Deep engineering surrounding rock temperature passive wireless monitoring device and method

Abstract

The application relates to the technical field of deep underground engineering monitoring, and discloses a deep engineering surrounding rock temperature passive wireless monitoring device and method, which aims to solve the problem that the existing method is difficult to realize maintenance-free and continuous and reliable monitoring. The device comprises a monitoring terminal and an inspection vehicle. The monitoring terminal generates electricity by using the temperature difference between the surrounding rock and the environment through a thermoelectric module, stores energy by using a lithium titanate super capacitor, realizes passive self-power supply, is fixed to a pre-buried clamping groove through a buckle type mounting structure, realizes lossless and rapid installation, and adopts a multilayer protective shell to resist high temperature and high humidity. The inspection vehicle is integrated with wireless charging and data receiving functions, can perform emergency charging for the monitoring terminal in the moving process, and receives the temperature data sent by the monitoring terminal, wherein the temperature data is bound with a unique point position number. The application realizes long-term stable maintenance-free monitoring of the surrounding rock temperature, and is particularly suitable for deep extreme environments.

Description

Technical Field

[0001] This invention relates to the field of monitoring technology for deep underground engineering projects, specifically to a passive wireless monitoring device and method for the temperature of surrounding rock in deep underground engineering projects. Background Technology

[0002] Deeply buried underground engineering projects (such as long transportation tunnels, water diversion tunnels for large hydropower stations, and deep mine roadways) typically refer to underground spaces with a depth exceeding 600 meters. These projects are situated in extremely complex geological environments, generally facing high ground stress, high osmotic pressure, and, most notably, high geothermal hazards. For example, in major projects like the Sichuan-Tibet Railway, the highest recorded original rock temperature in tunnels has reached 93.5℃, with some geothermal anomaly areas exceeding 150℃. Surrounding rock temperature is a key parameter for assessing the long-term stability of underground engineering structures, the durability of lining materials, and operational safety. Therefore, as a crucial indicator for evaluating the stability of underground engineering structures, the durability of lining materials, and operational safety, surrounding rock temperature requires long-term, continuous monitoring during the operation and maintenance period.

[0003] Currently, monitoring the temperature of surrounding rock in deep earth engineering mainly relies on the following three types of technical solutions:

[0004] One method is manual inspection: This method uses handheld contact or non-contact temperature measuring instruments (such as the FLUKE561 infrared thermometer), with technicians periodically entering the tunnel to take readings at preset measuring points or on the surface of the surrounding rock. This method has problems such as high labor costs, long measurement intervals, and poor data continuity.

[0005] The second method is wired sensor monitoring. This method uses high-temperature resistant thermocouples (such as type K thermocouples, with a temperature resistance of -270℃ to 1372℃) or resistance temperature detectors (such as PT100, with a temperature resistance of -200℃ to 850℃) as sensing elements, and connects the signal to a remote data acquisition unit via a metal cable. Although this method can achieve automated continuous monitoring, it requires drilling and wiring, which is difficult to install. Drilling in high ground pressure environments can easily cause rock bursts, resulting in low installation efficiency. Furthermore, the cables are prone to aging and damage in high-temperature and humid environments, leading to high maintenance costs.

[0006] Thirdly, there is the wireless sensor monitoring method: This method uses wireless sensor nodes that integrate temperature sensing, microprocessors, wireless transceiver modules, and built-in batteries, transmitting data via technologies such as Bluetooth and LoRa, avoiding the difficulties of wiring. However, the lithium batteries commonly used in this solution experience a sharp deterioration in electrochemical performance in high-temperature environments exceeding 100°C (especially above 120°C), with a cycle life typically less than one year. This necessitates frequent battery replacements, failing to achieve the design goal of "long-term maintenance-free operation." Furthermore, existing wireless sensors often lack adequate protection design for high-temperature and high-humidity environments in deep underground locations, easily leading to sensor drift and short circuits in the communication module; their wireless signals suffer severe attenuation in densely reinforced concrete lining structures, exhibiting weak anti-interference capabilities and reliability issues such as data packet loss and location confusion.

[0007] In summary, existing technologies are insufficient to achieve long-term, stable, and reliable wireless monitoring of surrounding rock temperature in deep-earth engineering environments characterized by high temperature, high humidity, high ground pressure, and strong electromagnetic interference, without damaging the surrounding rock or relying on fragile cables or short-life batteries. Summary of the Invention

[0008] This invention aims to solve the technical problem that existing methods for monitoring the temperature of surrounding rock in deep earth engineering are difficult to achieve maintenance-free and continuous reliable monitoring, and proposes a passive wireless monitoring device and method for the temperature of surrounding rock in deep earth engineering.

[0009] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0010] In a first aspect, the present invention provides a passive wireless monitoring device for the temperature of surrounding rock in deep-earth engineering, the device comprising a monitoring terminal and an inspection vehicle; the monitoring terminal comprising:

[0011] Thermoelectric power generation module 1 is used to generate electricity by utilizing the temperature difference between the surrounding rock and the air inside the tunnel;

[0012] The lithium titanate supercapacitor energy storage module 2 is connected to the thermoelectric power generation module 1 and is used to store electrical energy.

