Large-diameter shield power tunnel interior rebar-free prefabricated assembly structure and splicing method

Abstract

This invention relates to the field of novel prefabricated structures for the interior of shield tunnels, specifically to a prefabricated, non-reinforced assembly structure for large-diameter shield power tunnels and its splicing method. It mainly consists of prefabricated U-shaped components, prefabricated compartment slabs, and prefabricated steel columns. The top inner side of the prefabricated U-shaped components is concave, and the middle of the prefabricated compartment slabs is locally thickened. The splicing method involves assembling and limiting the U-shaped components, connecting the prefabricated compartment slabs to the U-shaped components, and connecting the prefabricated steel columns to the prefabricated compartment slabs. Plain concrete is used at the bottom of the prefabricated U-shaped components to control installation errors. The locally thickened section in the middle of the prefabricated compartment slab is connected to a pre-reserved groove at the top of the prefabricated U-shaped components. Finally, the steel columns are connected to the pre-embedded steel plates at the top of the prefabricated compartment slabs to complete the installation. This invention uses a U-shaped component as the core of the support and load-bearing system, avoiding damage to the shield segments caused by rebar installation or corbel placement. It fully integrates the functional characteristics of power tunnels, providing ample usable space for the power tunnel through the arrangement of multiple vertical components.

Description

Technical Field

[0001] This invention relates to the field of prefabricated construction technology for power tunnels, specifically to a prefabricated assembly structure for a large-diameter shield power tunnel that does not require rebar installation and its splicing method. Background Technology

[0002] Shield tunnels are widely used in urban underground power tunnel projects due to their high construction safety and minimal impact on the surrounding environment. With the continuous increase in the diameter of shield tunnels and the growing demand for power transmission, power shield tunnels typically require multi-layered, multi-compartment structures to meet the functional requirements of cable laying, maintenance access, and equipment installation.

[0003] In existing power shield tunnels, the internal structure is mostly fixed by installing brackets, embedded parts, or post-construction rebar on the shield segments to connect and fix the compartment slabs and columns. However, in shield tunnels with staggered joint assembly, the joint positions of the segments are random, and it is difficult to accurately pre-set the embedded parts. This results in a large amount of rebar installation work being required during construction, which not only makes the construction process complex and time-consuming, but also easily damages the integrity of the shield segments and affects the structural durability.

[0004] Meanwhile, the internal structure of large-diameter, multi-compartment power shield tunnels must simultaneously meet multiple requirements, including no need for rebar installation, reliable structural stress, prefabricated construction, and high space utilization efficiency. Especially in staggered-joint shield tunnels, the dispersed positions of the segment circumferential and longitudinal joints make it difficult to standardize the connection points of internal auxiliary structures. This makes it difficult for traditional internal structure solutions relying on segment anchoring to simultaneously meet installation accuracy, structural reliability, and segment protection requirements. In existing technologies, the stress path of the internal structure typically relies on the shield segments, making it difficult to simultaneously meet the aforementioned technical requirements. There is currently a lack of a technical solution that can achieve stable installation of the internal multi-compartment structure without relying on rebar installation or connectors for the shield segments. Summary of the Invention

[0005] To address the above problems, the present invention aims to provide a prefabricated assembly structure and splicing method for the interior of a large-diameter shield power tunnel that does not require rebar installation. By constructing a support and load-bearing system with a U-shaped component at the bottom of the shield tunnel, the internal structural load is transferred downward to the bottom of the tunnel through the U-shaped component. This eliminates the need for rebar installation, embedded parts, or corbels on the shield segments, thereby achieving stable installation of the internal multi-compartment structure without rebar installation.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A prefabricated assembly structure for the interior of a large-diameter shield power tunnel that does not require rebar installation includes: prefabricated U-shaped components, prefabricated compartment slabs, prefabricated steel columns, embedded steel plates, shield tunnel segments, and backfill plain concrete. The prefabricated U-shaped component is set at the bottom inside the shield tunnel segment and supported on the backfill plain concrete set between the shield tunnel segment and the prefabricated U-shaped component. No rebar, anchor bolt or pre-embedded connector is installed between the prefabricated U-shaped component and the shield tunnel segment. The prefabricated U-shaped component has a support groove on the inner side of its top; The prefabricated compartment plate has a locally thickened section in the middle along its length direction. The thickened section is embedded in the supporting groove to form a fixed connection. The precast compartment slabs located on the outside of the precast U-shaped components form a cantilever structure. Their loads are transferred to the precast U-shaped components through locally thickened sections, and further transferred to the bottom of the tunnel through backfill plain concrete, so that the main stress path of the internal structure is independent of the rebar or lateral anchoring connection of the shield tunnel segments. The upper surface of the prefabricated compartment slab is provided with a pre-embedded steel plate, and the prefabricated steel column is connected to the pre-embedded steel plate through a connector.

