2.5D steel mesh suitable for integrated lining and construction method

Abstract

This application relates to the field of 3D printing construction technology, and in particular to a 2.5D steel mesh suitable for integrated lining and its construction method. The 2.5D steel mesh includes a mesh body and radial connectors. The radial connectors include rigid connectors and flexible water-stop connectors. The rigid connectors and flexible water-stop connectors are fixedly distributed in a dot matrix on the mesh body. The rigid connectors and flexible water-stop connectors are used to radially connect the mesh body of the next layer of 2.5D steel mesh. The flexible water-stop connectors are also used to seal the radial flow channels of groundwater. During steel reinforcement construction, the 2.5D steel mesh is pre-tied or welded according to the drawings. The pre-set radial connectors can fix the next layer of 2.5D steel mesh more quickly. Compared with traditional steel reinforcement binding and installation, it can effectively shorten the construction period. At the same time, the pre-set radial connectors can also compensate for the tensile defects of concrete materials and improve the anti-slip ability and layer adhesion.

Description

Technical Field

[0001] This application relates to the field of 3D printing construction technology, and in particular to 2.5D steel mesh and construction method applicable to integrated lining. Background Technology

[0002] With the development of intelligent tunnel construction technology, 3D-printed integrated spraying lining is gradually being applied to tunnel support engineering due to its advantages of high construction efficiency and good structural integrity. As the core load-bearing component of the lining structure, the performance of the steel mesh directly determines the structural safety, waterproofing effect, and construction adaptability of the lining.

[0003] In existing technologies, traditional planar 2D steel mesh has weak adhesion to concrete and is prone to debonding between layers, which cannot meet the collaborative stress requirements of integrated lining.

[0004] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0005] The purpose of this application is to provide a 2.5D steel mesh and construction method suitable for integrated lining, so as to solve or alleviate the problems existing in the prior art.

[0006] To achieve the above objectives, this application provides the following technical solution: A 2.5D steel mesh suitable for integrated lining, the 2.5D steel mesh comprising a mesh body and radial connectors; the radial connectors comprising rigid connectors and flexible water-stop connectors; The rigid connectors and flexible water-stop connectors are fixedly distributed in a dot matrix on the mesh body; The rigid connector and the flexible water-stop connector are used to radially connect the mesh body of the next layer of 2.5D steel mesh. The flexible water-stop connector is also used to seal the radial flow channels of groundwater.

[0007] Preferably, the flexible waterstop connector is a T-shaped waterstop; one end of the vertical section of the T-shaped waterstop is fixedly connected to the mesh body, and one end of the horizontal section of the T-shaped waterstop is radially fastened to the mesh body of the next layer of 2.5D steel mesh.

[0008] Preferably, one end of the rigid connector is fixedly connected to the mesh body, and the other end is radially hooked to the mesh body of the next layer of 2.5D steel mesh.

[0009] Preferably, a flexible protective sleeve is fitted onto one end of the rigid connector that connects to the next layer of 2.5D steel mesh.

[0010] A construction method for 2.5D steel mesh suitable for integrated lining, the construction method comprising: Step S1: Splice 2.5D steel mesh along the circumference of the tunnel; Step S2: The first lining structure is constructed using 3D printing equipment, and the spraying thickness is controlled by radial connectors; Step S3: Based on the radial connectors of the upper layer of 2.5D steel mesh, splice the next layer of 2.5D steel mesh along the tunnel circumference; the rigid connectors and flexible water-stop connectors of adjacent 2.5D steel meshes are alternately set along the same radial direction; Step S4: The second lining structure is constructed using 3D printing equipment, and the spraying thickness is controlled by radial connectors.

[0011] Preferably, in step S3, the lower layer of 2.5D steel mesh is staggered with the upper layer of 2.5D steel mesh.

[0012] Preferably, the density of the rigid connectors gradually decreases from low to high along the tunnel circumference; the density of the flexible water-stop connectors gradually increases from low to high along the tunnel circumference.

[0013] Preferably, following the principles of bottom-up, symmetrical synchronization, segmented advancement, and closed-loop forming, the 3D printing construction of the first lining structure and the second lining structure is carried out layer by layer.

[0014] Preferably, following the principles of bottom-up, symmetrical synchronization, segmented advancement, and closed-loop forming, the 3D printing construction of the first lining structure and the second lining structure is carried out layer by layer according to an S-shaped trajectory.

