Construction environment control system for underground water-sealed storage in severe cold area and control method thereof

Abstract

The application discloses a construction environment control system for underground water-sealed caverns in severe cold regions and a control method thereof, and relates to the technical field of underground engineering construction. The system comprises an in-cavern environment maintaining module and a cavern mouth environment regulating module. The in-cavern environment maintaining module is arranged at the bottom of a ventilation shaft and comprises a warm air supply unit for supplying heat to a working face and an air flow blocking unit for blocking air flow in the shaft. The cavern mouth environment regulating module is sealingly connected to the entrance of a main roadway and comprises a heat preservation shed for forming a buffer air chamber, a jet flow pressurizing device for generating upward jet flow, and a warm air curtain machine for forming a barrier air curtain under the door. After the shaft is blocked, the jet flow pressurizing device and the warm air curtain machine are simultaneously started to establish and maintain a positive pressure environment inside the cavern mouth. Through modular cooperation, the application realizes the unity of stable maintenance of the heat field in the cavern and efficient discharge of pollutants at the cavern mouth, and effectively eliminates water mist and freezing damage.

Description

Technical Field

[0001] This invention belongs to the field of underground engineering construction technology, and in particular relates to an environmental control system and control method for underground water-sealed cavern construction in frigid regions. Background Technology

[0002] During the construction of various large underground water-sealed caverns (such as oil reserves), blasting, rock drilling, and the operation of diesel-powered machinery generate large amounts of pollutants, including blasting fumes (containing toxic gases such as CO), diesel engine exhaust, and rock dust. Therefore, the construction ventilation system must be able to dilute and effectively remove these pollutants from the cavern to ensure the health and safety of workers; this is a fundamental requirement for underground engineering construction. In mild, non-cold climates, basic ventilation and wastewater removal needs can usually be met by utilizing natural wind pressure or mechanical ventilation, organizing airflow through main tunnel entrances and ventilation shafts.

[0003] However, when constructing large-scale underground water-sealed caverns in frigid regions with long, harsh winters and extremely low temperatures, the aforementioned traditional ventilation methods face severe challenges, even failure. These regions have short effective construction windows, and the temperature difference between the inside and outside of the cavern in winter often reaches 30°C to 50°C or even greater. This huge temperature difference, combined with the complex cavern structure, triggers a series of interconnected and mutually reinforcing engineering challenges, creating a sharp contradiction between insulation and ventilation that is difficult to reconcile.

[0004] First, there is a severe water mist and visibility crisis at the tunnel entrance. The hot, humid, and polluted airflow exiting the tunnel mixes violently with the extremely cold, dry air entering from the outside in the main tunnel entrance area, resulting in intense heat and mass exchange. This condenses into a dense water mist that is widespread, highly concentrated, and lasts for a long time. This not only completely obscures the driver's vision of transport vehicles, posing a major traffic safety hazard, but the physical blockage of the water mist also severely interferes with and hinders the smooth discharge of polluted airflow, leading to the accumulation of pollutants in the tunnel entrance area and deteriorating the working environment.

[0005] Secondly, the influx of cold air causes frost damage at the tunnel entrance. A continuous and large influx of cold air from outside causes a sharp drop in temperature at the main tunnel entrance and its extensions, easily leading to icing on the road surface, ice formation on the tunnel walls, and frost heave in the rock mass—all phenomena known as "frost damage," directly threatening traffic safety and the stability of the surrounding rock. In practice, if only simple localized hot air curtains or heating systems are used at the tunnel entrance to prevent frost, while this can temporarily alleviate icing, it significantly weakens the thermal pressure difference (natural ventilation power) required to maintain smoke extraction inside and outside the tunnel. This results in insufficient sewage discharge power, causing pollutants to remain and accumulate in deeper areas of the tunnel—a superficial solution that does not address the root cause.

[0006] Third, the "chimney effect" causes uncontrolled disruption of the overall temperature field within the tunnel. This is a unique and complex challenge in the construction of ultra-long tunnels in frigid regions. Once the ventilation shaft is completed, the elevation difference between the shaft and the main tunnel entrance, combined with the significant temperature difference between the hot air inside the shaft and the cold air outside, creates a powerful, directional thermal pressure difference (i.e., a strong "chimney effect"). This effect uncontrollably intensifies the influx and speed of cold air from the main tunnel entrance, creating a "through draft." This powerful cold airflow rapidly penetrates and destroys the stable temperature field that has been established over a long period in the entire underground tunnel complex, triggering widespread and catastrophic freezing damage. Once the temperature field inside the tunnel is disrupted, it is extremely difficult to restore it in a short time using conventional methods in frigid environments, leading to a complete halt in construction and severely impacting the construction period, project quality, and costs.

[0007] In summary, a fundamental technical conflict exists between maintaining a suitable thermal environment (freezing prevention) and achieving efficient ventilation and wastewater removal (hazard reduction) during the construction of underground water-sealed caverns in frigid regions. Existing technologies lack a comprehensive solution that can systematically and collaboratively resolve this contradiction. Traditional single-method or simple combinations often address one aspect while neglecting another, failing to simultaneously eradicate fogging and freezing damage at the cavern entrance and ensure efficient pollutant removal. Therefore, developing a construction environment control system capable of intelligently sensing the environment, collaboratively controlling airflow and temperature, and comprehensively solving the aforementioned complex problems has become a critical technical challenge urgently needing to be addressed to ensure the safe, efficient, and continuous winter construction of large-scale underground water-sealed cavern projects in frigid regions. This invention is proposed precisely to overcome this technological gap. Summary of the Invention

[0008] To address the aforementioned deficiencies in existing technologies, the present invention aims to provide a construction environment control system and control method for underground water-sealed caverns in frigid regions. This system aims to solve the technical problems encountered during winter construction of underground water-sealed caverns in frigid regions, such as severe water mist at the cave entrance caused by the huge temperature difference between the inside and outside of the cave, frost damage caused by the influx of cold air, and the inefficiency of pollutant removal due to the contradiction between traditional ventilation methods and insulation requirements. This system aims to maintain a stable temperature field inside the cave while ensuring construction safety and the quality of the working environment.

