A frozen soil subgrade cooling system and method using pipe culvert flow water potential energy

Abstract

The application discloses a frozen soil roadbed cooling system and method using pipe culvert water flow potential energy. The system comprises a prefabricated pipe culvert structure, a hydraulic power generation device, an industrial computer, a storage battery, an information acquisition and storage device, a wireless signal transmitter, an electrically-driven cooling device and a sensor unit. The application has the following advantages: it is suitable for all seasons, and has high intelligence. The industrial computer controls the working efficiency of the electrically-driven cooling device according to the roadbed temperature and humidity conditions fed back by the sensor, so that the roadbed temperature and humidity conditions are always controlled within a range ensuring the stability of the roadbed and the safety of the road. The selection of the industrial computer and the storage battery is suitable for low-temperature work in cold regions, the buried sensor is buried in duplicate, other accessories are convenient to replace, and the service life of the frozen soil roadbed cooling system can be prolonged. The copyability of the monitoring data enables scientific research units to continuously update the frozen soil roadbed cooling system and method using pipe culvert water flow potential energy, and the excellent performance can be further exerted.

Description

Technical Field

[0001] This invention belongs to the field of road engineering technology, specifically relating to a cooling system and method for frozen soil subgrade utilizing the potential energy of flowing water in culverts. Background Technology

[0002] my country has a vast territory with diverse terrain, including extensive permafrost regions. To ensure balanced development across these areas, roads need to be built in permafrost regions. Roads leading to tunnel entrances at the foot of glaciers often wind their way up the mountain to meet gradient requirements and ensure the safety of vehicles climbing steep inclines at high altitudes. This inevitably leads to intersections with the downhill routes of glacial meltwater. In winter, glaciers melt slowly, resulting in smaller water flows. However, in summer, the amount of meltwater is greater, and without proper management, it can compromise the safety of the roadbed structure. Road design units typically design culverts based on the maximum summer meltwater flow to allow glacial meltwater to pass through the roadbed. These culverts are usually located at the lowest point of the roadbed section, and during construction, ditches are built to collect meltwater from the upper side of the roadbed and allow it to flow out through the culvert, preventing erosion of the roadbed structure. In summer, the roadbed temperature rises, causing the subgrade soil to melt. Combined with the thinner cross-section of the roadbed where the culvert is located, this can affect the safety of the road structure. Furthermore, power supply for monitoring and maintenance of roads built in high-altitude areas is often limited after commissioning, posing a challenge.

[0003] Therefore, if a cooling system and method for frozen soil subgrade utilizing the potential energy of flowing water in culverts could be provided, it would ensure high structural integrity and stability of the subgrade structure at the location of the culverts, guaranteeing road safety. Simultaneously, the electricity generated by the flowing water potential energy at the culverts could also be used to provide power for road structure monitoring and maintenance. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a system and method for cooling frozen soil subgrade using the potential energy of flowing water in culverts.

[0005] The technical solution of this invention is as follows:

[0006] A frozen soil subgrade cooling system utilizing the potential energy of flowing water in a culvert is characterized in that: the frozen soil subgrade cooling system is installed inside the subgrade structure and includes a precast culvert structure, a hydraulically driven power generation device, an industrial control computer, a battery, an information acquisition and storage device, a wireless signal transmitter, an electrically driven cooling device, and a sensor unit; the industrial control computer, battery, information acquisition and storage device, and wireless signal transmitter constitute an integrated assembly, and the components in the integrated assembly are electrically connected to each other; the integrated assembly is located at the top inside the precast culvert structure; the battery is used to power the various electrical components in the device; a hydraulically driven power generation device is also installed inside the precast culvert structure; the electrically driven cooling device and sensor unit are connected to the outside of the precast culvert structure; the industrial control computer is connected to the sensor unit.

[0007] Furthermore, the hydroelectric power generation device includes a turbine, a pressure pipe, a turntable, a generator, and a belt; the turntable and the generator are connected by a belt drive; the turntable is connected to the turbine via the pressure pipe; and the generator is connected to a battery. Except for the turbine, which is located at the bottom of the precast culvert structure, all other components are placed on top of the precast culvert structure.

[0008] Furthermore, the electrically driven cooling device includes a condenser, a compressor, a controller, a protective housing, an evaporator, copper pipes, refrigerant, and a temperature sensor; the condenser is connected to the compressor; the condenser, compressor, and controller are all housed inside the protective housing; a copper pipe is connected below the compressor, the inside of the copper pipe is filled with refrigerant, and an evaporator and temperature sensor are located outside the copper pipe; the temperature sensor feeds back the evaporator temperature to the controller; the controller controls the condenser, compressor, and evaporator, adjusting the operating power of the condenser, compressor, and evaporator; the evaporator is connected to the temperature sensor.

[0009] The protective shell is covered with solar panels on all four sides to compensate for the power supply pressure on the hydroelectric power generation device when the power demand is high in summer. Power access holes are left in the protective shell to facilitate power access for scientific research and road maintenance personnel. The industrial control computer uses data collected by the sensor unit to control the electric-driven cooling device to regulate the roadbed temperature, and the feedback and regulation response speed is extremely high.

