Spray irrigation combined construction system and method for tunnel primary support concrete

Abstract

The invention relates to a sprinkling irrigation combined construction system and method for tunnel primary support concrete.The sprinkling irrigation combined construction method for the tunnel primary support concrete.The sprinkling irrigation combined construction method for the tunnel primary support concrete.The sprinkling irrigation combined construction method for the tunnel primary support concrete.The sprinkling irrigation combined construction method is based on a steel arch frame installed in a tunnel and comprises the following steps that a formwork system is constructed, the magnetic attraction type formwork assembly and the steel arch jointly form a formwork supporting system through magnetic attraction force; side wall formwork building is conducted, specifically, a double-arm spray irrigation trolley is used for pouring primary supporting concrete into the formwork supporting system in a pumping formwork building mode, and a side wall primary supporting structure is formed; the combined technology of side wall molding and arch spraying is adopted, the advantages of the two technologies are fully played, synchronous operation of the double-arm sprinkling irrigation trolley is combined, and the efficiency is improved by about one time compared with that of a traditional single-arm spraying machine; and the side wall molding is basically free of dust and springback, so that the working environment is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of underground engineering construction technology, and specifically to a spraying and grouting combined construction system and method for the initial support concrete of tunnels. Background Technology

[0002] In the field of tunnel engineering, initial support is a crucial step in ensuring the stability of the tunnel structure and construction safety. Currently, when facing the initial support concrete construction in sections with arches, construction teams typically face two technological choices, each with significant drawbacks: Firstly, a single shotcrete process is used. Although this process is relatively fast, it brings serious dust pollution and a high material rebound rate, which not only endangers the health of workers and pollutes the environment, but also causes material waste and increased costs. In addition, the quality of shotcrete construction is highly variable, which can easily lead to voids behind the initial support and affect the uniformity of the support.

[0003] Secondly, a single formwork concrete process is used. Although this process can ensure construction quality and flatness, it lacks a formwork system for rapid support and dismantling during the initial support construction. This results in cumbersome formwork installation and dismantling procedures, slow overall construction speed, and difficulty in meeting the urgent need for rapid support of the surrounding rock after tunnel excavation. It also poses safety hazards in areas with weak surrounding rock.

[0004] Therefore, those skilled in the art have long faced a clear technical dilemma: how to combine the quality advantages of formwork construction with the speed advantages of spraying construction, and overcome the inherent defects of both. Specifically, there is an urgent need for a comprehensive construction method that can achieve low-dust, low-rebound, and high-quality formwork construction at the sidewalls, while also being able to quickly transition to the arch for efficient wet spraying operations, in order to resolve the contradiction between support efficiency, construction quality, and working environment in existing technologies. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a spraying and grouting combined construction system and method for tunnel initial support concrete, thereby solving the contradiction between support efficiency, construction quality and working environment in the prior art.

[0006] To achieve the above objectives, the present invention provides a method for the combined spraying and grouting construction of the initial support concrete of a tunnel, based on a steel arch frame already installed inside the tunnel, comprising the following steps: Template system construction: A magnetic template component is positioned and attached to the steel arch frame of the tunnel sidewall, so that the magnetic template component and the steel arch frame together form a template support system through magnetic attraction. Side wall formwork: Using a double-arm sprinkler truck, the initial support concrete is poured into the formwork support system by pumping to form the initial support structure of the side wall. Arch spraying: Following the sidewall formwork step, the same double-arm spraying trolley is used to switch its operation mode to wet spraying to carry out the initial support concrete construction of the tunnel arch. Finishing: While the arch spraying is being carried out, the magnetic formwork assembly is removed, and the surface of the initial support structure of the side wall and the initial support concrete of the arch is cleaned and sprayed for repair. The initial support concrete is configured to meet the performance requirements of both pumped casting and wet spraying construction.