[0009] The present invention solves the above-mentioned technical problems through the following technical solution: a construction environment control system for underground water-sealed caverns in frigid regions, comprising an internal environment maintenance module and an external environment control module;

[0010] The tunnel environment maintenance module is installed at the bottom of the ventilation shaft or inside the tunnel, which is connected to the main construction roadway, and includes:

[0011] The heating air supply unit is used to supply heated air to the working face of the underground water-sealed cavern.

[0012] An airflow isolation unit is installed on the bottom channel of the ventilation shaft to block the natural flow of air between the inside and outside of the ventilation shaft.

[0013] The portal environment control module is sealed and connected to the entrance of the main construction tunnel, and includes:

[0014] The retaining structure forms a closed buffer air chamber outside the entrance of the main construction roadway, and the retaining structure has an entrance and exit for construction vehicles to pass through.

[0015] A jet pressurization device, which is disposed in the buffer gas chamber, is used to generate an upward jet;

[0016] A warm air curtain machine is installed on both sides of the inlet and outlet to deliver warm airflow into the interior space or opening plane of the inlet and outlet, so as to form a barrier air curtain at the bottom of the inlet and outlet.

[0017] The control system is configured to: when the airflow isolation unit blocks the ventilation shaft, to make the jet pressurization device and the warm air curtain machine operate synchronously to establish and maintain a local environment at the inlet and outlet where the internal air pressure is higher than the external ambient air pressure.

[0018] This invention utilizes a jet pressurization device to generate an upward (vertically or obliquely upward) dominant jet within a buffer chamber. This jet, operating in conjunction with a warm air curtain, establishes and maintains a localized positive pressure environment at the inlet and outlet, where the internal air pressure is higher than the external pressure. This positive pressure environment forcibly pushes the polluted hot air out from the upper part of the inlet and outlet, significantly shortening the residence time of the hot, polluted air in the tunnel entrance area. It also greatly suppresses the large-scale water mist generated by the violent mixing of hot and cold air, thereby fundamentally improving visibility at the tunnel entrance and ensuring the safety of transport vehicles.

[0019] This invention completely eliminates the path of cold air intrusion caused by elevation and temperature differences by blocking the ventilation shaft passage through an airflow isolation unit. A warm air curtain is formed at the bottom of the inlet and outlet using a warm air curtain machine, combined with a buffer chamber formed by the retaining structure, physically restricting the intrusion of cold air from the outside. Simultaneously, a warm air supply unit continuously supplies heated air to the working face, effectively compensating for heat loss within the tunnel. The synergistic effect of these three elements ensures a stable temperature field at the main tunnel entrance and inside the tunnel, fundamentally preventing frost damage such as road surface icing and tunnel wall frost heave, thus guaranteeing the safety of the construction environment and structure.

[0020] The tunnel environment maintenance module of this invention focuses on "preservation" (continuous heating) and "prevention" (isolating the cold source in the vertical shaft), creating an undisturbed and stable thermal foundation for the tunnel entrance environment control module. The tunnel entrance environment control module focuses on "drainage" (upward jet pressurized sewage discharge) and "blockage" (lower warm air curtain obstruction), ensuring efficient discharge of pollutants while minimizing disturbance to the tunnel's thermal environment. The "positive pressure environment" ultimately established and maintained at the tunnel entrance is a direct manifestation and controllable result of the synergistic effect of the two modules. This environment provides a stable sewage discharge pressure differential and actively resists the intrusion of external cold air by virtue of its pressure direction, thus systematically and integratedly achieving stable maintenance of the tunnel's thermal environment and efficient discharge of construction pollutants, overcoming the long-standing technical contradiction of balancing "heat preservation" and "sewage discharge" in the construction of underground water-sealed tunnels in frigid regions.

[0021] Furthermore, the warm air supply unit includes an axial flow fan and an air heating device. The axial flow fan is used to send the outside air flowing in through the ventilation shaft into the air heating device, and the air heated by the air heating device is transported to the construction face through the air supply duct.

[0022] This invention integrates the heating air supply unit at the bottom of the ventilation shaft, directly utilizing the shaft channel as a centralized introduction and pre-treatment path for cold air. This achieves efficient capture of external cold air and on-site heat energy conversion, completely avoiding the significant heat loss and pipe blockage risks that are difficult to overcome when laying long-distance air intake pipes outside the frigid cave. The heated air is then directionally transported to the working face via internal air supply pipes, forming a stable hot air supply trunk line that is the shortest, least resistant, and fully controlled from the bottom of the shaft to the working face. This not only significantly improves the overall heating efficiency and temperature field uniformity of the entire cavern but also makes full use of the existing shaft structure, minimizing the engineering investment and system complexity of additional insulated air ducts.

[0023] Furthermore, the axial flow fan is a variable frequency fan, and its air volume is adjusted according to the minimum air volume required for the construction of the underground water-sealed cavern. The minimum air volume required is calculated based on the construction ventilation specifications and the cavern construction method, taking into account at least one of the following factors: the maximum number of personnel working simultaneously in the corresponding main cavern, the minimum allowable wind speed, the blasting smoke exhaust requirements, and the internal combustion engine exhaust gas dilution requirements. The maximum value of each calculation result is taken as the minimum air volume required.

[0024] This invention achieves precise matching and on-demand supply of ventilation and heating in tunnels by using a variable frequency axial flow fan and dynamically adjusting its air volume to strictly follow the minimum required air volume calculated according to the construction ventilation specifications. The system can consider key operating variables such as personnel density, safe wind speed, blasting dust, and mechanical exhaust in real time based on specific construction methods such as drill-and-blast or TBM methods. By taking the maximum value of each component, the final air volume is determined, ensuring that the ventilation capacity meets and slightly exceeds the lower limit requirements of actual safety and environmental control at any construction stage. This effectively avoids the safety and health hazards caused by insufficient ventilation, as well as the huge waste of heat energy and unstable temperature field in the tunnel caused by excessive ventilation, achieving the optimal balance between safety, energy saving, and thermal environment stability.

