Tunnel anti-crack maintenance system design method, anti-crack maintenance system and construction method

Abstract

The invention discloses a tunnel anti-crack maintenance system design method, an anti-crack maintenance system and a construction method, and the method comprises the following steps: design preparation: obtaining tunnel parameters and indexes, including tunnel length, construction progress, maintenance time requirement, pedestrian crossing spacing distance, ventilation facility installation condition, water supply facility installation condition, and temperature and humidity inside and outside a tunnel hole; determining the position of a sub-maintenance system; designing a ventilation device of the maintenance system according to the installation condition of ventilation facilities in the tunnel hole, including designing a ventilation pipeline line; a circulation device of the maintenance system is designed according to the installation condition of water supply facilities in the tunnel hole, arrangement design of a water circulation pipeline and a reclaimed water recovery device is included, and an arrangement diagram is drawn; calculating a turnover period and a turnover distance; a humidifying device is designed, the humidifying device comprises a humidifying material sheet made of a wet film, water is supplied to the humidifying device through a circulating device, and a ventilation device is used for humidifying external air through the humidifying device; and calculating the optimal wind speed and circulating water temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel engineering, and in particular, to a design method for a tunnel anti-crack maintenance system. In addition, the present invention also relates to an anti-crack maintenance system and a construction method comprising the design method for the tunnel anti-crack maintenance system. Background Art

[0002] Tunnel construction is commonly involved in urban roads, highway projects, railway projects, water conservancy and hydropower projects, and mining projects. In order to enhance the stability of tunnel surrounding rock and prevent tunnel surrounding rock collapse, tunnel projects usually require support engineering to reinforce the surrounding rock. Support engineering includes: spraying primary support concrete and pouring secondary lining concrete.

[0003] In conventional tunnel construction, due to the frequent exchange of air inside and outside the tunnel within 300m of the tunnel entrance, temperature cracks are easily generated on the surface of the secondary lining due to the temperature difference between day and night and seasonal temperature difference. At present, there is no other better method for prevention and control. It mainly relies on increasing the frequency of wetting and curing of the secondary lining within 300m of the tunnel entrance to keep warm and moisturize to reduce the probability of cracking. In conventional tunnel construction, due to the large tunnel section, the arch-shaped support concrete is not convenient for spray curing. Therefore, the following principles are usually used for curing:

[0004] (1) Spraying maintenance: 1. Connect the water pipe to the water source. 2. Use a water pump to provide power for the water flow, overcome the water's own weight, and spray directly onto the surface of the secondary lining concrete for moistening maintenance; spraying maintenance is simple and direct, with good maintenance effect. It can keep the supporting concrete surface moist for a relatively long time, but the longest wetting time still does not exceed the time required for the thickest attached water layer determined by the water layer's own weight to evaporate and dry. This method consumes a lot of water, has low water efficiency, and the corresponding water pump consumes a lot of electricity. In addition, too much water cannot adhere to the surface of the supporting concrete, and it is easy to flow along the surface or drip directly, causing problems such as open water drainage in the tunnel, slippery road surface, and poor 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 moistening 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 supporting concrete, which is not easy to flow. The environment in the tunnel is relatively clean, but the thickness of the attached layer often does not reach the maximum thickness, so the moistening time is short and it is easy to evaporate and dry up. Especially during tunnel construction, when the air circulation is always maintained in the tunnel through the ventilator, the evaporation and drying phenomenon is more obvious;

[0006] (3) Air film covering spray curing: On the basis of spray curing, a closed air film is added to prevent the spray wetting from evaporating and drying up too quickly, so as to shorten the curing interval. For example, the lining concrete thermal insulation and moisture retention curing device disclosed in Patent No.: 2021223385146 is an air film covering spray curing method; air film covering spray curing is based on spray curing and uses a closed air film to limit the scope of spray curing to the surface of one section of the second lining. It has all the advantages of spray curing and can keep the surface of the second lining moist from beginning to end, with the best curing effect. However, the trolley bracket covered with air film is complicated to process and operate, and can only cure one section of the second lining at a time, with low overall efficiency;

