Design methods, crack-resistant curing systems and construction methods for tunnels

Abstract

This invention discloses a design method, a crack-resistant maintenance system, and a construction method for a tunnel crack-resistant maintenance system, comprising the following steps: design preparation, obtaining tunnel parameters and indicators, including tunnel length, construction progress, maintenance time requirements, pedestrian crossing spacing, ventilation facility installation, water supply facility installation, and temperature and humidity inside and outside the tunnel, and determining the location of sub-maintenance systems; designing the ventilation device of the maintenance system based on the installation of ventilation facilities inside the tunnel, including the design of ventilation duct routes; designing the circulation device of the maintenance system based on the installation of water supply facilities inside the tunnel, including the layout design of water circulation pipes and greywater recycling devices, and drawing a layout diagram; calculating the turnover cycle and turnover distance; designing a humidification device, which includes a humidification material sheet made of wet film, the humidification device being supplied with water by the circulation device, and the ventilation device being used to humidify external air by passing through the humidification device; and calculating the optimal wind speed and circulating water temperature.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering technology, and in particular, to a design method for a tunnel crack-resistant maintenance system. Furthermore, this invention also relates to a crack-resistant maintenance system and its construction method that incorporates the aforementioned design method. Background Technology

[0002] Tunnel construction is commonly involved in urban road, highway, railway, water conservancy and hydropower, and mining projects. To enhance the stability of the surrounding rock and prevent its collapse, tunnel projects typically require support works to reinforce the surrounding rock. Support works include shotcreting of the initial support concrete and pouring of the secondary lining concrete.

[0003] In conventional tunnel construction, the frequent air exchange between the tunnel entrance and the outside environment within 300m of the tunnel makes the secondary lining surface prone to temperature cracks due to diurnal and seasonal temperature differences. Currently, there are no other effective methods for prevention; the main approach is to increase the frequency of wetting and curing the secondary lining within 300m of the tunnel entrance to maintain heat and moisture, thereby reducing the probability of cracking. In conventional tunnel construction, due to the large tunnel cross-section, the arched support concrete is not suitable for spray curing. Therefore, the following principles are typically used for curing:

[0004] (1) Spray curing: 1. Connect a water pipe from the water source. 2. Use a water pump to power the water flow, overcome the weight of the water, and spray it directly onto the surface of the secondary lining concrete for wetting and curing. Spray curing is simple, direct, and has good curing effect. It can keep the surface of the support concrete moist for a relatively long time, but the longest wetting time still does not exceed the time required for the thickest attached water layer to evaporate and dry due to the weight of the water layer. This method uses a large amount of water, has low water efficiency, and requires a large amount of electricity for the water pump. In addition, too much water cannot adhere to the surface of the support concrete and is easy to flow along the surface or drip directly down, causing problems such as open water discharge in the tunnel, slippery road surface, and harsh working environment.

[0005] (2) Spray curing: On the basis of spray curing, atomizing equipment such as atomizing nozzles, fog cannons, and ultrasonic atomizers are added to atomize the water flow and spray it into the air at a certain pressure and speed to form fine droplets, thereby covering the surface of the secondary lining concrete for wetting and curing; spray curing has high water efficiency and is relatively energy-saving. A thin layer of adhesive water can be attached to the surface of the support concrete, which is not easy to flow and the environment inside the tunnel is relatively clean. However, the thickness of the attached layer often does not reach the maximum thickness, so the wetting time is short and it is easy to evaporate and dry, especially when the airflow is always maintained by the ventilation fan during tunnel construction, the evaporation and drying situation is more obvious;

[0006] (3) Air-film covering spray curing: This method adds a closed air film to the spray curing process to prevent the sprayed moisture from evaporating and drying too quickly, thus shortening the curing interval. For example, the thermal insulation and moisture retention curing device for lining concrete disclosed in patent number 2021223385146 is an air-film covering spray curing method. Air-film covering spray curing uses a closed air film to limit the spray curing area to the surface of one section of the secondary lining. It has all the advantages of spray curing and can keep the surface of the secondary lining moist from beginning to end, resulting in the best curing effect. However, the fabrication and operation of the trolley support for air-film covering are complicated, and only one section of the secondary lining can be cured at a time, resulting in low overall efficiency.

[0007] Current spray curing methods often employ thermal evaporation humidification, ultrasonic humidification, high-pressure spray humidifiers, and two-fluid humidifiers. Thermal evaporation humidification, however, is energy-intensive and inefficient. The high-temperature water vapor it produces has a detrimental effect on the delivery pipelines and the working environment inside the tunnel. Using refrigeration to neutralize the temperature with cold air results in further energy waste, making it impractical. Other humidification methods utilize physical methods to spray micron-sized ultrafine particles. Large-scale atomization humidification generates white fog, affecting visibility inside the tunnel and creating safety hazards. Therefore, the area of ​​atomization humidification needs to be limited, for example, through pipeline delivery or air film coverage. Another measure to reduce white fog is to reduce the scale of atomization humidification. In this case, to ensure wetting effect, an arched trolley carrier needs to be constructed to attach the nozzle to the concrete support surface. Only single-section operations can be performed, with cyclic curing done section by section. Regardless of the method used to overcome the white fog problem, the scale of humidification curing is limited, resulting in low overall humidification efficiency. On the other hand, all physical atomization methods suffer from the problem of "white powder," primarily due to the presence of various minerals in tap water. When the humidifier's water has high hardness and contains many impurities, the mist it sprays will contain calcium and magnesium ions, resulting in white powder. This white powder is harmful to the human body. Inhaling this dust can cause discomfort to the respiratory mucosa or lead to allergies and other illnesses. It can also deposit on the surface of the tunnel lining, forming salt stains, polluting the surface, and causing aesthetic problems.

