Magnetic concrete form spraying device and construction method

Abstract

This invention relates to a magnetic concrete spraying device and construction method, comprising a concrete spraying equipment and a spraying robot. The spraying robot moves between two parallel steel arch frames, forming a concrete mold cavity with the robot, the rock wall, and the two steel arch frames. The concrete spraying equipment injects concrete into the mold cavity. The spraying robot includes a chassis, a walking mechanism, a magnetic suction mechanism, and a template mechanism. The walking mechanism is located at both the front and rear of the chassis, and the magnetic suction mechanism is located on the bottom of both the left and right sides of the chassis. The template mechanism is located below the chassis. The spraying robot crawls from the bottom of one side of the steel arch frame to the top of the arch, pouring concrete as it crawls. Then, the robot crawls from the bottom of the other side of the steel arch frame to the top of the arch, again pouring concrete as it crawls. Finally, the concrete at the top of the arch is poured. This invention achieves near-zero concrete rebound and simultaneously achieves casting and shaping during the crawling process, making construction convenient and improving efficiency.

Description

Technical Field

[0001] This invention relates to the field of concrete support technology, and in particular to a magnetic concrete spraying device and construction method. Background Technology

[0002] Initial tunnel support is a core component of tunnel construction, and its quality directly impacts the safety and stability of the project. Initial support utilizes shotcrete technology, where mixed concrete is transported under high pressure and sprayed at high speed onto the rock wall surface, rapidly hardening to form a concrete support layer. This concrete support layer exists between adjacent steel arches, which support the tunnel walls and prevent collapse.

[0003] Existing concrete spraying methods include manual labor and semi-automated equipment, which directly spray concrete onto the rock face. While spraying equipment can replace manual labor and reduce labor intensity, it still requires manual monitoring of the tunnel surface and adjustment of the spraying position. This method results in a high rebound rate, meaning the concrete material does not make firm contact with the rock face and bounces back, rendering the rebound material unusable. The poor surface finish necessitates reshaping. Consequently, construction efficiency, material utilization, support strength, and the construction environment cannot be guaranteed, severely restricting the overall quality and economic benefits of tunnel construction.

[0004] In recent years, with the continuous upgrading of engineering machinery technology, a series of molded shotcrete technologies and specialized equipment have emerged to address the problem of excessive rebound rate in shotcrete. Molded shotcrete technology involves arranging formwork between at least two adjacent steel arches, with gaps between the formwork and the rock wall. The formwork, rock wall, and steel arches are connected and combined to form a mold cavity, into which concrete is sprayed. This effectively limits the rebound rate and improves the smoothness of the formed surface. However, due to the large span of the arched steel arches, multiple formwork sections are required, leading to frequent and cumbersome formwork assembly and disassembly.

[0005] Specialized equipment: For example, the "Intelligent Concrete Spraying Device and Method for Tunnel Construction" with application number 202410300808.5 is a typical solution. However, this device is bulky and complex, requiring specially laid tracks for the track vehicle to move on, and it can easily interfere with other work processes during tunnel construction, limiting its practical application effectiveness. Therefore, developing a compact and small-sized concrete spraying robot has become a key need that urgently needs to be addressed in the current tunnel construction field. Summary of the Invention

[0006] To address the problems of high rebound rate in sprayed concrete and cumbersome formwork assembly and disassembly, this invention provides a magnetic concrete spraying device and construction method. A crawling robot is arranged on a steel arch frame. The robot carries its own formwork, which can be continuously updated. At the same time, it works with a concrete spraying device to pour fast-hardening concrete into the formwork cavity, effectively avoiding the problem of concrete rebound and improving the environmental quality of the construction site.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A magnetic concrete spraying device includes a concrete spraying equipment and a spraying robot. The spraying robot moves between two parallel steel arches. The spraying robot, the rock wall, and the two steel arches enclose a concrete cavity. The concrete spraying equipment injects concrete into the concrete cavity to facilitate its solidification between the two steel arches and the surface of the rock wall.

[0009] The spraying robot includes a chassis, a walking mechanism, a magnetic attraction mechanism, and a template mechanism. The walking mechanism is provided at both the front and rear of the chassis to drive the chassis to move along the steel arch frame. The magnetic attraction mechanism is provided at the bottom of both the left and right sides of the chassis to ensure that the chassis is attached to the steel arch frame.

