anchor bolts or prestressed anchor bolts are used for support and grouting through these pre-drilled holes. If necessary, pre-grouting with steel perforated pipes is also performed, thus forming a prefabricated closed support method for open-type TBM tunnels.

[0005] Although steel segments are used, the structure uses an arc-shaped ribbed steel shell with an integrated back plate and rib design that cannot be separated. Recycling the steel segments requires disassembling the entire steel segment. After backfilling and grouting, the steel segments are tightly bonded to the surrounding rock. The separation process of the steel segments from the surrounding rock causes significant disturbance to the surrounding rock and poses a high safety risk.

[0006] CN110924990A discloses an invention patent application entitled "An advanced support structure and support method using corrugated steel pipe segments". The structure includes multiple corrugated steel assembly modules that are overlapped and fixed together along the longitudinal direction of the tunnel, and grout injected into the space between the corrugated steel assembly modules and the surrounding rock of the tunnel. The corrugated steel assembly modules are composed of multiple corrugated steel pipe segments assembled by circumferential joints and longitudinal joints.

[0007] Although this structure can provide support, it uses a single-layer corrugated steel plate structure with a plate thickness of 8mm to 10mm, resulting in low structural strength and insufficient protection against strong and extremely strong rockbursts. During installation, continuous excavation is required, and the surrounding rock without initial support has poor stability. The excavation process disturbs the surrounding rock, further damaging its stability and posing a high safety risk. Summary of the Invention

[0008] The purpose of this invention is to provide a steel pipe segment for open-type TBM construction and a construction method, which has the advantages of providing reliable support strength, facilitating the recycling of some components, reducing disturbance to the surrounding rock, and reducing construction costs.

[0009] The objective of this invention is achieved through the following technical solution: a steel pipe segment for open-type TBM construction, wherein the steel pipe segment includes an arc-shaped back plate, and a movable steel frame and a fixed steel frame are arranged on the arc-shaped inner wall of the arc-shaped back plate and along the circumference of the arc-shaped back plate, the movable steel frame and the fixed steel frame are arranged alternately, and grouting holes are provided on the arc-shaped back plate.

[0010] The movable steel frame includes steel frame A and steel frame B arranged circumferentially along the arc-shaped inner wall of the arc-shaped back plate; the fixed steel frame includes steel frame C arranged circumferentially along the arc-shaped inner wall of the arc-shaped back plate, and steel frame C is located between steel frame A and steel frame B.

[0011] To facilitate the connection of adjacent steel pipe segments, end plates with connection holes are provided at both ends of steel frame A, both ends of steel frame B, and both ends of steel frame C.

[0012] To improve overall stability, longitudinal steel frames are installed between steel frame A and steel frame C, and between steel frame C and steel frame B.

[0013] In this invention, the steel frames A, B, and C are channel steel, I-beams, or H-beams.

[0014] For ease of disassembly, steel frames A3 and B4 are temporarily connected to the arc-shaped back plate by spot welding or bolts; steel frame C is fixedly connected to the arc-shaped back plate by welding or bolts.

[0015] A method for constructing steel segment tunneling machines (TBMs) in open-type TBM construction, the method comprising the following steps: 1) Transport the steel segments to the TBM steel segment assembly area; 2) Use a multi-functional steel frame assembly machine to grab the first steel pipe segment and install it in place; 3) Grab the second steel pipe segment and assemble it so that the first steel pipe segment and the second steel pipe segment are aligned end to end. Adjacent steel pipe segments are connected by bolts passing through the end plates. 4) Grab the remaining steel pipe segments one by one and connect them with bolts to form a ring, thus forming a steel pipe ring; 5) Install the longitudinal steel frame with bolts or clips to connect adjacent steel pipes in a ring; 6) Use grouting holes to drill and grout or backfill with concrete to reinforce the surrounding rock, and monitor and measure the steel pipe segments; determine the surrounding rock device by monitoring the status of the steel pipe segments, and after the surrounding rock status is stable, dismantle and retrieve the movable steel frame, while keeping the arc-shaped back plate and fixed steel frame in their original positions.

[0016] In step 6), the dismantling of the movable steel frame includes the following steps: (1) Remove the bolts connecting the movable steel frame to the end plate of the adjacent steel pipe segment; (2) Remove the bolts or clips connecting the movable steel frame and the longitudinal steel frame, and remove and recycle the movable steel frame; (3) The remaining movable steel frame was dismantled and recycled in sequence.