[0013] Temperature acquisition module 3 is used to acquire the temperature of the surrounding rock;

[0014] The microcontroller 6 is connected to the temperature acquisition module 3 and the lithium titanate supercapacitor energy storage module 2 respectively, and is used to control data acquisition and storage. Its built-in EEPROM stores a unique point number.

[0015] The wireless transmission module 5 is connected to the microcontroller 6 and is used to send temperature data including the surrounding rock temperature, point number and timestamp;

[0016] The protective housing 8 is used to house and protect the thermoelectric power generation module 1, the lithium titanate supercapacitor energy storage module 2, the temperature acquisition module 3, the microcontroller 6, and the wireless transmission module 5.

[0017] A snap-fit ​​mounting structure 9 is provided on the back plate of the protective housing 8;

[0018] The monitoring terminal is fixed in a slot embedded in the initial lining of the project by means of the snap-on installation structure 9;

[0019] The inspection vehicle includes:

[0020] The wireless charging transmission system 12 is used to provide emergency charging for the lithium titanate supercapacitor energy storage module 2 of the monitoring terminal during inspection.

[0021] Data receiving system 13 is used to receive temperature data sent by the monitoring terminal;

[0022] Data storage and analysis system 15, used to store and analyze received temperature data;

[0023] During its movement, the inspection vehicle interacts with the monitoring terminal via a wireless charging transmitter 12 and a data receiver 13, exchanging energy and data.

[0024] Furthermore, the monitoring terminal also includes an energy management chip 4, which is connected to the thermoelectric power generation module 1, the lithium titanate supercapacitor energy storage module 2, and the microcontroller 6, respectively, and is used to control the charging and discharging process of the thermoelectric power generation module 1 and achieve maximum power point tracking.

[0025] Furthermore, the protective shell 8 has a double-layer structure, including an outer protective shell layer 81, an inner protective shell layer 83, and a protective shell aerogel insulation layer 82 filled between the two; the protective shell panel 84 of the protective shell 8 has a thermal conductivity groove 86 for the thermoelectric power generation module and a thermal conductivity groove 87 for the temperature acquisition module.

[0026] Furthermore, the snap-on installation structure 9 is an elastic snap made of 316L stainless steel, and the slot embedded in the initial lining of the project is a U-shaped slot that cooperates with the elastic snap.

[0027] Furthermore, the wireless transmission module 5 adopts the Bluetooth 5.0 protocol and uses Gaussian frequency shift keying modulation and adaptive frequency hopping technology.

[0028] Furthermore, the monitoring terminal also includes an anti-interference antenna 7, which is a ceramic patch antenna, and its installation direction is configured such that the transmission direction is perpendicular to the tunnel axis.

[0029] Furthermore, the inspection vehicle also includes a detachable handheld inspection terminal 11, on which the wireless charging transmitting system 12 and the data receiving system 13 are integrated. The detachable handheld inspection terminal 11 also integrates a display screen 114.

[0030] Furthermore, the detachable handheld inspection terminal 11 also integrates a signal enhancement unit 14; the signal enhancement unit 14 includes a low-noise amplifier 141 and a surface acoustic wave filter 142;

[0031] The low-noise amplifier 141 is used to amplify the Bluetooth signal received by the data receiving system 13 in the initial stage and introduce additional noise; the surface acoustic wave filter 142 is connected to the stage after the low-noise amplifier 141 and is used to filter out specific frequency noise in the amplified signal.

[0032] Furthermore, the data storage and analysis system 15 is configured to issue an early warning when the temperature of the surrounding rock at a certain point continuously exceeds a preset threshold or when a single temperature rise exceeds a set value.

[0033] In a second aspect, the present invention provides a passive wireless monitoring method for the temperature of surrounding rock in deep-earth engineering, applied to the passive wireless monitoring device for the temperature of surrounding rock in deep-earth engineering as described in the first aspect, the method comprising:

[0034] Step 1: Pre-embed installation slots during the initial lining construction stage of the project;

[0035] Step 2: Install and fix the monitoring terminal in the slot using the snap-on installation structure 9;

[0036] Step 3: Drive the inspection vehicle along the inspection route. When it approaches the monitoring terminal, wake up the monitoring terminal through the wireless charging transmitter system 12 and charge it in an emergency. At the same time, receive the temperature data sent by the monitoring terminal, including the surrounding rock temperature, the location number and the timestamp, through the data receiving system 13.

[0037] Step 4: Store and analyze the temperature data through the data storage and analysis system 15, and issue an early warning for abnormal temperature based on preset rules.