[0007] Existing spray curing often adopts: thermal evaporation humidification, ultrasonic humidification, high-pressure spray humidifier, two-fluid humidifier and other methods. Among them, thermal evaporation humidification has high energy consumption and low energy efficiency. The high-temperature water vapor generated has a bad impact on the transmission pipeline and the working environment in the tunnel. The use of refrigeration and cold air to neutralize and reduce the temperature will cause more energy waste and low practicality. Other humidification methods all use physical methods to spray micron-level ultrafine particles. During large-scale atomization humidification, white fog will be generated, which will affect the vision in the tunnel and cause safety hazards in the tunnel operation. Therefore, it is necessary to limit the area of ​​atomization humidification to a certain range, such as using pipeline transportation or air film covering to close it. Another measure to reduce the generation of white fog is to reduce the scale of atomization humidification. At this time, in order to ensure the wetting effect, it is necessary to manufacture an arched trolley carrier to fit the nozzle to the supporting concrete surface. Only a single-section operation method can be adopted, and the curing can be carried out section by section. No matter which method is used to overcome the white fog problem, the scale of humidification curing is limited, resulting in low overall humidification efficiency. On the other hand, the physical atomization method has the problem of "white powder". The white powder is mainly caused by the presence of various minerals in tap water. When the curing water has a high hardness and many impurities, the water mist sprayed by the humidifier will contain calcium and magnesium ions, thus producing white powder. These white powders are harmful to the human body. Inhalation of these dusts can cause discomfort in the respiratory mucosa or allergic diseases. At the same time, they will also be deposited on the surface of the tunnel secondary lining, forming salt spots, polluting the surface, and causing visual quality problems.

[0008] On the other hand, both spray curing and spray curing involve related large-scale equipment and devices, which need to be installed on a platform carrier for operation or transported through a pipeline. Common curing carriers include:

[0009] (1) Gantry maintenance trolley: It is made of steel into a portal that fits the shape of the secondary lining section. The upper platform can be installed with a spray or mist maintenance device and people can stand to operate it. The lower portal can be used for tunnel operation machinery and equipment. It is usually driven by various methods such as human, hydraulic or electric, and moves along the axial direction of the tunnel by various methods such as rails and crawlers. Multiple spray heads are usually installed in the gantry in an annular direction and can operate simultaneously; this type of spray head fits the surface of the secondary lining concrete and can operate at multiple points at the same time, so the annular maintenance operation is convenient and efficient; but the axial travel speed is slow, and only one secondary lining section can be maintained at a time, which is a single-section operation; after the water layer attached to the surface of the secondary lining dries up, it needs to be maintained by reciprocating cycles, and the overall efficiency is low;

[0010] (2) Mobile maintenance trolley: A mobile chassis is made of steel, and the spray or mist curing device is installed on it. The trolley is used to move the tunnel axially, and is usually driven by diesel or electric means. The universal rotation function of the spray or mist curing device is used to wet and cover the circumferential secondary lining concrete. This type of trolley has a fast travel speed, but the curing operation is complicated. It can only cure one point on the 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. In addition, there is also the problem that the water layer attached to the surface of the secondary lining needs to be dries up and reciprocating cycle curing is required, and the overall efficiency is lower.

[0011] (3) Pre-buried maintenance device: Similar to the intelligent maintenance spraying system for prefabricated beam pedestals, intelligent sprinkler heads are pre-buried in the secondary lining of the tunnel for spraying maintenance. The structure is extremely complex, the installation is extremely complex, the cost is extremely high, and it is rarely used.

[0012] (4) Transportation by ventilation pipes: The water vapor generated by the humidifier is directly connected to the ventilation pipes, and then transported to the tunnel face through the ventilation pipes. Then, the water vapor is returned to the secondary lining for maintenance by using the air circulation of the forced ventilation. For example, a cooling and dust reduction type tunnel ventilation device disclosed in Patent No. 2022203697737 is a method of transporting water vapor through ventilation pipes. The water vapor transported by this method is mainly used to reduce dust on the tunnel face, and the water vapor returned to the secondary lining is very limited. In addition, the water vapor is easily condensed on the inner surface of the ventilation pipe during transportation, resulting in low humidification efficiency.

[0013] 4. Ventilation pipe transportation can maintain normal humidification of the tunnel face. However, all water vapor returns from the face through the ventilation duct, and the dust reduction effect on the face is good. Since the safe step distance from the face to the secondary lining is at least 70 to 120m (III, IV, V grade surrounding rock), the cross-sectional size of the ventilation duct is small, and the air volume in the duct is also limited. Therefore, even if the air reaches a saturated state, the moisture in the saturated air after a long journey from the face is difficult to keep the surface of the secondary lining moist. At the same time, the air humidified by the mobile humidification equipment is also prone to condensation on the inner surface of the pipe to form water droplets during the long journey in the ventilation duct, which causes the water content of the air to decrease, and it cannot reach a saturated state, and the effect is worse.