[0007] Furthermore, the backfill plain concrete is used to adjust the installation elevation and horizontal position of the precast U-shaped components to compensate for errors in shield tunnel construction.

[0008] Furthermore, the cantilevered section of the prefabricated compartment slab is a variable cross-section structure that gradually thins from the inside to the outside.

[0009] Furthermore, the precast steel column is fixedly connected to the embedded steel plate by high-strength bolts.

[0010] Furthermore, the locally thickened socket portion is a downwardly protruding boss structure provided along the length direction of the prefabricated compartment plate, and the supporting groove is a lower groove opening structure that mates with the boss structure. Furthermore, the prefabricated compartment plate is provided with a reserved interface for installing cable brackets.

[0011] Correspondingly, the present invention also provides a method for splicing a prefabricated assembly structure without rebar installation inside a large-diameter shield power tunnel, comprising the following steps: S1: The prefabricated U-shaped component is hoisted to the predetermined position at the bottom of the shield tunnel segment, and its elevation and position are adjusted by backfilling plain concrete to form an independent support foundation; S2: Embed the locally thickened section of the prefabricated compartment plate into the support groove on the top of the prefabricated U-shaped component to complete the embedded connection; S3: The precast steel columns are fixedly connected to the precast compartment panels by means of connectors.

[0012] Furthermore, in step S3, plain concrete is used to fill the gap (8) to seal and fix the connection gap.

[0013] Furthermore, in step S4, the precast steel column is fixedly connected to the embedded steel plate by high-strength bolts.

[0014] Compared with the prior art, the present invention has the following beneficial technical effects: By backfilling plain concrete to construct a prefabricated U-shaped foundation independent of the shield tunnel segments at the bottom, it is possible to avoid the need for rebar installation or embedded parts on the shield tunnel segments. This avoids the adverse effects on the integrity of the segments caused by drilling for rebar installation or setting corbels, and helps to ensure the structural integrity and long-term durability of the shield tunnel shell.

[0015] A locally thickened section is provided in the middle of the precast compartment slab, which is embedded and fixedly connected to the support groove at the top of the precast U-shaped component, so that the compartment slab forms a load-bearing mode of cantilever on the outside and support on the inside. The load of the precast compartment slab and its upper part is directly transferred to the precast U-shaped component through the locally thickened section, and then transferred downward to the bottom structure of the tunnel through the backfill plain concrete at the bottom of the precast U-shaped component. This realizes that the internal structural load is mainly transferred through the bottom area of ​​the tunnel, which changes the traditional load-bearing method of laterally transferring the load to the shield segment through reinforcement or corbels.

[0016] By using backfill plain concrete to fine-tune the elevation and position of precast U-shaped components, the construction errors of shield tunnels can be effectively absorbed, the installation accuracy and adaptability of the internal structure can be improved, and the dependence on the forming accuracy of shield tunnels can be reduced.

[0017] All major load-bearing components, including prefabricated U-shaped parts, prefabricated compartment slabs, and prefabricated steel columns, are prefabricated in the factory. On-site work only involves hoisting, embedding, and bolting, which significantly reduces on-site wet work and temporary supports, improves construction efficiency, and shortens the overall construction cycle of the shield power tunnel.

[0018] This structural system is highly adaptable to shield tunnels with staggered joints, is not limited by the location of segment joints, and does not require pre-embedded parts or post-processing on the segments, thus expanding the scope of application of the technical solution and possessing high engineering promotion value. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of one embodiment of the present invention; Figure 2 This is a schematic diagram of the connection between the prefabricated U-shaped component and the prefabricated compartment plate according to a certain embodiment of the present invention; Figure 3 This is a schematic diagram of the connection between the prefabricated compartment slab and the prefabricated steel column according to a certain embodiment of the present invention; Figure 4 This is a schematic diagram of the connection between a prefabricated U-shaped component and a shield tunnel according to a certain embodiment of the present invention.