[0038] The beneficial effects of this invention are as follows: The passive wireless monitoring device and method for surrounding rock temperature in deep-earth engineering provided by this invention constitutes a self-powered system through a thermoelectric power generation module and a lithium titanate supercapacitor energy storage module. This eliminates the reliance on lithium batteries with limited lifespans or easily damaged cables, allowing continuous operation using ambient temperature differences. Combined with emergency charging via an inspection vehicle, it achieves long-term maintenance-free operation, greatly reducing maintenance costs. The non-destructive installation method, using pre-embedded slots and elastic clips synchronized with the initial lining, eliminates the need for drilling, avoiding damage to the surrounding rock structure and potential rockburst risks associated with traditional solutions. Installation is convenient and adaptable to high ground pressure environments. The double-layer structure filled with an aerogel insulation layer ensures stable operation of internal components in harsh environments with temperatures up to 150°C and humidity up to 95%, guaranteeing data acquisition accuracy and reliability. The mobile inspection vehicle, integrating wireless charging and data receiving functions, enables automatic wake-up of the monitoring terminal, on-demand charging, and batch acquisition of temperature data during inspections. In summary, this invention enables long-term, stable, and reliable monitoring of surrounding rock temperature under extreme geological conditions. Attached Figure Description

[0039] Figure 1 A schematic diagram of the passive wireless monitoring device for surrounding rock temperature in deep underground engineering provided in this embodiment;

[0040] Figure 2 This is a schematic diagram of the monitoring terminal provided in the embodiment;

[0041] Figure 3 A schematic diagram of the structure of the protective housing backplate provided in the embodiment;

[0042] Figure 4 A schematic diagram of the structure of the protective housing panel provided in the embodiment;

[0043] Figure 5 A schematic diagram of the inspection vehicle provided for an embodiment;

[0044] Figure 6 This is a schematic diagram of the detachable handheld inspection terminal provided in the embodiment;

[0045] Figure 7 A flowchart illustrating the passive wireless monitoring method for surrounding rock temperature in deep earth engineering provided for an embodiment;

[0046] Explanation of reference numerals in the attached figures:

[0047] 1-Thermoelectric power generation module; 2-Lithium titanate supercapacitor energy storage module; 3-Temperature acquisition module; 4-Energy management chip; 5-Wireless transmission module; 6-Microcontroller; 7-Anti-interference antenna; 8-Protective housing; 81-Outer layer of protective housing; 82-Aerogel insulation layer of protective housing; 83-Inner layer of protective housing; 84-Protective housing panel; 85-Back plate of protective housing; 86-Heat conduction groove of thermoelectric power generation module; 87-Heat conduction groove of temperature acquisition module; 9-Snap-on installation structure; 10-Circuit board; 101-Terminal cable; 102-Aluminum housing; 11-Detachable handheld inspection terminal; 111-Lithium battery; 112-Inner... 113 - Card storage; 114 - Multi-function interface; 12 - Display screen; 121 - Wireless charging transmitter system; 122 - High-frequency inverter module; 123 - Charging transmitter coil; 124 - Charging control chip; 15 - Data receiving system; 161 - Bluetooth receiver module; 17 - Signal enhancement unit; 181 - Low noise amplifier; 192 - Surface acoustic wave filter; 103 - Data parsing chip; 194 - Data storage and analysis system; 101 - Solid state drive; 122 - Data analysis module; 133 - Touch screen display; 144 - Vehicle and power system; 155 - Lead-acid battery; 166 - Vehicle cockpit; 173 - Inspection vehicle cables. Detailed Implementation

[0048] Existing methods for monitoring surrounding rock temperature suffer from limitations such as short battery life, damage to the surrounding rock caused by wired installation, and inability to operate stably for extended periods in high-temperature and high-humidity environments. Consequently, it is difficult to achieve long-term, stable, and reliable wireless monitoring of surrounding rock temperature in deep-earth engineering environments with extreme geological conditions. Based on this, the technical solution of this invention is proposed.

[0049] In this invention, a monitoring terminal deployed on the surface of the surrounding rock utilizes its built-in thermoelectric power generation module to capture the temperature difference between the surrounding rock and the air inside the tunnel and convert it into electrical energy, which is stored in a high-temperature resistant lithium titanate supercapacitor energy storage module. This provides continuous power to the temperature acquisition module, microcontroller, and wireless transmission module, achieving self-powered operation. Simultaneously, the monitoring terminal is quickly and non-destructively fixed to the pre-embedded U-shaped slot within the initial lining of the tunnel using its snap-fit ​​installation structure, and its protective shell provides physical protection in high-temperature and high-humidity environments. During monitoring, when a mobile inspection vehicle approaches the terminal, its wireless charging transmitter system provides emergency charging to the terminal via electromagnetic induction. Simultaneously, the data receiving system receives temperature data sent by the terminal's wireless transmission module, which is bound to a unique location number. Finally, the data storage and analysis system performs centralized processing and analysis of the data, thus forming a collaborative monitoring device integrating energy self-sufficiency, non-destructive installation, reliable protection, and mobile inspection.

[0050] The technical solutions in this embodiment will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0051] Figure 1 A schematic diagram of a passive wireless monitoring device for surrounding rock temperature in deep earth engineering is shown. Please refer to [link / reference]. Figure 1 The device includes a monitoring terminal and an inspection vehicle.