[0015] Preferably, the layered printing thickness of the first lining structure and the second lining structure gradually decreases from low to high along the tunnel circumference.

[0016] Compared with the closest prior art, the technical solution of this application has the following beneficial effects: In this application, during the reinforcement construction, the 2.5D steel mesh is pre-tied or welded according to the drawings. The pre-set radial connectors can fix the next layer of 2.5D steel mesh more quickly. Compared with the traditional steel reinforcement binding and installation, the construction period can be effectively shortened. At the same time, the pre-set radial connectors can also make up for the tensile defects of concrete materials and improve the anti-slip ability and layer adhesion. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. Wherein: Figure 1 This is a schematic diagram of the 2.5D steel mesh arrangement provided according to some embodiments of this application; Figure 2This is a schematic diagram of a T-shaped waterstop structure provided according to some embodiments of this application.

[0018] Explanation of reference numerals in the attached figures: 1. Mesh body; 2. Rigid connector; 3. T-shaped waterstop; 4. Horizontal section; 5. Vertical section; 6. Mounting hole; 7. Relief groove; 8. Arc-shaped slot; 9. First lining structure; 10. Second lining structure. Detailed Implementation

[0019] The present application will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation and not by way of limitation. In fact, those skilled in the art will recognize that modifications and variations can be made to the present application without departing from the scope or spirit thereof. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the present application encompass such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0020] In the following description, the terms "first / second / third" are used merely to distinguish similar objects and do not represent a specific order of objects. It is understood that "first / second / third" may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing embodiments of this disclosure only and is not intended to limit this disclosure.

[0022] In the description of this application, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and do not require that this application be constructed and operated in a specific orientation, and therefore should not be construed as limiting this application. The terms "connected," "linked," and "set up" used in this application should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; direct connections or indirect connections through intermediate components; wired connections, radio connections, or wireless communication signal connections. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0023] The following will be combined with the appendix Figure 1-2This application provides a further detailed description of the 2.5D steel mesh and construction method applicable to integrated lining.

[0024] A 2.5D steel mesh suitable for integrated lining, comprising a mesh body 1 and radial connectors; the radial connectors include rigid connectors 2 and flexible water-stop connectors; Rigid connector 2 and flexible water-stop connector are fixedly distributed in a dot matrix on the mesh body 1; Rigid connector 2 and flexible water-stop connector are used to radially connect the mesh body 1 of the next layer of 2.5D steel mesh. Flexible water-stop connectors are also used to seal radial flow channels of groundwater.

[0025] In a specific embodiment of this application, the mesh body 1 is made of HRB400 grade hot-rolled ribbed steel bars welded together, with a mesh size of 25cm×25cm and a steel bar diameter of 8mm. The size of a single mesh body 1 is adapted to the working range of the tunnel 3D printing robotic arm, designed as 100cm (circumferential)×150cm (axial). A 10cm overlap length is reserved at the edge of the mesh body 1 to accommodate circumferential and axial splicing requirements. The rigid connectors 2 and the flexible water-stop connectors are fixed to the grid nodes of the mesh body 1 in a staggered quincunx pattern. For example, two adjacent rigid connectors 2... One flexible water-stop connector is installed between the layers, with a basic spacing of 30cm×30cm, and the two do not overlap or interfere with each other; the rigid connector 2 is made of Q235 grade round steel, one end is fixed to the grid node of the mesh body 1, and the other end extends radially along the tunnel to connect to the next layer of mesh body 1, and undertakes the functions of interlayer support and thickness limit; the flexible water-stop connector is made of water-swellable rubber, one end is fixed to the mesh body 1, and the other end extends radially to connect to the next layer of mesh body 1, filling the interlayer gaps, blocking the radial flow channel of groundwater, and achieving interlayer sealing and water-stopping.

[0026] In this application, during the construction of the steel reinforcement, the 2.5D steel mesh is pre-tied or welded according to the drawings. The next layer of 2.5D steel mesh can be fixed more quickly through the pre-set radial connectors. Compared with the traditional steel reinforcement binding and installation, the construction period can be effectively shortened. At the same time, the pre-set radial connectors can also make up for the tensile defects of concrete materials and improve the anti-slip ability and the bonding force of the layers. Furthermore, the radial connectors employ a combination of rigid connector 2 and flexible water-stop connector. The rigid connector 2 provides vertical support between layers, precise thickness control, and load transfer, compensating for the deficiencies of the flexible connector in terms of pressure deformation and uncontrolled thickness. The flexible water-stop connector achieves flexible interlayer bonding and sealing, blocking the through-seepage cold bridge of the rigid connector 2, and compensating for the deficiencies of the rigid connector 2 in terms of leakage and stress concentration-induced cracking. Together, they achieve a lining skeleton structure that combines rigidity and flexibility.