[0017] By adopting the above-mentioned technical solution, the open-type TBM construction steel segments and construction method provided in this application, through the design of the steel segments including the arc-shaped back plate, the movable steel frame and the fixed steel frame, combined with the steps in the construction method, can effectively support the surrounding rock and achieve the recyclability of some components. This solves the problems of insufficient support strength, large steel consumption and difficult recycling in traditional technologies, and has the advantages of providing reliable support strength, facilitating the recycling of some components, reducing surrounding rock disturbance and reducing construction costs. Attached Figure Description

[0018] The accompanying drawings of this invention are described below: Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 for Figure 1 A three-dimensional image; Figure 3 This is a schematic diagram of the structure after assembly; Figure 4 Schematic diagram for dismantling the movable steel frame structure; Figure 5 This is a structural diagram after the movable steel frame has been dismantled. Detailed Implementation

[0019] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. However, the present invention is not limited to these embodiments. Any improvements or substitutions based on the basic spirit of these embodiments shall still fall within the scope of protection claimed by the claims of the present invention.

[0020] Example 1: As Figure 1 , 2As shown, a steel pipe segment for open-type TBM construction includes an arc-shaped back plate 1. Movable steel frames and fixed steel frames are arranged on the arc-shaped inner wall of the arc-shaped back plate 1 and along the circumference of the arc-shaped back plate 1. The movable steel frames and fixed steel frames are arranged alternately. Grouting holes 2 are provided on the arc-shaped back plate 1.

[0021] In this invention, steel pipe segment refers to a structural unit used for the initial support of tunnels. It is usually made of steel, has a certain curvature, and can adapt to the shape of the surrounding rock of the tunnel, providing support and protection for the tunnel.

[0022] The arc-shaped back plate 1 refers to the main structure of the steel pipe segment, which is arc-shaped and used to withstand the pressure of the surrounding rock and serve as the installation base for other components.

[0023] Movable steel frames are steel structural support components installed on the inner wall of an arc-shaped back panel that can be disassembled and recycled under specific conditions. Their main function is to provide temporary or auxiliary support in the early stages of construction.

[0024] Fixed steel frames refer to steel structural support components installed on the inner wall of the curved back panel, which work in conjunction with movable steel frames to provide long-term or primary support. They are usually kept in place after construction is completed.

[0025] Grouting hole 2 refers to the hole pre-reserved on the arc-shaped back plate, which is used to inject grout or concrete into the surrounding rock or the gap between the steel pipe segment and the surrounding rock to reinforce the surrounding rock, fill the gap, or carry out monitoring and measurement.

[0026] The curved backplate 1 can be formed by bending a single layer of steel plate or by splicing and welding multiple steel plates. Its thickness can be selected according to the tunnel diameter and surrounding rock pressure; for example, steel plates with a thickness of 10mm to 20mm can be used. The material of the curved backplate 1 can be ordinary carbon structural steel or low-alloy high-strength structural steel.

[0027] Movable and fixed steel frames are installed on the inner curved wall of the curved backplate 1 and along its circumference. The movable and fixed steel frames can be welded from steel profiles or steel plates. These steel frames extend circumferentially along the curved backplate and can be connected to the inner wall of the curved backplate by welding, bolting, or riveting. The number and spacing of the movable and fixed steel frames can be adjusted according to actual engineering needs to provide sufficient support strength. For example, two sets of movable steel frames and one set of fixed steel frames can be installed, or multiple sets of movable and fixed steel frames can be arranged alternately.

[0028] The movable and fixed steel frames are arranged alternately. As the movable and fixed steel frames extend circumferentially along the inner wall of the curved back plate 1, they maintain a roughly parallel relationship. This alternating arrangement can be achieved through precise measurement and positioning during the manufacturing process.

[0029] Grouting holes 2 are provided on the arc-shaped back plate 1. The grouting holes 2 can be pre-reserved during the manufacturing of the arc-shaped back plate. The diameter and number of grouting holes 2 can be designed according to the grouting process and surrounding rock conditions. For example, circular holes with a diameter of 50mm to 100mm can be provided and arranged at certain intervals along the circumference of the arc-shaped back plate.