[0008] On the other hand, both spray curing and mist curing involve large-scale equipment and devices, which must be installed on a platform or transported through pipelines. Common curing platforms include:

[0009] (1) Gantry Curing Trolley: Made of steel with a portal opening that fits the shape of the secondary lining cross-section. The upper platform can be equipped with spray or mist curing devices and personnel can stand and operate. The lower portal can be used for tunnel construction machinery. It is usually driven by multiple methods such as manual, hydraulic or electric, and moves along the tunnel axis by rails, tracks or other means. Multiple spray heads are usually installed on the gantry in the circumferential direction, which can work simultaneously. These spray heads fit the surface of the secondary lining concrete and can work at multiple points at the same time, so the circumferential curing operation is convenient and efficient. However, the axial movement speed is slow, and only one secondary lining cross-section can be cured at a time, which is a single-section operation. After the water layer attached to the secondary lining surface dries, repeated cycles of curing are required, resulting in low overall efficiency.

[0010] (2) Mobile curing trolley: A mobile chassis made of steel is used to install the spraying or misting curing device. The trolley moves axially through the tunnel, usually driven by diesel or electric power. The spraying or misting curing device uses its own omnidirectional rotation function to wet and cover the circumferential secondary lining concrete for curing. This type of trolley has a relatively fast travel speed, but the curing operation is complicated. It can only cure one point of one secondary lining section at a time, which is a single-point operation. However, the spraying point is far from the surface of the secondary lining concrete, and the circumferential wetting and covering needs to be done sequentially. Therefore, the circumferential operation is slow. It also has the problem of needing to repeat the curing operation after the water layer attached to the secondary lining surface dries, resulting in lower overall efficiency.

[0011] (3) Embedded curing device: Similar to the intelligent curing spraying system for precast beam pedestals, intelligent spray heads are embedded in the secondary lining of the tunnel for spraying curing; the structure is extremely complex, the installation is extremely complex, the cost is extremely high, and it is rarely used.

[0012] (4) Ventilation duct delivery: The water vapor generated by the humidifier is directly connected to the ventilation duct and transported to the tunnel face. Then, the water vapor is returned to the secondary lining for curing using forced ventilation air circulation. For example, a cooling and dust-reducing tunnel ventilation device disclosed in patent number 2022203697737 uses a ventilation duct to deliver water vapor. The water vapor delivered in this way is mainly used for dust reduction at the tunnel face, and the amount of water vapor returned to the secondary lining is very limited. Moreover, the water vapor is prone to condensation on the inner surface of the ventilation duct during the transportation process, resulting in low humidification efficiency.

[0013] 4. Ventilation ducts can maintain constant humidification at the tunnel face. However, all water vapor returns from the face through the ventilation ducts, resulting in good dust suppression at the face. Because the safe distance from the face to the secondary lining is at least 70-120m (for Class III, IV, and V surrounding rock), the cross-sectional size of the ventilation ducts is small, and the air volume within the ducts is limited. Therefore, even if the air reaches saturation, the moisture in the saturated air after its long journey back from the face is insufficient to keep the secondary lining surface moist. Furthermore, air humidified by mobile humidification equipment is prone to condensation on the inner surface of the ventilation ducts during its long journey, leading to a decrease in air moisture content and preventing saturation, thus further reducing the effectiveness.

[0014] In summary, current common maintenance measures mainly suffer from problems such as complex maintenance operations and short duration of single-cycle wetting. Common maintenance carriers operate at single points and on single sections, requiring repeated cycles to maintain long-term wetting of the secondary lining surface, resulting in low overall efficiency. Furthermore, the manufacturing of the trolley carrier is complex and costly. Existing technologies suggest using ventilation pipes to address these issues, but in practice, the limited water vapor in the ventilation pipes and the excessively long transport distance from the humidifier to the tunnel face and back to the secondary lining lead to poor maintenance results. Among existing atomization humidification methods, thermal evaporation humidification consumes a lot of energy, has low energy efficiency, and is not very practical. Other atomization humidification methods also suffer from "white mist" and "white powder" problems, which can easily affect visibility inside the tunnel, create safety hazards, cause occupational health problems, and affect the appearance and quality of the concrete during large-scale humidification operations. Summary of the Invention

[0015] This invention provides a design method, a crack-resistant maintenance system, and a construction method for a tunnel crack-resistant maintenance system, in order to solve the technical problems of existing maintenance systems, such as complex operation, low efficiency, high energy consumption, and high cost.

[0016] According to one aspect of the present invention, a design method for a tunnel crack-resistant curing system is provided for crack-resistant curing of secondary tunnel lining, comprising the following steps:

[0017] S1. Design preparation: Obtain tunnel parameters and indicators, including tunnel length, construction progress, maintenance time requirements, pedestrian crossing spacing, ventilation facility installation, water supply facility installation, temperature and humidity inside and outside the tunnel, and determine the location of one or more sub-maintenance systems.

