3D printing tunnel integrated lining construction method

Abstract

The invention provides a 3D printing tunnel integrated lining construction method. The 3D printing tunnel integrated lining construction method comprises the steps that S1, after a tunnel face is determined, a step method is adopted for tunnel excavation; s2, after the supporting arch frame and the corresponding inverted arch frame are connected, concrete primary spraying is conducted; the method comprises the following steps: S1, primarily spraying concrete on the inner wall of the lining, S3, spraying a waterproof coating on the inner wall of the primarily sprayed concrete, S4, mounting grid lagging jacks, and fixedly connecting the adjacent grid lagging jacks through longitudinal bars by virtue of a steel bar trolley, S5, moving the steel bar trolley forwards according to the binding progress of an outer-layer steel bar mesh, and S6, printing the lining, and troweling before the initial setting of the lining concrete. According to the tunnel lining construction method, the working procedures of tunnel excavation, primary supporting, waterproofing, steel bar binding, 3D printing and trowelling are organically integrated, the mode of supporting while excavation, segmented circulation and line production is adopted, the switching and waiting time between the working procedures is shortened, the problems that in traditional construction, the working procedures are tedious, and connection is not smooth are solved, the tunnel lining construction efficiency is greatly improved, and the construction period is shortened.

Description

Technical Field

[0001] This invention belongs to the technical field of tunnel 3D printing, specifically relating to a method for constructing integrated lining for 3D printed tunnels. Background Technology

[0002] Traditional tunnel lining construction typically employs cast-in-place concrete, a method requiring multiple steps such as formwork erection, rebar tying, and concrete pouring. This method suffers from long construction cycles, high labor demands, complex formwork turnover, and difficulties in quality control at construction joints. Particularly for tunnels with complex cross-sections, the flexibility and efficiency of traditional methods are significantly limited. In recent years, 3D printing technology has demonstrated immense potential in the construction field. Its characteristics of requiring no formwork, high automation, and the ability to freely shape materials offer new ideas for tunnel engineering. However, how to organically integrate 3D printing technology into the entire process of tunnel excavation, initial support, waterproofing, and rebar engineering to form an efficient, reliable, and quality-controllable integrated construction system remains a pressing technical challenge.

[0003] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and to provide a 3D-printed integrated tunnel lining construction method.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A method for constructing integrated tunnel lining using 3D printing, comprising: Step S1: Conduct surveying and setting out to determine the tunnel face, and then use the bench method for tunnel excavation; Step S2: The arch support frame is constructed using the method of excavation and erection simultaneously. After the arch support frame is connected to the corresponding invert arch frame, initial concrete spraying is carried out. Step S3: After the initial shotcrete reaches the preset strength, a waterproof coating is sprayed onto the inner wall of the initial shotcrete. After the waterproof coating has initially set into a waterproof membrane, the tunnel invert arch is poured. Step S4: After the tunnel invert reaches the preset strength, install the grid arch frame, fix adjacent grid arch frames with longitudinal bars using a steel bar trolley, and tie the outer steel mesh with the longitudinal bars as the reference. Step S5: The steel bar trolley moves forward according to the binding progress of the outer steel bar mesh. During the forward movement, the outer lining concrete is printed by the tunnel 3D printing equipment behind. After the outer lining has initially set, the inner steel bar mesh is bound. Step S6: Print the inner lining and smooth it before the inner lining concrete sets.

[0006] Preferably, the outer steel mesh is provided with J-shaped connecting bars, and the inner steel mesh is connected to the outer steel mesh through the J-shaped connecting bars.

[0007] Preferably, the arch feet on both sides of the tunnel are respectively provided with connecting steel frames extending along the tunnel mileage direction, and the grid arch frame is fixed on the connecting steel frame accordingly; The connecting steel frame is equipped with an adjustment pad corresponding to the grid arch frame.

[0008] Preferably, pipe roofs are used for advance support before the tunnel face is excavated, and monitoring instruments are installed after the tunnel excavation is completed to monitor the deformation of the tunnel wall.