[0010] The template mechanism is located below the chassis. The template mechanism includes a template and a vibration motor mounted on the template. The template is elastically slidably connected to the chassis. The template contacts the steel arch frame through support wheels. Guide wheels are provided at the corners of the template to guide the chassis to move along the steel arch frame. An injection pipe is also provided on the template. The two ends of the injection pipe are connected to the concrete mold cavity and the concrete spraying equipment, respectively.

[0011] Furthermore, the concrete spraying equipment is a wet spraying trolley, which is equipped with spray nozzles. Both the wet spraying trolley and the spray nozzles are existing technologies and will not be described in detail here.

[0012] Furthermore, the chassis is a steel frame structure with a certain structural strength. The chassis is hollow inside. The walking mechanism includes a walking motor, a drive shaft, and walking wheels. There are two walking motors, which are arranged on the left and right sides of the chassis. The walking motors are worm gear reducers with their own motors. The drive shaft is located between the two walking motors, and the two walking motors drive one drive shaft simultaneously. The end of the drive shaft passes through the walking motor and is connected to the walking wheel, which facilitates driving the walking wheel to rotate. The walking wheel rolls along the surface of the steel arch frame.

[0013] Furthermore, the magnetic attraction mechanism includes multiple permanent magnets arranged at intervals, with gaps between the permanent magnets and the surface of the steel arch frame, and the permanent magnets and the traveling wheels on the same side of the chassis are arranged in a straight line.

[0014] Furthermore, the template is a rectangular plate, bent into an arc shape, and has four guide pillars detachably connected to it. These four guide pillars are arranged in a rectangular pattern, and each guide pillar is a cylinder with a "T"-shaped cross-section. The guide pillars pass through the base and connect to the template, allowing the template to slide up and down along the base guided by the guide pillars. Compression springs are fitted onto the guide pillars between the base and the template. The cooperation between the guide pillars and the compression springs facilitates the elastic sliding of the template.

[0015] Furthermore, the template edge is provided with four flange plates, each corresponding to a guide post. Each flange plate is rotatably connected to a support wheel, which rolls across the template and onto the surface of the steel arch frame, creating a gap between the template and the surface of the steel arch frame.

[0016] Furthermore, four wheel seats are provided at the corners of the template. Each wheel seat is rotatably connected to a guide wheel. The guide wheel is a flat wheel body and rolls along the side edge of the steel arch frame to facilitate the straight movement of the chassis. The vibration motor is arranged inside the chassis, and the injection pipe is bent into an "L" shape.

[0017] The magnetic concrete spraying method, based on the aforementioned spraying device, includes the following steps:

[0018] Step 1: Attach the spraying robot to the bottom of one side of the steel arch frame, adjust the spraying robot so that the bottom of its template is in close contact with the ground. At this time, the spraying robot, the rock wall and the two adjacent steel arch frames will form a mold cavity.

[0019] Step 2: Adjust the concrete spraying equipment so that the spray nozzle is directly facing the opening above the mold cavity and spraying the quick-hardening concrete downwards. At the same time, turn on the vibration motor to eliminate air bubbles in the concrete through high-frequency vibration, and complete the initial pouring.

[0020] Step 3: Based on the concrete setting rate, control the movement of the concrete spraying robot to ensure that the concrete maintains a stable shape and does not deform after demolding. Simultaneously, control the concrete spraying equipment to adjust the nozzle posture, ensuring continuous spraying of concrete into the mold cavity. Continue this process until the arch is topped.

[0021] Step 4: After climbing to the top of the arch, the concrete spraying robot is in a horizontal position, and the concrete injection is paused; control the concrete spraying robot to crawl to the bottom of the other side of the steel arch, and repeat the operation process of Steps 1-4;

[0022] Step 5: After climbing to the top of the arch, the spraying robot forms a sealed cavity with the already poured parts on the left and right sides and the tunnel walls. Adjust the spray nozzle to insert into the injection pipe, adjust the spraying pressure, and pressurize to inject concrete. After the concrete at the top of the arch has solidified, turn off the vibration motor and control the spraying robot to climb to the bottom of the steel arch frame to complete the spraying operation.