[0014] In summary, the common maintenance measures currently have the problems of complex maintenance operations and short wetting time for a single maintenance; the common maintenance carriers currently have single-point and single-section operations, which require reciprocating cycles to keep the secondary lining surface moistened for a long time, low overall efficiency, complex processing and manufacturing of the trolley carrier, and high cost; the prior art provides a carrier method using ventilation pipes to solve the above technical problems, but in actual use, due to the small amount of water vapor in the ventilation pipe, the excessively long transportation loss of the humidifier-face-return to the secondary lining will lead to poor actual maintenance effects; among the existing atomization humidification methods, thermal evaporation humidification has high energy consumption, low energy efficiency, and low practicality, and other atomization humidification methods have problems with "white mist" and "white powder", which can easily affect the field of vision in the tunnel during large-scale humidification operations, cause safety hazards in tunnel operations, and cause occupational health problems and problems with the visual quality of concrete. Summary of the invention

[0015] The present invention provides a tunnel anti-crack maintenance system design method, an anti-crack maintenance system and a construction method to solve the technical problems of the existing maintenance system such as complex operation, low efficiency, high energy consumption and high cost.

[0016] According to one aspect of the present invention, a method for designing a tunnel anti-crack maintenance system is provided, which is used for anti-crack maintenance of a tunnel secondary lining, and comprises the following steps:

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

[0018] S2. Design the ventilation device of the maintenance system according to the installation of ventilation facilities in the tunnel, including the design of ventilation duct lines; design the circulation device of the maintenance system according to the installation of water supply facilities in the tunnel, including the layout design of water circulation pipelines and the layout design of the grey water recovery system, and draw the layout diagram;

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

[0020] S4. Design a humidifying device, the humidifying device comprising a humidifying material sheet made of a wet film, the humidifying device being supplied with water by a circulation device, and the ventilation device being used to humidify external air through the humidifying device;

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

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

[0023] Write the control program.

[0024] As a further improvement of 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 secondary lining maintenance time requirements, and the pedestrian crossing interval distance.

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

[0027] The sub-maintenance system is arranged at the i-th pedestrian crossing closest to the second lining mileage pile number and at the position L in the direction of the tunnel entrance from the i-th pedestrian crossing; the value of L is determined according to the formula,

[0028] L = max{secondary lining maintenance time corresponding to the length of the advance, the distance between pedestrian crossing passages} (1).

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

[0030] With the progress of the secondary lining construction, the sub-maintenance systems are arranged one by one according to the positions of the pedestrian crossings, and a maintenance range of L in front and behind is formed with the pedestrian crossing where the sub-maintenance system is located as the center.

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

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

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

[0034] Design the structural dimensions of the thermal insulation device according to the size of the tunnel entrance; match the thermal insulation method and layout method according to the traffic conditions of construction personnel and vehicles.

[0035] According to another aspect of the present invention, there is also provided an anti-crack maintenance system, to which any of the above-mentioned tunnel anti-crack maintenance system design methods is applied, and the anti-crack maintenance system comprises:

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

[0037] A ventilation device, comprising a fan arranged outside a tunnel portal, a main pipe connected to the fan, and a branch pipe connected to the main pipe, wherein the main pipe extends into the tunnel, and the branch pipe is used to extend into a pedestrian crossing, and the ventilation device is used to introduce external air into the tunnel and pass the introduced external air through the humidifying device;

[0038] A circulation device is used to circulate water to the anti-cracking maintenance system, including a circulating water tank, a driving mechanism and a water distribution mechanism. The circulating water tank is provided with a heating device for heating the water in the circulating water tank; the mounting frame is also used to be arranged on the water tank, the water distribution mechanism is arranged above the mounting frame, and the driving 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 penetrate the wet membrane from top to bottom;

[0039] A monitoring and control device, connected to the circulation device, for monitoring the temperature and humidity in the tunnel and for controlling the water supply power and water supply temperature of the circulation device;

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

[0041] According to another aspect of the present invention, a construction method is provided, using the above-mentioned anti-cracking maintenance system, the construction method comprising:

[0042] A1. Construction preparation;

[0043] A2. Installation of ventilation device;

[0044] A3. Install circulating water tank;

[0045] A4. Humidification device installation;

[0046] A5. Installation of driving mechanism and water pipeline;

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

[0048] A7.Insulation device installation;

[0049] A8.Debugging.