[0025] Furthermore, the enclosure structure is an insulated shed;

[0026] The length L of the heat-insulating shed t Satisfy: L t >5D0, where D0 is the hydraulic diameter of the main construction tunnel entrance;

[0027] The width W of the heat-insulating shed t With height H t Satisfy: W0 < W t ≤2W0, and H t ≤1.5H0,

[0028] Where W0 is the width of the main construction tunnel entrance and H0 is the height of the main construction tunnel entrance.

[0029] This invention establishes a precise quantitative correlation between the geometric dimensions of the insulation shed and the parameters of the main tunnel entrance, constructing a buffer air chamber with optimized dimensions outside the tunnel entrance. This design ensures that the intense heat and cold exchange process that would normally occur at the exposed tunnel entrance is completely contained and shifted inside the insulation shed, effectively isolating the direct impact of extreme external climate on the temperature field of the main tunnel. Furthermore, by controlling the width and height of the insulation shed, the internal airflow space and speed are limited. While ensuring the passage of construction vehicles, this minimizes ineffective air volume and heat loss, providing a stable and efficient working space for active airflow organization measures such as jet pressurization and air curtain blocking. Thus, with minimal structural scale and energy consumption, the controllable transformation of the thermal environment and sewage discharge path in the tunnel entrance area is achieved.

[0030] Furthermore, the jet pressurization device includes a jet fan, a guide vane assembly, and a perforated grid; the jet fan is located in the middle of the buffer air chamber and below the ground of the buffer air chamber, the guide vane assembly is located at the outlet of the jet fan and is used to guide the airflow in a vertically upward or inclined upward direction, and the perforated grid covers the top of the guide vane assembly.

[0031] This invention integrates a jet fan, guide vane assembly, and perforated grille into a single semi-buried jet pressurization device, centrally positioned within a buffer chamber. This creates a bottom-up, concentrated, and directional forced airflow drive core. The jet fan, placed underground, effectively utilizes underground space and reduces the impact on surface traffic. The generated initial airflow is precisely guided by the guide vane assembly to form a concentrated jet that is vertically or obliquely upward. Through the flow equalization and protection provided by the perforated grille above, it is transformed into a uniform, stable, and directionally controllable upward force acting on the entire cross-section of the buffer chamber. This design not only significantly enhances the tendency of hot, polluted air to gather and be discharged towards the top of the insulation shed, but also maximizes the range of airflow disturbance and efficiency due to its central location within the chamber. Thus, with minimal equipment power input, it achieves reliable dominance and efficient organization of the sewage flow field in the entire opening area.

[0032] Furthermore, the angle θ between the direction of the guide vanes of the guide vane assembly and the horizontal plane... b satisfy:

[0033] ;

[0034] Among them, H ie L represents the height of the inlet and outlet, d represents the burial depth of the jet fan below ground level, and L represents the height of the inlet and outlet. b This refers to the vertical distance between the guide vane assembly and the inlet / outlet.

[0035] The aforementioned formula provides a precise geometric design basis for the installation angle of the guide vanes in the guide vane assembly. Its core purpose is to optimize the initial jet direction of the airflow generated by the jet fan. By setting the installation angle, the high-speed jet can act on the upper space of the buffer chamber with the most ideal trajectory, thereby efficiently stimulating and maintaining the overall upward airflow circulation within the entire buffer chamber. This optimized flow field ensures that the momentum carried by the jet is converted to the maximum extent into a directional driving force that propels the polluted hot air in the upper part of the buffer chamber toward the single outlet (i.e., inlet and outlet), and causes pollutants to be concentrated and discharged mainly from the upper area of ​​the inlet and outlet. Thus, this formula significantly improves the efficiency of jet energy transfer and utilization from the geometric design source, effectively avoiding problems such as premature diffusion, energy dissipation, or unnecessary impact on the sidewalls caused by improper airflow direction, laying a key technical foundation for achieving the efficient and stable composite flow field organization mode of "upper discharge and lower resistance".

[0036] Furthermore, the air supply direction of the air curtain machine is configured to be horizontal towards the center of the inlet and outlet or inclined towards the interior of the buffer air chamber, and its installation height is 1 / 2 to 2 / 3 of the height of the inlet and outlet.

[0037] This invention constructs a dynamic barrier of warm air that extends horizontally in the lower part of the working door by limiting the air supply direction of the warm air curtain machine to be horizontal towards the center of the inlet and outlet or slightly inclined inward, and controlling its installation height to 1 / 2 to 2 / 3 of the height of the inlet and outlet. This configuration allows the ejected warm airflow to form a continuous and close-fitting barrier layer above the minimum clearance required for vehicle passage, effectively blocking the bottom path through which cold air is most likely to enter. At the same time, due to its horizontal or inward flow direction, it avoids direct interference with the upper exhaust jet, achieving a clear separation and coordinated operation of the lower barrier and the upper exhaust in terms of space and airflow organization, forming a stable and reliable temperature and pressure boundary at the opening with the lowest energy consumption.

[0038] Furthermore, the airflow isolation unit is an openable and closable steel structure damper;

[0039] The control system further includes a control unit, which is configured to: acquire the opening and closing status signal of the steel structure damper; and when the steel structure damper is in a closed blocking state, control the jet pressurization device and the warm air curtain machine to start and operate synchronously.

[0040] This invention establishes a logically rigorous system coordination start-up and shutdown and operation guarantee mechanism by setting up an openable and closable steel structure damper as an airflow isolation unit and introducing a control unit that uses the opening and closing status of the damper as a trigger signal. The steel structure damper provides reliable physical isolation, ensuring that the vertical shaft passage can be rigidly blocked when needed. The control unit automatically and forcibly activates the jet pressurization device and the warm air curtain at the opening based on the actual closing status signal of the damper. This eliminates the risk of ineffective operation of the opening equipment when the vertical shaft is not isolated, or the risk of environmental loss of control due to the failure of the opening equipment to start after the vertical shaft is isolated. It ensures that the entire system operates with the correct timing and complete configuration of "isolation first, control later" under any working condition, and realizes the automated coordination of system functions and a significant improvement in operational reliability.