[0023] The beneficial effects of the present invention through the above technical solution are:

[0024] This invention utilizes a spraying robot in conjunction with concrete spraying equipment for concrete support operations. It involves spraying concrete onto a rock face between any two adjacent steel arches to form concrete support. The spraying robot's chassis is equipped with a walking mechanism for crawling; a magnetic attachment mechanism to securely attach the chassis to the steel arches and prevent the robot from falling off; and a template mechanism to form a cavity with the steel arches and rock face, facilitating concrete injection and effectively preventing concrete rebound. Furthermore, the template mechanism is equipped with guide wheels to guide the robot's linear movement.

[0025] The construction method of this invention involves first attaching the spraying robot to the bottom left side of the steel arch frame. However, in actual construction, the starting side can be selected depending on the environment. The spraying robot and the steel arch frame form a casting cavity approximately 1m high. The concrete spraying equipment is controlled to insert the nozzle into the cavity, and fast-hardening concrete is sprayed into the cavity with low air pressure. The concrete spraying speed is matched with the robot's walking speed, enabling continuous construction without waiting. Following this working method, when the work reaches the top of the arch frame, concrete spraying is stopped, and the spraying robot is controlled to crawl to the bottom of the right arch frame, repeating the construction process for the left arch frame.

[0026] When the spraying robot travels to the top of the arch again, the concrete and steel arch frame on both sides form a closed cavity with the spraying robot. Adjust the nozzle to connect it with the injection pipe of the spraying robot and start injecting concrete. After the concrete at the top of the arch solidifies, control the spraying robot to travel to the bottom of the arch frame, retract the robot, and complete the operation, achieving near-zero rebound of concrete in the initial support lining. Attached Figure Description

[0027] Figure 1 This is one of the overall structural schematic diagrams of the magnetic concrete molding spraying device of the present invention.

[0028] Figure 2 This is the second schematic diagram of the overall structure of the magnetic concrete molding and spraying device of the present invention.

[0029] Figure 3 This is an isometric view of the spraying robot of the magnetic concrete spraying device of the present invention.

[0030] Figure 4 This is a cross-sectional view of the spraying robot of the magnetic concrete spraying device of the present invention.

[0031] Figure 5 This is a cross-sectional view of the magnetic concrete molding and spraying device of the present invention, showing the molding and spraying robot walking along the steel arch frame.

[0032] Figure 6This is a schematic diagram of the construction steps of the magnetic concrete molding and spraying method of the present invention. In the figure, a represents a schematic diagram of concrete pouring on one side of the steel arch frame, b represents a schematic diagram of concrete pouring on the other side of the steel arch frame, and c represents a schematic diagram of concrete pouring on the top of the steel arch frame.

[0033] The attached diagram is labeled as follows: 1 Concrete spraying equipment, 101 Spraying nozzle, 102 Robotic arm, 2 Mold spraying robot, 3 Steel arch frame, 4 Mold cavity, 5 Chassis, 6 Walking motor, 7 Drive shaft, 8 Walking wheel, 9 Permanent magnet, 10 Template, 11 Vibration motor, 13 Guide column, 14 Compression spring, 15 Flange plate, 16 Support wheel, 17 Guide wheel, 18 Wheel seat, 19 Injection pipe, 20 Control box. Detailed Implementation

[0034] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings:

[0035] like Figures 1-5 As shown, the magnetic concrete spraying device includes a concrete spraying equipment 1 and a spraying robot 2. The concrete spraying equipment 1 is existing technology and can be a wet spraying trolley. The concrete spraying equipment 1 is equipped with a spraying nozzle 101 and a robotic arm 102. The spraying nozzle 101 is mounted on the robotic arm 102, which can drive the spraying nozzle 101 to move flexibly with multiple degrees of freedom. The mixed concrete is transported to the spraying nozzle 101 through a conveying pipeline and sprayed out at high speed from the spraying nozzle 101.

[0036] Concrete spraying equipment 1 works in conjunction with molding spraying robot 2 to perform molding spraying operations. During this process, concrete spraying equipment 1 moves freely inside the tunnel, while molding spraying robot 2 moves along the steel arch frame 3 in an arched trajectory. Spraying nozzle 101 adjusts its position flexibly to follow the movement of molding spraying robot 2 and cooperates with it to carry out molding spraying operations.

[0037] In this embodiment, the spraying robot 2 moves between two parallel steel arch frames 3. Several steel arch frames 3 are arranged inside the tunnel, along the tunnel's extension direction. The steel arch frames 3 are arranged in an arch shape on the tunnel wall, closely adhering to the rock wall and supporting the tunnel. Each steel arch frame 3 is an I-beam structure, consisting of an integrally formed web and flanges. Flanges are horizontally arranged at both ends of the web, which is existing technology.