[0007] By adopting this technical solution, firstly, the combination of sidewall molding and arch spraying, performed sequentially using the same double-arm spraying trolley, allows the method to leverage the advantages of high quality and smoothness of molding in the sidewall area, overcoming the quality defects of single spraying in this area. Simultaneously, it maintains the advantages of fast construction speed and strong adaptability in the arch area, overcoming the bottleneck of slow speed in full-section construction using single molding, achieving a balance between high efficiency and high quality. Secondly, the use of pump-assisted molding in the sidewall area fundamentally eliminates the huge dust source generated by sprayed concrete, greatly improving the working environment inside the tunnel and achieving near-zero rebound of the concrete in this area, significantly saving materials and effectively solving the problems of high pollution and serious waste associated with single spraying. Thirdly, by using the same double-arm spraying trolley to sequentially complete sidewall molding and arch spraying, the equipment switching and waiting time that may be required in traditional processes are eliminated, resulting in tighter process connections, a smoother construction flow, and improved overall construction efficiency.

[0008] Furthermore, in the sidewall casting and arch spraying steps, the output air pressure of the double-arm sprinkler trolley is adaptively adjusted as follows: The output air pressure during the sidewall molding process is 0.05-0.15 MPa; The output air pressure during arch jetting is 0.4-0.6 MPa.

[0009] By adopting this technical solution, and by dynamically adjusting the air pressure, low-pressure air is used to assist in the dispersion of quick-setting agents and reduce the side pressure of the template during the sidewall molding process, while high-pressure air is used to ensure the spray density in the arch. This is a key measure to ensure a smooth transition of the sprinkler irrigation mode and to balance the safety of the sidewall and the quality of the arch.

[0010] Furthermore, the slump of the initial support concrete is 200-240mm, the spread is 500-600mm, the initial setting time is 2-5 minutes, and the final setting time is 8-12 minutes.

[0011] By adopting this technical solution, the fluidity and self-compacting properties required for pumping and molding can be met, as well as the cohesiveness and rapid setting requirements for shotcrete construction. This avoids problems such as pipe blockage, high rebound, or slow support strength development caused by material performance mismatch, thus ensuring smooth construction and high-quality final construction from the source.

[0012] The present invention also provides a magnetic template assembly, comprising: One template main body; A magnetic actuator integrated on the template body is configured to generate an adsorption force when energized, thereby fixing the template body to the steel arch frame. An intelligent controller electrically connected to the magnetic actuator is configured to monitor the state of the template body in real time and dynamically adjust the adsorption force of the magnetic actuator based on the monitoring data.

[0013] By adopting this technical solution, the template can be installed and dismantled quickly; the template body with integrated magnetic actuator is directly attached to the steel arch frame by generating magnetic force when energized, eliminating cumbersome mechanical connections, making installation and dismantling simple and quick, and improving work efficiency; at the same time, the introduction of intelligent controller makes it possible to monitor the status of the template body in real time.

[0014] Furthermore, the magnetic actuator includes a solenoid electromagnetic coil and a soft magnetic material core disposed therein.

[0015] By adopting this technical solution, using a solenoid electromagnetic coil with a soft magnetic material core, the overall magnetic field strength can be greatly enhanced, thereby increasing the attraction force on the steel arch frame and ensuring the reliability of the template body fixation.

[0016] Furthermore, the intelligent controller includes: A sensor used to sense the lateral pressure on the template body; An adjustment module connected to the sensor signal is used to adjust the current flowing to the magnetic actuator based on the sensor signal. An alarm unit is used to trigger an alarm when the adsorption force exceeds the safe range.

[0017] By adopting this technical solution, the magnetic attraction force of the magnetic actuator can be dynamically detected, warned, and adjusted in a timely manner. By detecting changes in side pressure and adjusting the current through sensors, it can ensure that the template body is in close contact with the steel arch frame, preventing the template body from falling due to insufficient attraction or wasting energy due to excessive attraction. The audible and visual warning can directly indicate the danger and improve safety.