[0018] S2. Design the ventilation system of the maintenance system based on the installation of ventilation facilities inside the tunnel, including the design of ventilation duct routes; design the circulation system of the maintenance system based on the installation of water supply facilities inside the tunnel, including the layout design of water circulation pipes and the layout design of the greywater recycling system, and draw up the layout diagram.

[0019] S3. Calculate the turnover cycle and turnover distance;

[0020] S4. Design a humidification device, which includes a humidification material sheet made of a wet film, a water supply device for the humidification device, and a ventilation device for humidifying the outside air by passing through the humidification device;

[0021] S5. Calculate the optimal wind speed and circulating water temperature.

[0022] As a further improvement to the above technical solution, the maintenance system also includes a monitoring and control device for monitoring the temperature and humidity inside the tunnel and for controlling the water supply power and water supply temperature of the circulation device; the design method also includes step S6:

[0023] Write the control program.

[0024] As a further improvement to the above technical solution, step S3 includes:

[0025] The coverage area L of the maintenance system is calculated based on the average daily construction progress, the required curing time for the secondary lining, and the spacing of pedestrian crossings.

[0026] As a further improvement to the above technical solution, step S3 also includes:

[0027] The sub-maintenance system is installed at the i-th pedestrian crossing closest to the secondary lining mileage marker, and at a distance L from the i-th pedestrian crossing towards the tunnel entrance; the value of L is determined according to the formula.

[0028] L = max{the length of the secondary lining curing time corresponding to the advance length, and the spacing of the pedestrian cross passage} (1).

[0029] As a further improvement to the above technical solution, step S3 also includes:

[0030] As the secondary lining construction progresses, the location of the maintenance system is determined according to the position of the pedestrian crossing, and a maintenance range of L before and after the pedestrian crossing where the maintenance system is located is formed.

[0031] As a further improvement to the above technical solution, step S4 also includes: matching the thickness, area and quantity of humidifying material sheets according to humidification requirements.

[0032] Step S5 also includes: calculating the optimal wind speed and optimal circulating water temperature based on the tunnel secondary lining curing time requirements, air humidity requirements, air temperature and humidity inside and outside the tunnel, and the humidifying material sheet parameters calculated in S4, and matching the corresponding wind speed and water temperature adjustment ranges.

[0033] As a further improvement to the above technical solution, step S7 is also included:

[0034] The structural dimensions of the heat insulation device are designed according to the tunnel entrance dimensions; the heat insulation method and layout are matched according to the traffic conditions of construction personnel and vehicles.

[0035] According to another aspect of the present invention, a crack-resistant curing system is also provided, which applies any of the above-described tunnel crack-resistant curing system design methods, the crack-resistant curing system comprising:

[0036] A humidifying device is installed in a pedestrian crossing at a target location to humidify dry air passing through the humidifying device; the humidifying device includes a mounting frame serving as a carrier and a wet film disposed on the mounting frame;

[0037] The ventilation device includes a fan installed outside the tunnel entrance, a main duct connected to the fan, and a branch duct connected to the main duct. The main duct extends into the tunnel, and the branch duct extends into the pedestrian crossing. The ventilation device is used to introduce external air into the tunnel and allow the introduced external air to pass through the humidification device.

[0038] A circulation device is used to circulate water to the crack-resistant curing system. It includes a circulating water tank, a drive mechanism, and a water distribution mechanism. The circulating water tank is equipped with a heating device to heat the water in the circulating water tank. The mounting frame is also used to be mounted on the water tank. The water distribution mechanism is located above the mounting frame. The drive mechanism is used to transport the water in the circulating water tank to the water distribution mechanism and then transport the water to the top of the mounting frame so that the water can permeate the wet film from top to bottom.

[0039] The monitoring and control device, connected to the circulation device, is used to monitor the temperature and humidity inside the tunnel and to control the water supply power and water temperature of the circulation device.

[0040] Thermal insulation devices are used to block or slow down the exchange of hot and humid air inside the tunnel with the air outside.

[0041] According to another aspect of the present invention, a construction method is also provided, which applies the above-mentioned crack-resistant curing system, the construction method comprising:

[0042] A1. Construction preparation;

[0043] A2. Installation of ventilation equipment;

[0044] A3. Install a circulating water tank;

[0045] A4. Humidifier installation;

[0046] A5. Installation of drive mechanism and water pipes;

[0047] A6. Installation of detection and control devices;

[0048] A7. Installation of thermal insulation devices;

[0049] A8. Debugging.

[0050] The present invention has the following beneficial effects:

[0051] This design method determines the location and scope of the sub-maintenance system based on tunnel parameters and indicators such as tunnel length, construction progress, maintenance time requirements, pedestrian crossing spacing, ventilation facility installation, water supply facility installation, and temperature and humidity inside and outside the tunnel. Based on the tunnel's own ventilation system and water supply, ventilation devices, humidification devices, and circulation devices are further designed. External air is introduced through the tunnel ventilation system and ventilation devices, and humidified by humidifying material sheets, thus achieving a certain humidity level inside the tunnel. The humidifying material sheets are made of a wet film based on highly absorbent material. The circulation device supplies high-temperature water to the humidification device via the tunnel water supply and recycles water not used by the wet film, effectively maintaining the humidity of the wet film. This method provides balanced, all-weather, and all-around wetting and curing of the secondary lining concrete within the main tunnel area at the target location. Compared to existing single-point or single-section curing technologies, it significantly improves curing efficiency. Furthermore, the application of wet film effectively avoids problems such as "white fog" and "white powder," mitigating the high energy consumption, low energy efficiency, reduced visibility within the tunnel, safety hazards during tunnel operations, occupational health issues, and compromised concrete appearance associated with large-scale humidification curing methods. Additionally, the humidification device specifications are matched to humidification requirements, and the turnover cycle and distance are calculated to ensure the sub-curing system is integrated with the secondary lining construction, ensuring timely curing. By calculating the optimal wind speed and circulating water temperature to match the best control mode, energy consumption is reduced, efficiency is improved, and costs are lowered.