[0038] After the spraying robot 2 is placed between two adjacent steel arch frames 3, the spraying robot 2, the rock wall, and the two steel arch frames 3 together form a concrete mold cavity 4. The concrete spraying equipment 1 injects concrete into the concrete mold cavity 4 through the spray nozzle 101. In this way, the concrete material is blocked by the spraying robot 2 and no longer bounces back. The spraying robot 2 can be regarded as a template that can move along the steel arch frames 3, so that templates can be continuously laid along the steel arch frames 3, making template assembly and disassembly more convenient.

[0039] In this embodiment, the spray painting robot 2 includes a chassis 5, a walking mechanism, a magnetic suction mechanism, and a template 10 mechanism. The chassis 5 is a steel frame structure with a "U"-shaped cross-section and a hollow interior. The chassis 5 serves as a carrier for mounting other mechanisms and components. Walking mechanisms are provided at both the front and rear of the chassis 5, resulting in two walking mechanisms. These mechanisms drive the chassis 5 to move along the steel arch frame 3.

[0040] Each walking mechanism includes a walking motor 6, a drive shaft 7, and walking wheels 8. There are two walking motors 6, arranged on the left and right sides of the chassis 5. Each walking motor 6 is a worm gear reducer with a built-in stepper motor. Since there are two walking mechanisms, each mechanism also has two walking motors 6, resulting in a total of four walking motors 6 on the chassis 5. The entire molding robot moves by the simultaneous operation of these four walking motors 6. The drive shaft 7 is positioned between the two walking motors 6, with the end of the drive shaft 7 passing through one of the walking motors 6 and connecting to the walking wheels 8.

[0041] In short, a drive shaft 7 is arranged between the two worm gear reducers. The end of the drive shaft 7 passes through the worm gear reducer and connects to the traveling wheel 8. The traveling wheel 8 rolls along the surface of the steel arch frame 3, that is, it moves along the upper surface of the flange of the steel arch frame 3. The stepper motor outputs driving force as a power source, which is decelerated and increased in torque by the worm gear reducer, and finally the power is transmitted to the traveling wheel 8 via the drive shaft 7.

[0042] Since the chassis 5 is powered, to prevent it from detaching from the steel arch frame 3, magnetic attraction mechanisms are installed on the bottom of both sides of the chassis 5. These mechanisms ensure that the chassis 5 adheres to the steel arch frame 3, firmly pressing the robot against its surface. Each magnetic attraction mechanism includes four permanent magnets 9 arranged at intervals. The permanent magnets 9 are rectangular blocks made of neodymium iron boron material. They are bolted to the bottom of the chassis 5, and the chassis 5 is attracted to the steel arch frame 3 by the magnetic force of the permanent magnets 9. The permanent magnets 9 and the wheels 8 on the same side of the chassis 5 are arranged in a straight line.

[0043] It is important to note that there is a gap between the permanent magnet 9 and the surface of the steel arch 3, meaning that the permanent magnet 9 and the steel arch 3 remain in a non-contact state during the robot's crawling process. The magnetic attraction mechanism uses magnetic force to firmly press the robot against the surface of the steel arch 3. The resulting static friction, together with the robot's own weight, the weight of the concrete, and other external forces, forms a static balance system, ensuring the stability and safety of the robot during construction.

[0044] A template 10 mechanism is installed below the chassis 5, and the chassis 5 drives the template 10 mechanism to move. The template 10 mechanism includes a template 10 and a vibrating motor 11 mounted on the template 10. The template 10 is a rectangular plate, but it is bent into an arc shape to accommodate the curvature of the steel arch frame 3. The width of the template 10 is smaller than the width of the chassis 5, but larger than the minimum distance between two adjacent steel arch frames 3. The template 10 is elastically slidable below the chassis 5, thus allowing the template 10 to slide elastically up and down, equivalent to the chassis 5. The template 10 prevents concrete rebound, and the moving template 10 can also smooth the concrete.