[0030] The steel segments for open-type TBM construction proposed in this application, through the combination of an arc-shaped back plate 1 and a detachable movable steel frame and a fixed steel frame, effectively reduce steel consumption and lower construction costs while ensuring initial support strength. The placement of grouting holes facilitates surrounding rock reinforcement and reduces rockfall. The detachability of the movable steel frame allows the steel segments to be recovered after the surrounding rock has stabilized, significantly reducing disturbance to the surrounding rock during recovery and improving construction safety and economic efficiency.

[0031] The movable steel frame includes steel frame A3 and steel frame B4 arranged circumferentially along the arc-shaped inner wall of the arc-shaped back plate 1; the fixed steel frame includes steel frame C5 arranged circumferentially along the arc-shaped inner wall of the arc-shaped back plate 1, and steel frame C5 is located between steel frame A3 and steel frame B4.

[0032] Specifically, the movable steel frame is a structure inside the steel segments of an open-type TBM (Tunnel Boring Machine) used to provide temporary support. Its design feature is that it can be dismantled and recycled after the surrounding rock of the tunnel has stabilized. In addition to being composed of steel frames A3 and B4, the movable steel frame can also employ detachable truss units, retractable hydraulic support devices, or modularly assembled frame structures to adapt to different construction conditions and recycling requirements. The fixed steel frame is a structure inside the steel segments of an open-type TBM used to provide permanent or semi-permanent support. Working in conjunction with the movable steel frame, it maintains the structural integrity of the steel segments and a certain degree of support capacity even after the movable steel frame is dismantled. In addition to being composed of steel frame C5, the fixed steel frame can also be constructed by welding reinforcing ribs to the inside of the curved back plate, embedding steel mesh, or using reinforcing ribs integrally formed with the curved back plate to enhance the overall structural rigidity and load-bearing capacity. Steel frames A3, B4, and C5 are the basic members constituting the movable and fixed steel frames. Their main function is to bear and transfer loads and maintain the geometry of the steel frames. These steel frames are arranged circumferentially along the inner arc of the curved backplate, meaning their long axis is approximately parallel to the tunnel excavation direction. The steel frames can be solid round steel, square steel, rectangular steel pipes, or, as further specified in subsequent embodiments, channel steel, I-beams, or H-beams. Their specific cross-sectional shape and dimensions can be optimized based on the expected load-bearing capacity, stiffness requirements, and connection method with the curved backplate. Steel frame C5 is located between steel frames A3 and B4; this is a specific spatial arrangement, meaning that the fixed steel frame C5 is within the area defined by the movable steel frames A3 and B4. This arrangement allows steel frame C5 to be precisely located on the geometric center line of steel frames A3 and B4 to achieve symmetrical stress distribution; alternatively, depending on actual engineering needs, steel frame C5 can be positioned between steel frames A3 and B4 but slightly offset to one side to optimize local stress distribution or facilitate installation.

[0033] Through the above technical solution, this application further clarifies the internal structure of the steel frame, based on the existing open-type TBM construction steel pipe segment including an arc-shaped back plate 1, with movable and fixed steel frames arranged circumferentially on its arc-shaped inner wall. Specifically, the movable steel frame is refined into steel frames A3 and B4 arranged circumferentially along the arc-shaped inner wall of the arc-shaped back plate, and the fixed steel frame is refined into steel frame C5 arranged circumferentially along the arc-shaped inner wall of the arc-shaped back plate, with steel frame C5 located between steel frames A3 and B4. This specific structural design makes the internal support frame of the steel pipe segment clearer and more standardized, thereby effectively solving the problems of inaccurate installation position and insufficient structural strength caused by the lack of specific structural design in the prior art. By clarifying the composition and relative position of each steel frame, more precise positioning and alignment can be achieved during manufacturing and installation, ensuring the integrity and stability of the steel frame, and thus improving the support strength of the steel pipe segment. Meanwhile, the arrangement of steel frame C5 between steel frames A3 and B4 forms a clear structural zoning. This allows for the targeted removal of steel frames A3 and B4 when dismantling the movable steel frames after the tunnel surrounding rock has stabilized. The fixed steel frame C5, as a permanent component, has a clearly defined position and does not cause complex interference with the movable parts, thus simplifying the dismantling process of the movable steel frames and improving the convenience of recovery and construction efficiency. This design not only optimizes the mechanical properties of the steel segments but also facilitates subsequent connection and dismantling operations, enhancing the safety and economy of the entire TBM construction process.

[0034] To further describe, end plates 7 with connection holes 6 are provided at both ends of the steel frame A3, both ends of the steel frame B4, and both ends of the steel frame C5.