[0041] Based on the same concept, the present invention also provides a method for controlling the construction environment of underground water-sealed caverns in frigid regions, applied to the construction environment control system for underground water-sealed caverns in frigid regions as described above, the control method comprising:

[0042] Control the airflow isolation unit to block the natural flow of air between the inside and outside of the ventilation shaft;

[0043] When the airflow isolation unit is in the blocked state, the jet pressurization device and the warm air curtain machine are controlled to operate synchronously.

[0044] Adjust the operating power of the jet pressurization device to establish and maintain a local environment at the inlet and outlet where the internal air pressure is higher than the external ambient air pressure.

[0045] This invention decomposes the system's operation into a series of logically rigorous control steps: "first, block the cold source in the shaft; then, coordinately activate the environmental control module at the tunnel entrance; and finally, dynamically maintain positive pressure at the tunnel entrance." This solidifies and reproduces the core collaborative workflow of the system. It ensures that at any construction stage, the activation of environmental control begins with the reliable isolation of the most significant source of interference (the through-draft in the shaft), thereby simultaneously activating the upper sewage discharge and lower blocking functions at the tunnel entrance. By continuously adjusting the jet power, it stabilizes and maintains the positive pressure state at the tunnel entrance, which is a key indicator of the overall control results. Thus, with clear and programmable operating logic, it achieves the systematic and sequential attainment of multiple objectives of "prevention, discharge, and stability" in the construction environment, making complex environmental control tasks orderly, reliable, and automatable.

[0046] Further, adjusting the operating power of the jet pressurization device includes:

[0047] Real-time acquisition of ambient temperature;

[0048] The airflow setpoint of the jet pressurization device is determined based on the ambient temperature, and the jet pressurization device is controlled to operate at an operating frequency corresponding to the airflow setpoint; wherein:

[0049] When the ambient temperature is greater than the first temperature threshold, the air supply volume setting value is the preset minimum air supply volume.

[0050] When the ambient temperature is greater than or equal to the second temperature threshold and less than or equal to the first temperature threshold, the formula for calculating the air supply volume setpoint is:

[0051] ;

[0052] in, This indicates the airflow setting value of the jet pressurization device; This indicates the preset minimum air supply volume; This indicates the preset maximum air volume; Indicates the first temperature threshold; Indicates the ambient temperature;

[0053] When the ambient temperature is less than the second temperature threshold, the air supply volume setting value is the preset maximum air supply volume.

[0054] This invention establishes a piecewise linear mapping relationship between the ambient temperature and the set value of the air volume of the jet pressurization device, thereby achieving adaptive and precise intelligent control of the sewage discharge power at the tunnel entrance. The system can continuously and smoothly adjust the jet intensity between the minimum and maximum air volume according to the real-time temperature. It operates in energy-saving mode when the temperature is high, and automatically increases to full load under severe cold conditions to ensure sewage discharge and anti-interference capabilities. This ensures that the system's operating status is always precisely matched with the environmental cooling load and sewage discharge requirements. While ensuring that the environmental control effect at the tunnel entrance is stable and reliable under any climatic conditions, it minimizes unnecessary energy consumption and achieves a dynamic optimal balance between environmental control efficiency and operational economy.

[0055] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0056] This invention utilizes a jet pressurization device in conjunction with a heated air curtain to establish and maintain a positive pressure environment at the inlet and outlet, forcing polluted hot air to be concentrated and rapidly discharged from above. This significantly reduces the residence time of pollutants at the opening and effectively suppresses the dense water mist generated by the intense mixing of hot and cold air, thereby ensuring traffic safety and clear visibility during construction and transportation.

[0057] This invention actively blocks the ventilation shaft passage through an airflow isolation unit, eliminating the primary path for cold source intrusion and the "through draft" effect. Simultaneously, a heating air supply unit continuously supplies heat to the tunnel face, and a heating air curtain machine forms an air barrier at the bottom of the inlet and outlet. The combination of these three elements ensures a stable temperature field inside the tunnel, fundamentally preventing frost damage problems such as road surface icing and tunnel wall frost heave.

[0058] This invention innovatively divides the system into two complementary modules: the tunnel environment maintenance module is responsible for "maintaining" (maintaining the thermal environment) and "preventing" (isolating cold sources), creating a stable foundation for the tunnel entrance environment control module; the tunnel entrance environment control module is responsible for "draining" (directional pressurized sewage discharge) and "blocking" (air curtain isolation), minimizing disturbance to the tunnel's thermal environment while efficiently discharging sewage. The controllable positive pressure environment ultimately formed at the entrance and exit is a direct manifestation of the synergistic effect of the two modules, simultaneously achieving the dual goals of maintaining a stable thermal environment and efficiently discharging pollutants—goals that are difficult to achieve simultaneously using traditional methods. Attached Figure Description

[0059] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0060] Figure 1 This is a schematic diagram of the construction environment control system for underground water-sealed caverns in frigid regions, as described in this embodiment of the invention.

[0061] Figure 2 This is a schematic diagram of the underground water-sealed cavern structure in an embodiment of the present invention;

[0062] Figure 3 This is a schematic diagram of the structure of the cave environment maintenance module in an embodiment of the present invention;

[0063] Figure 4 This is a schematic diagram of the insulation shed structure in an embodiment of the present invention;

[0064] Figure 5 This is a schematic diagram of the structure of the heat-insulating shed in an embodiment of the present invention;

[0065] Figure 6 This is a schematic diagram of the hollow grid structure in an embodiment of the present invention;

[0066] Figure 7 This is a schematic diagram of the jet pressurization device in an embodiment of the present invention;

[0067] Figure 8 This is a schematic diagram of the damper design in an embodiment of the present invention;

[0068] Figure 9 This is the temperature change curve of the cavern before the control system of the present invention is adopted in this embodiment of the invention;

[0069] Figure 10 This is the temperature change curve of the cave after the control system of the present invention is adopted in the embodiment of the present invention;

[0070] Figure 11 This is a simulation diagram of the water content at the entrance of the main roadway before the jet pressurization device is used in an embodiment of the present invention;

[0071] Figure 12 This is a simulation diagram of the water content at the entrance of the main tunnel after the jet pressurization device is used in an embodiment of the present invention.