[0045] During installation, the template 10 is detachably connected to four guide posts 13. These guide posts 13 can be installed with the template 10 using threaded or screw connections. The four guide posts 13 are arranged in a rectangular pattern, that is, they are positioned at the corners of the rectangle. Each guide post 13 is a cylinder with a "T"-shaped cross-section. The smaller diameter end of the guide post 13 passes through the base plate 5 and connects to the template 10, with the guide post 13 sliding against the base plate 5. In this way, the template 10 can slide up and down along the base plate 5 guided by the guide posts 13, while the larger diameter end of the guide posts 13 prevents the template 10 from detaching from the base plate 5 during sliding. Each guide post 13 between the base plate 5 and the template 10 is fitted with a compression spring 14, allowing the template 10 to slide elastically.

[0046] It should be noted that the template 10 does not directly contact the steel arch frame 3, but rather there is a gap between the template 10 and the surface of the steel arch frame 3. Therefore, the template 10 contacts the steel arch frame 3 via support wheels 16. Four flange plates 15 are provided on the edge of the template 10, arranged perpendicularly to the template 10. Each flange plate 15 corresponds to a guide post 13, and a support wheel 16 is rotatably connected to each flange plate 15. The support wheels 16 roll across the template 10 and connect with the surface of the steel arch frame 3. The circumferential direction of the support wheels 16 is consistent with that of the traveling wheels 8. There is a fixed height difference between the bottom of the support wheels 16 and the template 10, and they are in direct contact with the steel arch frame 3, ensuring that a fixed gap is maintained between the template 10 and the surface of the steel arch frame 3 during the crawling process.

[0047] Four support wheels 16 work together to support the template 10, effectively lifting it and preventing it from contacting the steel arch frame 3, thus ensuring a gap between the template 10 and the steel arch frame 3. The support wheels 16 roll along the upper surface of the flange of the steel arch frame 3. At this time, the compression spring 14 is compressed, but it tends to extend, causing the template 10 to move away from the base plate 5. Because the support wheels 16 are in contact with the steel arch frame 3, the template 10 remains close to the base plate 5. To accommodate height differences between the surfaces of the two sides of the steel arch frame 3, the compression spring 14 between the base plate 5 and the template 10 ensures that the support wheels 16 are always pressed against the surface of the steel arch frame 3.

[0048] The template 10 only moves up and down relative to the base 5; it does not move left and right or forward and backward relative to the base 5. To ensure the straightness of the movement of the base 5, guide wheels 17 are provided at the corners of the template 10. There are four guide wheels 17, which are used to guide the base 5 to move along the steel arch frame 3.

[0049] During installation, guide wheels 17 are mounted on four wheel seats 18 at the corners of the template 10. Each wheel seat 18 is rotatably connected to a guide wheel 17. The wheel seats 18 and guide wheels 17 are distributed on the upper and lower sides of the template 10. The guide wheels 17 are flat wheels that roll along the side edges of the steel arch frame 3. That is, the guide wheels 17 engage with the side of the wing plate of the steel arch frame 3 and travel along the side of the wing plate, thereby preventing the chassis 5 from shifting.

[0050] Vibration motors 11 on the template 10 are arranged inside the chassis 5. High-frequency vibration eliminates air bubbles in the concrete, improving its density and enhancing the bond between the concrete and the steel arch frame 3. An injection pipe 19 is also installed on the template 10. The injection pipe 19 is bent into an "L" shape, with both ends connected to the concrete mold cavity 4 and the concrete spraying equipment 1, respectively. The template 10, together with the steel arch frames 3 on both sides and the rock wall, forms the mold cavity 4. The entire template 10 mechanism, on the one hand, evenly compresses the concrete between the two parallel steel arch frames 3; on the other hand, it moves synchronously along the contour surface of the steel arch frame 3 according to the concrete's setting rate, ultimately achieving the initial goal of continuous, zero-rebound initial lining.

[0051] A control box 20 is also installed on the chassis 5. The control box 20 integrates a controller, a wireless communication module, and sensors, including attitude sensors and position sensors. The controller controls the operation of the vibration motor 11 and the walking motor 6, and communicates with the wireless communication module. The entire molding and spraying robot 2 is remotely controlled. The remote controller also contains a wireless communication module, and the controller communicates wirelessly with the remote controller via this module. This wireless communication module can be a Bluetooth module or a Wi-Fi module to achieve remote control of the robot. Furthermore, the entire molding and spraying robot 2 is powered by a cable.