[0010] Furthermore, the sensor unit includes a deformable grating sensor, an acceleration sensor, a temperature and humidity sensor, an earth pressure sensor, and a small ground-based weather station. The number and location of the sensors in the sensor unit can be optimized after sensitivity analysis based on hydrogeological data from the engineering site and numerical simulation results of roadbed structural parameters. Because the sensor unit is buried in the roadbed, it is difficult to replace if damaged; therefore, calibration and performance testing are performed before burial, and spare sensors are also buried. Other components can be easily replaced if damaged. A small weather station is installed on the above-ground portion of the electrically driven cooling device to monitor information such as temperature and wind speed. This weather station is powered by the system's battery and solar energy, and is equipped with a hard shell to withstand harsh environments such as low temperatures, strong winds, rain, and snow. It also provides data support for on-site roadbed monitoring and numerical simulation.

[0011] Furthermore, the wireless transmitter has two modes: intermittent sleep mode and constant wake-up mode. This is because the wireless transmitter chip has an ultra-low power broadband RF receiver. While the main communication RF transceiver is powered off to save power, the receiver can listen for wake-up signals and provide a standby mode. Upon receiving a correct RF wake-up signal, it responds quickly with extremely low power consumption. Wake-up signals generated by fixed-location beacon tags and other devices can display device sleep and wake-up information, facilitating engineers to wake the system at any time for data transmission. In addition, the wireless transmitter and the information receiving terminal receiver have independent identification code systems. After connection, data transmission can be performed directly, and there are signal indicator lights for information transmission. This allows road maintenance personnel to copy data without the need for data-requiring units to constantly travel to copy data; they only need to mail the information receiving terminal.

[0012] Furthermore, the industrial control computer uses an STM32 WL microcontroller. This microcontroller employs a dual-core architecture, supports wake-up frequency band modulation, and features ultra-high sensitivity for RF signal reception and transmission, long-distance signal transmission, and ultra-low power consumption. It also exhibits good performance in extreme environments, making it suitable for the cold-region road engineering mentioned in this invention. Subsequent use of an AI chip for system component allocation is also feasible. The industrial control computer constructs an artificial neural network model, based on historical monitoring data of the roadbed in the information acquisition and storage device, to train the model, identify subtle but critical structural performance changes in the roadbed structure, provide early warnings of structural damage, and generate a roadbed structural condition report containing roadbed structural stability and structural damage warnings. Finally, staff copy the roadbed structural condition report and historical monitoring data compressed package back via a terminal matched with a wireless signal transmitter for in-depth data mining and analysis, providing a basis for research on cold-region road engineering.

[0013] Furthermore, the information acquisition and storage device, under the control of the industrial control computer, has data compression and storage functions, and can also adjust the sampling frequency of sensor information. Staff can calculate the time interval for data copying based on these two functions to ensure that data is not overwritten or lost.

[0014] Furthermore, the hydroelectric power generation device, the electric cooling device, the sensor unit, and the integrated components are connected by a JHS waterproof cable behind the culvert, which has good waterproof performance.

[0015] Furthermore, the prefabricated culvert structure is pre-embedded with mounting holes for the hydraulically driven power generation device and cable passage holes during factory prefabrication, and the holes are sealed after the hydraulically driven power generation device is installed and the cable passes through using an underwater non-dispersible polymer with waterproof sealing properties.

[0016] Furthermore, the battery used is a nickel-metal hydride battery. This is a relatively new type of battery with advantages such as high energy density, long lifespan, and environmental friendliness. It also performs well in low-temperature environments, with an operating temperature range generally between -20℃ and 50℃, maintaining high discharge capacity and operating voltage even in cold conditions. Combined with the solar panels on the ground-based portion of the electrically driven cooling device and the ultra-low power consumption of the industrial control computer, the system can maintain normal power supply even when there is no water flow during winter. Most importantly, the battery has a charging protection function; once fully charged, it stops charging, and the electrical energy converted from the flowing water and solar energy is directly supplied to the various electrical components through the control of the industrial control computer.

[0017] Furthermore, the hydraulically driven power generation device includes a turbine, a pressure pipe, a turntable, a generator, and a belt. Except for the turbine, which is located at the bottom of the prefabricated culvert structure, all other components are placed away from the waterline (at the top of the culvert) to extend their service life. Additionally, the turbine's blade area, deflection angle, number, and installation location require numerical simulation optimization based on the culvert's hydrological information to achieve maximum efficiency.

[0018] Furthermore, the electrically driven cooling device consists of two parts: above ground and underground. It includes a condenser, compressor, controller, protective casing, evaporator, copper pipes, refrigerant, and temperature sensors. The condenser and compressor are connected to the evaporator via copper pipes. The copper pipes have a variable shape, allowing for controlled density distribution within the roadbed according to calculations. Multiple underground evaporators can share a single above-ground condenser and compressor. The copper pipes contain a relay device to ensure sufficient upward energy for the gaseous refrigerant. The protective casing is covered with solar panels on its four sides to compensate for the power supply pressure on the hydroelectric generator during periods of high summer electricity demand. Power access holes are provided in the protective casing for convenient power access by research and road maintenance personnel. The industrial control computer regulates the roadbed temperature using data collected from sensors, exhibiting extremely high feedback and adjustment response speeds.

[0019] Furthermore, a polymer board (PU board) with thermal insulation effect is laid inside the roadbed structure. The PU layer is buried at a depth that takes into account the need to minimize (or even eliminate) the impact of traffic stress on the PU layer and to ensure that its thermal insulation effect meets design requirements. The PU layer is also positioned as close as possible to the top surface of the roadbed to reduce construction costs.

[0020] Based on the characteristics of vehicle loads, the principle of stress diffusion under the road surface, and the allowable bearing capacity of the PU layer, etc. Figure 8 The following formula can be derived to calculate the reasonable embedding depth of the PU layer.