[0009] Preferably, the construction joints of the initial shotcrete, outer lining concrete, and inner lining concrete are staggered in the tunnel mileage direction, and a waterproof coating is sprayed at the construction joints of the outer lining concrete and inner lining concrete. The initial shotcrete is C30 concrete; the outer lining concrete is water-repellent concrete; and the inner lining concrete is impermeable concrete.

[0010] Preferably, the tunnel is excavated in sections, with each three sections forming a cycle, to carry out initial shotcrete, outer lining concrete, and inner lining concrete construction respectively.

[0011] Preferably, in step S4, the steel rails of the corresponding smoothing equipment are laid on the upper surface of the invert arch, and multiple calibration points are set at the centerline of the tunnel. The tunnel construction design parameters of the corresponding points are measured to assist the smoothing equipment in smoothing.

[0012] Preferably, the smoothing equipment includes: The main frame has multiple drive wheels at its bottom that move along the rails; The smoothing template includes an arched template and a side template that are hinged to each other. The inner wall of the side template is supported on the main frame by multiple driving cylinders, and its outer wall is the arched surface corresponding to the inside of the tunnel. The controller senses calibration points through a sensing module and controls the smoothing template based on the construction design parameters of the calibration points.

[0013] Preferably, a guide plate is provided in front of the smoothing template and fixed on the main frame. The guide plate has a conical shell that matches the shape of the smoothing template, and the rear end of the guide plate extends to the end of the smoothing template.

[0014] Preferably, the arched template is fixed above the support, and the edge of the arched template is provided with a folding hydraulic cylinder that is corresponding to the side template. The middle and lower edge of the side template are respectively hinged to the main frame through driving hydraulic cylinders. A lifting cylinder corresponding to the drive wheel is provided below the main frame.

[0015] Beneficial effects: This invention organically integrates tunnel excavation, initial support, waterproofing, rebar binding, 3D printing, and smoothing processes. It adopts a mode of excavation and support as it is excavated, segmented cycle, and continuous operation, which reduces the switching and waiting time between processes. It solves the problems of cumbersome processes and poor connection in traditional construction, greatly improves the efficiency of tunnel lining construction, and shortens the construction cycle.

[0016] The steel bar trolley enables precise positioning and secure connection of the grid arch frame, longitudinal reinforcement, and inner and outer layers of steel mesh. Combined with 3D printing technology, the lining concrete is printed in layers with precision, ensuring high dimensional accuracy of the lining structure, uniform steel bar arrangement, and high concrete density. At the same time, the inner and outer layers of steel mesh are connected by J-shaped connecting bars, and the construction joints are staggered and an additional waterproof coating is added, further improving the integrity, impermeability, and load-bearing capacity of the lining structure. This effectively avoids quality defects such as steel bar positioning deviation and insufficient concrete density during 3D printing construction. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein: Figure 1 This is a simplified structural diagram of the smoothing device provided in a specific embodiment of the present invention; Figure 2 This is a simplified structural diagram of the guide plate in a specific embodiment of the present invention; Figure 3 This is a schematic diagram of the assembly of the smoothing template in a specific embodiment of the present invention.

[0018] In the diagram: 1. Main frame; 2. Arch roof formwork; 3. Guide plate; 4. Rail; 5. Drive wheel; 6. Concrete nozzle; 7. Arched guide rail; 8. Side formwork; 9. Drive cylinder; 10. Folding cylinder; 11. Lifting cylinder; 12. Slide seat; 13. Arched rack. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0020] In the description of this invention, 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 the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected" and "linked" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0021] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0022] like Figure 1-3 As shown, a 3D-printed integrated tunnel lining construction method includes: Step S1, conducting surveying and setting out to determine the tunnel face location. The tunnel is excavated using a bench method to control the excavation cross-section and stabilize the surrounding rock. Before excavating the tunnel face, pre-support can be provided by constructing pipe roofs to enhance the stability of the excavation face. After tunnel excavation is completed, monitoring instruments are promptly installed to monitor the deformation of the tunnel wall in real time, guiding subsequent construction. During the bench method excavation, the bench height and length are rationally determined according to the surrounding rock grade. Temporary support is promptly implemented after the upper bench excavation to prevent surrounding rock collapse. The lower bench excavation closely follows the upper bench excavation to avoid prolonged exposure of the tunnel face. The excavation cross-section dimensions are strictly controlled during the excavation process to reduce over-excavation and under-excavation, ensuring the smooth progress of subsequent lining construction.