[0052] This invention enables the initial mortar work between the steel arch frames 3 of a tunnel. The result is that the spraying robot 2, relying on a magnetic attraction mechanism, firmly adheres to the steel arch frame 3. While crawling, driven by a walking mechanism, it uses the template 10 mechanism to compress concrete between the steel arch frames 3. This allows for efficient and continuous completion of the initial tunnel support, achieving near-zero concrete rebound.

[0053] like Figure 6 As shown, the magnetic concrete spraying construction method includes the following steps:

[0054] Step 1: Attach the spraying robot 2 to the bottom of one side of the steel arch frame 3, using the magnetic force between the permanent magnet 9 and the steel arch frame 3 to ensure the robot 2 adheres to the frame. Adjust the spraying robot 2 so that the bottom of its template 10 is tightly fitted to the ground to prevent concrete from flowing out. At this point, the spraying robot 2, the rock wall, and the two adjacent steel arch frames 3 together form the mold cavity 4.

[0055] Step 2: Adjust the concrete spraying equipment 1 so that the spray nozzle 101 is facing the opening above the mold cavity 4 and sprays the quick-hardening concrete downward with low air pressure. At the same time, turn on the vibration motor 11 to make the formwork 10 vibrate. The high-frequency vibration eliminates air bubbles in the concrete, improves the density of the concrete, and completes the initial pouring.

[0056] Step 3: Control the spraying robot 2 to crawl along the steel arch frame 3. A stepper motor drives a worm gear reducer, which in turn rotates the drive shaft 7 and the walking wheels 8, enabling the spraying robot 2 to crawl. The walking speed of the spraying robot 2 is controlled according to the concrete setting rate to ensure that the concrete maintains a stable shape and does not deform after demolding. Simultaneously, the concrete spraying equipment 1 is controlled to adjust the posture of the spray nozzle 101, allowing concrete to be continuously sprayed into the mold cavity 4. This process continues until the arch is topped.

[0057] Step 4: After climbing to the top of the arch, the spraying robot 2 will be in a horizontal position. At this point, the concrete cannot fill the mold cavity 4 under the action of gravity, so stop the operation and pause the concrete injection. Control the spraying robot 2 to climb to the bottom of the other side of the steel arch 3 and repeat the operation process of steps 1-4.

[0058] Step 5: After climbing to the top of the arch, the spraying robot 2 forms a sealed cavity 4 with the already poured sections on the left and right sides and the tunnel walls. Adjust the spray nozzle 101 and insert it into the injection pipe 19, adjust the spraying pressure, and inject concrete under pressure. After the concrete at the top of the arch has solidified, turn off the vibration motor 11 and control the spraying robot 2 to climb to the bottom of the steel arch frame 3 to complete the spraying operation.

[0059] This invention achieves near-zero rebound in concrete construction through the synergistic effect of a spraying robot 2 and low-pressure shotcrete. It fundamentally solves the problem of material scattering and waste in traditional spraying processes, significantly improving material utilization and drastically reducing construction waste and dust pollution during construction. In terms of economic benefits, the zero-rebound characteristic directly reduces material loss and also reduces the labor and time required for cleanup. From the perspective of the entire construction cycle, this efficient material utilization model effectively controls project costs, achieving the dual goals of resource conservation and environmental protection. This technological breakthrough makes tunnel construction more in line with modern green construction concepts and provides new technical support for the sustainable development of engineering projects.

[0060] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the claims of the present invention should be included within the scope of the present invention.