[0052] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0053] 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. In the drawings:

[0054] Figure 1 This is a schematic diagram of the overall structure of a preferred embodiment of the present invention;

[0055] Figure 2 This is a schematic diagram of the layout structure of a preferred embodiment of the present invention;

[0056] Figure 3 This is a schematic diagram of the ventilation system layout structure according to a preferred embodiment of the present invention;

[0057] Figure 4 This is a schematic diagram of the humidification device according to a preferred embodiment of the present invention;

[0058] Figure 5 This is a schematic diagram of the circulation device structure according to a preferred embodiment of the present invention;

[0059] Figure 6 This is a schematic diagram of the water distributor structure according to a preferred embodiment of the present invention;

[0060] Figure 7 This is a schematic diagram of the humidification device layout structure according to a preferred embodiment of the present invention;

[0061] Figure 8 This is a flowchart of a preferred embodiment of the present invention.

[0062] Legend:

[0063] 1. Humidification device 11. Mounting frame 12. Wet film 13. Buckle 2. Ventilation device 21. Branch pipe 3. Circulation device 31. Water inlet pipe 32. Circulating water tank 33. Water outlet pipe 34. Drive mechanism 35. Water distributor 351. Sprinkler hole 4. Heat insulation device 5. Monitoring and control device 6. Pedestrian crossing 7. Water supply pipe 8. Greywater recycling device. Detailed Implementation

[0064] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0065] Figure 1 This is a schematic diagram of the overall structure of a preferred embodiment of the present invention; Figure 2 This is a schematic diagram of the layout structure of a preferred embodiment of the present invention; Figure 3 This is a schematic diagram of the ventilation system layout structure according to a preferred embodiment of the present invention; Figure 4 This is a schematic diagram of the humidification device according to a preferred embodiment of the present invention;

[0066] Figure 5 This is a schematic diagram of the circulation device structure according to a preferred embodiment of the present invention; Figure 6 This is a schematic diagram of the water distributor structure according to a preferred embodiment of the present invention; Figure 7 This is a schematic diagram of the humidification device layout structure according to a preferred embodiment of the present invention; Figure 8 This is a flowchart of a preferred embodiment of the present invention.

[0067] like Figures 1 to 8 As shown, the tunnel crack-resistant maintenance system design method of this embodiment includes the following steps:

[0068] S1. Design preparation: Obtain tunnel parameters and indicators, including tunnel length, construction progress, maintenance time requirements, pedestrian crossing spacing, ventilation facility installation, water supply facility installation, temperature and humidity inside and outside the tunnel, and determine the location of one or more sub-maintenance systems.

[0069] S2. Design the ventilation device 2 of the maintenance system based on the installation of ventilation facilities inside the tunnel, including the design of ventilation duct routes; design the circulation device 3 of the maintenance system based on the installation of water supply facilities inside the tunnel, including the layout design of water circulation pipes and the layout design of the greywater recycling system, and draw a layout diagram.

[0070] S3. Calculate the turnover cycle and turnover distance;

[0071] S4. Design a humidification device 1, which includes a humidification material sheet made of a wet film 12, is supplied with water by a circulation device 3, and has a ventilation device 2 for humidifying the outside air by passing through the humidification device 1.

[0072] S5. Calculate the optimal wind speed and circulating water temperature.

[0073] The humidification device 1 is installed in the pedestrian crossing 6 closest to or second closest to the sub-maintenance system, making full use of the space inside the tunnel and having no interference or impact on the main tunnel construction operation; the sub-maintenance system specifically includes the tunnel entrance sub-maintenance system and the tunnel face sub-maintenance system;

[0074] It should be noted that during tunnel construction, due to the different cross-sectional dimensions of the secondary lining, the pouring trolley needs to be modified. Therefore, the construction of the secondary lining in the emergency stopping lane often lags behind the construction of the secondary lining in the main tunnel. As a result, it is common for the secondary lining of the main tunnel to be completed close to the tunnel face, while the secondary lining in the widened section of the emergency stopping lane is left unfinished. If the surrounding rock of the emergency stopping lane is rich in water, water vapor is often observed to seep out from the initial support face, travel through the main tunnel to a distance of hundreds of meters in front and behind, and then condense into water droplets on the surface of the secondary lining, resulting in a long-term wet and covered secondary lining surface for hundreds of meters in front and behind. In severe cases, even a thick fog may form inside the tunnel. In this case, it is only necessary to solve the problem of the fog affecting visibility, and this situation can be artificially created for a long time to ensure that the secondary lining surface is kept moist and properly maintained.