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

[0051] In this design method, the location and scope of the sub-maintenance system are determined based on tunnel parameters and indicators such as tunnel length, construction progress, maintenance time requirements, pedestrian crossing intervals, ventilation facility installation, water supply facility installation, temperature and humidity inside and outside the tunnel, etc. The ventilation device, humidification device and circulation device are further designed based on the ventilation system and tunnel water supply of the tunnel project itself. The external air introduced through the tunnel ventilation system and ventilation device is humidified through the humidification material sheet, so that the air in the tunnel has a certain humidity. The humidification material sheet is made of a wet film prepared based on a highly absorbent material. The circulation device supplies high-temperature water to the humidification device through the tunnel water supply, and recycles the water not used by the wet film for recycling, and effectively maintains the humidity of the wet film, so as to achieve The balanced wetting and curing of the secondary lining concrete in the main tunnel of the target tunnel at all times, all weather and in all directions can greatly improve the curing efficiency compared with the single point curing or single section curing of the existing technology. At the same time, the application of wet film can effectively avoid the problems of "white fog" and "white powder", and effectively avoid the large-scale humidification curing method. The energy consumption and low energy efficiency affect the field of vision in the tunnel, cause safety hazards in tunnel operations, cause occupational health problems and concrete appearance quality problems. At the same time, the specifications of the humidification device are set according to the humidification needs, and the turnover cycle and turnover distance are calculated to match the setting of the sub-curing system with the secondary lining construction, so as to ensure timely connection and maintenance. The optimal wind speed and circulating water temperature are calculated to match the better control mode, thereby reducing energy consumption, improving efficiency and reducing costs.

[0052] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

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

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

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

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

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

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

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

[0061] Figure 8 It is a flow chart of a preferred embodiment of the present invention.

[0062] Legend:

[0063] 1. Humidifier 11. Mounting frame 12. Wet membrane 13. Buckle 2. Ventilator 21. Branch pipe 3. Circulation device 31. Water inlet pipe 32. Circulation water tank 33. Water outlet pipe 34. Driving mechanism 35. Water distributor 351. Sprinkler hole 4. Heat insulation device 5. Monitoring and control device 6. Pedestrian crossing 7. Water supply pipe 8. Recycled water recovery device. DETAILED DESCRIPTION

[0064] The embodiments of the present invention are 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 It is a schematic diagram of the overall structure of a preferred embodiment of the present invention; Figure 2 It is a schematic diagram of the layout structure of a preferred embodiment of the present invention; Figure 3 It is a schematic diagram of the layout structure of the ventilation system of a preferred embodiment of the present invention; Figure 4 is a schematic structural diagram of a humidifying device according to a preferred embodiment of the present invention;

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

[0067] like Figures 1 to 8 As shown, the tunnel anti-crack 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 6 interval distance, ventilation facility installation, water supply facility installation, tunnel inside and outside temperature and humidity, determine the location of one or more sub-maintenance systems;

[0069] S2. Design the ventilation device 2 of the maintenance system according to the installation of ventilation facilities in the tunnel, including the design of ventilation duct lines; design the circulation device 3 of the maintenance system according to the installation of water supply facilities in the tunnel, including the layout design of water circulation pipelines and the layout design of the grey water recovery system, and draw a layout diagram;

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

[0071] S4. Design of a humidifying device 1, the humidifying device 1 comprises a humidifying material sheet made of a wet film 12, water is supplied by a circulation device 3, and a ventilation device 2 is used to humidify the external air through the humidifying device 1;

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

[0073] The humidifying device 1 is arranged in the nearest or second nearest pedestrian crossing 6 of the sub-maintenance system, making full use of the space in the tunnel and having no interference or influence on the main tunnel construction work; the sub-maintenance system specifically includes the tunnel opening sub-maintenance system and the face sub-maintenance system;

[0074] It should be noted that in tunnel construction, due to the different cross-sectional dimensions of the secondary lining, the casting trolley needs to be modified, so the construction of the secondary lining of the emergency stop strip often lags behind the construction of the secondary lining of the main tunnel. Therefore, it is often the case that the secondary lining of the main tunnel closely follows the heading face, while the secondary lining of the widened section of the emergency stop strip is retained and not yet implemented. If the surrounding rock of the emergency stop strip is rich in water, it is often observed that water vapor seeps from the primary support surface, spreads through the main tunnel to a distance of hundreds of meters before and after, and then condenses into water droplets on the surface of the secondary lining, covering the surface of the secondary lining for hundreds of meters before and after for a long time. In severe cases, even fog will form in the tunnel. At this time, it is only necessary to solve the problem of fog affecting the visibility of the field of vision to artificially create this situation for a long time, and ensure that the surface of the secondary lining is moistened and maintained for a long time.