[0052] Please see Figures 2 to 4 The monitoring terminal includes:

[0053] Thermoelectric power generation module 1 is used to generate electricity by utilizing the temperature difference between the surrounding rock and the air inside the tunnel;

[0054] The lithium titanate supercapacitor energy storage module 2 is connected to the thermoelectric power generation module 1 and is used to store electrical energy.

[0055] Temperature acquisition module 3 is used to acquire the temperature of the surrounding rock;

[0056] The microcontroller 6 is connected to the temperature acquisition module 3 and the lithium titanate supercapacitor energy storage module 2 respectively, and is used to control data acquisition and storage. Its built-in EEPROM stores a unique point number.

[0057] The wireless transmission module 5 is connected to the microcontroller 6 and is used to send temperature data including the surrounding rock temperature, point number and timestamp;

[0058] The protective housing 8 is used to house and protect the thermoelectric power generation module 1, the lithium titanate supercapacitor energy storage module 2, the temperature acquisition module 3, the microcontroller 6, and the wireless transmission module 5.

[0059] A snap-fit ​​mounting structure 9 is provided on the back plate of the protective housing 8;

[0060] The monitoring terminal is fixed in a slot embedded in the initial lining of the project by means of the snap-on installation structure 9.

[0061] Specifically, the monitoring terminal in this embodiment is an integrated passive wireless temperature monitoring device designed specifically for the high temperature, high humidity, and high ground pressure environments of deep-earth engineering. Its core lies in achieving self-powered operation through environmental energy harvesting, and in achieving rapid, non-destructive installation and long-term reliable operation through optimized structural design. Its composition and working principle are explained in detail below:

[0062] The monitoring terminal includes the following core modules, all of which are integrated inside the protective housing 8:

[0063] Thermoelectric module 1: Its function is to generate electricity by utilizing the stable temperature difference (typically ≥5℃) between the surrounding rock and the air inside the tunnel in deep-earth engineering. Thermoelectric module 1 is directly attached to the heat conduction groove 86 of the protective shell panel 84 of the protective shell 8, ensuring good thermal contact with the surrounding rock. The protective shell panel 84 refers to the panel close to the surrounding rock. When the temperature of the surrounding rock is higher than the temperature of the air inside the tunnel, heat is transferred to the hot end of the module through the heat conduction groove, creating a temperature difference with the cold end. Based on the Seebeck effect, an electromotive force is generated, thereby directly converting environmental heat energy into electrical energy, providing initial energy for the monitoring terminal.

[0064] Lithium titanate supercapacitor energy storage module 2: This module is connected to the output terminal of thermoelectric power generation module 1 via power / data transmission terminal cable 101. Its function is to store the electrical energy generated by thermoelectric power generation. The lithium titanate material system was chosen because it has extremely high stability and ultra-long cycle life (≥1 million cycles) in a wide temperature range of -40℃ to 150℃, perfectly adapting to the high-temperature environment of deep earth, overcoming the fatal defect of short high-temperature life of traditional lithium batteries, and enabling long-term maintenance-free operation.

[0065] Temperature acquisition module 3: Used for accurate sensing of surrounding rock temperature. Its sensing part is in close contact with the surrounding rock through the temperature acquisition module heat conduction groove 87 opened on the protective shell panel 84 of the protective shell 8, ensuring accurate temperature measurement. Temperature acquisition module 3 can operate in the range of -40℃ to 250℃, and the accuracy can reach ±0.1℃ at 150℃. It transmits the acquired analog or digital temperature signal to the microcontroller 6 through the terminal cable 101.

[0066] Microcontroller 6: As the control core of the terminal, it is connected to both the temperature acquisition module 3 and the lithium titanate supercapacitor energy storage module 2. It is responsible for controlling the acquisition, analog-to-digital conversion, and storage of temperature data. In particular, its built-in EEPROM (Electrically Erasable Programmable Read-Only Memory) is pre-written with a unique 16-bit identifier (e.g., "DK123+456-Vault-01") before leaving the factory, and this identifier is permanently bound to the physical installation location.

[0067] Wireless transmission module 5: Employs a high-temperature resistant Bluetooth 5.0 chip and connects to microcontroller 6. Its function is to wirelessly transmit data processed by microcontroller 6, including the surrounding rock temperature value, a unique location number, and a data acquisition timestamp. The use of Bluetooth facilitates integration with portable inspection equipment.

[0068] In this embodiment, the wireless transmission module 5 adopts the Bluetooth 5.0 protocol and uses Gaussian frequency shift keying modulation and adaptive frequency hopping technology.

[0069] Specifically, the wireless transmission module 5 adopts GFSK modulation (Gaussian Frequency Shift Keying) (concentrating the spectrum and reducing the attenuation rate in the reinforced concrete area by 30%), and has built-in adaptive frequency hopping (AFH) technology with a frequency hopping rate of 1600 times / second and an interference avoidance rate of ≥99.5%, which can avoid the interference frequency bands of equipment such as frequency converters and ventilation fans; in addition, the transmission power is dynamically adjustable, and the transmission power is automatically increased in areas with dense reinforced concrete (such as the steel support of the arch), expanding the signal coverage range by more than 50%.