[0075] Understandably, this design method determines the location and scope of the sub-maintenance system based on tunnel parameters and indicators such as tunnel length, construction progress, maintenance time requirements, pedestrian crossing spacing, ventilation facility installation, water supply facility installation, and temperature and humidity inside and outside the tunnel. Based on the tunnel's own ventilation system and water supply, a ventilation device 2, a humidification device 1, and a circulation device 3 are further designed. External air is introduced through the tunnel ventilation system and ventilation device 2, and humidified by a humidifying material sheet, thus maintaining a certain humidity level inside the tunnel. The humidifying material sheet is made of a wet film 12 based on a highly absorbent material. The circulation device 3 supplies high-temperature water to the humidification device 1 via the tunnel water supply and recycles water not utilized by the wet film 12, effectively maintaining humidity. The wet membrane 12 achieves balanced wetting and curing of the secondary lining concrete within the tunnel's main tunnel area at all times, in all weather conditions, and from all directions. Compared to existing single-point or single-section curing technologies, this significantly improves curing efficiency. Furthermore, the application of the wet membrane 12 effectively avoids problems such as "white fog" and "white powder," mitigating the high energy consumption, low energy efficiency, reduced visibility within the tunnel, safety hazards during tunnel operations, occupational health issues, and compromised concrete appearance caused by large-scale humidification curing methods. Simultaneously, the specifications of the humidification device 1 are matched to the humidification requirements, and the turnover cycle and distance are calculated to ensure the sub-curing system is integrated with the secondary lining construction, ensuring timely curing. By calculating the optimal wind speed and circulating water temperature to match the best control mode, energy consumption is reduced, efficiency is improved, and costs are lowered.

[0076] In one embodiment, the maintenance system further includes a monitoring and control device 5 for monitoring the temperature and humidity inside the tunnel and for controlling the water supply power and water supply temperature of the circulation device 3; the design method further includes step S6:

[0077] Write the control program.

[0078] By setting up monitoring and control device 5, and writing control program according to the corresponding relationship achieved by the calculation results of S5, the temperature and humidity in the tunnel are monitored in real time. Then, the water supply power and water supply temperature of circulation device 3 can be intelligently adjusted according to the actual temperature and humidity in the tunnel and the required humidity, so as to maintain a stable humidity in the tunnel. It should be understood that the monitoring and control device 5 is implemented through existing technologies such as temperature sensors, humidity sensors, and control boards.

[0079] In one embodiment, step S2 further includes: drawing a layout diagram; the pipeline layout should be short, flat, and smooth to reduce material consumption and the impact on construction;

[0080] In one embodiment, step S3 includes:

[0081] The coverage area L of the maintenance system is calculated based on the average daily construction progress, the required curing time for the secondary lining, and the 6-interval distance of the pedestrian crossing.

[0082] The maintenance system is designed to maintain an area of ​​200-300m before and after the pedestrian cross passage where the equipment is located. When used in long tunnels, it needs to be rotated according to the actual situation.

[0083] Furthermore, step S3 also includes:

[0084] The sub-maintenance system is installed at the i-th pedestrian crossing 6, which is closest to the secondary lining mileage marker, and at a distance L from the i-th pedestrian crossing 6 towards the tunnel entrance; the value of L is determined according to Equation 1.

[0085] L = max{the length of the secondary lining curing time corresponding to the advance length, and the spacing of the pedestrian cross passage} (1).

[0086] Furthermore, step S3 also includes:

[0087] As the secondary lining construction progresses, the location of the maintenance system is determined according to the position of the pedestrian crossing 6, and a maintenance range of L before and after the pedestrian crossing where the maintenance system is located is formed.

[0088] In this embodiment, step S4 further includes: matching the thickness, area, and quantity of humidifying material sheets according to humidification requirements;

[0089] Specifically, the air humidification effect increases with the thickness of the humidifying material; once the thickness reaches a certain level, the humidification effect no longer improves. Simultaneously, the ventilation area of ​​the humidification device 1 also affects the humidification effect; the larger the area, the more pronounced the effect. In this embodiment, the humidifying material sheet can be set with a suitable area and thickness according to humidification requirements, or the thickness can be increased by installing multiple layers of humidifying material sheets. Based on this, the humidification device 1 has an assembled structure, including an installation frame 11 serving as a carrier and a wet film 12 disposed on the installation frame 11. The assembled structure of the humidification device 1 also allows for adjustments to the actual application thickness at any time.

[0090] In this embodiment, step S5 further includes: calculating the optimal wind speed and optimal circulating water temperature based on the tunnel secondary lining curing time requirements, air humidity requirements, air temperature and humidity inside and outside the tunnel, and the humidifying material sheet parameters calculated in S4; matching the corresponding wind speed and water temperature adjustment range; and generating the corresponding formula or graph of the relationship between humidity and wind speed and temperature.

[0091] In this embodiment, step S7 is also included:

[0092] Based on the tunnel entrance dimensions, design the structural dimensions of the heat insulation device 4; based on the traffic conditions of construction personnel and vehicles, match the heat insulation method and layout.

[0093] Specifically, the boundaries of the sub-maintenance system are equipped with heat insulation devices 4 to block or slow down the exchange of hot and humid air inside the tunnel with the air outside. The tunnel entrance maintenance system is located at the first pedestrian crossing 6 at the entrance of the tunnel, and a heat insulation device 4 is arranged at a predetermined distance on both sides as the boundary of the maintenance range according to its maintenance range. The sub-face maintenance system is located at the pedestrian crossing 6 closest to or second closest to the working face of the secondary lining according to its scale, and a heat insulation trolley is arranged at a predetermined distance in the direction of the tunnel entrance as the boundary of the maintenance range, while the other side covers the working face. Furthermore, the heat insulation device 4 includes heat insulation curtains and / or heat insulation air curtains to reduce the exchange of hot and humid air inside the tunnel with the air outside the tunnel, and ensure that the surface of the secondary lining within 200-300m near the tunnel entrance maintains a uniform temperature.