[0072] Explanation of reference numerals in the attached drawings: 1-Ventilation shaft, 2-Main construction tunnel, 3-Axial flow fan, 4-Air heating device, 5-Steel structure air door, 6-Construction branch tunnel, 7-Main chamber, 8-Air supply duct, 9-Construction working face, 10-Stale hot air, 11-Heated warm air, 12-Entrance of main construction tunnel, 13-Heat curtain machine, 14-Insulation shed, 15-Perforated grille, 16-Jet fan, 17-Inlet / outlet, 18-Guide vane. Detailed Implementation

[0073] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0074] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0075] In the context of this invention, the term "severely cold region" has a specific engineering climatology definition, referring specifically to underground engineering construction environments that meet the following conditions:

[0076] Temperature benchmark: During the winter construction period at the project site, the average temperature of the coldest month will not exceed -10℃, and the extreme minimum temperature can reach below -20℃. Under these conditions, the temperature difference between the air inside the tunnel (construction work face) and the outside environment will normally exceed 25℃, and can easily reach over 30℃.

[0077] The core problem is characterized by the following: The huge temperature difference directly induces the three major engineering problems that this invention aims to solve: (1) The main tunnel entrance is continuously covered with dense water mist, and the visibility is lower than the requirements for safe driving; (2) The tunnel entrance and nearby tunnel sections are covered with ice and ice on the tunnel walls, which cause freezing damage; (3) The uncontrolled "through wind" (chimney effect) caused by the strong thermal pressure difference between the shaft and the tunnel entrance seriously damages the overall thermal environment stability inside the tunnel.

[0078] The system and method provided by this invention are specifically designed to effectively alleviate the construction environment in frigid regions characterized by the aforementioned climatic parameters and engineering problems.

[0079] Example 1

[0080] This invention provides an environmental control system for underground water-sealed cavern construction in frigid regions, aiming to solve a series of complex technical problems during the construction of large underground water-sealed caverns under frigid conditions, such as severe water mist at the cave entrance caused by the huge temperature difference between the inside and outside of the cavern, freezing damage caused by the influx of cold air, and the contradiction between ventilation and sewage treatment and heat preservation requirements.

[0081] like Figures 1 to 7 As shown, the control system provided by this invention is divided into two major functionally coordinated modules in its overall architecture: the cave environment maintenance module and the cave entrance environment control module.

[0082] The core function of the underground environment maintenance module is to provide a stable basic heat source for the underground cavern and to cut off the main external cold interference channels. The underground environment maintenance module is located at the bottom of the ventilation shaft 1, which is connected to the main construction roadway 2.

[0083] Specifically, the tunnel environment maintenance module includes a warm air supply unit and an airflow isolation unit. The warm air supply unit includes an axial flow fan 3 and an air heating device 4. The axial flow fan 3 is responsible for drawing in external cold air flowing in through the ventilation shaft 1. The drawn-in cold air is then sent to the air heating device 4 and heated to a suitable temperature (e.g., 5°C, meeting the requirements of winter concrete construction specifications). The heated warm air 11 is then directly and efficiently delivered to each construction face 9 through air supply ducts 8 laid in the construction branch tunnel 6, establishing and maintaining a stable thermal environment for the entire main tunnel 7. This invention directly utilizes the shaft structure as the air intake channel, avoiding the significant heat loss and freezing risks associated with laying long-distance cold air ducts outside the tunnel.

[0084] In this embodiment, the air heating device 4 uses a far-infrared heating device. The axial flow fan 3 is a variable frequency fan, and its air volume is not fixed, but dynamically adjusted according to the minimum air volume required for construction inside the tunnel. The determination of this minimum air volume strictly follows the construction ventilation specifications (such as the "Technical Specification for Ventilation in Hydraulic Tunnels"). Based on specific construction methods such as drill-and-blast, the required fresh air volume for the maximum number of personnel working simultaneously inside the tunnel, the air volume required to meet the minimum allowable wind speed, the air volume required to dilute the blasting fumes after blasting, and the air volume required to dilute the exhaust gas from internal combustion machinery are calculated separately, and the maximum value among the calculated results is taken as the minimum air volume required. This on-demand supply adjustment method minimizes energy waste while ensuring a safe and healthy working environment.

[0085] The airflow isolation unit uses a steel structure damper 5, which is firmly installed on the horizontal corridor at the bottom of the ventilation shaft 1. The steel structure damper 5 is normally closed after the ventilation shaft 1 is completed. Its core function is to rigidly block the destructive "through draft" (chimney effect) caused by the elevation and temperature differences between the ventilation shaft 1 and the entrance (i.e., the main construction tunnel entrance 12). Through physical isolation, the main path for large-scale, disorderly influx of cold air from the outside into the tunnel through the ventilation shaft is eliminated, creating a stable internal pressure basis for environmental control at the tunnel entrance. The steel structure damper 5 has pre-drilled duct holes to ensure that the air supply duct 8 can pass through it to achieve the air supply function. The damper uses a steel structure to resist the pressure caused by the elevation difference between the main construction tunnel 2 and the ventilation shaft 1, preventing the damper from deforming.

[0086] The core function of the tunnel entrance environmental control module is to create a controllable local environment at the entrance 12 of the main construction tunnel, enabling efficient and directional discharge of pollutants and effective isolation from external cold air. It is sealed to the outside of the main construction tunnel entrance 12 through an enclosure structure (such as an insulation shed 14), forming a closed buffer chamber.

[0087] Specifically, the tunnel entrance environment control module includes a retaining structure, a jet pressurization device, and a warm air curtain machine 13. The retaining structure forms a closed buffer air chamber outside the main tunnel entrance 12. The retaining structure has an entrance / exit 17 for construction vehicles to pass through. The jet pressurization device is installed in the buffer air chamber to generate an upward jet. The warm air curtain machine 13 is installed on both sides of the entrance / exit 17 to send warm air flow into the internal space or opening plane of the entrance / exit 17 to form a barrier air curtain at the bottom of the entrance / exit 17.