[0021]

[0022] Where: p—tire pressure (MPa);

[0023] d——Equivalent circle diameter of single wheel pressure transmission surface (m);

[0024] r — Weighted average unit weight of all structural layers above the insulation layer (MN / m³) 3 );

[0025] Φ—Weighted average stress diffusion angle (°) above the insulation layer and the structural layer;

[0026] h——Reasonable burial depth of the insulation layer (m);

[0027] б——Allowable compressive stress of the insulation layer (MPa).

[0028] Different thermal insulation materials have different allowable compressive stresses (σ). Different fillers on the thermal insulation layer correspond to different weighted average stress diffusion angles (Φ) and structural layer unit weights (r). By substituting different parameters, the appropriate burial depth can be calculated.

[0029] Furthermore, the thickness of the polymer (PU) board with thermal insulation effect laid within the roadbed structure is the main factor affecting the thermal insulation effect. From the perspective of reducing heat transfer, the thicker the PU layer, the better. However, the thermal insulation effect is not directly proportional to the PU layer thickness. As the PU layer thickness increases, the increase in thermal insulation effect gradually decreases, and an excessively thick PU layer is also economically unreasonable. Through numerical simulation, the temperature difference caused by PU layers of different thicknesses was obtained.

[0030] Furthermore, a polymer board (PU board) with thermal insulation properties is laid within the roadbed structure. Laying a double layer of PU in a frozen soil roadbed improves the thermal insulation effect and further enhances the stability of the roadbed structure under higher summer temperatures. The embedment depth, thickness, number of layers, and distance between the two layers of PU boards are arranged by comprehensively considering the stability of the roadbed structure, the impact of traffic load diffusion, and economic efficiency. Before installation, a sensitivity analysis was conducted through numerical simulation based on the characteristics of the roadbed soil at the site to find the most suitable construction scheme.

[0031] A method for using a frozen soil subgrade cooling system that utilizes the potential energy of flowing water in a culvert includes the following steps:

[0032] S1: Embed prefabricated culvert structures and electric-driven cooling devices, and install hydraulic-driven power generation devices in the roadbed structure; among them, the turbine of the hydraulic-driven power generation device is installed in the prefabricated culvert structure according to the position of the numerical simulation results, and other components are installed above the water level line; the double-layer PU boards embedded in the roadbed are installed and laid according to the depth, thickness and spacing of the simulation results of the on-site hydrological data and pavement structure parameters.

[0033] S2: In summer, the melted glacial snow water gathers on one side of the roadbed and flows downstream through the culvert, driving the water turbine in the hydraulic power generation device to rotate and generate pressure. The pressure is transferred to the turntable through the pressure pipe. The rotation of the turntable's driving wheel drives the driven wheel of the generator to rotate through the belt to generate electricity, which is then stored in the battery.

[0034] S3: The industrial control computer analyzes the road temperature and humidity data, deformation data, soil pressure data, and vibration acceleration data when vehicles pass by, which are measured by the sensor unit, and calculates the temperature and humidity data that the road needs to reduce.

[0035] Taking the roadbed soil as the research object, it can be seen that after the soil is loosened, it will be in an unconstrained (or weakly constrained) state, and its dynamic response to external vibration can be used as follows: Figure 9The computational model shown is analyzed. It is assumed that the surface soil is divided into n layers of spring elements with mass and damping along the depth direction. Each element is connected in parallel with the elements in the adjacent upper and lower layers, and the dynamic force is transmitted and attenuated layer by layer. It is easy to see that when the vibration originates from the surface layer, the top element is most affected by the vibration, and the response decreases with increasing depth. When the vibration source originates from the bottom, depending on the energy level, it will induce associated vibrations in the upper part of the springs in the model.

[0036] Assume that the spring element of the bottom nth layer of soil is subjected to an external force F. n The excitation effect of (t) transmits the force to the j-th layer as F. j (t)(1≤i≤j≤n). Considering the damping effect, F j (t) will gradually decrease as j decreases until it becomes zero, then the vibration equation of the spring element can be established, as shown in equation (2):

[0037]

[0038] Where: m j ,k j and c j These are the mass coefficient, stiffness coefficient, and damping coefficient of the soil spring element j, respectively, where 1 ≤ i ≤ j ≤ n; x j This is the horizontal displacement value of spring element j. Vibration analysis is performed on the j-th layer of spring elements, and the vibration equation is shown in equation (3):

[0039]

[0040] Using Duhamel's integral principle, assume F j (t) Follow F j (t)=a j t+b j The attenuation law leads to the theoretical solution of equation (3) as shown in equation (4):

[0041]

[0042] In the formula: ω j 2 =k j / m j ξ j =c j / 2m j ω j ,

[0043]

[0044] Substituting the known conditions of the spring unit into the theoretical solution (4) of equation (3), and calculating using MATLAB, we can see that: assuming the damping of the spring unit during the melting process is c... jThe change is not significant, when the spring unit stiffness k j As it increases, its dynamic deformation x j As the value decreases, the looseness of the roadbed soil decreases. Therefore, k can be calculated by monitoring the dynamic deformation of the soil at the top edge of the roadbed slope under vehicle dynamic load. j This allows for the evaluation of the looseness of the roadbed soil and the prediction of roadbed stability. For roadbeds in cold regions where freeze-thaw damage occurs, the looseness of the soil decreases during the winter freezing period and increases during the spring thaw, thus affecting k. j Significant periodic changes are occurring.