[0035] The end plate 7 is a plate-shaped component located at the end of the structural member for connection or closure. The thickness, size, and shape of the end plate 7 can be designed according to the cross-sectional form of the steel frame and the required connection strength. For example, it can be designed as a rectangular, square, or irregularly shaped plate conforming to the cross-sectional profile of the steel frame. The connecting holes 6 are holes pre-drilled in the end plate 7 for fasteners to pass through and achieve structural connections. These connecting holes 6 can be formed by drilling, punching, or laser cutting, and their shape can be circular, elliptical, or slotted to accommodate different connection requirements and installation tolerances. The size and spacing of the connecting holes should match the specifications of the selected fasteners and meet the strength requirements of the structural connection; for example, multiple circular holes can be designed for bolt connections.

[0036] By installing end plates 7 with connection holes 6 at both ends of steel frame A3, steel frame B4, and steel frame C5, a standardized and reliable connection interface is provided for the movable and fixed steel frames in the aforementioned open-type TBM construction steel segments. Specifically, the connection holes 6 on the end plates 7 allow for quick and precise alignment and fixing using bolts and other fasteners during the steel segment assembly process, significantly improving assembly efficiency. This connection method avoids the inconvenience and instability that may result from traditional temporary fixing or on-site welding, ensuring a tight connection between the steel frame and adjacent components. This enhances the overall rigidity and stability of the entire steel segment structure, effectively resisting surrounding rock pressure and reducing the risk of deformation or loosening during construction and use. Furthermore, the standardized connection hole design facilitates subsequent disassembly and recycling operations, improving construction flexibility and economy.

[0037] This application further proposes that longitudinal steel frames 8 are provided between steel frame A3 and steel frame C5, and between steel frame C5 and steel frame B4.

[0038] The longitudinal steel frame 8 is a structural member arranged along the longitudinal direction of the arc-shaped back plate. Its main function is to connect and fix adjacent steel frames A3, B4, and C5, thereby forming a more robust and integrated steel frame structure. One implementation is that the longitudinal steel frame 8 can be made of the same or similar steel material as steel frames A3, B4, and C5, such as channel steel, angle steel, or flat steel, and fixed between steel frames A3 and C5, and between steel frames C5 and B4, by welding. Another implementation is that the longitudinal steel frame 8 can be made of high-strength steel plates or steel bars, and connected to steel frames A3, B4, and C5 by bolts or riveting to enhance its overall rigidity. The longitudinal steel frame 8 independently enhances the lateral connection strength of the internal steel frame structure of the steel tube segment, effectively limiting the relative displacement and deformation of steel frames A3, B4, and C5 under stress, providing fundamental support for solving the problem of weak connections.

[0039] By incorporating longitudinal steel frames 8 between steel frames A3 and C5, and between steel frames C5 and B4, this application effectively integrates the previously relatively independent steel frames A3, B4, and C5 into a more compact whole. These longitudinal steel frames 8 act as transverse support beams, firmly connecting the main load-bearing components (steel frames A, B, and C) to form a closed or semi-closed grid structure. This structure can distribute local loads more evenly throughout the entire steel frame system, thus avoiding excessive stress on a single connection point or component. Given that in some of the above embodiments, the connections between steel frames may not be strong enough, leading to insufficient structural stability and affecting support strength, this application significantly enhances the overall stiffness and stability of the internal steel frame structure of the steel tubular segment by introducing longitudinal steel frames 8. With end plates 7 equipped with connection holes 6 at both ends of steel frames A3, B4, and C5, the addition of longitudinal steel frames 8 further strengthens the internal connections of the steel frames. This allows the entire steel segment to achieve not only circumferential connections through the end plates 7 but also stronger overall synergy through the internal longitudinal steel frames 8 when subjected to external rock pressure. This effectively prevents deformation or damage to the steel segments due to uneven stress or localized stress concentration during TBM construction, thereby significantly improving the support strength and structural reliability of the steel segments and ensuring the safety and efficiency of tunnel construction.

[0040] In this invention, the steel frames A3, B4 and C5 are channel steel, I-beams or H-beams.