[0023] Step S2 involves constructing the support arch frame using a method of excavation and stabilization. The support arch frame is an I-shaped steel arch, which is fixed to the tunnel using anchor bolts after construction. During installation, it is ensured that the arch frame axis is aligned with the tunnel axis, and the arch frame spacing meets design requirements. The support arch frame is connected to the invert arch frame using bolts to ensure a secure and reliable connection. After the support arch frame is connected to the corresponding invert arch frame, a preliminary support system is formed. Subsequently, initial shotcrete is applied to the support arch frame and the excavated rock surface to form an initial support layer, quickly sealing the surrounding rock and controlling deformation. The initial shotcrete can be C30 grade and applied using a wet spraying process.

[0024] Step S3: After the initial shotcrete reaches the preset strength (75% strength), a waterproof coating is sprayed onto the inner wall of the initial shotcrete. After the waterproof coating initially sets into a continuous and complete waterproof membrane, the tunnel invert arch pouring construction is carried out.

[0025] The waterproof coating is an acrylic waterproof spray film with a thickness of not less than 3mm. Before spraying the waterproof coating, the inner wall of the initial sprayed concrete must be cleaned with a blower to remove surface dust, debris and loose parts, ensuring that the waterproof coating adheres tightly to the initial sprayed concrete.

[0026] Step S4: After the tunnel invert reaches the preset strength, the grid arch frame is installed inside the tunnel. The grid arch frames and supporting arch frames are staggered along the tunnel's mileage direction. Adjacent grid arch frames are fixedly connected by longitudinal reinforcement bars using a rebar trolley, and the outer layer of steel mesh is tied with the longitudinal reinforcement bars as a reference. The grid arch frames are fixed to the corresponding connecting steel frame by welding or bolting. Adjusting shims with adjusting bolts can be installed on the connecting steel frame for easy adjustment and positioning. After a section of grid arch frame is installed, adjacent grid arch frames are fixedly connected by longitudinal connecting reinforcement bars (longitudinal bars) using a mobile rebar trolley to form a spatial skeleton. Subsequently, the outer layer of steel mesh is tied with these longitudinal reinforcement bars as a reference and support. Before installing the grid arch frame, precise positioning is required to ensure that the position, elevation, and spacing of the arch frame meet the design requirements. After the grid arch frame is firmly installed, the longitudinal bars are welded and fixed to the grid arch frame using a steel bar trolley. The longitudinal bars are evenly distributed, and the welding quality meets the specifications. The outer layer of steel mesh is tied using a binding process, with the longitudinal bars as the reference for positioning and binding. The spacing and lap length of the steel mesh meet the design requirements. During the binding process, the steel mesh is ensured to be flat and firm to avoid loosening or displacement.

[0027] In step S5, the rebar trolley moves forward segment by segment according to the binding progress of the outer rebar mesh. During this movement, the tunnel 3D printing equipment located behind it (in the area where the rebar has already been bound) begins operation, printing the outer lining (outer lining) concrete along the erected grid arch and the bound outer rebar mesh. The rebar trolley's forward movement speed matches the binding progress of the outer rebar mesh, maintaining trolley stability during the movement to avoid disturbing the bound rebar mesh. After the outer lining concrete has initially set, the inner rebar mesh is bound to its inner side. To facilitate connection, J-shaped connecting bars can be pre-installed or welded onto the outer rebar mesh. The inner rebar mesh is then bound or welded to these J-shaped connecting bars, achieving the connection between the inner and outer rebar meshes. When binding the inner rebar mesh, the designed spacing must be maintained between it and the outer rebar mesh, ensuring a secure and reliable binding.

[0028] The initial shotcrete is C30 concrete; the outer lining concrete is water-repellent concrete; the inner lining concrete is impermeable concrete, and a hardener can be added to increase the setting speed.