[0045] During the heating process, the central part of the frozen soil in the roadbed changes from a completely frozen state to a completely thawed state. In the completely frozen state, the k of each layer of spring elements... j Since the frequencies at the center of the frozen soil are the same, the response frequency is consistent with the input frequency at the bottom. When the soil sample is in a partially thawed state, the elastic deformation capacity of the soil gradually recovers, and the spring elements at the lower part of the soil center vibrate in parallel. Assuming the overall stiffness is K at this time, then 1 / K = 1 / k n +1 / k n-1 +…+1 / k i-1 +1 / k i The smaller i is, meaning the farther the calculation location is from the vehicle load location, the smaller K is. Therefore, when the frozen soil begins to thaw, the vibration frequency at the center location increases, reflecting the dynamic amplification effect of the vibration response. When the soil is completely thawed, the dynamic response frequency of the soil reaches its extreme value and remains basically stable. This extreme value reflects the looseness of the soil after the freeze-thaw effect. Indoor test results show that, under the same initial roadbed compaction conditions, the higher the moisture content, the stronger the destructive effect of frost heave on the soil integrity, and the greater the soil looseness, the higher the vibration response frequency of the soil after complete thawing. This makes it more likely to cause a decrease in soil stability at the edge of the roadbed slope, inducing local instability and failure under external load disturbance.

[0046] Therefore, by burying acceleration sensors shallowly at the edge of the roadbed slope to collect the soil vibration response caused by passing vehicles, the soil looseness can be evaluated and stability monitored based on changes in the response frequency. This feedback can then be used to inform the industrial control computer of the required temperature reduction.

[0047] S4: The industrial control computer controls the operation of the electrically driven cooling device; the cooling process of the electrically driven cooling device is as follows: First, the liquid refrigerant enters the evaporator and absorbs the heat from the surrounding frozen soil layer, becoming a low-temperature, low-pressure gaseous refrigerant, thereby producing a cooling effect; the gaseous refrigerant is drawn in by the compressor and compressed into a high-temperature, high-pressure gas, and the condensation temperature rises; then the high-temperature, high-pressure gas enters the condenser, and with the assistance of the cooling fan, the heat is released to the environment, and after liquefaction, it enters the evaporator to re-vaporize and cool;

[0048] S5: Temperature sensors in the frozen soil foundation feed the temperature back to the controller in real time, and dynamically adjust the operating status of the compressor according to the preset temperature value; under the dynamic adjustment of the industrial control computer, the temperature and humidity of the road are always kept in a stable state, the settlement and deformation of the road are reduced, and the resulting damage is also reduced.

[0049] S6: The hydrogeological and dynamic response data of the roadbed structure monitored by the sensor unit will be stored in the signal storage device; the wireless signal transmitter and the information receiving terminal receiver have independent identification code systems, and data transmission will be carried out directly after connection. There are signal indicator lights for information transmission.

[0050] S7: The industrial control computer constructs an artificial neural network model based on historical monitoring data of the roadbed in the information collection and storage device. The model is trained to identify subtle but critical structural performance changes in the roadbed structure, provide early warnings of structural damage, and generate a roadbed structural condition report that includes roadbed stability and structural damage warnings. Finally, staff copy the roadbed structural condition report and the compressed historical monitoring data package back via a terminal matched with a wireless signal transmitter for in-depth data mining and analysis, providing a basis for research on road engineering in cold regions.

[0051] S8: The electrical energy converted from the kinetic energy of the water stored in the battery and the electrical energy converted from solar energy are also output through the ground part of the electric cooling device, providing power to the electrical devices used for scientific research and pavement maintenance in the area.

[0052] Compared with existing technologies, the frozen soil subgrade cooling system utilizing the potential energy of flowing water in culverts provided by this invention has the following advantages:

[0053] 1) Suitable for all seasons. In summer, the roadbed temperature is high, resulting in abundant glacial meltwater and increased power generation. In winter, glacial meltwater is scarce, and the roadbed requires less cooling. Furthermore, the electricity stored during winter can be used in summer. When there is insufficient electricity in winter due to lack of water, solar power can also provide power.

[0054] 2) High level of intelligence: The industrial control computer can control the working efficiency of the electric cooling device based on the temperature and humidity of the roadbed fed back by the sensors, so as to keep the temperature and humidity of the roadbed within a range that ensures the stability of the roadbed and the safety of road traffic.

[0055] 3) Storing electrical energy: In areas where the power supply may be insufficient, hydropower and solar power can be used to supply the power needs of road monitoring and maintenance in the region.

[0056] 4) The selection of industrial control computer and storage battery is suitable for low-temperature operation in cold regions. The buried sensors are buried in duplicate, and other accessories are easy to replace, all of which can extend the service life of the frozen soil roadbed cooling system.

[0057] 5) Monitoring data and reports on the roadbed structure based on the monitoring data enable research units to continuously iterate and update the frozen soil roadbed cooling system and methods that utilize the potential energy of culvert water flow, thereby giving full play to their excellent performance. Attached Figure Description

[0058] Figure 1 This is a front view of the frozen soil subgrade cooling system utilizing the potential energy of flowing water in a culvert, as provided by the present invention.

[0059] Figure 2 This is a front view of the hydroelectric power generation device provided by the present invention.

[0060] Figure 3 This is a front view of the electrically driven cooling device provided by the present invention.

[0061] Figure 4 This is a prefabricated culvert structure according to an embodiment of the present invention.

[0062] Figure 5 This is the structure of the artificial neural network model in an embodiment of the present invention.

[0063] Figure 6 The source code for the artificial neural network model in this embodiment of the invention is shown below.