[0088] In a specific embodiment of the present invention, the enclosure structure is an insulated shed 14. The dimensions of the insulated shed 14 are optimized to form a quantitative proportional relationship with the dimensions of the main construction tunnel entrance 12, so as to ensure the best environmental control effect and engineering economy. Specifically, the length L of the insulated shed 14 is... t The hydraulic diameter D0 (L) of the main tunnel entrance 12 is greater than 5 times. t >5D0), so that the intense heat exchange process can be completely contained within the insulation shed 14 without affecting the temperature field of the main construction roadway 2; its width W t Width greater than 12 W0 at the entrance of the main construction tunnel, but not exceeding twice the width (W0 < W0). t ≤2W0), to reduce the airflow speed of cold air inside the insulation shed 14; its height H t The height H0 at the entrance of the main construction roadway shall not exceed 1.5 times (H0 < H0). t The dimensions are ≤1.5H0), which reduces the power of the jet pressurization device. This size design effectively limits the airflow space inside the canopy while ensuring vehicle passage space, thus reducing heat loss.

[0089] The jet pressurization device is the core component for organizing airflow within the insulation shed 14 and achieving active sewage discharge. It is specifically composed of a jet fan 16, a guide vane assembly, and a perforated grille 15. The jet fan 16 is positioned below ground level in the middle of the insulation shed 14 (i.e., the buffer air chamber) to save ground space; the guide vane assembly is located at the outlet of the jet fan 16, and the perforated grille 15 covers the top of the guide vane assembly.

[0090] The airflow generated by the jet fan 16 is precisely guided by the guide vane assembly, forming a concentrated jet that is vertically or obliquely upward. This jet, then uniformly distributed and protected by the perforated grille 15, is transformed into a uniform, stable, and directionally controllable upward force acting on the entire cross-section of the buffer chamber. The installation angle θ of the guide vane 18 in the guide vane assembly...b (That is, the direction of the guide vanes relative to the horizontal plane) After precise calculation, the following relationship is satisfied:

[0091] (1)

[0092] Among them, H ie The height of inlet / outlet 17 (i.e., the working door of the insulation shed 14) is d, where d is the burial depth of the jet fan 16 below ground level, and L is the height of the inlet / outlet 17 (i.e., the working door of the insulation shed 14). b This refers to the vertical distance of the guide vane assembly from the inlet / outlet, which is 17.

[0093] Formula (1) is used to optimize the installation angle of the guide vane 18, with the aim of enabling the concentrated airflow generated by the jet fan 16 to act most effectively on the upper space of the buffer chamber, thereby establishing and maintaining a dominant upward overall airflow circulation within the buffer chamber. This airflow circulation will ensure that the polluted hot air 10 inside the insulation shed 14 is concentrated and efficiently discharged from the upper area of ​​the inlet and outlet 17 under positive pressure, while creating favorable conditions for the blocking effect of the lower air curtain.

[0094] The air curtain unit 13 is symmetrically arranged on both sides of the inlet / outlet 17 (i.e., the working door of the insulation canopy 14). Its air supply direction is configured to be horizontal towards the center of the inlet / outlet 17 or slightly inclined towards the interior of the buffer air chamber. The installation height is approximately 1 / 2 to 2 / 3 of the height of the inlet / outlet 17. After the air curtain unit 13 is started, it can form a continuous, warm horizontal air curtain in the lower half of the inlet / outlet 17, physically blocking the inflow of cold air from the lower part of the inlet / outlet 17. It is the second active line of defense for protecting the thermal environment of the inlet / outlet 17.

[0095] The dimensions of the inlet / outlet 17 are smaller than those of the main construction tunnel entrance 12. The design is based on the maximum dimensions of the muck-carrying vehicles during construction to reduce the influx of cold air.

[0096] In a specific embodiment of the present invention, the control system further includes a control unit (not shown in the figure), which is configured to acquire the opening and closing status signal of the steel structure damper 5, and only activate the jet pressurization device and the warm air curtain 13 when it is confirmed that the steel structure damper 5 is in a reliably closed blocking state. This control logic ensures that the system operates in the correct mode of "first cutting off the cold source of the shaft, then starting the opening control" in terms of timing, thus ensuring the overall synergistic effect.

[0097] In actual construction, the system works collaboratively according to the following process:

[0098] First, the steel structure damper 5 at the bottom of the ventilation shaft is closed to cut off the "through draft" path. Then, the control unit detects the damper closure signal and automatically activates the jet pressurization device and the warm air curtain machine 13 inside the insulation shed 14. Based on the real-time ambient temperature, the control unit adjusts the operating power of the jet pressurization device (i.e., the jet fan 16) according to a preset algorithm, generating an upward directional jet to establish positive pressure inside the insulation shed 14. This forces the hot, polluted air discharged from the tunnel to be quickly discharged from the top of the working door of the insulation shed 14, effectively eliminating water mist. Simultaneously, the warm air curtain machine 13 operates, forming a warm air barrier below the doorway to prevent cold air from entering. At the same time, the warm air supply unit inside the tunnel continues to operate, delivering warm air to the working face to compensate for heat loss.

[0099] By coordinating the timing and functionality of the cave environment maintenance module and the cave entrance environment control module, this invention successfully transforms the heat exchange and pollutant emission process in the cave entrance area from an uncontrollable natural state into a controllable and efficient process under positive pressure, in which pollutants are "directly discharged upwards," cold air is "actively blocked," and the cave's thermal environment is "stablely maintained."

[0100] To verify the effectiveness of this invention, the system was applied to a large-scale underground water-sealed cavern project in a frigid region (winter minimum temperature -38.5℃). The main construction tunnel was a 9m × 8.5m archway, with the insulation shed measuring 75m long, 18m wide, and 10m high. The working door measured 4m × 6m. The cavern's heating system used three high-power (2 × 160kW) variable frequency fans (each corresponding to one main cavern chamber), along with a far-infrared heating device (45kW heating power). Two 45kW jet fans (buried 0.8m deep) were installed at the cavern entrance as jet pressurization devices, with the guide vane assembly installed at an 8° angle. A total of 120kW warm air curtain units were installed on both sides of the working door at a height of 5.5m.