[0020] The following items are numbered in the diagram: 1. Precast U-shaped component, 2. Precast compartment slab, 3. Precast steel column, 4. Embedded steel plate, 5. Shield tunnel segment, 6. Backfill concrete, 7. Cable bracket, 8. Plain concrete grout, 9. High-strength bolt. Detailed Implementation

[0021] Please see Figures 1 to 4 This invention provides a prefabricated assembly structure for a large-diameter shield power tunnel that requires no rebar installation. It includes a prefabricated U-shaped component 1, prefabricated compartment slabs 2, prefabricated steel columns 3, shield tunnel segments 5, and backfill plain concrete 6. The prefabricated U-shaped component 1, prefabricated compartment slabs 2, and prefabricated steel columns 3 are all factory-prefabricated concrete or steel components, assembled on-site.

[0022] Please see Figure 1 and Figure 4 The prefabricated U-shaped component 1 is positioned at a predetermined location at the bottom of the shield tunnel segment 5. During installation, a layer of backfill plain concrete 6 is first laid at the bottom of the shield tunnel segment 5, and then the prefabricated U-shaped component 1 is hoisted into place. The backfill plain concrete 6 is used to fine-tune the installation elevation and position of the prefabricated U-shaped component 1, effectively absorbing construction errors in the shield tunnel. No rebar, anchor bolts, or embedded connectors are installed between the prefabricated U-shaped component 1 and the shield tunnel segment 5; installation, positioning, and load-bearing are achieved solely through its own weight and the backfill plain concrete 6 beneath it, thus forming a support foundation at the bottom of the tunnel independent of the shield tunnel segment 5. Figure 4 As shown, the bottom of the precast U-shaped component 1 is completely supported by the backfill plain concrete 6, and there is an installation gap between its side wall and the shield tunnel segment 5, and the two do not form a rigid connection.

[0023] Please see Figure 1 and Figure 2 The precast U-shaped component 1 has a downwardly recessed support groove on its inner top side. The precast compartment slab 2 has a downwardly protruding, locally thickened section at its midpoint along its length. During installation, the locally thickened section is embedded into the support groove at the top of the precast U-shaped component 1, forming a fixed socket connection. This locally thickened section and the support groove constitute the main pressure-bearing interface. After installation, the section of the precast compartment slab 2 located outside the precast U-shaped component 1 forms a cantilever structure. This cantilever section is not supported by the shield tunnel segment 5 or its connectors, but rather the vertical load is transferred to the precast U-shaped component 1 through the locally thickened section and the fixed connection. Figure 2 As shown, the outer thickness of the cantilevered section of the precast compartment slab 2 is less than its inner thickness. This variable cross-section design optimizes the stress performance and saves materials. After the precast compartment slab 2 is embedded in the support groove, plain concrete grout 8 can be used to seal and fix the joint to ensure the tightness and stability of the connection.

[0024] Please see Figure 1 and Figure 3 A precast steel plate 4 is embedded in the upper surface of the precast compartment slab 2. Precast steel columns 3 are connected to the embedded steel plate 4 via connectors, thus forming a vertical support system inside the power tunnel. In this embodiment, high-strength bolts 9 are used as connectors, and the bottom flange of the precast steel column 3 is fastened to the embedded steel plate 4 using high-strength bolts 9. After installation, cable brackets 7 and other equipment can be further installed on the precast steel columns 3 to meet the functional requirements of cable laying and maintenance access.

[0025] Based on the above structure, the splicing method of the prefabricated assembly structure for the internal rebar-free large-diameter shield power tunnel of the present invention mainly includes the following steps: First, step S1 is performed: the precast U-shaped component 1 is hoisted to the predetermined position at the bottom of the shield tunnel segment 5. Before or during hoisting, the elevation and horizontal position of the precast U-shaped component 1 are precisely adjusted by laying or adjusting the backfill plain concrete 6 to form a stable independent support foundation.

[0026] Next, step S2 is executed: the precast compartment slab 2 is hoisted into place, ensuring that the locally thickened section at the middle of its length is accurately embedded into the support groove at the top of the precast U-shaped component 1, thus completing the embedded connection. At this point, the precast compartment slab 2 automatically forms a stress state with the precast U-shaped component 1 as the main support under gravity. To ensure the long-term stability of the connection, plain concrete grout 8 can be used to seal and fix the connection after embedding.

[0027] Finally, step S3 is performed: the precast steel column 3 is hoisted to the predetermined position on the upper surface of the precast compartment slab 2, and fixedly connected to the embedded steel plate 4 using high-strength bolts 9, completing the installation of the entire internal structure. Afterwards, cable brackets 7 and other auxiliary facilities can be installed on the precast steel column 3 as needed.