[0064] Figure 7 The flowchart of the method for cooling frozen soil subgrade using the potential energy of flowing water in culverts provided by the present invention is shown.

[0065] Figure 8 This is a schematic diagram of vehicle load diffusion according to an embodiment of the present invention.

[0066] Figure 9 This is a calculation model for the horizontal vibration of unconstrained roadbed soil. Detailed Implementation

[0067] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, illustrates the frozen soil subgrade cooling system utilizing the potential energy of flowing water in a culvert, provided by the present invention. It should be noted that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, for ease of description, only the parts relevant to the present invention are shown in the figures.

[0068] Example 1

[0069] like Figure 1As shown, the frozen soil subgrade cooling system utilizing the potential energy of flowing water in a culvert provided by this invention includes a prefabricated culvert structure 1, a hydraulically driven power generation device 2, an industrial control computer 3, a storage battery 4, an information acquisition and storage device 5, a wireless signal transmitter 6, an electrically driven cooling device 7, a sensor unit 8, and a subgrade structure 9. The sensor unit 8 includes a deformable grating sensor, an acceleration sensor, a temperature and humidity sensor, an earth pressure sensor, and a small ground weather station. Other types of sensors can also be added according to the needs of the engineering site. The industrial control computer 3, the storage battery 4, the information acquisition and storage device 5, and the wireless signal transmitter 6 constitute an integrated component, which are electrically connected to each other. The storage battery 4 is used to power the various electrical components in this device, and the industrial control computer 3 is connected to the sensor unit 8.

[0070] The hydroelectric power generation device 2 includes a water turbine 21, a pressure pipe 22, a turntable 23, a generator 24, and a belt 25; the turntable 23 and the generator 24 are driven by the belt 25; the turntable 23 is connected to the water turbine 21 through the pressure pipe 22; except for the water turbine 21 of the hydroelectric power generation device 2, which is arranged at the bottom of the precast culvert structure 1, the other devices are placed on the top of the precast culvert structure 1.

[0071] The electrically driven cooling device 7 consists of two parts: an above-ground part and an underground part. The above-ground part includes a condenser 71, a compressor 72, a controller 73, and a protective casing 74. The underground part includes an evaporator 75, a copper pipe 76, a refrigerant 77, and a temperature sensor 78. The electrically driven cooling device 7 comprises a condenser 71, a compressor 72, a controller 73, a protective casing 74, an evaporator 75, a copper pipe 76, a refrigerant 77, and a temperature sensor 78. The condenser 71 is connected to the compressor 72. The condenser 71, compressor 72, and controller 73 are all housed inside the protective casing 74. A copper pipe 76 is connected below the compressor 72. The copper pipe 76 is filled with refrigerant 77, and the evaporator 75 and temperature sensor 78 are located outside the copper pipe 76. The temperature sensor 78 feeds back the temperature of the evaporator 75 to the controller 73. The controller 73 controls the condenser 71, compressor 72, and evaporator 75, and adjusts the operating power of the condenser 71, compressor 72, and evaporator 75. The evaporator 75 is connected to the temperature sensor 78. The protective shell 74 is covered with solar panels on its four sides to compensate for the power supply pressure of the hydroelectric power generation device when the power demand is high in summer. A power outlet is provided at the location of the protective shell to facilitate power access for scientific research and road maintenance personnel. The industrial control computer uses the data collected by the sensor unit 8 to regulate the electric-driven cooling device to adjust the roadbed temperature, and the feedback and adjustment response speed is extremely high.

[0072] In this embodiment, sensor unit 8 includes a deformable grating sensor, an acceleration sensor, a temperature and humidity sensor, an earth pressure sensor, and a ground-based small weather station.

[0073] In this embodiment, the wireless signal transmitter 6 has two modes: intermittent sleep mode and always-on mode, which saves power.

[0074] In this embodiment, the industrial control computer 3 uses a single-chip microcomputer of model STM32 WL.

[0075] In this embodiment, the hydro-driven power generation device 2, the electric-driven cooling device, the sensor unit 8, and the integrated components are connected by a JHS waterproof cable behind the culvert.

[0076] In this embodiment, the prefabricated culvert structure 1 is prefabricated in the factory to reserve installation holes for the hydraulic drive power generation device and cable passage holes, and the holes are sealed after the hydraulic drive power generation device is installed and the cable passes through using an underwater non-dispersible polymer with waterproof sealing properties; the battery 4 is a nickel-metal hydride battery.

[0077] Example 2

[0078] When the frozen soil subgrade cooling system utilizing the potential energy of flowing water in a culvert, as provided in this invention, is required, the method is as follows (the flowchart of the frozen soil subgrade cooling method utilizing the potential energy of flowing water in a culvert is provided). Figure 7 ):

[0079] S1: The road construction unit shall embed precast culvert structure 1 in the roadbed structure 9 according to the design requirements (e.g., Figure 4 The hydraulically driven power generation device 2 is installed in the prefabricated culvert structure 1, along with the electric cooling device 7. The turbine of the hydraulically driven power generation device 2 is installed at an appropriate position according to the numerical simulation results, while other components are installed above the waterline, generally at the top inside the prefabricated culvert structure (1). The PU boards embedded in the roadbed are installed with appropriate depth, thickness, and spacing based on the simulation results of on-site hydrological data and pavement structure parameters.