Claims

1. A magnetic concrete spraying device, characterized in that, The system includes a concrete spraying device (1) and a molding robot (2). The molding robot (2) moves between two parallel steel arch frames (3). The molding robot (2), the rock wall, and the two steel arch frames (3) enclose a concrete mold cavity (4). The concrete spraying device (1) injects concrete into the concrete mold cavity (4). The spraying robot (2) includes a chassis (5), a walking mechanism, a magnetic suction mechanism and a template mechanism. The walking mechanism is provided at both the front and rear of the chassis (5) to drive the chassis (5) to move along the steel arch frame (3). The chassis (5) is a steel frame structure with a hollow interior. The walking mechanism includes a walking motor (6), a transmission shaft (7), and a walking wheel (8). There are two walking motors (6), which are arranged on the left and right sides of the chassis (5). The walking motor (6) is a worm gear reducer with its own motor. The transmission shaft (7) is located between the two walking motors (6). The end of the transmission shaft (7) passes through the walking motor (6) and is connected to the walking wheel (8). The walking wheel (8) rolls along the surface of the steel arch frame (3). The bottom of both sides of the chassis (5) is equipped with a magnetic attraction mechanism to ensure that the chassis (5) is attracted to the steel arch frame (3); the magnetic attraction mechanism includes multiple permanent magnets (9) arranged at intervals, and there is a gap between the permanent magnets (9) and the surface of the steel arch frame (3). The permanent magnets (9) and the walking wheels (8) on the same side of the chassis (5) are arranged in a straight line. The template mechanism is provided below the chassis (5). The template mechanism includes a template (10) and a vibration motor (11) installed on the template (10). The template (10) is elastically slidably connected to the chassis (5). The template (10) contacts the steel arch frame (3) through support wheels (16). Guide wheels (17) are provided at the corners of the template (10) to guide the chassis (5) to move along the steel arch frame (3). An injection pipe (19) is also provided on the template (10). The two ends of the injection pipe (19) are connected to the concrete mold cavity (4) and the concrete spraying equipment (1) respectively. The template (10) is a rectangular plate, which is bent into an arc shape. Four guide posts (13) are detachably connected to the template (10). The four guide posts (13) are arranged in a rectangular shape. The guide posts (13) are cylinders with a "T" shaped cross section. After passing through the base plate (5), the guide posts (13) are connected to the template (10). The template (10) slides up and down along the base plate (5) with the guide posts (13) as guides. A compression spring (14) is sleeved on the guide posts (13) between the base plate (5) and the template (10). The template (10) is provided with four flange plates (15) on its edge. The flange plates (15) and guide columns (13) correspond one-to-one. Each flange plate (15) is rotatably connected with a support wheel (16). The support wheel (16) passes over the template (10) and rolls to connect with the surface of the steel arch frame (3). There is a gap between the template (10) and the surface of the steel arch frame (3).

2. The magnetic concrete spraying device according to claim 1, characterized in that, The concrete spraying equipment (1) is a wet spraying trolley, and the concrete spraying equipment (1) is equipped with a spray nozzle (101).

3. The magnetic concrete spraying device according to claim 1, characterized in that, The template (10) is provided with wheel seats (18) at the corners. There are four wheel seats (18). Each wheel seat (18) is rotatably connected to the guide wheel (17). The guide wheel (17) is a flat wheel body and rolls along the side edge of the steel arch frame (3). The vibration motor (11) is arranged in the chassis (5). The injection pipe (19) is bent into an "L" shape.

4. A magnetic concrete spraying method, characterized in that, The molding and spraying apparatus according to any one of claims 1 to 3 includes the following steps: Step 1: Attach the spraying robot (2) to the bottom of one side of the steel arch frame (3), adjust the spraying robot (2) so that the bottom of its template (10) is in close contact with the ground. At this time, the spraying robot (2), the rock wall and the two adjacent steel arch frames (3) enclose and form a concrete mold cavity (4). Step 2: Adjust the concrete spraying equipment (1) so that the spray nozzle (101) is facing the opening above the concrete mold cavity (4) and spraying the quick-hardening concrete downwards. At the same time, turn on the vibration motor (11) to eliminate air bubbles in the concrete through high-frequency vibration and complete the initial stage of pouring. Step 3: According to the concrete setting rate, control the mold spraying robot (2) to crawl, so that the concrete can be stable and not deformed after demolding. At the same time, control the concrete spraying equipment (1) to adjust the posture of the spray nozzle (101) so that the concrete is continuously sprayed into the concrete mold cavity (4) and the operation continues until the top of the arch. Step 4: After climbing to the top of the arch, the spraying robot (2) is in a horizontal position, and the concrete injection is paused; control the spraying robot (2) to climb to the bottom of the other side of the steel arch frame (3), and repeat the operation process of Step 1-Step 4; Step 5: After climbing to the top of the arch, the spraying robot (2) forms a sealed concrete cavity (4) with the cast-in-place parts on the left and right sides and the tunnel wall. Adjust the spray nozzle (101) to insert into the injection pipe (19), adjust the spraying pressure, and pressurize to inject concrete. After the concrete at the top of the arch solidifies, turn off the vibration motor (11), control the spraying robot (2) to climb to the bottom of the steel arch frame (3) to complete the spraying operation.

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