[0101] To ensure the steel structure damper can withstand the wind pressure generated by the thermal pressure ("chimney effect") caused by the huge elevation and temperature differences after the vertical shaft is completed, and to maintain structural stability and prevent deformation, a special stress design and verification of the damper is required. In this embodiment, the wind pressure borne by the damper can be estimated based on fluid mechanics formulas. It is estimated that under the most unfavorable working conditions in this project, the maximum total pressure acting on the damper is approximately 375 kN. To resist this load, the damper uses a steel plate as the main load-bearing panel, transferring the load to the reinforcing frame behind it (using I18 steel). Ultimately, the load is borne by six HRB400 grade steel bars with a diameter of 25 mm as the main load-bearing components. Figure 8 As shown. Structural calculations show that this damper structure system can provide a maximum compressive strength of approximately 706.5 kN, meeting the design requirement of 706.5 kN > 375 kN, thus ensuring the damper's sealing reliability and long-term service safety under extreme pressure differentials.

[0102] Figure 9 and Figure 10 The temperature change curves of the tunnel before and after implementing the control system of this invention are shown respectively. The length of the monitoring section from the tunnel entrance refers to the distance from the monitoring section inside the tunnel to the entrance of the main construction roadway. Figure 9 and Figure 10 It can be seen that before the control system of the present invention was adopted, the lowest temperature at the entrance of the main tunnel reached -11℃, and a 500m long frozen section appeared; after the control system of the present invention was adopted, the average temperature at the entrance of the main tunnel rose to 10.83℃, and the temperature inside the tunnel stabilized at around 12℃, completely eliminating frost damage.

[0103] Figure 11 and Figure 12 Simulation diagrams of the water content at the main roadway entrance before and after the application of the jet pressurization device are shown. Figure 11 and Figure 12 It is known that without the jet pressurization device of this invention, the absolute moisture content of the air inside the insulation shed was as high as 6.21 g / kg, resulting in severe dense water mist and extremely low visibility. After 480 seconds of active ventilation using the jet pressurization device, monitoring data showed that the water mist in the front area of ​​the insulation shed near the entrance of the main construction tunnel had been largely eliminated, and visibility had significantly recovered. At this time, the residual water mist, which had settled and accumulated at the bottom of the insulation shed due to its higher density, was gradually lifted and eventually discharged to the outside of the tunnel entrance under the continuous entrainment and driving action of the high-speed upward airflow generated by the jet fan. After ventilating for another 600 seconds, the absolute moisture content of the air in the entire insulation shed section had steadily decreased to below 0.77 g / kg, indicating that the water mist had been completely removed. This experimental data fully demonstrates that adding a jet pressurization device can efficiently organize the airflow at the tunnel entrance, quickly eliminate water mist, fundamentally ensure the visibility and transportation safety of operations in the tunnel entrance area, and solve the major safety hazards caused by poor visibility.

[0104] Example 2

[0105] Based on the same inventive concept as the system in Embodiment 1, this invention also provides a method for controlling the construction environment of underground water-sealed caverns in frigid regions. This method is applied to the construction environment control system for underground water-sealed caverns in frigid regions in Embodiment 1, achieving intelligent regulation of the construction environment through a logically rigorous and sequentially executed automated control process. The control method includes the following core steps:

[0106] S1: Shaft passage blockage. First, control the airflow isolation unit (i.e., the steel structure damper) to close it, thereby rigidly blocking the natural airflow between the inside and outside of the ventilation shaft. This step is a prerequisite for the effectiveness of all subsequent shaft control measures, aiming to eliminate the interference of through drafts caused by the "chimney effect" and stabilize the basic environment inside the shaft.

[0107] S2: Coordinated Start-up of Exit Equipment. After confirming that the airflow isolation unit is in a reliable blocking state, the control unit immediately issues a command to control the jet pressurization device (i.e., jet fan) and the warm air curtain machine to start and run synchronously. This timing control logic forcibly ensures the integrity of the system's operation, avoiding energy waste and environmental control failure caused by starting the exit equipment when the shaft is not isolated.

[0108] S3: Dynamically maintain a positive pressure environment at the tunnel entrance. During the operation of the jet pressurization device, its operating power is continuously adjusted. The core objective is to establish and maintain a local positive pressure environment at the inlet and outlet where the working door of the insulated shed is located, where the internal air pressure is stably higher than the external ambient air pressure. This positive pressure environment is a direct result and key characteristic of the system's coordinated operation, providing both the power to drive pollutant discharge and actively resisting the influx of cold air.

[0109] In a specific embodiment of the present invention, the process of adjusting the operating power of the jet pressurization device in step S3 adopts an adaptive intelligent strategy based on ambient temperature, including:

[0110] S31: Real-time acquisition of ambient temperature.

[0111] S32: Dynamically determine the airflow setpoint of the jet pressurization device based on the ambient temperature. The calculation logic is as follows:

[0112] When the ambient temperature is greater than the first temperature threshold (e.g., 5°C), it indicates that the ambient cooling load is small, and the system operates in energy-saving mode with the air supply volume set to the preset minimum air supply volume.

[0113] When the ambient temperature is greater than or equal to the second temperature threshold (e.g., 0°C) and less than or equal to the first temperature threshold, the ambient cooling load increases significantly, requiring the system to linearly enhance its sewage discharge and anti-interference capabilities. In this case, the air supply volume setpoint is dynamically calculated using the formula:

[0114] (2)

[0115] in, This indicates the airflow setting value of the jet pressurization device; This indicates the preset minimum air supply volume; This indicates the preset maximum air volume; Indicates the first temperature threshold; This represents the ambient temperature. Formula (2) achieves the desired airflow setpoint. and The smooth adjustment between them increases linearly as the temperature decreases.

[0116] When the ambient temperature is lower than the second temperature threshold, the system enters the severe cold operation mode, and the air supply volume is set to the preset maximum air supply volume, so that the jet pressurization device operates at its rated maximum capacity, ensuring the absolute reliability of the sewage discharge power and positive pressure maintenance at the hole under extreme conditions.