[0080] Taking the burial depth calculation of PU material as an example, with a standard axle load of BZZ-100, Φ=36°, and r=0.023MN / m, 3The pressure is σ = 0.68 MPa. Considering the potential negative impact of traffic on the PU layer after completion and the safety factor (1.4), the PU layer thickness simulation considers economic cost and temperature insulation. The depth of the lower layer of the double-layer PU board is determined through a scaled-down test with a geometric similarity ratio of 1:10. Finally, based on the experimental and numerical simulation results, a double-layer PU board arrangement is adopted. The reasonable burial depth of the first layer is approximately 0.3–0.5 m, and the suitable thickness is 0.03–0.05 m. The burial depth of the lower PU board in the double-layer PU board arrangement should be approximately 1.60–1.80 m. The PU boards are prefabricated in the factory, with a unit size of 1m*1m. Factory prefabrication ensures the manufacturing quality of the PU boards. The application of PU boards is not limited to culvert locations; they can also be used in other roadbed locations or arranged along the entire length of the road.

[0081] The sensor unit is calibrated and bound before installation, and its performance is then verified using construction loads during the installation process. The integrated component consisting of the industrial control computer 3, battery 4, information acquisition and storage device 5, and wireless signal transmitter 6 undergoes performance testing before installation; installation proceeds only after the testing is successful. The materials and equipment required for the frozen soil subgrade cooling system utilizing the potential energy of culvert water in this embodiment are shown in the table below.

[0082] Table 1. Materials and equipment required for the cooling system of frozen soil subgrade

[0083]

[0084]

[0085]

[0086] S2: In summer, the melted glacial snow water gathers on one side of the roadbed and flows downstream through the culvert, driving the water turbine 21 in the hydraulic power generation device 2 to rotate and generate pressure. The pressure is transferred to the turntable 23 through the pressure pipe 22. The drive wheel of the turntable 23 rotates through the belt 25 to drive the driven wheel of the generator 24 to rotate and generate electricity, which is then stored in the battery 4.

[0087] S3: The industrial control computer 3 calculates the temperature and humidity data that the road needs to be reduced by analyzing the road temperature and humidity data, deformation data, soil pressure data and vibration acceleration data when vehicles pass by, which are measured by the sensor unit 8.

[0088] S4: The industrial control computer 3 controls the operation of the electrically driven cooling device 7. The cooling process of the electrically driven cooling device is as follows: First, the liquid refrigerant 77 enters the evaporator 75 and absorbs the heat from the surrounding frozen soil layer, becoming a low-temperature, low-pressure gaseous refrigerant 77, thereby producing a cooling effect; the gaseous refrigerant 77 is drawn in by the compressor 72 and compressed into a high-temperature, high-pressure gas, and the condensation temperature rises; then the high-temperature, high-pressure gas enters the condenser 71, where, with the assistance of a cooling fan, it releases heat to the environment, liquefies, and then enters the evaporator 75 to re-vaporize and cool.

[0089] S5: The temperature sensor 78 in the frozen soil foundation feeds back the temperature to the controller 73 in real time, and dynamically adjusts the operating status of the compressor 72 according to the preset temperature value. Under the dynamic adjustment of the operating condition machine 3, the temperature and humidity of the road are always maintained in a stable state, the settlement and deformation of the road are reduced, and the resulting damage is also reduced.

[0090] S6: The hydrogeological and dynamic response data of the roadbed structure monitored by sensor unit 8 are also stored in signal storage device 5. Staff will periodically copy the data. Wireless signal transmitter 6 and information receiving terminal receiver have independent identification code systems; once connected, data can be transmitted directly, indicated by a signal indicator light. Operation is simple, allowing road maintenance personnel to copy data without requiring the data provider to constantly travel to copy it; only the information receiving terminal needs to be mailed. Because wireless transmitter 6 consumes a lot of power when constantly operating, it is set to intermittently sleep mode when not in use. Staff can briefly wake it during its sleep intervals to connect and set it to a long-awaited mode. After data transmission is complete, it can be set to sleep again, preventing data from being copied by other personnel due to the external connection structure.

[0091] S7: Industrial PC 3 constructs an artificial neural network model (such as...) Figure 5 and Figure 6 Based on historical monitoring data of the roadbed stored in information collection and storage device 5, a model is trained to identify subtle but critical structural performance changes in the roadbed structure, provide early warnings of structural damage, and generate a roadbed structural condition report that includes roadbed structural stability and structural damage warnings. Finally, staff copy the roadbed structural condition report and the compressed historical monitoring data package back to the system via a terminal matched with wireless signal transmitter 6 for in-depth data mining and analysis, providing a basis for research on road engineering in cold regions.

[0092] S8: The electrical energy converted from the kinetic energy of the flowing water and the electrical energy converted from solar energy stored in the battery 4 are also output through the ground part of the electric cooling device, providing power to electrical devices used for scientific research and road maintenance in the area.

[0093] For those skilled in the art, any changes, modifications, substitutions, and variations made to the embodiments without departing from the principles and spirit of the present invention will still fall within the protection scope of the present invention, in accordance with the teachings of the present invention.