[0070] To ensure high efficiency and ultra-high reliability of data transmission in the complex electromagnetic environment of deep-earth engineering (especially affected by steel mesh shielding and equipment interference), in this embodiment, the wireless transmission module 5 adopts a customized data transmission protocol and verification mechanism:

[0071] First, a custom Bluetooth broadcast protocol is adopted, with a single frame length of 32 bytes (including 4 bytes of temperature + 8 bytes of location number + 4 bytes of timestamp + 2 bytes of checksum), and a single transmission time of ≤0.3 seconds, reducing the exposure time to interference environments by 70%.

[0072] Secondly, a dual verification method is employed: hardware CRC16 check (error detection rate ≥99.999%) + software XOR check, triggering retransmission upon error (retransmission success rate ≥99%). Hardware CRC16 check refers to implementing 16-bit cyclic redundancy check through dedicated hardware circuitry.

[0073] Protective Housing 8: A double-layer structure made of Inconel 625 alloy, comprising an outer protective housing layer 81, an inner protective housing layer 83, and an aerogel insulation layer 82 filled between them, forming the main protective system. This design effectively isolates external temperatures up to 150℃, maintaining the internal temperature below 125℃, meeting the temperature resistance requirements of all internal electronic components. The housing seams are sealed with copper sealing rings (temperature resistance -40℃~200℃), combined with a conformal coating process on the circuit board, achieving IP68-level moisture protection and ensuring reliable operation of the internal circuitry in environments with humidity levels above 95%.

[0074] Snap-on installation structure 9: This structure is integrally formed into the protective shell back plate 85 of the protective shell 8. The protective shell back plate 85 refers to the back plate close to the lining side. Specifically, the snap-on installation structure 9 is an elastic snap-on device made of 316L stainless steel with pre-compression. During installation, it is directly pushed into the 316L stainless steel U-shaped groove pre-embedded in the tunnel's initial lining concrete, utilizing the snap-on's elastic restoring force to achieve a tight fixation. This process eliminates the need for drilling in the surrounding rock, achieving rapid and non-destructive installation. Furthermore, the snap-on can withstand a radial pressure of 20MPa, adapting to high ground pressure environments.

[0075] In this embodiment, the monitoring terminal also includes an energy management chip 4, which is connected to the thermoelectric power generation module 1, the lithium titanate supercapacitor energy storage module 2 and the microcontroller 6 respectively via a power / data transmission terminal cable 101, and is used to control the charging and discharging process of the thermoelectric power generation module 1 and achieve maximum power point tracking.

[0076] Specifically, firstly, the energy management chip 4 controls the charging current and voltage curve of the electrical energy from the thermoelectric power generation module 1 based on the voltage state of the supercapacitor, achieving constant current-constant voltage charging and avoiding overcharging. Simultaneously, it monitors the load at the output terminal to prevent over-discharge of the supercapacitor, thereby effectively extending the supercapacitor's lifespan and ensuring its ultra-long cycle life (≥1 million cycles). Secondly, the output power of the thermoelectric power generation module 1 changes non-linearly with the temperature difference between the surrounding rock and the air. The energy management chip 4 incorporates an MPPT algorithm, which continuously monitors the output voltage and current of the thermoelectric power generation module 1 and dynamically adjusts its equivalent load to ensure that the thermoelectric power generation module 1 always operates near its maximum power output point. Its MPPT efficiency is no less than 75%, thereby maximizing the capture and utilization of limited environmental thermal energy and improving energy harvesting efficiency.

[0077] The energy management chip 4, the wireless transmission module 5, and the microcontroller 6 are integrated on the circuit board 10.

[0078] In this embodiment, the monitoring terminal further includes an anti-interference antenna 7, which is a ceramic patch antenna configured to transmit perpendicularly to the tunnel axis. By employing the anti-interference antenna 7, i.e., the ceramic patch antenna, which transmits perpendicularly to the tunnel axis, penetration is enhanced.

[0079] In summary, please refer to Table 1 for the technical parameters of each module in the monitoring terminal provided in this embodiment.

[0080] Table 1. Schematic diagram of technical parameters of each module in the monitoring terminal

[0081]

[0082] Please see Figure 5 The inspection vehicle includes:

[0083] The wireless charging transmission system 12 is used to provide emergency charging for the lithium titanate supercapacitor energy storage module 2 of the monitoring terminal during inspection.

[0084] Data receiving system 13 is used to receive temperature data sent by the monitoring terminal;

[0085] Data storage and analysis system 15, used to store and analyze received temperature data;

[0086] During its movement, the inspection vehicle interacts with the monitoring terminal via a wireless charging transmitter 12 and a data receiver 13, exchanging energy and data.

[0087] The vehicle and power system 16 is the mobile platform and energy center of the inspection vehicle, mainly including lead-acid battery 161, vehicle cab 162, and inspection vehicle cables 163.