[0018] Furthermore, the main body of the template is integrated with a viewing window for observing the pouring status of the concrete.

[0019] By adopting this technical solution, a viewing window can be set up to observe the pouring of local concrete during the sidewall molding process, which facilitates dynamic adjustment of the pouring position, thereby ensuring the compactness of the sidewall molding and avoiding internal defects.

[0020] Furthermore, the main body of the template is a retractable modular structure, and its size can adapt to different steel arch spacing and tunnel excavation contours.

[0021] By adopting this technical solution, the formwork body can be adjusted according to the spacing of the steel arch frame, adapting to different steel arch frame spacings and excavation contours, thereby improving the versatility and on-site adaptability of the formwork body.

[0022] The present invention also provides a dual-arm sprinkler irrigation trolley, comprising: Self-propelled frame structure; The first and second robotic arms are mounted on the self-propelled frame structure and are arranged independently and symmetrically. A hydraulically driven dual-pumping system is used to synchronously and evenly supply concrete flow to the first and second robotic arms. An integrated control unit is used to independently and precisely control the pumping flow rate, accelerator dosage and air pressure of each robotic arm, so that each robotic arm can be independently configured in pumping molding operation mode or wet spraying operation mode.

[0023] By adopting this technical solution, the system has two independent and symmetrical robotic arms that can achieve balanced flow and dual output from two pumps, which improves the efficiency of spraying by about 100%. At the same time, by finely controlling the pumping, quick-setting agent and air pressure, the trolley has the ability to spray and irrigate, and to combine spraying and irrigation, which is the key to achieving multi-purpose functionality.

[0024] The present invention also provides a fresh concrete composition, which is composed of aggregates, cementitious materials and admixtures, and has the following fresh mix properties: slump 200-240mm, spread 500-600mm, initial setting time 2-5 minutes, and final setting time 8-12 minutes.

[0025] By adopting this technical solution, the special materials used in the construction method ensure the feasibility of the method in terms of key properties such as fluidity and rapid setting, which is the material guarantee for the successful implementation of the entire process.

[0026] Compared with the prior art, the present invention has the following advantages: 1. The combined process of sidewall molding and arch spraying fully leverages the advantages of both processes. Combined with the synchronous operation of the double-arm spraying trolley, the efficiency is about twice that of the traditional single-arm shotcrete machine. The sidewall molding process is virtually dust-free and free of rebound, greatly improving the working environment.

[0027] 2. The sidewalls are constructed using formwork, resulting in a high degree of surface flatness and a dense structure, which effectively prevents voids behind the secondary lining; the arches are constructed using wet spraying, ensuring close contact with the surrounding rock; and specialized concrete materials ensure stable performance under different construction modes.

[0028] 3. The magnetic template assembly enables quick installation, removal, and reliable fixation of the template body. Its intelligent monitoring and early warning functions effectively prevent safety and quality accidents such as template body falling or bulging.

[0029] 4. The entire system and method are highly flexible and can be used to select various modes such as full formwork, full spraying, or a combination of sprinkler irrigation, depending on the site geological conditions and construction requirements. It has a wide range of applications. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the construction method for the combined spraying and grouting of the initial support concrete of the tunnel in this invention. Figure 2 This is a schematic diagram of the longitudinal section of the sidewall sprinkler irrigation inside the tunnel of the double-arm sprinkler trolley in this invention. Figure 3 This is a detailed drawing of the magnetic template component in this invention; Figure 4 This is a schematic diagram of the cross-section of the inner sidewall of the double-arm sprinkler trolley in this invention. Figure 5 This is a schematic diagram of the cross-section of the moldless spraying section inside the arch of the double-arm sprinkler trolley in this invention.