[0075] It can be understood that in this design method, the location and scope of the sub-maintenance system are determined based on tunnel parameters and indicators such as tunnel length, construction progress, maintenance time requirements, pedestrian crossing 6 spacing, ventilation facility installation, water supply facility installation, temperature and humidity inside and outside the tunnel, etc. The ventilation device 2, humidification device 1 and circulation device 3 are further designed based on the ventilation system and tunnel water supply of the tunnel project itself. The external air is introduced through the tunnel ventilation system and the ventilation device 2, and the introduced external air is humidified through the humidification material sheet, so that the air in the tunnel has a certain humidity. The humidification material sheet is made of a wet film 12 prepared based on a highly absorbent material. The circulation device 3 supplies high-temperature water to the humidification device 1 through the tunnel water supply, and recycles the water not used by the wet film 12 for recycling, and effectively maintains humidity. The humidity of membrane 12 can realize the all-time, all-weather and all-round balanced wetting and curing of the secondary lining concrete within the main tunnel of the target location tunnel, which greatly improves the curing efficiency compared with the single-point curing or single-section curing in the existing technology. At the same time, the application of wet membrane 12 can effectively avoid the problems of "white fog" and "white powder", and effectively avoid the large-scale humidification curing method. The energy consumption is large and the energy efficiency is low, which affects the field of vision in the tunnel, causes safety hazards in the tunnel operation, causes occupational health problems and concrete appearance quality problems; at the same time, the specifications of the humidifying device 1 are set according to the humidification demand, and the turnover cycle and turnover distance are calculated to match the setting of the sub-curing system with the secondary lining construction, so as to connect the maintenance in time, and calculate the optimal wind speed and circulating water temperature to match the better control mode, so as to reduce energy consumption, improve efficiency and reduce costs.

[0076] In one embodiment, the maintenance system further includes a monitoring and control device 5 for monitoring the temperature and humidity in 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 the monitoring and control device 5, a control program is written according to the corresponding relationship obtained by the calculation result of S5, and the temperature and humidity in the tunnel are monitored in real time, and then the water supply power and water supply temperature of the circulation device 3 can be intelligently adjusted according to the actual temperature and humidity in the tunnel and the required humidity, so that the humidity in the tunnel is kept stable; it should be understood that the monitoring and control device 5 is realized by the temperature sensor, humidity sensor, control board, etc. of the prior art;

[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 impact on construction;

[0080] In one embodiment, step S3 includes:

[0081] Calculate the coverage L of the maintenance system based on the average daily construction footage, the secondary lining maintenance time requirements, and the 6-way interval of the pedestrian crossing;

[0082] The maintenance area designed for the maintenance system is 200 to 300 meters before and after the pedestrian crossing where the equipment is located. When used in a long tunnel, it needs to be rotated according to actual conditions.

[0083] Furthermore, step S3 also includes:

[0084] The sub-maintenance system is arranged at the i-th pedestrian crossing 6 closest to the second lining mileage pile number and at the position L in the direction of the tunnel entrance from the i-th pedestrian crossing 6; the value of L is determined according to formula 1,

[0085] L = max{secondary lining maintenance time corresponding to the length of the advance, the distance between pedestrian crossing passages} (1).

[0086] Furthermore, step S3 also includes:

[0087] With the progress of the secondary lining construction, the sub-maintenance system is arranged one by one according to the position of the pedestrian crossing 6, and a maintenance range of L in front and behind is formed with the pedestrian crossing where the sub-maintenance system is located as the center.

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

[0089] Specifically, the air humidification effect will increase with the increase of the thickness of the humidification material. When the thickness reaches a certain level, the humidification effect will no longer increase. At the same time, the ventilation area of ​​the humidification device 1 will also affect the humidification effect. The larger the area, the more obvious the effect. The humidification material sheet of this embodiment can be set to a suitable area and thickness according to the humidification requirements, or the thickness of the humidification material can be increased by installing multiple layers of humidification material sheets. Based on this, the humidification device 1 is an assembled structure, including an installation frame 11 used as a carrier and a wet film 12 arranged on the installation frame 11. The humidification device 1 of the assembled structure can also change the actual application thickness at any time.

[0090] In this embodiment, step S5 further includes: according to the tunnel secondary lining maintenance time requirement, air humidity requirement, air temperature and humidity conditions inside and outside the tunnel, and the humidification material sheet parameters calculated in S4, calculating the optimal wind speed and optimal circulating water temperature, matching the corresponding wind speed and water temperature adjustment range, and generating the corresponding relationship formula or relationship diagram between humidity, wind speed and temperature;

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

[0092] Design the structural dimensions of the heat insulation device 4 according to the size of the tunnel opening; match the heat insulation method and layout method according to the traffic conditions of construction personnel and vehicles;

[0093] Specifically, a heat-insulating device 4 is provided at the boundary of the sub-maintenance system to block or slow down the exchange of hot and humid air in the tunnel with the air outside the tunnel. The tunnel entrance maintenance system is arranged at the first pedestrian crossing 6 entering the tunnel, and a heat-insulating device 4 is arranged at a preset distance on both sides as the boundary of the maintenance range according to its maintenance range; the sub-face maintenance system is arranged at the pedestrian crossing 6 closest to or second closest to the secondary lining face according to its scale, and an insulation trolley is arranged at a preset distance in the direction of the tunnel entrance as the boundary of the maintenance range, and the other side covers the face; further, the heat-insulating device 4 includes an insulation curtain and / or an insulation air curtain to reduce the exchange of high-humidity and hot air in the tunnel with the air outside the tunnel, so as to ensure that the surface of the secondary lining within 200-300m near the tunnel door maintains a temperature balance;