[0088] The lead-acid battery 161 serves as the main power source for the inspection vehicle, providing stable power to all onboard equipment, including the wireless charging transmitter system 12 and the data receiving system 13. The driver's cab 162 provides a driving and control space for the operator, integrating interactive devices such as a touchscreen display for the onboard data storage and analysis system 15, facilitating real-time monitoring of the inspection status. The inspection vehicle cable 163, as the backbone of the onboard electrical system, reliably transmits electrical energy and data signals between the lead-acid battery, various functional systems, and the detachable handheld inspection terminal 11. This system provides fundamental mobility, energy security, and system integration support for the entire mobile inspection operation.

[0089] In this embodiment, the inspection vehicle also includes a detachable handheld inspection terminal 11. The wireless charging transmission system 12 and the data receiving system 13 are integrated on the detachable handheld inspection terminal 11, and the detachable handheld inspection terminal 11 also integrates a display screen 114.

[0090] The detachable handheld inspection terminal 11 also integrates a signal enhancement unit 14; the signal enhancement unit 14 includes a low-noise amplifier 141 and a surface acoustic wave filter 142.

[0091] The low-noise amplifier 141 is used to amplify the Bluetooth signal received by the data receiving system 13 in the initial stage and introduce additional noise; the surface acoustic wave filter 142 is connected to the stage after the low-noise amplifier 141 and is used to filter out specific frequency noise in the amplified signal.

[0092] In this embodiment, the data storage and analysis system 15 is configured to issue an early warning when the temperature of the surrounding rock at a certain point continuously exceeds a preset threshold or when a single temperature rise exceeds a set value.

[0093] Specifically, the inspection vehicle is used to replenish energy and collect data from the fixed monitoring terminal during mobile inspections. Its specific structure and working principle are as follows:

[0094] Wireless charging transmitter system 12: Used during inspections, when a vehicle approaches the monitoring terminal (within approximately 5 meters), it provides emergency power to the lithium titanate supercapacitor energy storage module 2 of the monitoring terminal. The wireless charging transmitter system 12 typically consists of a high-frequency inverter module 121, a charging transmitter coil 122, and a charging control chip 123. It can quickly charge the monitoring terminal within 10 seconds via electromagnetic induction, ensuring that the monitoring terminal can maintain normal operating voltage even when thermoelectric power generation is insufficient.

[0095] Data receiving system 13: mainly includes Bluetooth receiving module 131, which is used to receive temperature data packets containing surrounding rock temperature, point number and timestamp sent by monitoring terminal wireless transmission module 5 in real time, and to complete preliminary parsing.

[0096] Data storage and analysis system 15: typically includes solid-state drive 151, data processing module 152 and touch screen 153, used to store parsed data and has automatic analysis functions, such as generating temperature time series curves and comparing preset thresholds, and issuing audible and visual alarms through the touch screen when abnormal temperature is detected (such as continuous over-limit or sudden rise), providing decision support for operation and maintenance personnel.

[0097] In practical applications, the inspection vehicle can automatically complete closed-loop interaction with the monitoring terminals along the tunnel, including wake-up, charging / communication, and sleep modes, without stopping while moving along the tunnel at a speed of about 5 km / h, which greatly improves inspection efficiency.

[0098] Please see Figure 6 In this embodiment, to enhance the flexibility of device deployment and use, the inspection vehicle also integrates a detachable handheld inspection terminal 11. The wireless charging transmitter system 12 and the data receiver system 13 are integrated on the detachable handheld inspection terminal 11. The detachable handheld inspection terminal 11 also integrates a lithium battery 111, a memory card 112, a multi-function interface 113, and a display screen 114. The lithium battery 111 provides power for the detachable handheld inspection terminal 11 to operate independently in its detached state; the memory card 112 is used to temporarily store raw data received from the monitoring terminal during the inspection process, serving as a data buffer and backup; the multi-function interface 113 is a data transmission / charging interface used to export data to the vehicle system or host computer, update terminal firmware, and charge the built-in lithium battery; the display screen 114 displays the terminal's operating status, signal strength, received temperature data, location number, and alarm information in real time, providing an intuitive human-machine interface for on-site operators. Its design meets the needs of two key scenarios: First, during the construction and installation phase, staff can hold the terminal at close range to wake up and test the monitoring terminal to confirm whether its installation and communication are normal; second, in some local areas that cannot be reached by vehicles, it can be disassembled for manual inspection, which greatly enhances the applicability of the device.

[0099] To address the severe shielding and attenuation of wireless signals by steel mesh in deep tunnels, the detachable handheld inspection terminal 11 also integrates a dedicated signal enhancement unit 14, including:

[0100] Low-noise amplifier 141: Located at the very beginning of the receiving link, it amplifies the Bluetooth signal, which has become very weak after being blocked by steel bars and captured by the antenna of the data receiving system 13, in the initial stage. It has low-noise characteristics, that is, while amplifying the useful signal, it generates very little additional electronic noise, thereby preventing the signal-to-noise ratio from deteriorating further during the amplification stage.