[0031] Explanation of reference numerals in the attached drawings: 1. Steel arch frame; 2. Magnetic template assembly; 21. Template body; 22. Magnetic actuator; 23. Intelligent controller; 3. Double-arm sprinkler trolley; 4. Side wall. Detailed Implementation

[0032] The present invention specifically relates to a method for combined spraying and irrigation construction of tunnel initial support concrete, special equipment (magnetic template assembly 2, double-arm spraying trolley 4) for implementing the method, and materials (initial support concrete composition).

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0034] In a tunnel project with arched sections in Class V surrounding rock, the sprinkler irrigation combined with the construction system and method of this invention was applied for initial support construction. The specific implementation process is as follows: 1. Construction Preparation First, the initial support steel arch frame 1 and anchor mesh were installed in accordance with the tunnel construction specifications to provide a basic support structure for subsequent construction.

[0035] 2. Template System Construction Reference Figure 2 and3 The magnetic template assembly 2 is transported to the tunnel sidewall. Its retractable modular template body 21 is adjusted to adapt to the actual spacing of the steel arch frame 1 on site. After the power is turned on, the electromagnetic coil in the magnetic actuator 22 is energized to generate a magnetic field, which, together with the soft magnetic material iron core, enhances the magnetic force, so that the template body 21 is firmly attached to the steel arch frame 1. At this time, the intelligent controller 23 starts to work, and monitors the stress state of the template body 21 in real time through sensors, preparing to dynamically adjust the magnetic force during the concrete pouring process.

[0036] 3. Concrete preparation and transportation The initial support concrete composition is produced according to the mix proportions required by this invention, with its slump controlled at 220mm±20mm, spread at 550mm±50mm, initial setting time at 3min±2min, and final setting time at 10min±2min. After the concrete is qualified in the mixing plant, it is transported to the construction site by a transport vehicle.

[0037] 4. Sidewall formwork construction Reference Figure 2 and Figure 4 After the dual-arm sprinkler trolley 3 is in place: The two robotic arms were aligned with the formwork support system at four locations on the left and right side walls respectively; The robotic arm is set to pumping molding mode via an integrated control unit. Adjust the output air pressure to a low pressure of 0.1MPa (range 0.05-0.15MPa); Concrete is poured from bottom to top through the pouring ports opened on the formwork body 21 or reserved between the formwork bodies 21. The concrete filling process can be observed in real time through the viewing window on the template body 21; The section near the working face is sealed using shotcrete.

[0038] 5. Arch spraying Reference Figure 5 After the sidewalls are cast: Immediately move the robotic arm of the same double-arm sprinkler trolley 3 to the arch work area; The operation mode is switched to wet spraying mode through the integrated control unit; Adjust the output air pressure to 0.5MPa (range 0.4-0.6MPa) high pressure air; The arch was sprayed with concrete according to the principle of layering and segmentation.

[0039] 6. Organize homework Simultaneously with the arch shotcreting: After the side wall concrete reaches the predetermined strength, cut off the power to the magnetic template assembly 2 and remove it from the steel arch frame 1. The double-arm sprinkler trolley 3 was used to perform restorative sweeping and spraying on the side wall concrete surface of the removed magnetic template assembly 2; At the same time, the concrete surface of the arch is repaired to ensure the thickness of the protective layer of the steel arch frame 1. Implementation effect

[0040] By employing dual robotic arms operating simultaneously, the shotcrete efficiency is approximately doubled compared to traditional single-arm shotcrete machines. The formwork construction of the side wall reduced the dust concentration in this area by more than 70%, and the concrete rebound rate was close to zero. The surface flatness of the initial support of the sidewall is controlled within ±5mm as required by the specifications, effectively preventing voids behind the secondary lining. The intelligent magnetic template system enables rapid installation and dismantling, reducing single-cycle operation time by 40%. The entire system is highly adaptable and can flexibly choose between full molding or full spraying modes depending on the surrounding rock conditions.

[0041] It should be noted that the introduction of a power source in the above embodiments is necessary for the realization of this invention. The power source can be a power supply integrated on the template body 21 or an externally connected power source, ensuring that the magnetic template assembly 2 can be successfully attached to the steel arch frame 1 after being powered on.