[0094] Among them, when using the insulation air curtain method to insulate the tunnel entrance, an air curtain machine is set on the top of the insulation trolley to form an insulation air curtain to reduce the exchange of air inside and outside; when using insulation curtains for insulation, it affects the 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 recognition device connected to the automatic opening and closing device. The sensing recognition device can be a micro radar or an infrared sensor to identify pedestrians or vehicles approaching, and then transmit an opening and closing signal. Its structural principle can be realized by referring to the automatic door of the prior art; the heat insulation curtain is driven by the automatic opening and closing device to realize automatic opening and closing, which is convenient for people and vehicles to pass through;

[0096] Furthermore, in some embodiments, the two structures of the thermal insulation curtain and the thermal insulation air curtain can be combined, leaving a passage area under the trolley and using the thermal insulation air curtain for insulation, and the rest of the area is covered with the thermal insulation curtain, which can achieve better insulation.

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

[0098] In this embodiment, step S8 is also included: writing an operation instruction book, according to the system results determined by the above calculation process, writing an operation instruction book for the large-scale maintenance and anti-cracking system of the tunnel secondary lining, and briefing it to the management personnel and the team.

[0099] On the other hand, the preferred embodiment further provides an anti-crack maintenance system, to which the above-mentioned tunnel anti-crack maintenance system design method is applied, and the tunnel secondary lining anti-crack maintenance system comprises:

[0100] A humidifying device 1 is arranged in a pedestrian crossing 6 at a target location, and is used to humidify dry air passing through the humidifying device 1; the humidifying device 1 includes a mounting frame 11 used as a carrier and a wet film 12 arranged on the mounting frame 11;

[0101] The ventilation device 2 includes a fan arranged outside the tunnel portal, a main pipeline connected to the fan, and a branch pipeline 21 connected to the main pipeline, the main pipeline extends into the tunnel, and the branch pipeline 21 is used to extend into the pedestrian crossing 6. The ventilation device 2 is used to introduce external air into the tunnel and pass the introduced external air through the humidifying device 1;

[0102] The circulation device 3 is used for circulating water to the anti-cracking maintenance system, and includes a circulating water tank 32, a driving mechanism 34 and a water distribution mechanism. The circulating water tank 32 is provided with a heating device for heating the water in the circulating water tank 32; the mounting frame 11 is also used to be arranged on the water tank, the water distribution mechanism is arranged above the mounting frame 11, and the driving 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 can penetrate the wet membrane 12 from top to bottom;

[0103] A monitoring and control device 5, connected to the circulation device 3, for monitoring the temperature and humidity in the tunnel, and for controlling 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 in the tunnel and the air outside the tunnel.

[0105] It can be understood that the anti-cracking maintenance system of the secondary lining of the tunnel fully utilizes the space inside the tunnel by setting a humidifying device 1 at the pedestrian crossing 6 at the target location, and has no interference or impact on the construction work of the main tunnel; and a circulation device 3 is set to supply water of preset temperature to the humidifying device 1 through the water supply pipeline of the tunnel, and the ventilation device 2 introduces external air through the ventilation system of the tunnel and humidifies it through the humidifying device 1 as the external air source, thereby realizing the humidification of the air in the main tunnel of the tunnel, and realizing the full-time, all-weather, and all-round balanced wetting maintenance of the secondary lining concrete within the main tunnel of the tunnel at the target location. Compared with the single-point maintenance or single-section maintenance in the existing technology, the maintenance efficiency is greatly improved. At the same time, the application of the humidification device 1 effectively avoids the problems of "white fog" and "white powder", and effectively avoids the large-scale humidification maintenance method. The energy consumption and low energy efficiency affect the field of vision in the tunnel, cause safety hazards in tunnel operations, cause occupational health problems and concrete appearance quality problems; by setting up a monitoring and control device 5, the temperature and humidity in the tunnel are monitored in real time, and then the water supply power and water supply temperature of the circulation device 3 can be adjusted according to the actual temperature and humidity in the tunnel and the required humidity, so that the humidity in the tunnel is kept stable.