[0101] Surface acoustic wave filter 142: Connected after low-noise amplifier 141. Used to filter out specific frequencies of industrial electromagnetic interference noise (such as interference from equipment like fans and pumps) mixed in with the amplified signal. It can precisely allow the Bluetooth signal band to pass through while significantly attenuating out-of-band interference (e.g., filtering out 80% of the noise), thereby purifying the signal and improving the accuracy of data analysis.

[0102] Data parsing chip 143: Connected to the output end of surface acoustic wave filter 142. Used for digital demodulation and data packet parsing of the analog Bluetooth signal after low-noise amplification and filtering.

[0103] Through the above design, the inspection vehicle not only serves as a mobile energy station and data collection center, but its detachable handheld terminal 11 and built-in signal enhancement unit 14 also ensure reliable wireless communication within complex engineering structures, ensuring the stable and reliable operation of the entire monitoring device in real deep-earth environments.

[0104] In summary, please refer to Table 2 for the technical parameters of each module in the inspection vehicle provided in this embodiment.

[0105] Table 2. Technical parameters of each module in the inspection vehicle

[0106]

[0107] In practice, firstly, U-shaped slots are pre-embedded during the initial tunnel lining construction stage. After curing, the monitoring terminal, with its unique number, is quickly pushed into the slot and fixed using its snap-fit ​​installation structure 9. During the maintenance period, the inspection vehicle travels along the tunnel at approximately 5 km / h. When it approaches the monitoring terminal, the vehicle's wireless charging transmitter 12 automatically generates an alternating magnetic field, waking the dormant terminal and providing emergency charging for its lithium titanate supercapacitor energy storage module 2. Simultaneously, the monitoring terminal transmits temperature data packets with the bound point number via the wireless transmission module 5. This signal, after being attenuated by the tunnel's steel mesh, is amplified, filtered, and analyzed by the inspection vehicle's signal enhancement unit 14, and finally reliably received by the data receiving system 13, which stores it along with a timestamp in the data storage and analysis system 15. After the inspection vehicle leaves, the monitoring terminal automatically returns to dormancy. The background system analyzes the data in real time, generates temperature change curves, and immediately alarms when abnormalities such as continuous exceeding limits or sudden increases are detected, thus completing a closed-loop automatic monitoring system with no human intervention throughout the entire lifecycle from data acquisition, transmission, processing to early warning.

[0108] In summary, the passive wireless monitoring device for surrounding rock temperature in deep-earth engineering provided in this embodiment adopts a self-powered system composed of thermoelectric power generation and lithium titanate supercapacitors. This completely eliminates the limitations of traditional batteries with short lifespan at high temperatures and wired power supplies that are prone to aging, achieving theoretically decades of maintenance-free continuous operation and greatly reducing the overall maintenance cost. Through the combination of pre-embedded slots and elastic buckles, non-destructive and rapid installation without drilling is achieved, avoiding damage to the surrounding rock structure and construction risks, and adapting to high ground pressure environments. Through a double-layer Inconel alloy shell, aerogel insulation layer, and multiple sealing protections, the internal electronic components are ensured to operate stably for a long time in an environment with a high temperature of 150℃ and a high humidity of 95%, ensuring that the temperature acquisition accuracy deviation is ≤0.5℃. Utilizing a mobile inspection vehicle that integrates wireless charging, signal enhancement, and data reception functions, an efficient closed-loop operation is achieved during the inspection process, including automatic terminal wake-up, on-demand power replenishment, and batch data acquisition. Combined with an anti-interference communication protocol and data binding mechanism, the reliability and traceability of data transmission in areas with dense reinforced concrete are ensured. In summary, this embodiment enables long-term, stable, and reliable monitoring of the surrounding rock temperature under extreme geological conditions.

[0109] Based on the above technical solution, this embodiment also provides a passive wireless monitoring method for the temperature of surrounding rock in deep earth engineering, applied to the passive wireless monitoring device for the temperature of surrounding rock in deep earth engineering described in the embodiment. Please refer to [link to relevant documentation]. Figure 7 The method includes:

[0110] Step 1: Pre-embed installation slots during the initial lining construction stage of the project;

[0111] Step 2: Install and fix the monitoring terminal in the slot using the snap-on installation structure 9;

[0112] Step 3: Drive the inspection vehicle along the inspection route. When it approaches the monitoring terminal, wake up the monitoring terminal through the wireless charging transmitter system 12 and charge it in an emergency. At the same time, receive the temperature data sent by the monitoring terminal, including the surrounding rock temperature, the location number and the timestamp, through the data receiving system 13.

[0113] Step 4: Store and analyze the temperature data through the data storage and analysis system 15, and issue an early warning for abnormal temperature based on preset rules.

[0114] It is understood that since the passive wireless monitoring method for the temperature of the surrounding rock in deep engineering described in this embodiment is based on the passive wireless monitoring device for the temperature of the surrounding rock in deep engineering described in the embodiment, the method disclosed in the embodiment is relatively simple to describe because it corresponds to the device disclosed in the embodiment. For relevant parts, please refer to the device description.