[0041] Specifically, channel steel is a long strip of steel with a U-shaped cross-section, whose cross-sectional shape determines its good bending resistance and load-bearing capacity. The flanges and web of the channel steel form a stable structure that can effectively resist loads in both vertical and horizontal directions. In practical applications, channel steel can be divided into various specifications according to its cross-sectional dimensions and thickness to meet different structural strength requirements. For example, ordinary channel steel (such as Q235B or Q345B material) or lightweight channel steel can be used, balancing strength and weight by selecting the appropriate model. I-beam is a long strip of steel with an I-shaped cross-section. Its upper and lower flanges and the structure of the middle web make it excellent in terms of bending and shear resistance. I-beams have a large section modulus, providing high bending stiffness and load-bearing capacity, and are especially suitable for structures subjected to large bending moments. Common I-beams include ordinary I-beams and lightweight I-beams, with various materials and specifications, which can be selected according to the specific stress requirements and economic considerations of the project. For example, hot-rolled ordinary I-beams or welded I-beams can be selected. H-beams are long steel bars with an H-shaped cross-section. They are characterized by wide flanges, high lateral stiffness, and strong bending resistance. The cross-sectional properties of H-beams give them good bending performance in all directions, and their high section utilization rate effectively saves steel. H-beams are generally classified into wide-flange, medium-flange, and narrow-flange H-beams, and are made of high-strength materials such as Q345B or Q420B, suitable for applications requiring high structural strength and stability.

[0042] By defining steel frames A3, B4, and C5 as channel steel, I-beams, or H-beams, this application effectively solves the problems of insufficient support strength, excessive steel consumption, and high construction costs in steel segment structures. These specific types of steel, such as channel steel, I-beams, and H-beams, all possess optimized cross-sectional designs and superior mechanical properties, providing higher load-bearing capacity and resistance to deformation. When these steel frames work in conjunction with the curved backplate and the longitudinal steel frames 8 positioned between steel frames A3 and C5, and between steel frames C5 and B4, they collectively construct a robust and efficient skeleton structure. This structure not only significantly enhances the overall stiffness and stability of the steel segments, effectively resisting the complex stresses of the surrounding rock during TBM construction, but also, due to its efficient mechanical properties, optimizes steel consumption while meeting strength requirements, thereby reducing material costs and overall construction costs. Furthermore, the use of standardized, easily processed, and connected channel steel, I-beams, or H-beams simplifies the manufacturing and on-site installation process of the steel segments, improving construction efficiency and project reliability.

[0043] Further description: the steel frame A3 and steel frame B4 are temporarily connected to the arc-shaped back plate 1 by spot welding or bolts; the steel frame C5 is fixedly connected to the arc-shaped back plate 1 by welding or bolts.

[0044] like Figure 3 , 4As shown in Figure 5, a method for constructing steel segments for open-type TBM construction includes the following steps: 1) Transport the steel segments to the TBM steel segment assembly area; 2) Use a multi-functional steel frame assembly machine to grab the first steel pipe segment and install it in place; 3) Grab the second steel pipe segment and assemble it so that the first steel pipe segment and the second steel pipe segment are aligned end to end. Adjacent steel pipe segments are connected by bolts passing through the end plates. 4) Grab the remaining steel pipe segments one by one and connect them with bolts to form a ring, thus forming a steel pipe ring; 5) Install the longitudinal steel frame with bolts or clips to connect adjacent steel pipes in a ring; 6) Use grouting holes to drill and grout or backfill with concrete to reinforce the surrounding rock, and monitor and measure the steel pipe segments; determine the surrounding rock device by monitoring the status of the steel pipe segments, and after the surrounding rock status is stable, dismantle and retrieve the movable steel frame, while keeping the arc-shaped back plate and fixed steel frame in their original positions.

[0045] Specifically, the method first involves transporting the steel segments to the TBM segment assembly area. This step aims to ensure that the steel segments required for construction arrive at the construction site or pre-designated assembly area in a timely and accurate manner, providing a fundamental guarantee for subsequent installation operations. The steel segments can be transported from the manufacturing plant or temporary storage point to the assembly area behind the TBM using specialized transport vehicles, such as flatbed trucks or rail transport vehicles. This TBM segment assembly area can be a pre-designated temporary storage area within the tunnel or an assembly platform integrated with the TBM.

[0046] Subsequently, a multi-functional steel frame assembly machine is used to grab the first steel segment and install it in place. This step is the starting point for steel pipe ring assembly, achieving initial positioning of the steel segment through high-precision equipment. The multi-functional steel frame assembly machine can be a segment assembly machine specifically designed for TBM construction, typically equipped with hydraulic grippers and a precise positioning system; alternatively, it can be a gantry crane or robotic arm system combined with customized clamps, used to grab the steel segment from the transport location and accurately place it into the predetermined installation position.