[0094] When using an insulated air curtain for tunnel entrance insulation, an air curtain machine is installed on top of the insulation trolley to form an insulated air curtain, reducing the exchange of air between the inside and outside; when using insulated curtains for insulation, it affects tunnel traffic.

[0095] In one embodiment, the heat insulation device 4 includes a heat insulation trolley, an automatic opening and closing device connected to the heat insulation curtain, and a sensing and identification device connected to the automatic opening and closing device. The sensing and identification device can be a microwave radar or an infrared sensor to identify approaching pedestrians or vehicles and then transmit opening and closing signals. Its structural principle can be implemented with reference to the automatic door of the prior art. The automatic opening and closing device drives the heat insulation curtain to achieve automatic opening and closing, which facilitates the passage of people and vehicles.

[0096] Furthermore, in some embodiments, the two structural methods of heat-insulating curtain and heat-insulating air curtain can be combined. A passage area is left under the trolley and heat-insulating air curtain is used for heat insulation, while the rest is covered with heat-insulating curtain, which can provide better heat insulation.

[0097] The heat insulation trolley can reduce the exchange of heat and moisture between the tunnel main and the outside air while ensuring the smooth passage of construction machinery and equipment. It can better maintain a balanced microclimate and microenvironment inside the tunnel, improve the prevention and control of temperature cracks in the secondary lining near the tunnel entrance, and further reduce system energy consumption.

[0098] In this embodiment, step S8 is also included: writing a work instruction manual. Based on the system results determined by the above calculation process, a work instruction manual for the large-scale maintenance and crack resistance system of tunnel secondary lining is written, and the manual is explained to the management personnel and work teams.

[0099] On the other hand, this preferred embodiment also provides a crack-resistant curing system, which applies the above-mentioned tunnel crack-resistant curing system design method. The tunnel secondary lining crack-resistant curing system includes:

[0100] Humidifier 1 is installed in the pedestrian crossing 6 at the target location to humidify the dry air passing through it; humidifier 1 includes a mounting frame 11 for use as a carrier and a wet film 12 disposed on the mounting frame 11.

[0101] Ventilation device 2 includes a fan installed outside the tunnel entrance, a main pipe connected to the fan, and a branch pipe 21 connected to the main pipe. The main pipe extends into the tunnel, and the branch pipe 21 extends into the pedestrian crossing 6. Ventilation device 2 is used to introduce external air into the tunnel and allow the introduced external air to pass through humidification device 1.

[0102] The circulation device 3 is used to circulate water to the crack-resistant curing system. It includes a circulating water tank 32, a drive mechanism 34, and a water distribution mechanism. The circulating water tank 32 is equipped with a heating device for heating the water in the circulating water tank 32. The mounting frame 11 is also used to be mounted on the water tank. The water distribution mechanism is arranged above the mounting frame 11. The drive mechanism 34 is used to transport the water in the circulating water tank 32 to the water distribution mechanism and then transport the water to the top of the mounting frame 11 so that the water permeates the wet membrane 12 from top to bottom.

[0103] The monitoring and control device 5 is connected to the circulation device 3 and is used to monitor the temperature and humidity inside the tunnel, and to control the water supply power and water supply temperature of the circulation device 3.

[0104] The heat insulation device 4 is used to block or slow down the exchange of hot and humid air inside the tunnel with the air outside the tunnel.

[0105] Understandably, this tunnel secondary lining crack-resistant curing system fully utilizes the tunnel space by installing a humidification device 1 at the pedestrian crossing 6 at the target location, without interfering with or affecting the main tunnel construction operations. A circulation device 3 supplies water at a preset temperature to the humidification device 1 via the tunnel's water supply pipeline. A ventilation device 2 introduces external air through the tunnel's ventilation system, which is then humidified by the humidification device 1, serving as an external air source. This achieves humidification of the air inside the main tunnel, enabling balanced wetting and curing of the secondary lining concrete within the main tunnel area at the target location, all-weather, and all-around. Compared to… Compared with existing single-point or single-section curing technologies, this method significantly improves curing efficiency. At the same time, the application of humidification device 1 effectively avoids the problems of "white fog" and "white powder". It also effectively avoids the problems of high energy consumption, low energy efficiency, impact on visibility inside the tunnel, safety hazards in tunnel operations, occupational health problems, and poor appearance quality of concrete caused by large-scale humidification curing methods. By setting up monitoring and control device 5, the temperature and humidity inside the tunnel are monitored in real time. Then, the water supply power and water supply temperature of circulation device 3 can be adjusted according to the actual temperature and humidity inside the tunnel and the required humidity, so as to maintain a stable humidity inside the tunnel.