[0106] It should be understood that the monitoring and control device 5 is implemented by a temperature sensor, a humidity sensor, a control board, etc. of the prior art;

[0107] In one embodiment, the humidifying device 1 includes a mounting frame 11 used as a carrier and a wet film 12 arranged on the mounting frame 11; the wet film 12 is made of a highly water-absorbent material, and the mounting frame 11 is arranged to fix the wet film 12 according to a certain thickness to form a humidifying material sheet that is easy to install and disassemble. The circulation device 3 leads water to the top of the humidifying device 1, and the water permeates downward along the humidifying material under the action of gravity. The water is absorbed by the humidifying material to form a uniform water film. When dry air passes through the humidifying material, the water molecules fully absorb the heat in the air and vaporize and evaporate to increase the humidity of the air, forming humid air; the humidification principle of the wet film 12 is used to effectively avoid the problems of "white fog" and "white powder", and avoid the large energy consumption and low energy efficiency brought about by large-scale humidification and maintenance methods, which affect the field of vision in the tunnel, cause safety hazards in tunnel operations, cause occupational health problems and concrete appearance quality problems;

[0108] In one embodiment, the circulation device 3 includes a circulation water tank 32, a driving mechanism 34 and a water distribution mechanism. The circulation water tank 32 is provided with a heating device for heating the water in the circulation water tank 32; the mounting frame 11 is also used to be arranged on the circulation water tank 32, the water distribution mechanism is arranged above the mounting frame 11, and the driving mechanism 34 is used to transport the water in the circulation 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 can penetrate the wet membrane 12 from top to bottom;

[0109] Among them, a buckle 13 is provided at the lower part of the mounting frame 11 to cooperate with the circulating water tank 32 for installation, and a hanging ring can also be provided on its side wall 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 keep the circulating water at a suitable temperature; the driving 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 watering holes 351 to evenly spray water onto the wet film 12;

[0110] Furthermore, the circulation device 3 includes a reclaimed water recovery device 8 for recovering the curing water of the secondary lining concrete. The water inlet pipe 31 of the circulation water tank 32 is connected to the tunnel water supply pipe 7 and is connected to the reclaimed water recovery device 8; that is, the high-temperature curing water sprayed by the water supply pipe 7 and / or the spray curing system installed on the secondary lining trolley is used to supply water to the circulation water tank 32, and the temperature difference between the high-humidity hot air and the surface of the secondary lining is utilized to naturally form condensed water on the surface of the secondary lining, so as to perform long-term and stable wetting and curing of the secondary lining. The humidifying device 1 of this embodiment has low energy consumption based on the setting of the circulation device 3. Further utilizing the curing water of the secondary lining concrete and the hydration heat of the secondary lining concrete to improve the air humidification efficiency can further improve the energy efficiency and water use efficiency. Based on this, in the entire curing system, only the energy consumption of the wet film 12 wetting pump and the heating device needs to be additionally increased to achieve efficient and stable anti-cracking curing;

[0111] It can be understood that the circulating water tank 32 is provided with a water outlet pipe 33 for draining water to empty the water tank when necessary.

[0112] In some embodiments, the monitoring and control device 5 also includes a control valve arranged on the branch pipe 21, which is used to control the output air volume of the branch pipe 21; specifically, when humidifying using the wet film 12, the humidification effect will also increase with the increase of wind speed, but too high a wind speed will cause the contact time between the air and the wet film 12 to 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 arranged on the ventilation branch pipe in this embodiment, and the monitoring and control device 5 can intelligently control the opening and closing of the valve to control the wind speed and air volume, thereby controlling the air humidity in the tunnel.

[0113] The construction method of this embodiment uses the above-mentioned anti-cracking maintenance 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 for large-scale maintenance and crack resistance system of the tunnel secondary lining;

[0115] A2. Installation of ventilation device 2: Install ventilation ducts according to the layout of ventilation device 2, connect branch duct 21 to the corresponding position, and place the duct overhead and adjust it to a suitable height so as not to affect traffic and construction; install control valves at the corresponding positions of branch duct 21;

[0116] A3. Install the circulating water tank 32; Place the circulating water tank 32 according to the cross section size of the pedestrian crossing 6, and leave a passage for a single person in the passage to facilitate workers to pass and inspect equipment; Connect all pipes of the circulating device 3, including the water inlet pipe 31 and the water outlet pipe 33;

[0117] A4. Installation of the humidifying device 1; installing a mounting frame 11 having a wet film 12 on the circulating water tank 32;

[0118] A5. Install the drive mechanism 34 and the water pipeline; install the circulating water pump and related pipelines, and install the water distributor 35 directly above the humidifier 1, and ensure that water can be evenly sprayed on the humidifier 1;

[0119] A6. Installation of detection and control device; According to the monitoring requirements of the monitoring and control device 5, a temperature and humidity monitor and controller are installed at the corresponding position;

[0120] A7.Insulation device 4 is installed; an insulation trolley is installed at the tunnel entrance, and insulation curtains and / or insulation air curtains are arranged;

[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 factors such as the complexity and high cost of maintenance work, the operation team directly abandons maintenance and compensates for the strength loss caused by the lack of maintenance by increasing the cement content in the mix ratio. Conventional operation trolleys and platforms have high mobility, and supervision and supervision by all parties are also very difficult. The use of this system and construction method can achieve full wetting coverage within the working range, greatly reducing the difficulty of supervision and supervision by owners, supervisors, and construction units, while reducing the cement content in the mix ratio, further saving project costs.