[0047] Next, the second steel segment is picked up and assembled, aligning the first and second segments end-to-end. Adjacent segments are connected by bolts passing through the end plates. This step aims to achieve precise alignment and secure connection between the segments to construct a stable ring structure. End-to-end alignment between segments can be achieved using locating pins, guide grooves, or the assembly machine's own vision / sensor-assisted positioning system. Connections between adjacent segments are secured using high-strength bolts passing through pre-drilled holes in the end plates. These bolts can be standard high-strength bolts or self-locking bolts to ensure reliable connections.

[0048] Building upon this, the remaining steel pipe segments are individually grasped and bolted together to form a ring, creating a steel pipe ring. This step involves repeating the assembly and connection process described above until a complete ring-shaped support structure is formed. Through continuous bolt connections, the structural integrity and load-bearing capacity of the entire steel pipe ring are ensured.

[0049] Furthermore, longitudinal steel frames are installed using bolts or clips to connect adjacent steel pipe rings. This step aims to enhance the longitudinal integrity and stability of the tunnel lining and prevent relative displacement between the steel pipe rings. The longitudinal steel frames can be steel plates, structural steel, or specially designed connecting rods, which are fixed to the connection points of adjacent steel pipe rings by bolts; alternatively, quick-installation clip mechanisms, such as interlocking clips or special clamps, can be used to securely connect the longitudinal steel frames to the steel pipe rings.

[0050] Finally, the surrounding rock is reinforced by drilling and grouting or backfilling with concrete using the grouting holes. The condition of the steel pipe segments is monitored and measured, including deformation monitoring and stress monitoring. The condition of the surrounding rock is determined by the monitoring of the steel pipe segments. After the surrounding rock condition stabilizes, the movable steel frame is dismantled and recycled; the arc-shaped back plate and fixed steel frame remain in place. This step is the core of this method, aiming to achieve permanent reinforcement of the surrounding rock and recycling of temporary support. Specifically, through the grouting holes reserved on the steel pipe segments, grout (such as cement grout or chemical grout) is drilled into the surrounding rock and injected or concrete is pumped to fill the voids in the surrounding rock and consolidate the fractured rock mass, thereby improving the overall stability and bearing capacity of the surrounding rock. During and after the grouting or backfilling process, the deformation and stress state of the steel pipe segments need to be continuously monitored and measured. For example, by installing equipment such as displacement gauges, stress gauges, and inclinometers, parameters such as deformation and stress changes of the steel pipe segments are monitored in real time to assess the stability of the surrounding rock. The removal of the movable steel frame can only proceed once monitoring data shows that the surrounding rock has reached the expected stable state and the permanent support (the consolidated body formed by grouting or backfilling) has been fully utilized. Removal of the movable steel frame may include loosening or removing its connections to the steel segments or longitudinal steel frame, and then moving the movable steel frame out of the tunnel.

[0051] Through the above technical solution, this application provides a safer and more efficient open-type TBM construction method. This method significantly reduces the disturbance and safety risks to the surrounding rock caused by the tight adhesion between the steel segments and the surrounding rock during traditional steel segment recycling by removing the movable steel frame only after the surrounding rock has been reinforced and stabilized. Specifically, after the steel segments are installed and form initial support, the surrounding rock is actively reinforced through grouting or concrete backfilling, supplemented by strict monitoring and measurement to ensure that the surrounding rock has sufficient self-stabilizing capacity and permanent support strength before the movable steel frame is removed. This "reinforce before dismantling" strategy ensures that the surrounding rock no longer heavily relies on the steel segment structure for support when removing the temporary movable steel frame, thus avoiding large-scale collapses or rockfalls that may occur when forcibly separating the steel segments from the surrounding rock. Simultaneously, since only the movable steel frame, rather than the entire steel segment structure, needs to be removed, the complexity of the recycling operation and the degree of mechanical disturbance to the surrounding rock are significantly reduced, effectively improving construction safety, reducing the workload of manual debris removal, and increasing construction efficiency.

[0052] Furthermore, in step 6), the dismantling of the movable steel frame includes the following steps: (1) Remove the bolts connecting the movable steel frame to the end plate of the adjacent steel pipe segment; (2) Remove the bolts or clips connecting the movable steel frame and the longitudinal steel frame, and remove and recycle the movable steel frame; (3) The remaining movable steel frame was dismantled and recycled in sequence.