[0029] Step S6 involves printing the inner lining (inner lining) concrete. During the inner lining concrete printing process, a smoothing device is used to smooth and finish the surface to obtain a smooth and even tunnel inner surface. The inner lining printing is performed in conjunction with the outer lining printing. A dedicated smoothing device is used for the smoothing operation, which is completed before the initial setting of the inner lining concrete. During the smoothing process, the inner lining surface is ensured to be flat and smooth. After smoothing, the inner lining concrete is cured promptly, and the curing time meets the specifications to ensure a steady increase in concrete strength.

[0030] In one optional embodiment, the arch feet on both sides of the tunnel are respectively provided with connecting steel frames extending along the tunnel mileage direction. The connecting steel frames are square steel cages that fit tightly against the surrounding rock of the tunnel arch feet during installation. The grid arch frames are fixed on the connecting steel frames. The connecting steel frames can provide stable support for the grid arch frames, ensuring that multiple grid arch frames are connected as one, thus ensuring the stability of the tunnel support system.

[0031] The connecting steel frame is equipped with corresponding adjusting pads for the grid arches, which can ensure the installation accuracy of the grid arches. The adjusting pads are made of steel plates, and the pad data for each grid arch can be adjusted according to the actual installation requirements. By adjusting the pads, the elevation of the grid arch can be finely adjusted to ensure accurate positioning of the grid arch. At the same time, it can distribute the pressure of the grid arch on the connecting steel frame and improve the load-bearing capacity of the connection.

[0032] Before excavation at the tunnel face, pre-support is provided using pipe roofs. After tunnel excavation, monitoring instruments are installed to monitor the deformation of the tunnel inner wall. Seamless steel pipes are used for the pipe roofs, and the spacing, length, and insertion angle of the pipe roofs meet the design requirements. The monitoring instruments, including displacement sensors and pressure sensors, are installed at key locations on the tunnel inner wall to monitor the deformation and stress changes of the tunnel inner wall in real time. The monitoring data is transmitted to the monitoring center promptly. If the monitoring data exceeds the warning value, construction is immediately stopped, and corresponding reinforcement measures are taken to ensure the safety of tunnel construction.

[0033] Furthermore, the construction joints of the initial shotcrete, outer lining concrete, and inner lining concrete are staggered along the tunnel mileage direction. This staggered arrangement of construction joints can prevent the formation of through joints, improve the impermeability and integrity of the lining structure, and prevent groundwater from seeping through the construction joints. A waterproof coating is sprayed at the construction joints of the outer and inner lining concrete, which can further enhance the waterproof effect of the construction joints and eliminate the risk of leakage.

[0034] To improve construction efficiency, the tunnel is excavated in sections, with each cycle consisting of three sections. These sections are used for initial shotcreting, outer lining concrete, and inner lining concrete construction, respectively. The length of each section is determined based on factors such as the surrounding rock grade and the performance of the construction equipment. Generally, each section is 5-15 meters long. This three-section cycle construction mode enables continuous operation of each process, including excavation, initial shotcreting, outer lining printing, and inner lining printing. This reduces waiting time between processes, improves construction efficiency, and facilitates quality control of each process, ensuring uniform and stable lining construction quality.

[0035] In another optional embodiment, in step S4, the steel rail 4 corresponding to the smoothing equipment is laid on the upper surface of the invert arch. The steel rail 4 is constructed after the concrete of the invert arch has solidified, and multiple calibration points are set at the centerline of the tunnel. The calibration points are located using high-precision measuring instruments. The tunnel construction design parameters of each point are determined by measurement. The smoothing equipment obtains the corresponding construction design parameters by sensing the calibration points through the sensing module, and adjusts the position and angle of the smoothing template in real time to ensure the accuracy of the smoothing operation, so that the lining surface is flat and smooth and meets the design standards.

[0036] In this embodiment, the smoothing equipment for smoothing the inner wall of the tunnel includes a smoothing template and a controller. It is made of welded steel sections and has sufficient strength and rigidity to withstand various loads during the smoothing operation. The bottom of the template is provided with multiple drive wheels 5 that move along the steel rail 4. The drive wheels 5 can be driven by a servo motor or a hub motor, which can drive the smoothing equipment to move smoothly along the steel rail 4. The moving speed can be adjusted according to the smoothing requirements.