[0027] The flexible waterstop connector is a T-shaped waterstop 3; one end of the vertical section 5 of the T-shaped waterstop 3 is fixedly connected to the mesh body 1, and one end of the horizontal section 4 of the T-shaped waterstop 3 is radially fastened to the mesh body 1 of the next layer of 2.5D steel mesh.

[0028] In a specific embodiment of this application, the T-shaped waterstop 3 is an integrally vulcanized water-swellable rubber T-shaped waterstop 3; one end of the vertical section 5 of the T-shaped waterstop 3 is provided with an installation hole 6, and lead wire or thin iron wire is passed through the installation hole 6 to tie it to the reinforcing bars around the grid node; one end of the horizontal section 4 of the T-shaped waterstop 3 is integrally formed with two cross-shaped arc-shaped grooves 8 with self-locking function, and anti-slip teeth are provided in the grooves. The opening width of the grooves is adapted to the diameter of the reinforcing bars at the grid node, and can directly fasten the horizontal and vertical reinforcing bars at the grid node of the next layer of mesh body 1 in the radial direction to achieve tool-free quick connection; furthermore, the middle of one end of the vertical section 5 of the T-shaped waterstop 3 is provided with a clearance groove 7 to avoid the end of the rigid connector 2 of the upper layer, and the installation hole 6 is symmetrically arranged on both sides of the clearance groove 7.

[0029] One end of the rigid connector 2 is fixedly connected to the mesh body 1, and the other end is radially hooked to the mesh body 1 of the next layer of 2.5D steel mesh.

[0030] In a specific embodiment of this application, one end of the rigid connector 2 is fixed to the mesh node of the mesh body 1 by double-sided welding, and rust prevention treatment is performed after welding; the other end extends radially, and the end is bent into a closed hook. The inner diameter of the hook is adapted to the diameter of the steel bar of the next layer of mesh body 1, and can be directly hooked on the mesh node of the next layer of mesh body 1 to achieve radial positioning and connection.

[0031] To further ensure the integrity of the tunnel lining structure, a flexible protective sleeve is fitted on one end of the rigid connector 2 that connects to the next layer of 2.5D steel mesh.

[0032] In a specific embodiment of this application, the flexible protective sleeve is a cylindrical protective sleeve made of water-swellable rubber. After swelling with water, it can seal the capillary gaps at the interface between the steel bar and the concrete, blocking the water seepage channel of the rigid connector 2. At the same time, it buffers the stress concentration at the end of the hook, reducing the generation of micro-cracks in the concrete. During the factory prefabrication stage, the flexible protective sleeve is directly fitted onto the end of the hook of the rigid connector 2, covering the entire hook and the end of the steel bar, and fixed to the steel bar with rubber adhesive to prevent it from falling off during construction.

[0033] Construction methods for 2.5D steel mesh suitable for integrated linings include: Step S1: Splice 2.5D steel mesh along the circumference of the tunnel; Step S2: The first lining structure 9 is constructed using 3D printing equipment, and the spraying thickness is controlled by radial connectors; Step S3: Based on the radial connectors of the upper layer of 2.5D steel mesh, splice the next layer of 2.5D steel mesh along the tunnel circumference; the rigid connectors 2 and flexible water-stop connectors of adjacent 2.5D steel meshes are alternately set along the same radial direction; Step S4: The second lining structure 10 is constructed using 3D printing equipment, and the spraying thickness is controlled by radial connectors.