[0053] The above technical solution achieves safe and efficient steel frame recovery. Specifically, by first removing the bolts connecting the movable steel frame to the end plates of adjacent steel segments, the movable steel frame is separated from the fixed structure, avoiding overall stress transfer during dismantling. Then, by removing the bolts or clips connecting the movable steel frame to the longitudinal steel frame, the movable steel frame is removed and recovered, ensuring that it can detach independently without interfering with the fixed parts. Finally, by sequentially dismantling and recovering the remaining movable steel frame, the systematic nature of the dismantling process is maintained, preventing simultaneous operations from causing rock instability. This sequential operation allows the movable steel frame to be removed gradually without disassembling the entire steel segment, thus significantly reducing disturbance to the surrounding rock and improving construction safety and economic efficiency.

[0054] In some of the solutions mentioned above in this application, the movable steel frame is dismantled after the surrounding rock condition has stabilized in order to recover steel and reduce material costs. However, in the process of its implementation, the dismantling operation may lack systematic steps, which may lead to an increased risk of disturbance to the surrounding rock or low dismantling efficiency, thereby affecting the overall construction safety and resource recovery effect.

Claims

1. A type of steel segment for open-type TBM construction, characterized in that: The steel pipe segment includes an arc-shaped back plate (1), on the arc-shaped inner wall of the arc-shaped back plate (1) and along the circumference of the arc-shaped back plate (1), a movable steel frame and a fixed steel frame are arranged alternately, and a grouting hole (2) is provided on the arc-shaped back plate (1).

2. The steel segment for open-type TBM construction as described in claim 1, characterized in that: The movable steel frame includes steel frame A (3) and steel frame B (4) arranged circumferentially along the arc-shaped inner wall of the arc-shaped back plate (1); the fixed steel frame includes steel frame C (5) arranged circumferentially along the arc-shaped inner wall of the arc-shaped back plate (1), and the steel frame C (5) is located between steel frame A (3) and steel frame B (4).

3. The steel segment for open-type TBM construction as described in claim 2, characterized in that: in End plates (7) with connecting holes (6) are provided at both ends of steel frame A (3), both ends of steel frame B (4), and both ends of steel frame C (5).

4. The steel segment for open-type TBM construction as described in claim 3, characterized in that: in Longitudinal steel frames (8) are provided between steel frame A (3) and steel frame C (5), and between steel frame C (5) and steel frame B (4).

5. The steel segment for open-type TBM construction as described in claim 4, characterized in that: The steel frames A (3), B (4) and C (5) are channel steel, I-beams or H-beams.

6. The steel segment for open-type TBM construction as described in claim 5, characterized in that: The steel frame A (3) and steel frame B (4) are temporarily connected to the arc-shaped back plate (1) by spot welding or bolts; the steel frame C (5) is fixedly connected to the arc-shaped back plate (1) by welding or bolts.

7. A method for constructing steel segment tunneling in open-type TBM construction, characterized in that, The method includes the following steps: 1) Transport the steel segments to the TBM steel segment assembly area; 2) Use a multi-functional steel frame assembly machine to grab the first steel pipe segment and install it in place; 3) Grab the second steel pipe segment and assemble it so that the first steel pipe segment and the second steel pipe segment are aligned end to end. Adjacent steel pipe segments are connected by bolts passing through the end plates. 4) Grab the remaining steel pipe segments one by one and connect them with bolts to form a ring, thus forming a steel pipe ring; 5) Install the longitudinal steel frame with bolts or clips to connect adjacent steel pipes in a ring; 6) Use grouting holes to drill and grout or backfill with concrete to reinforce the surrounding rock, and monitor and measure the steel pipe segments; determine the surrounding rock device by monitoring the status of the steel pipe segments, and after the surrounding rock status is stable, dismantle and retrieve the movable steel frame, while keeping the arc-shaped back plate and fixed steel frame in their original positions.

8. The method for constructing steel segments for open-type TBM construction as described in claim 7, characterized in that, In step 6), the dismantling of the movable steel frame includes the following steps: (1) Remove the bolts connecting the movable steel frame to the end plate of the adjacent steel pipe segment; (2) Remove the bolts or clips connecting the movable steel frame and the longitudinal steel frame, and remove and recycle the movable steel frame; (3) The remaining movable steel frame was dismantled and recycled in sequence.

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