[0042] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. Those skilled in the art can make various modifications to the present invention based on the above description. Therefore, certain details in the embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention shall be defined by the appended claims.

Claims

1. A method for spraying and grouting concrete construction of initial support concrete in tunnels, based on steel arch frames already installed inside the tunnel, characterized in that... Includes the following steps: Template system construction: A magnetic template component is positioned and attached to the steel arch frame of the tunnel sidewall, so that the magnetic template component and the steel arch frame together form a template support system through magnetic attraction. Side wall formwork: Using a double-arm sprinkler truck, the initial support concrete is poured into the formwork support system by pumping to form the initial support structure of the side wall. Arch spraying: Following the sidewall formwork step, the same double-arm spraying trolley is used to switch its operation mode to wet spraying to carry out the initial support concrete construction of the tunnel arch. Finishing: While the arch spraying is being carried out, the magnetic formwork assembly is removed, and the surface of the initial support structure of the side wall and the initial support concrete of the arch is cleaned and sprayed for repair. The initial support concrete is configured to meet the performance requirements of both pumped casting and wet spraying construction.

2. The method for combined spraying and grouting construction of tunnel initial support concrete according to claim 1, characterized in that, During the sidewall molding and arch spraying steps, the output air pressure of the double-arm sprinkler trolley is adaptively adjusted as follows: The output air pressure during the sidewall molding process is 0.05-0.15 MPa; The output air pressure during arch jetting is 0.4-0.6 MPa.

3. The method for combined spraying and grouting construction of tunnel initial support concrete according to claim 1, characterized in that, The slump of the initial concrete support is 200-240mm, the spread is 500-600mm, the initial setting time is 2-5 minutes, and the final setting time is 8-12 minutes.

4. A magnetic formwork assembly for implementing the construction method according to any one of claims 1-3, characterized in that, include: One template main body; A magnetic actuator integrated on the template body is configured to generate an adsorption force when energized, thereby fixing the template body to the steel arch frame. An intelligent controller electrically connected to the magnetic actuator is configured to monitor the state of the template body in real time and dynamically adjust the adsorption force of the magnetic actuator based on the monitoring data.

5. The magnetic template assembly according to claim 4, characterized in that, The magnetic actuator includes a solenoid electromagnetic coil and a soft magnetic material core placed inside it.

6. The magnetic template assembly according to claim 4, characterized in that, The intelligent controller includes: A sensor used to sense the lateral pressure on the template body; An adjustment module connected to the sensor signal is used to adjust the current flowing to the magnetic actuator based on the sensor signal. An alarm unit is used to trigger an alarm when the adsorption force exceeds the safe range.

7. The magnetic template assembly according to claim 4, characterized in that, The template body is equipped with a viewing window for observing the concrete pouring status.

8. The magnetic template assembly according to claim 4, characterized in that, The main body of the template is a retractable modular structure, and its size can adapt to different steel arch spacing and tunnel excavation contours.

9. A double-arm sprinkler trolley for implementing the construction method according to any one of claims 1-3, characterized in that, include: Self-propelled frame structure; The first and second robotic arms are mounted on the self-propelled frame structure and are arranged independently and symmetrically. A hydraulically driven dual-pumping system is used to synchronously and evenly supply concrete flow to the first and second robotic arms. An integrated control unit is used to independently and precisely control the pumping flow rate, accelerator dosage and air pressure of each robotic arm, so that each robotic arm can be independently configured in pumping molding operation mode or wet spraying operation mode.

10. A primary support concrete composition specifically used in the construction method described in any one of claims 1-3, characterized in that, It consists of aggregates, cementitious materials and admixtures, and has the following fresh mix properties: slump 200-240mm, spread 500-600mm, initial setting time 2-5 minutes, and final setting time 8-12 minutes.

Images