Claims

1. A method for using a frozen soil subgrade cooling system that utilizes the potential energy of flowing water in a culvert, characterized in that: Includes the following steps: Includes the following steps: S1: A prefabricated culvert structure (1) and an electric-driven cooling device (7) are embedded in the roadbed structure (9), and a hydraulic-driven power generation device (2) is installed in the prefabricated culvert structure (1); the turbine of the hydraulic-driven power generation device (2) is installed in the prefabricated culvert structure (1) according to the position of the numerical simulation results, and other components are installed above the water level line, generally located at the top inside the prefabricated culvert structure (1); the double-layer PU board embedded in the roadbed is installed and laid according to the depth, thickness and spacing of the simulation results of the on-site hydrological data and pavement structure parameters; S2: In summer, the melted glacial snow water gathers on one side of the roadbed and flows downstream through the culvert, driving the water turbine (21) in the hydraulic power generation device (2) to rotate and generate pressure. The pressure is transferred to the turntable (23) through the pressure pipe (22). The drive wheel of the turntable (23) rotates through the belt (25) to drive the driven wheel of the generator (24) to rotate and generate electricity, which is then stored in the battery (4). S3: The industrial control computer (3) calculates the temperature and humidity data that the road needs to be reduced by analyzing the road temperature and humidity data, deformation data, soil pressure data and vibration acceleration data when the vehicle passes by the sensor unit (8). Taking the foundation soil as the research object, it can be seen that after the soil is loosened, it will be in an unconstrained or weakly constrained state. Assuming that the surface soil is divided into n layers of spring elements with mass and damping in the depth direction, each element is connected in parallel with the adjacent upper and lower layers, and the dynamic action is transmitted and attenuated layer by layer; it is easy to see that when the vibration comes from the surface layer, the top element is most affected by the vibration, and the response decreases with the increase of depth; when the vibration source comes from the bottom, depending on the energy, it will induce the associated vibration of the springs in the upper part of the model. Assume that the spring element of the bottom nth layer of soil is subjected to an external force F. n The excitation effect of (t) transmits the force to the j-th layer as F. j (t)(1≤i≤j≤n); Considering the damping effect, F j (t) will gradually decrease as j decreases until it becomes zero, then the vibration equation of the spring element can be established, as shown in equation (2): Where: m j ,k j and c j These are the mass coefficient, stiffness coefficient, and damping coefficient of the soil spring element j, respectively, where 1 ≤ i ≤ j ≤ n; x j It is the horizontal displacement value of spring element j; take the j-th layer spring element for vibration analysis, and the vibration equation is shown in equation (3): Using Duhamel's integral principle, assume F j (t) Follow F j (t)=a j t+b j The attenuation law leads to the theoretical solution of equation (3) as shown in equation (4): In the formula: ω j 2 =k j / m j ξ j =c j / 2m j ω j , Substituting the known conditions of the spring unit into the theoretical solution (4) of equation (3), and calculating using MATLAB, we can see that: assuming the damping of the spring unit during the melting process is c... j The change is not significant, when the spring unit stiffness k j As it increases, its dynamic deformation x j As the value decreases, the looseness of the roadbed soil decreases; therefore, k is calculated by monitoring the dynamic deformation of the soil at the top edge of the roadbed slope under vehicle dynamic load. j This allows for the evaluation of the looseness of the roadbed soil and the prediction of roadbed stability. For roadbeds in cold regions where freeze-thaw damage occurs, the looseness of the soil decreases during the winter freezing period and increases during the spring thaw, thus affecting k. j Significant periodic changes are occurring; During the heating process, the central part of the frozen soil in the roadbed changes from a completely frozen state to a completely thawed state; in the completely frozen state, the k of each layer of spring unit... j Therefore, the response frequency at the center of the frozen soil is consistent with the input frequency at the bottom; when the soil sample is in a partially thawed state, the elastic deformation capacity of the soil gradually recovers, and the spring elements at the lower part of the soil center vibrate in parallel; assuming the overall stiffness is K at this time, then... 1 / K=1 / k n +1 / k n-1 +…+1 / k i-1 +1 / k i When i is smaller, that is, when the calculation location is farther away from the vehicle load location, K is smaller; therefore, when the frozen soil begins to thaw, the vibration frequency at the center location increases, reflecting the dynamic amplification effect of the vibration response; when the soil is completely thawed, the dynamic response frequency of the soil reaches an extreme value and remains basically stable. This extreme value reflects the looseness of the soil after the freeze-thaw effect; the results of the indoor test show that under the same initial roadbed compaction, the higher the water content, the stronger the damage to the integrity of the soil caused by frost heave, the greater the looseness of the soil, the greater the vibration response frequency of the soil after complete thawing, and the more likely it is to cause a decrease in the stability of the soil at the edge of the roadbed slope, and induce local instability and failure under external load disturbance; Therefore, by burying acceleration sensors in the shallow layer at the edge of the roadbed slope top to collect the soil vibration response caused by vehicles passing by, the soil looseness can be evaluated and stability monitored based on the changes in response frequency; and then the industrial control computer can be fed back to the temperature that needs to be reduced. S4: The industrial control computer (3) controls the operation of the electric-driven cooling device (7); the cooling process of the electric-driven cooling device is as follows: first, the liquid refrigerant (77) enters the evaporator (75) and absorbs the heat of the surrounding frozen soil layer to become a low-temperature, low-pressure gaseous refrigerant (77), thereby producing a cooling effect; the gaseous refrigerant (77) is drawn in by the compressor (72) and compressed into a high-temperature, high-pressure gas, and the condensation temperature rises; then the high-temperature, high-pressure gas enters the condenser (71), and with the assistance of the cooling fan, it releases heat to the environment, liquefies, and enters the evaporator (75) to re-vaporize and cool; S5: The temperature sensor (78) in the frozen soil foundation near the evaporator (75) feeds back the temperature to the controller (73) in real time, and dynamically adjusts the operating status of the compressor (72) according to the preset temperature value; Under the dynamic adjustment of the industrial control computer (3), the temperature and humidity of the road are always kept in a stable state, the settlement and deformation of the road are reduced, and the resulting damage is also reduced; S6: The hydrogeological and dynamic response data of the roadbed structure monitored by the sensor unit (8) will be stored in the information acquisition and storage device (5); the wireless signal transmitter (6) and the information receiving terminal receiver have independent identification code systems. After being connected, they can directly transmit data. There are signal indicator lights for information transmission. S7: The industrial control computer (3) constructs an artificial neural network model, and based on the historical monitoring data of the roadbed in the information collection and storage device (5), it trains the model to identify subtle but critical structural performance change trends in the roadbed structure, provides early warning of structural damage in the roadbed, and generates a roadbed structure status report containing roadbed structure stability and structural damage warning; finally, the staff copy the roadbed structure status report and historical monitoring data compressed package back through a terminal matched with the wireless signal transmitter (6) for in-depth data mining and analysis, providing a basis for the study of cold region road engineering; S8: The electrical energy converted from the kinetic energy of the flowing water stored in the battery (4) and the electrical energy converted from the solar energy are also output through the ground part of the electric cooling device (7) to provide electrical energy for the electrical devices used for scientific research and daily maintenance. The frozen soil subgrade cooling system is installed inside the subgrade structure (9) and includes a precast culvert structure (1), a hydraulically driven power generation device (2), an industrial control computer (3), a storage battery (4), an information acquisition and storage device (5), a wireless signal transmitter (6), an electric-driven cooling device (7), and a sensor unit (8). The industrial control computer (3), the storage battery (4), the information acquisition and storage device (5), and the wireless signal transmitter (6) constitute an integrated assembly. The components in the integrated assembly are electrically connected to each other. The integrated assembly is located at the top inside the precast culvert structure (1). The storage battery (4) is used to supply power to the electrical components in this equipment. The precast culvert structure (1) is also equipped with a hydraulically driven power generation device (2). The precast culvert structure (1) is externally connected to an electric-driven cooling device (7) and a sensor unit (8). The industrial control computer (3) is connected to the sensor unit (8). The hydroelectric power generation device (2) includes a water turbine (21), a pressure pipe (22), a turntable (23), a generator (24), and a belt (25); the turntable (23) and the generator (24) are driven by the belt (25); the turntable (23) is connected to the water turbine (21) through the pressure pipe (22); the generator (24) is connected to the storage battery (4); Except for the turbine (21) of the hydro-driven power generation device (2) which is located at the bottom of the precast culvert structure (1), all other devices are placed on the top of the precast culvert structure (1). The electrically driven cooling device (7) includes a condenser (71), a compressor (72), a controller (73), a protective shell (74), an evaporator (75), a copper pipe (76), a refrigerant (77), and a temperature sensor (78). The condenser (71) is connected to the compressor (72). The condenser (71), compressor (72), and controller (73) are all located inside the protective shell (74). A copper pipe (76) is connected below the compressor (72). The copper pipe (76) is filled with refrigerant (77). An evaporator (75) and a temperature sensor (78) are located outside the copper pipe (76). The temperature sensor (78) feeds back the temperature of the evaporator (75) to the controller (73). The controller (73) controls the condenser (71), compressor (72), and evaporator (75) and adjusts the working power of the condenser (71), compressor (72), and evaporator (75). The evaporator (75) is connected to the temperature sensor (78). Among them, the protective shell (74) is covered with solar panels on all four sides to make up for the power supply pressure of the hydro-driven power generation device when the power demand is large in summer; power access holes are left in the protective shell to facilitate the power access of pavement inspection personnel; the industrial control computer controls the electric-driven cooling device to regulate the roadbed temperature by using the data collected by the sensor unit (8). The prefabricated culvert structure (1) has reserved installation holes for the hydraulic drive power generation device and cable passage holes during factory prefabrication, and the holes are sealed after the hydraulic drive power generation device (2) is installed and the cable passes through by an underwater non-dispersible polymer with waterproof sealing performance. The hydro-driven power generation device (2), the electric-driven cooling device (7), the sensor unit (8), and the integrated components are connected by a JHS waterproof cable behind the culvert.