[0028] like Figures 1 to 4 As shown, the structural system of this invention constructs a load-bearing system inside the shield tunnel with the tunnel bottom as the main load-bearing foundation through the embedding and bolting of prefabricated U-shaped components 1, prefabricated compartment slabs 2, and prefabricated steel columns 3. The prefabricated compartment slabs 2 and their upper loads are transferred to the prefabricated U-shaped components 1 through locally thickened sections, and then transferred downwards to the tunnel bottom structure through the backfill plain concrete 6 at the bottom of the prefabricated U-shaped components 1. That is, the prefabricated compartment slabs 2 and their upper loads are transferred to the tunnel bottom area through the prefabricated U-shaped components 1 and the backfill plain concrete 6, thereby avoiding the transfer of loads to the sidewalls of the tunnel segments through rebar, corbels, or lateral anchoring connections. This avoids structural damage caused by rebar or corbels on the tunnel segments, and the shield tunnel segments 5 do not need to bear additional bending moments or shear forces from the internal structure. The entire structural system has good adaptability to shield tunnels with staggered joint assembly. The main components can be prefabricated in the factory, and on-site assembly is mainly carried out, which improves construction efficiency and the degree of prefabrication of the structure.

[0029] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A prefabricated assembly structure for the interior of a large-diameter shield power tunnel that requires no rebar installation, characterized in that: It includes precast U-shaped components (1), precast compartment slabs (2), precast steel columns (3), embedded steel plates (4), shield tunnel segments (5), and backfill plain concrete (6); The prefabricated U-shaped component (1) is set at the bottom inside the shield tunnel segment (5) and supported on the backfill plain concrete (6) set between the shield tunnel segment (5) and the prefabricated U-shaped component (1). No rebar, anchor bolt or pre-embedded connector is installed between the prefabricated U-shaped component (1) and the shield tunnel segment (5). The prefabricated U-shaped component (1) has a support groove on the inner side of its top; The prefabricated compartment plate (2) has a locally thickened section in the middle of its length direction. The thickened section is embedded in the support groove to form a fixed connection. The precast compartment slab (2) located outside the precast U-shaped component (1) forms a cantilever structure. Its load is transferred to the precast U-shaped component (1) through the locally thickened section, and further transferred to the bottom of the tunnel through the backfill plain concrete (6). The upper surface of the prefabricated compartment plate (2) is provided with a pre-embedded steel plate (4), and the prefabricated steel column (3) is connected to the pre-embedded steel plate (4) through a connector.

2. The prefabricated assembly structure for the interior of a large-diameter shield power tunnel without rebar installation as described in claim 1, characterized in that, The backfill plain concrete (6) is used to adjust the installation elevation and horizontal position of the precast U-shaped component (1) to compensate for the construction error of the shield tunnel.

3. The prefabricated assembly structure for the interior of a large-diameter shield power tunnel without rebar installation as described in claim 1, characterized in that, The cantilevered section of the prefabricated compartment slab (2) is a variable cross-section structure that gradually thins from the inside to the outside.

4. The prefabricated assembly structure for the interior of a large-diameter shield power tunnel without rebar installation as described in claim 1, characterized in that, The precast steel column (3) is fixedly connected to the embedded steel plate (4) by high-strength bolts (9).

5. The prefabricated assembly structure for the interior of a large-diameter shield power tunnel without rebar installation as described in claim 1, characterized in that, The locally thickened socket is a downward protruding boss structure set along the length direction of the prefabricated compartment plate (2), and the supporting groove is a lower groove opening structure that cooperates with the boss structure.

6. The prefabricated assembly structure for the interior of a large-diameter shield power tunnel without rebar installation as described in claim 1, characterized in that, The prefabricated compartment plate (2) is provided with a reserved interface for installing cable brackets (7).

7. A method for splicing a prefabricated, non-reinforced assembly structure inside a large-diameter shield power tunnel as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1: The prefabricated U-shaped component (1) is hoisted to the predetermined position at the bottom of the shield tunnel segment (5), and its elevation and position are adjusted by backfilling plain concrete (6) to form an independent support foundation; S2: Embed the locally thickened section of the prefabricated compartment plate (2) into the support groove on the top of the prefabricated U-shaped part (1) to complete the embedded connection; S3: The precast steel column (3) and the precast compartment plate (2) on the upper surface are fixedly connected by connectors.

8. The splicing method according to claim 7, characterized in that, In step S3, plain concrete is used to fill the gap (8) to seal and fix the connection gap.

9. The splicing method according to claim 7, characterized in that, In step S4, the precast steel column (3) is fixedly connected to the embedded steel plate (4) by high-strength bolts (9).

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