[0117] S33: Power Execution. Controls the jet pressurization device to operate at a frequency corresponding to the calculated airflow setpoint, thereby precisely adjusting its output power.

[0118] Through the above method, this invention transforms complex engineering environmental control tasks into a clear, programmable, and adaptive automated process. From isolating the cold source to coordinated startup and dynamic maintenance, this method systematically resolves the conflict between insulation and wastewater disposal, ensuring a safe, stable, and efficient construction environment under any frigid conditions.

[0119] The above description only discloses specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or modifications that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A construction environment control system for underground water-sealed caverns in frigid regions, characterized in that, The control system includes an in-cavity environment maintenance module and an in-cavity entrance environment control module. The tunnel environment maintenance module is installed at the bottom of the ventilation shaft or inside the tunnel, which is connected to the main construction roadway, and includes: The heating air supply unit is used to supply heated air to the working face of the underground water-sealed cavern. An airflow isolation unit is installed on the bottom channel of the ventilation shaft to block the natural flow of air between the inside and outside of the ventilation shaft. The portal environment control module is sealed and connected to the entrance of the main construction tunnel, and includes: The retaining structure forms a closed buffer air chamber outside the entrance of the main construction roadway, and the retaining structure has an entrance and exit for construction vehicles to pass through. A jet pressurization device is disposed in the buffer air chamber to generate an upward jet; the jet pressurization device includes a jet fan, a guide vane assembly, and a perforated grid; the jet fan is disposed in the middle of the buffer air chamber and below the ground of the buffer air chamber, the guide vane assembly is disposed at the outlet of the jet fan and is used to guide the airflow in a vertically upward or inclined upward direction, and the perforated grid covers the top of the guide vane assembly; A warm air curtain machine is installed on both sides of the inlet and outlet to deliver warm airflow into the interior space or opening plane of the inlet and outlet to form a barrier air curtain at the bottom of the inlet and outlet; the air delivery direction of the warm air curtain machine is configured to be horizontal towards the center of the inlet and outlet or inclined towards the interior of the buffer air chamber, and its installation height is 1 / 2 to 2 / 3 of the height of the inlet and outlet. The control system is configured to: when the airflow isolation unit blocks the ventilation shaft, to make the jet pressurization device and the warm air curtain machine operate synchronously to establish and maintain a local environment at the inlet and outlet where the internal air pressure is higher than the external ambient air pressure.

2. The construction environment control system for underground water-sealed caverns in frigid regions according to claim 1, characterized in that, The warm air supply unit includes an axial flow fan and an air heating device. The axial flow fan is used to send the outside air flowing in through the ventilation shaft into the air heating device. The air heated by the air heating device is then transported to the working face through the air supply duct.

3. The construction environment control system for underground water-sealed caverns in frigid regions according to claim 2, characterized in that, The axial flow fan is a variable frequency fan, and its air volume is adjusted according to the minimum air volume required for the construction of the underground water-sealed cavern. The minimum air volume required is calculated based on the construction ventilation specifications and the cavern construction method, taking into account at least one of the following factors: the maximum number of personnel working simultaneously in the corresponding main cavern, the minimum allowable wind speed, the blasting smoke exhaust requirements, and the internal combustion engine exhaust gas dilution requirements. The maximum value of each calculation result is taken as the minimum air volume required.

4. The construction environment control system for underground water-sealed caverns in frigid regions according to claim 1, characterized in that, The enclosure structure is an insulated shed; The length L of the heat-insulating shed t Satisfy: L t >5D0, where D0 is the hydraulic diameter of the main construction tunnel entrance; The width W of the heat-insulating shed t With height H t Satisfy: W0 < W t ≤2W0, and H t ≤1.5H0, Where W0 is the width of the main construction tunnel entrance and H0 is the height of the main construction tunnel entrance.

5. The construction environment control system for underground water-sealed caverns in frigid regions according to claim 1, characterized in that, The angle θ between the direction of the guide vanes of the guide vane assembly and the horizontal plane b satisfy: tanθ b =(H ie +d) / L b ; Among them, H ie L represents the height of the inlet and outlet, d represents the burial depth of the jet fan below ground level, and L represents the height of the inlet and outlet. b This refers to the vertical distance between the guide vane assembly and the inlet / outlet.

6. The construction environment control system for underground water-sealed caverns in frigid regions according to any one of claims 1 to 5, characterized in that, The airflow isolation unit is an openable and closable steel structure damper; The control system further includes a control unit, which is configured to: acquire the opening and closing status signal of the steel structure damper; and when the steel structure damper is in a closed blocking state, control the jet pressurization device and the warm air curtain machine to start and operate synchronously.

7. A method for controlling the construction environment of underground water-sealed caverns in frigid regions, characterized in that, The control method, applied to the construction environment control system for underground water-sealed caverns in frigid regions as described in any one of claims 1 to 6, comprises: Control the airflow isolation unit to block the natural flow of air between the inside and outside of the ventilation shaft; When the airflow isolation unit is in the blocked state, the jet pressurization device and the warm air curtain machine are controlled to operate synchronously. Adjust the operating power of the jet pressurization device to establish and maintain a local environment at the inlet and outlet where the internal air pressure is higher than the external ambient air pressure.

8. The method for controlling the construction environment of underground water-sealed caverns in frigid regions according to claim 7, characterized in that, Adjusting the operating power of the jet pressurization device includes: Real-time acquisition of ambient temperature; The airflow setpoint of the jet pressurization device is determined based on the ambient temperature, and the jet pressurization device is controlled to operate at an operating frequency corresponding to the airflow setpoint; wherein: When the ambient temperature is greater than the first temperature threshold, the air supply volume setting value is the preset minimum air supply volume. When the ambient temperature is greater than or equal to the second temperature threshold and less than or equal to the first temperature threshold, the formula for calculating the air supply volume setpoint is: ； in, This indicates the airflow setting value of the jet pressurization device; This indicates the preset minimum air supply volume; This indicates the preset maximum air volume; Indicates the first temperature threshold; Indicates the ambient temperature; When the ambient temperature is less than the second temperature threshold, the air supply volume setting value is the preset maximum air supply volume.

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