[0034] In a specific embodiment of this application, Step S1: After the tunnel excavation is completed, C25 concrete is first sprayed using a spraying machine to level the surrounding rock base surface; then a six-axis industrial robotic arm is used with a mesh grabbing tool to splice the 2.5D steel mesh prefabricated in the factory along the tunnel circumference piece by piece. The circumferential and axial overlap length of adjacent mesh pieces is not less than 10cm. The overlap is fixed with plastic clips to form a closed initial mesh layer. Step S2: The first lining structure uses 9C40 water-repellent concrete, which is sprayed in layers along the circumference of the tunnel using a 3D-printed spraying robotic arm. During the spraying process, the laser rangefinder on the robotic arm detects the thickness of the concrete spray in real time, and the radial length of the rigid connector 2 is used as the limit reference for the spray thickness. When the concrete spray surface reaches the design height of the rigid connector 2, the spraying of that area is automatically stopped. Step S3: After the concrete of the first lining structure 9 reaches the initial setting strength (50% of the design strength), the next layer of 2.5D steel mesh is hoisted and positioned; the mesh nodes of the next layer are hooked and fixed to the hooks of the rigid connector 2 of the previous layer, and the arc-shaped groove 8 of the flexible water-stop connector of the previous layer is fastened and fixed to the steel bars of the next layer. The rigid connector 2 and the flexible water-stop connector are alternately set on the same radial line. Through the mutual cooperation of the 2.5D steel mesh at different layers, the seepage channel of the rigid connector 2 is further blocked, and the problem of leakage along the reinforcement is solved. At the same time, the inner and outer radial alternation can further realize the staggered distribution of load and avoid concentrated stress. Step S4: The second lining structure 10 is C40 impermeable concrete, and the 3D printed spraying robot arm is used for layer spraying construction; the radial length of the rigid connector 2 in this layer is used as the limit reference for the spraying thickness; after the full ring spraying is completed, a layer of mesh body 1 is directly laid through the radial connector, and the inner surface of the lining is finished by using a robot arm equipped with a smoothing tool.

[0035] To avoid through-joint defects in the 2.5D steel mesh system, improve the overall stiffness and continuity of the 2.5D steel mesh, reduce stress concentration along the lap joint of the lining structure, prevent lining cracking, and improve the overall integrity and durability of the structure, in step S3, the lower layer of 2.5D steel mesh is staggered with the upper layer of 2.5D steel mesh.

[0036] In a specific embodiment of this application, when splicing the next layer of 2.5D steel mesh, the position of the lap joint of the mesh body 1 is strictly controlled to ensure that the circumferential lap joint of the next layer of mesh body 1 is staggered from the circumferential lap joint of the previous layer of mesh body 1; the axial lap joint of the next layer of mesh body 1 is also staggered from the axial lap joint of the previous layer of mesh body 1, and through joints are strictly prohibited.

[0037] To adapt to the different working conditions in different areas of the tunnel, the density of rigid connectors 2 gradually decreases from low to high along the tunnel circumference; the density of flexible water-stop connectors gradually increases from low to high along the tunnel circumference.

[0038] In a specific embodiment of this application, the tunnel is divided into four working zones along the circumference, with differentiated connection density settings: 1) Arch foot area (0°-60° range from the bottom of the tunnel): Rigid connector 2 has the highest density; Flexible water-stop connector has the lowest density; 2) Side wall area (60°-120° and 240°-300° circumference of the tunnel): Rigid connectors 2 and flexible water-stop connectors are arranged in an alternating pattern with equal density; 3) Arch waist area (120°-150° and 210°-240° circumference of the tunnel): The density of rigid connector 2 is less than the arrangement density of flexible water-stop connector; 4) Arch area (150°-210° circumference of the tunnel): The density of rigid connector 2 is the lowest; the density of flexible water-stop connector is the highest.

[0039] Following the principles of bottom-up, symmetrical synchronization, segmented advancement, and closed-loop forming, the 3D printing construction of the first lining structure 9 and the second lining structure 10 was carried out layer by layer.

[0040] In a specific embodiment of this application, based on the consideration of concrete anti-sag performance, the 3D printing construction of the first lining structure 9 is carried out in sections and layers from bottom to top, following the order of arch foot, side wall, arch waist, and arch crown. Before construction, the base surface is inspected, and floating slag and debris are cleaned to ensure that the 2.5D steel mesh is installed in place. Then, the two arch feet are sprayed upwards layer by layer, with the spray gun kept perpendicular to the sprayed surface and the spraying distance controlled at 0.8-1.2m. After the arch foot construction is completed, the spraying is paused until the concrete at the arch foot has cured to 50% of the design strength before continuing the construction of the side wall, arch waist, and arch crown upwards to avoid the upper concrete from slipping due to the lower concrete not being solidified. After each section is sprayed, the surface is checked for voids and cracks in a timely manner. If there are defects, they are treated by re-spraying to ensure that the lining is dense and there is no risk of water seepage.

[0041] Following the principles of bottom-up, symmetrical synchronization, segmented advancement, and closed-loop forming, the 3D printing construction of the first lining structure 9 and the second lining structure 10 was carried out layer by layer according to the S-shaped trajectory.