[0037] The smoothing template includes an arched template 2 and side templates 8 that are hinged together. The arched template 2 and side templates 8 are made of steel plates, and their outer wall curvature is consistent with the design curvature of the tunnel lining. The inner walls of the arched template 2 and side templates 8 are supported by multiple drive cylinders 9, and their outer walls are the arched surfaces corresponding to the inside of the tunnel. The drive cylinders 9 can precisely adjust the height and angle of the arched template 2 and side templates 8, so that the angle can be adjusted according to the tunnel cross-sectional dimensions, so that it can be smoothly displaced inside the tunnel after shrinking. The controller senses the calibration point through the sensing module and controls the smoothing template based on the positioning information of the calibration point.

[0038] The controller employs a PLC controller, and the sensing module utilizes NFC sensing elements, laser sensors, or Hall effect sensors to quickly and accurately sense the calibration point location information. Based on this sensing information, the controller controls the drive cylinder 9 in real time to adjust the position of the smoothing template, ensuring smoothing accuracy. The calibration point is preferably an NFC sensing element. NFC, also known as Near Field Communication, is a short-range, high-frequency wireless communication technology that allows for contactless point-to-point data transmission between electronic devices, enabling the retrieval of corresponding construction design parameters.

[0039] Preferably, a guide plate 3 is fixed in front of the sizing template. The guide plate 3 is made of steel plate and has a conical shell that matches the shape of the sizing template. The conical shell structure can pre-level the inner lining concrete in the initial setting state. The rear end of the guide plate 3 extends to the end of the sizing template, which can guide the concrete flow and reduce the workload of the sizing template. The rear end of the guide plate 3 extends to the end of the sizing template, which can achieve seamless connection between pre-leveling and sizing operations, and improve sizing efficiency and quality.

[0040] The arched template 2 is fixed above the support. The edge of the arched template 2 is equipped with a folding cylinder 10 corresponding to the hinged side template 8. The middle and lower edge of the side template 8 are hinged by drive cylinders 9. Below, a lifting cylinder 11 corresponding to the drive wheel 5 is provided. The folding cylinder 10 controls the folding and unfolding of the side template 8, facilitating the installation, debugging, and movement of the sizing equipment. When the angle of the side template 8 needs adjustment, the folding cylinder 10 and drive cylinder 9 work together to precisely control the posture of the side template 8. Below, a lifting cylinder 11 corresponding to the drive wheel 5 is provided. The height of the lifting cylinder 11 can be adjusted to allow the sizing template to adapt to lining sizing operations at different elevations. Simultaneously, when the sizing equipment stops operating, the lifting cylinder 11 lifts the drive wheel 5 to prevent it from deforming under prolonged pressure, thus extending the equipment's service life.

[0041] In an optional embodiment, an arched guide rail 7 is provided on the outer wall of the smaller end of the guide plate 3. The arched guide rail 7 can be a forging. The curvature of the arched guide rail 7 is adapted to the conical profile of the guide plate 3 and the curvature of the tunnel lining design. The concrete nozzle 6 is slidably mounted on the arched guide rail 7 through the slide seat 12 to ensure that the slide seat 12 can move smoothly back and forth along the arched guide rail 7, thereby driving the concrete nozzle 6 to move back and forth along the arched guide rail 7.

[0042] The concrete nozzle 6 precisely delivers concrete between the outer surface of the guide plate 3 and the inner wall of the tunnel, filling the gap between them. During the forward movement of the trolley, it guides the concrete towards the space between the formwork and the inner wall of the tunnel, thus achieving concrete molding. Quick-setting concrete is used to improve the quality of the concrete molding. The concrete nozzle 6 is connected to the concrete pump via a corresponding pipe, and the controller communicates with the drive wheel 5 and the concrete pump.