[0106] It should be understood that the monitoring and control device 5 is implemented using existing technologies such as temperature sensors, humidity sensors, and control boards;

[0107] In one embodiment, the humidification device 1 includes an installation frame 11 serving as a carrier and a wet film 12 disposed on the installation frame 11. The wet film 12 is made of a highly absorbent material. By setting the installation frame 11, the wet film 12 is fixed to a certain thickness to form a humidification material sheet that is easy to install and disassemble. The circulation device 3 leads water to the top of the humidification device 1. Under the action of gravity, the water permeates downward along the humidification material. The water is absorbed by the humidification material to form a uniform water film. When dry air passes through the humidification material, the water molecules fully absorb the heat in the air and vaporize and evaporate, increasing the humidity of the air and forming humid air. The humidification principle of using the wet film 12 effectively avoids the problems of "white fog" and "white powder". It avoids the problems of high energy consumption, low energy efficiency, impact on visibility inside the tunnel, safety hazards in tunnel operations, occupational health problems, and poor appearance quality of concrete caused by large-scale humidification curing methods.

[0108] In one embodiment, the circulation device 3 includes a circulating water tank 32, a drive mechanism 34, and a water distribution mechanism. The circulating water tank 32 is equipped with a heating device for heating the water in the circulating water tank 32. The mounting frame 11 is also used to be mounted on the circulating water tank 32. The water distribution mechanism is arranged above the mounting frame 11. The drive mechanism 34 is used to transport the water in the circulating water tank 32 to the water distribution mechanism and then transport the water to the top of the mounting frame 11 so that the water permeates the wet membrane 12 from top to bottom.

[0109] The mounting frame 11 has a buckle 13 at the bottom to cooperate with the circulating water tank 32 for installation, and its side wall can also be equipped with a lifting ring for easy turnover; the heating device is connected to the monitoring and control device 5, and the water tank can be heated and kept warm by setting the target temperature to maintain the circulating water at a suitable temperature; the drive mechanism 34 is a circulating water pump, which can pump the water in the circulating water tank 32 to the water distributor 35; the surface of the water distributor 35 is provided with evenly distributed spray holes 351 to spray water evenly onto the wet film 12;

[0110] Furthermore, the circulation device 3 includes a greywater recycling device 8 for recycling the curing water of the secondary lining concrete. The inlet pipe 31 of the circulating water tank 32 is connected to the tunnel water supply pipe 7 and the greywater recycling device 8. The circulating water tank 32 can be supplied with water through the water supply pipe 7 and / or through the high-temperature curing water sprayed by the spray curing system installed on the secondary lining trolley. By utilizing the temperature difference between the high-humidity and hot air and the surface of the secondary lining, condensate is naturally formed on the surface of the secondary lining, which provides long-term stable wetting and curing for the secondary lining. The humidification device 1 in this embodiment has low energy consumption due to the setting of the circulation device 3. By further utilizing the curing water of the secondary lining concrete and the heat of hydration of the secondary lining concrete to improve the air humidification efficiency, the energy efficiency and water efficiency can be further improved. Based on this, the entire curing system only needs to add the energy consumption of the wet film 12 wetting pump and the heating device to achieve efficient and stable crack-resistant curing.

[0111] Understandably, the circulating water tank 32 is equipped with an outlet pipe 33 for draining water to empty the tank when needed.

[0112] In some embodiments, the monitoring and control device 5 further includes a control valve disposed on the branch pipe 21 for controlling the output air volume of the branch pipe 21. Specifically, when humidifying with the wet film 12, the humidification effect will also increase with the increase of wind speed. However, if the wind speed is too high, the contact time between the air and the wet film 12 will be shortened and the air resistance will also increase sharply, resulting in a weakening of the humidification effect. In order to facilitate the control of the ventilation wind speed of the maintenance system, a control valve is disposed on the ventilation branch pipe in this embodiment. The opening and closing of the valve can be intelligently controlled by the monitoring and control device 5 to control the wind speed and air volume, thereby controlling the air humidity in the tunnel.

[0113] The construction method of this embodiment utilizes the aforementioned crack-resistant curing system, and the construction method includes:

[0114] A1. Construction preparation; Specifically, prepare the materials required for each device of the maintenance system according to the operation instructions of the large-scale maintenance and crack resistance system for tunnel secondary lining.

[0115] A2. Installation of ventilation device 2; Install ventilation ducts according to the layout diagram of ventilation device 2, connect branch pipes 21 to the corresponding positions, suspend the pipes, adjust them to a suitable height so as not to affect passage and construction; install control valves at the corresponding positions of branch pipes 21;

[0116] A3. Install the circulating water tank 32; place the circulating water tank 32 according to the cross-sectional dimensions of the pedestrian crossing 6, leaving a passage for one person to pass through so that workers can pass through and inspect the equipment; connect all the pipes of the circulation device 3, including the inlet pipe 31 and the outlet pipe 33, etc.

[0117] A4. Installation of humidification device 1; Installation of mounting frame 11 with wet film 12 on circulating water tank 32;

[0118] A5. Installation of drive mechanism 34 and water pipe installation; installation of circulating water pump and related pipes, and installation of water distributor 35 directly above humidifier 1, ensuring that water can be sprayed evenly onto humidifier 1;

[0119] A6. Installation of detection and control devices; According to the monitoring requirements of monitoring and control device 5, install temperature and humidity monitors and controllers in the corresponding locations;

[0120] A7. Installation of heat insulation device 4; Install a heat insulation trolley at the tunnel entrance and arrange heat insulation curtains and / or heat insulation air curtains;

[0121] A8. Debugging; After the system is installed, debug the control system to ensure accurate control of tunnel humidification.