2. The method of using the frozen soil subgrade cooling system utilizing the potential energy of flowing water in a culvert as described in claim 1, characterized in that: The sensor unit (8) includes a deformable grating sensor, an acceleration sensor, a temperature and humidity sensor, an earth pressure sensor, and a ground-based small weather station.

3. The method of using the frozen soil subgrade cooling system utilizing the potential energy of flowing water in a culvert as described in claim 1, characterized in that: The wireless signal transmitter (6) has two modes: intermittent sleep mode and always-on mode.

4. The method of using the frozen soil subgrade cooling system utilizing the potential energy of flowing water in a culvert as described in claim 1, characterized in that: The industrial control computer (3) is an STM32 WL microcontroller.

5. The method of using the frozen soil subgrade cooling system utilizing the potential energy of flowing water in a culvert as described in claim 1, characterized in that: The storage battery (4) is a nickel-metal hydride battery.

6. The method of using the frozen soil subgrade cooling system utilizing the potential energy of flowing water in a culvert as described in claim 1, characterized in that: The roadbed structure (9) is lined with a polymer PU layer that provides thermal insulation; the appropriate burial depth of the polymer PU layer is: Where: p—tire pressure (MPa); d——Equivalent circle diameter of single wheel pressure transmission surface (m); r — Weighted average unit weight of all structural layers above the insulation layer (MN / m³) 3 ); Φ—Weighted average stress diffusion angle (°) above the insulation layer and the structural layer; h——Reasonable burial depth of the insulation layer (m); б——Allowable compressive stress of the insulation layer (MPa).

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