[0043] In another optional embodiment, the guide plate 3 is provided with an arched rack 13 corresponding to the arched guide rail 7. The arched rack 13 is arranged parallel to the arched guide rail 7 and fixed to the outer wall of the guide plate 3. The arched rack 13 can mesh with the gear of the drive motor. The slide 12 is provided with a drive motor corresponding to the arched rack 13. The drive motor is fixed on the slide 12, and a gear is provided on the output shaft. The drive motor meshes with the arched rack 13 through the gear. The drive motor is a servo motor, which can drive the gear to move smoothly along the arched rack 13, thereby driving the slide 12 and the concrete nozzle 6 to reciprocate along the arched guide rail 7.

[0044] In this embodiment, the concrete nozzle is slidably mounted on the arched guide rail 7 via the slide block 12. The connection and assembly method between the two adopts a high-precision fitting structure, which takes into account both smooth sliding and accurate positioning. Specifically, the structure can adopt two fitting assembly methods: The first assembly method is rolling assembly (preferred). The arched guide rail 7 adopts an "I" shaped cross-section structure. The upper and lower flanges of the guide rail serve as sliding support surfaces. The web is fixed to the outer wall of the guide plate 3. The slide 12 has two sets of symmetrically arranged rolling components inside. Each set of rolling components includes 2-4 deep groove ball bearings or needle roller bearings. The bearings are fixed to the inner side of the slide 12 through bearing seats. The outer ring of the bearing is in close contact with the upper and lower flange surfaces of the arched guide rail 7 to form rolling support. The inner side of the slide 12 has a limiting groove that matches the web of the guide rail. A gap of 0.5-2mm is reserved between the groove and the web to avoid frictional interference between the two and to prevent the slide 12 from shifting along the width direction of the guide rail, thus achieving precise guidance.

[0045] To improve assembly stability, dustproof retaining rings are provided at both ends of the slide block 12. The retaining rings are made of elastic rubber and fit tightly against the surface of the guide rail to prevent dust and concrete slurry in the tunnel from entering the sliding pair and avoid bearing jamming and wear.

[0046] The second assembly method is sliding assembly. The arched guide rail 7 adopts a "T-shaped" cross-section structure. The transverse flange of the guide rail serves as a sliding support surface, and the longitudinal web is used for limiting. The surface of the guide rail is coated with a wear-resistant polytetrafluoroethylene coating with a thickness of 0.3-0.5mm.

[0047] The inner side of the slide block 12 is provided with a groove that is adapted to the T-shaped guide rail. The bottom of the groove is provided with a wear-resistant liner made of nylon or bronze. The liner is in close contact with the guide rail support surface to form a sliding friction pair. Elastic limit blocks are provided on both sides of the groove. The limit blocks are in close contact with the web of the guide rail to play a lateral limiting role and prevent the slide block 12 from shifting laterally during sliding.

[0048] In this embodiment, to avoid jamming during sliding, grease is periodically added between the sliding pairs. Regardless of the assembly method, the connection between the slide block 12 and the concrete nozzle 6 is fixed with bolts. A certain safety gap (5-10mm) is reserved between the slide block 12 and the guide plate 3 to avoid frictional interference between the slide block 12 and the guide plate 3 during sliding, thus ensuring the rationality of the assembly structure and the stability of operation.

[0049] The larger end profile of the guide plate 3 is smaller than that of the forming template. The end of the guide plate 3 is provided with an end plate corresponding to the guide plate 3. The guide plate 3 is provided with a sealing strip corresponding to the end plate. The sealing strip slides and seals with the end plate.

[0050] The guide plate 3 consists of multiple interconnected pieces. The larger end of the guide plate 3 is slightly smaller than the forming template, generally 20-50cm smaller, to facilitate movement within the tunnel. In this embodiment, it includes two portal frames, which are spaced apart along the tunnel mileage direction. Multiple crossbeams are provided between the two portal frames to form a stable frame structure. A truss corresponding to the arch template 2 is provided above the crossbeams. The two ends of the truss are fixed to the portal frames, and multiple support points are evenly distributed in the middle. The inner wall of the arch template 2 is fixed to the truss with bolts.

[0051] Vibration elements are evenly distributed on the inner wall of the molding template. The vibration elements are made of vibration motors or vibrators, which can make the concrete fully compacted, remove air bubbles inside the concrete, and reduce quality defects such as honeycomb and pitting on the lining surface.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention shall be within the scope of protection of the pending claims of the present invention.