[0122] In conventional construction, due to the complexity and high cost of curing operations, work teams often forgo curing altogether, compensating for the strength loss caused by the lack of curing by increasing the cement content in the mix. The high mobility of conventional work platforms and trolleys makes supervision and monitoring by all parties involved very difficult. This system and construction method can achieve full wetting coverage within the work area, significantly reducing the difficulty of supervision and monitoring for owners, supervisors, and construction units. Simultaneously, it reduces the amount of cement in the mix, further saving on project costs.

[0123] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A design method for a tunnel crack-resistant curing system, used for crack-resistant curing of secondary tunnel lining, characterized in that, The crack-resistant curing system includes: A humidifying device is installed in a pedestrian crossing at a target location to humidify dry air passing through the humidifying device; the humidifying device includes a mounting frame serving as a carrier and a wet film disposed on the mounting frame; The ventilation device includes a fan installed outside the tunnel entrance, a main duct connected to the fan, and a branch duct connected to the main duct. The main duct extends into the tunnel, and the branch duct extends into the pedestrian crossing. The ventilation device is used to introduce external air into the tunnel and allow the introduced external air to pass through the humidification device. A circulation device is used to circulate water to the crack-resistant curing system. It includes a circulating water tank, a drive mechanism, and a water distribution mechanism. The circulating water tank is equipped with a heating device to heat the water in the circulating water tank. The mounting frame is also used to be mounted on the water tank. The water distribution mechanism is located above the mounting frame. The drive mechanism is used to transport the water in the circulating water tank to the water distribution mechanism and then transport the water to the top of the mounting frame so that the water can permeate the wet film from top to bottom. The monitoring and control device, connected to the circulation device, is used to monitor the temperature and humidity inside the tunnel and to control the water supply power and water temperature of the circulation device. Thermal insulation devices are used to block or slow down the exchange of hot, humid air inside the tunnel with air outside. The design method for tunnel crack-resistant maintenance systems includes the following steps: S1. Design preparation: Obtain tunnel parameters and indicators, including tunnel length, construction progress, maintenance time requirements, pedestrian crossing spacing, ventilation facility installation, water supply facility installation, temperature and humidity inside and outside the tunnel, and determine the location of one or more sub-maintenance systems. S2. Design the ventilation system of the maintenance system based on the installation of ventilation facilities inside the tunnel, including the design of ventilation duct routes; design the circulation system of the maintenance system based on the installation of water supply facilities inside the tunnel, including the layout design of water circulation pipes and the layout design of greywater recycling devices, and draw up the layout diagram. S3. Calculate the turnover cycle and turnover distance; S4. Design a humidification device, which includes a humidification material sheet made of a wet film, a water supply device for the humidification device, and a ventilation device for humidifying the outside air by passing through the humidification device; S5. Calculate the optimal wind speed and circulating water temperature.

2. The design method for a tunnel crack-resistant maintenance system according to claim 1, characterized in that, The maintenance system also includes a monitoring and control device for monitoring the temperature and humidity inside the tunnel and for controlling the water supply power and water temperature of the circulation device; the design method also includes step S6: Write the control program.

3. The design method for a tunnel crack-resistant maintenance system according to claim 1, characterized in that, Step S3 includes: The coverage area L of the maintenance system is calculated based on the average daily construction progress, the required curing time for the secondary lining, and the spacing of pedestrian crossings.

4. The design method for a tunnel crack-resistant maintenance system according to claim 3, characterized in that, Step S3 also includes: The sub-maintenance system is installed at the i-th pedestrian crossing closest to the secondary lining mileage marker and at a distance L from the i-th pedestrian crossing towards the tunnel entrance; the value of L is determined according to formula (1). L=max{the length of the secondary lining curing time corresponding to the advance length, the spacing of the pedestrian cross passage} (1).

5. The design method for a tunnel crack-resistant maintenance system according to claim 4, characterized in that, Step S3 also includes: As the secondary lining construction progresses, the location of the maintenance system is determined according to the position of the pedestrian crossing, and a maintenance range of L before and after the pedestrian crossing where the maintenance system is located is formed.

6. The design method for a tunnel crack-resistant maintenance system according to claim 1, characterized in that, Step S4 also includes: matching the thickness, area, and quantity of humidifying material sheets according to humidification requirements.

7. The design method for a tunnel crack-resistant maintenance system according to claim 6, characterized in that, Step S5 also includes: calculating the optimal wind speed and optimal circulating water temperature based on the tunnel secondary lining curing time requirements, air humidity requirements, air temperature and humidity inside and outside the tunnel, and the humidifying material sheet parameters calculated in S4, and matching the corresponding wind speed and water temperature adjustment ranges.

8. The design method for a tunnel crack-resistant maintenance system according to claim 1, characterized in that, It also includes step S7: The structural dimensions of the heat insulation device are designed according to the tunnel entrance dimensions; the heat insulation method and layout are matched according to the traffic conditions of construction personnel and vehicles.

9. A construction method, characterized in that, The application uses the tunnel crack-resistant maintenance system design method according to any one of claims 1-8, wherein the construction method includes: A1. Construction preparation; A2. Installation of ventilation equipment; A3. Install a circulating water tank; A4. Humidifier installation; A5. Installation of drive mechanism and water pipes; A6. Installation of detection and control devices; A7. Installation of thermal insulation devices; A8. Debugging.

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