[0123] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A tunnel anti-crack maintenance system design method for tunnel secondary lining anti-crack maintenance, characterized in that: The following steps are involved: S1. Design preparation, obtaining tunnel parameters and indicators, including tunnel length, construction progress, maintenance time requirements, pedestrian crossing distance, ventilation facility installation, water supply facility installation, temperature and humidity inside and outside the tunnel, and determining the location of one or more sub-maintenance systems; S2. Design the ventilation device of the maintenance system according to the installation of ventilation facilities in the tunnel, including the design of ventilation duct lines; design the circulation device of the maintenance system according to the installation of water supply facilities in the tunnel, including the layout design of water circulation pipelines and the layout design of the grey water recovery device, and draw the layout diagram; S3. Calculate the turnover period and turnover distance; S4. Design a humidifying device, the humidifying device comprising a humidifying material sheet made of a wet film, the humidifying device being supplied with water by a circulation device, and the ventilation device being used to humidify external air through the humidifying device; S5. Calculate the optimal wind speed and circulating water temperature.

2. The method for designing a tunnel anti-crack 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 in the tunnel and for controlling the water supply power and water supply temperature of the circulation device; the design method also includes step S6: Write the control program.

3. The design method of tunnel anti-crack 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 secondary lining maintenance time requirements, and the pedestrian crossing interval distance.

4. The method for designing a tunnel anti-crack maintenance system according to claim 3, characterized in that: Step S3 also includes: The sub-maintenance system is arranged at the i-th pedestrian crossing closest to the second lining mileage pile number and at the position L from the i-th pedestrian crossing to the tunnel entrance; the value of L is determined according to formula (1): L = max{secondary lining maintenance time corresponding to the length of the advance, the distance between pedestrian crossing passages} (1).

5. The design method of tunnel anti-crack maintenance system according to claim 4, characterized in that: Step S3 also includes: With the progress of the secondary lining construction, the sub-maintenance systems are arranged one by one according to the positions of the pedestrian crossings, and a maintenance range of L in front and behind is formed with the pedestrian crossing where the sub-maintenance system is located as the center.

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

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

8. The method for designing a tunnel anti-crack maintenance system according to claim 1, characterized in that: The step S7 is also included: Design the structural dimensions of the thermal insulation device according to the size of the tunnel entrance; match the thermal insulation method and layout method according to the traffic conditions of construction personnel and vehicles.

9. An anti-crack maintenance system, characterized in that: The method for designing a tunnel anti-crack maintenance system according to any one of claims 1 to 8 is applied, and the anti-crack maintenance system comprises: A humidifying device is arranged in the pedestrian crossing at the target location, and is used to humidify the dry air passing through the humidifying device; the humidifying device includes a mounting frame used as a carrier and a wet film arranged on the mounting frame; A ventilation device, comprising a fan arranged outside a tunnel portal, a main pipe connected to the fan, and a branch pipe connected to the main pipe, wherein the main pipe extends into the tunnel, and the branch pipe is used to extend into a pedestrian crossing, and the ventilation device is used to introduce external air into the tunnel and pass the introduced external air through the humidifying device; A circulation device is used to circulate water to the anti-cracking maintenance system, including a circulating water tank, a driving mechanism and a water distribution mechanism. The circulating water tank is provided with a heating device for heating the water in the circulating water tank; the mounting frame is also used to be arranged on the water tank, the water distribution mechanism is arranged above the mounting frame, and the driving 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 penetrate the wet membrane from top to bottom; A monitoring and control device, connected to the circulation device, for monitoring the temperature and humidity in the tunnel and for controlling the water supply power and water supply temperature of the circulation device; Thermal insulation device used to block or slow down the exchange of hot and humid air inside the tunnel with the air outside the tunnel.

10. A construction method, characterized in that: The anti-cracking maintenance system according to claim 9 is applied, and the construction method comprises: A1. Construction preparation; A2. Installation of ventilation device; A3. Install circulating water tank; A4. Humidification device installation; A5. Installation of driving mechanism and water pipeline; A6. Installation of detection and control devices; A7.Insulation device installation; A8.Debugging.

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