Claims

1. A method for constructing integrated tunnel lining using 3D printing, characterized in that, include: Step S1: Conduct surveying and setting out to determine the tunnel face, and then use the bench method for tunnel excavation; Step S2: The arch support frame is constructed using the method of excavation and erection simultaneously. After the arch support frame is connected to the corresponding invert arch frame, initial concrete spraying is carried out. Step S3: After the initial shotcrete reaches the preset strength, a waterproof coating is sprayed onto the inner wall of the initial shotcrete. After the waterproof coating has initially set into a waterproof membrane, the tunnel invert arch is poured. Step S4: After the tunnel invert reaches the preset strength, install the grid arch frame, fix adjacent grid arch frames with longitudinal bars using a steel bar trolley, and tie the outer steel mesh with the longitudinal bars as the reference. Step S5: The steel bar trolley moves forward according to the binding progress of the outer steel bar mesh. During the forward movement, the outer lining concrete is printed by the tunnel 3D printing equipment behind. After the outer lining has initially set, the inner steel bar mesh is bound. Step S6: Print the inner lining and smooth it before the inner lining concrete sets.

2. The 3D-printed integrated tunnel lining construction method according to claim 1, characterized in that, The outer steel mesh is provided with J-shaped connecting bars, and the inner steel mesh is connected to the outer steel mesh through the J-shaped connecting bars.

3. The 3D-printed integrated tunnel lining construction method according to claim 1, characterized in that, The arch feet on both sides of the tunnel are respectively equipped with connecting steel frames extending along the tunnel mileage direction, and the grid arch frame is fixed on the connecting steel frame accordingly; The connecting steel frame is equipped with an adjustment pad corresponding to the grid arch frame.

4. The 3D-printed integrated tunnel lining construction method according to claim 1, characterized in that, Before the tunnel face is excavated, pipe roofs are used for advance support, and monitoring instruments are installed after the tunnel excavation is completed to monitor the deformation of the tunnel wall.

5. The 3D-printed integrated tunnel lining construction method according to claim 1, characterized in that, The construction joints of the initial shotcrete, outer lining concrete, and inner lining concrete are staggered in the tunnel mileage direction, and a waterproof coating is sprayed at the construction joints of the outer lining concrete and inner lining concrete. The initial shotcrete is C30 concrete; the outer lining concrete is water-repellent concrete; and the inner lining concrete is impermeable concrete.

6. The 3D-printed integrated tunnel lining construction method according to claim 1, characterized in that, The tunnel was excavated in sections, with each cycle consisting of three sections, for the separate construction of initial shotcrete, outer lining concrete, and inner lining concrete.

7. The 3D-printed integrated tunnel lining construction method according to claim 1, characterized in that, In step S4, the steel rails of the corresponding smoothing equipment are laid on the upper surface of the invert arch, and multiple calibration points are set at the centerline of the tunnel. The tunnel construction design parameters of the corresponding points are measured to assist the smoothing equipment in smoothing.

8. The 3D-printed integrated tunnel lining construction method according to claim 7, characterized in that, Smoothing equipment includes: The main frame has multiple drive wheels at its bottom that move along the rails; The smoothing template includes an arched template and a side template that are hinged to each other. The inner wall of the side template is supported on the main frame by multiple driving cylinders, and its outer wall is the arched surface corresponding to the inside of the tunnel. The controller senses calibration points through a sensing module and controls the smoothing template based on the construction design parameters of the calibration points.

9. The 3D-printed integrated tunnel lining construction method according to claim 8, characterized in that, A guide plate is provided in front of the smoothing template and is fixed on the main frame. The guide plate has a conical shell that matches the shape of the smoothing template, and the rear end of the guide plate extends to the end of the smoothing template.

10. The 3D-printed integrated tunnel lining construction method according to claim 8, characterized in that, The arched template is fixed above the support, and the edge of the arched template is provided with a folding hydraulic cylinder that is corresponding to the side template. The middle and lower edge of the side template are respectively hinged to the main frame through driving hydraulic cylinders. A lifting cylinder corresponding to the drive wheel is provided below the main frame.

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