[0042] In a specific embodiment of this application, an S-shaped printing trajectory with one circle overlapping half a circle is adopted, which can significantly improve the interlayer density and reduce the interlayer voids and weak linear seams that are prone to occur in traditional straight-line printing. The S-shaped printing trajectory can also make the concrete bundle more stable, with less impact and a lower rebound rate. The 3D printing equipment does not have frequent start-stop, reversal, or breakpoints, the robotic arm moves more smoothly, and the printing efficiency is higher.

[0043] The layered printing thickness of the first lining structure 9 and the second lining structure 10 gradually decreases from low to high along the tunnel circumference.

[0044] In a specific embodiment of this application, the arch foot is the main load-bearing support point and seepage collection area of ​​the lining structure. It is subject to complex stress, has high waterproof requirements, and has good concrete stacking stability. Therefore, a larger layer printing thickness, such as 100mm, is adopted to improve the structural density, early strength and impermeability. However, the side walls, arch waist and arch top are prone to concrete slippage and detachment, so a smaller layer thickness is required to ensure molding quality and dimensional accuracy.

[0045] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A 2.5D steel mesh suitable for integrated lining, characterized in that, The 2.5D steel mesh includes a mesh body and radial connectors; the radial connectors include rigid connectors and flexible water-stop connectors. The rigid connectors and flexible water-stop connectors are fixedly distributed in a dot matrix on the mesh body; The rigid connector and the flexible water-stop connector are used to radially connect the mesh body of the next layer of 2.5D steel mesh. The flexible water-stop connector is also used to seal the radial flow channels of groundwater.

2. The 2.5D steel mesh suitable for integrated lining as described in claim 1, characterized in that, The flexible water-stop connector is a T-shaped water-stop strip; one end of the vertical section of the T-shaped water-stop strip is fixedly connected to the mesh body, and one end of the horizontal section of the T-shaped water-stop strip is radially fastened to the mesh body of the next layer of 2.5D steel mesh.

3. The 2.5D steel mesh suitable for integrated lining as described in claim 1, characterized in that, One end of the rigid connector is fixedly connected to the mesh body, and the other end is radially hooked to the mesh body of the next layer of 2.5D steel mesh.

4. The 2.5D steel mesh suitable for integrated lining as described in claim 1, characterized in that, The rigid connector is fitted with a flexible protective sleeve at one end that connects to the next layer of 2.5D steel mesh.

5. The construction method for 2.5D steel mesh suitable for integrated lining as described in any one of claims 1-4, characterized in that, The construction method includes: Step S1: Splice 2.5D steel mesh along the circumference of the tunnel; Step S2: The first lining structure is constructed using 3D printing equipment, and the spraying thickness is controlled by radial connectors; Step S3: Based on the radial connectors of the upper layer of 2.5D steel mesh, splice the next layer of 2.5D steel mesh along the tunnel circumference; the rigid connectors and flexible water-stop connectors of adjacent 2.5D steel meshes are alternately set along the same radial direction; Step S4: The second lining structure is constructed using 3D printing equipment, and the spraying thickness is controlled by radial connectors.

6. The construction method for 2.5D steel mesh suitable for integrated lining as described in claim 5, characterized in that, In step S3, the lower layer of 2.5D steel mesh is staggered with the upper layer of 2.5D steel mesh.

7. The construction method for 2.5D steel mesh suitable for integrated lining as described in claim 5, characterized in that, The density of the rigid connectors gradually decreases from low to high along the tunnel circumference; the density of the flexible water-stop connectors gradually increases from low to high along the tunnel circumference.

8. The construction method for 2.5D steel mesh suitable for integrated lining as described in claim 5, characterized in that, Following the principles of bottom-up, symmetrical synchronization, segmented advancement, and closed-loop forming, the 3D printing construction of the first lining structure and the second lining structure was carried out layer by layer.

9. The construction method for 2.5D steel mesh suitable for integrated lining as described in claim 8, characterized in that, Following the principles of bottom-up, symmetrical synchronization, segmented advancement, and closed-loop forming, the 3D printing construction of the first lining structure and the second lining structure was carried out layer by layer according to an S-shaped trajectory.

10. The construction method for 2.5D steel mesh suitable for integrated lining as described in claim 8, characterized in that, The layered printing thickness of the first lining structure and the second lining structure gradually decreases from low to high along the tunnel circumference.

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