Claims

1. A passive wireless monitoring device for the temperature of surrounding rock in deep-earth engineering, characterized in that, The device includes a monitoring terminal and an inspection vehicle; the monitoring terminal includes: Thermoelectric power generation module (1) is used to generate electricity by utilizing the temperature difference between the surrounding rock and the air inside the tunnel; A lithium titanate supercapacitor energy storage module (2) is connected to the thermoelectric power generation module (1) for storing electrical energy; Temperature acquisition module (3) is used to acquire the temperature of the surrounding rock; The microcontroller (6) is connected to the temperature acquisition module (3) and the lithium titanate supercapacitor energy storage module (2) respectively, and is used to control data acquisition and storage. Its built-in EEPROM stores a unique point number. The wireless transmission module (5) is connected to the microcontroller (6) and is used to send temperature data including the surrounding rock temperature, point number and timestamp; The protective housing (8) is used to house and protect the thermoelectric power generation module (1), the lithium titanate supercapacitor energy storage module (2), the temperature acquisition module (3), the microcontroller (6), and the wireless transmission module (5). A snap-fit ​​mounting structure (9) is provided on the back plate of the protective housing (8); The monitoring terminal is fixed in a slot embedded in the initial lining of the project by means of the snap-on installation structure (9); The inspection vehicle includes: A wireless charging transmission system (12) is used to provide emergency charging for the lithium titanate supercapacitor energy storage module (2) of the monitoring terminal during inspection; The data receiving system (13) is used to receive temperature data sent by the monitoring terminal; Data storage and analysis system (15) for storing and analyzing received temperature data; During its movement, the inspection vehicle interacts with the monitoring terminal via a wireless charging transmitter (12) and a data receiver (13) to exchange energy and data.

2. The passive wireless monitoring device for surrounding rock temperature in deep-earth engineering according to claim 1, characterized in that, The monitoring terminal also includes an energy management chip (4), which is connected to the thermoelectric power generation module (1), the lithium titanate supercapacitor energy storage module (2) and the microcontroller (6) respectively, and is used to control the charging and discharging process of the thermoelectric power generation module (1) and realize maximum power point tracking.

3. The passive wireless monitoring device for surrounding rock temperature in deep-earth engineering according to claim 1, characterized in that, The protective shell (8) has a double-layer structure, including an outer protective shell layer (81), an inner protective shell layer (83), and a protective shell aerogel insulation layer (82) filled between the two; the protective shell panel (84) of the protective shell (8) is provided with a thermal conductivity groove (86) for the thermoelectric power generation module and a thermal conductivity groove (87) for the temperature acquisition module.

4. The passive wireless monitoring device for surrounding rock temperature in deep-earth engineering according to claim 1, characterized in that, The snap-on installation structure (9) is an elastic snap made of 316L stainless steel, and the slot embedded in the initial lining of the project is a U-shaped slot that cooperates with the elastic snap.

5. The passive wireless monitoring device for surrounding rock temperature in deep-earth engineering according to claim 1, characterized in that, The wireless transmission module (5) adopts the Bluetooth 5.0 protocol and uses Gaussian frequency shift keying modulation and adaptive frequency hopping technology.

6. The passive wireless monitoring device for surrounding rock temperature in deep-earth engineering according to claim 1, characterized in that, The monitoring terminal also includes an anti-interference antenna (7), which is a ceramic patch antenna and its installation direction is configured such that the transmission direction is perpendicular to the tunnel axis.

7. The passive wireless monitoring device for surrounding rock temperature in deep-earth engineering according to claim 1, characterized in that, The inspection vehicle also includes a detachable handheld inspection terminal (11), the wireless charging transmission system (12) and the data receiving system (13) are integrated on the detachable handheld inspection terminal (11), and the detachable handheld inspection terminal (11) also integrates a display screen (114).

8. The passive wireless monitoring device for surrounding rock temperature in deep-earth engineering according to claim 7, characterized in that, The detachable handheld inspection terminal (11) also integrates a signal enhancement unit (14); the signal enhancement unit (14) includes a low noise amplifier (141) and a surface acoustic wave filter (142). The low-noise amplifier (141) is used to amplify the Bluetooth signal received by the data receiving system (13) in the initial stage and introduce additional noise; the surface acoustic wave filter (142) is connected to the stage after the low-noise amplifier (141) and is used to filter out specific frequency noise in the amplified signal.

9. The passive wireless monitoring device for surrounding rock temperature in deep-earth engineering according to claim 1, characterized in that, The data storage and analysis system (15) is configured to issue an early warning when the temperature of the surrounding rock at a certain point continuously exceeds a preset threshold or when a single temperature rise exceeds a set value.

10. A passive wireless monitoring method for the temperature of surrounding rock in deep earth engineering, characterized in that, The method, applied to the passive wireless monitoring device for surrounding rock temperature in deep earth engineering as described in any one of claims 1 to 9, comprises: Step 1: Pre-embed installation slots during the initial lining construction stage of the project; Step 2: Install and fix the monitoring terminal in the slot using the snap-on installation structure (9); Step 3: Drive the inspection vehicle along the inspection route. When it approaches the monitoring terminal, wake up the monitoring terminal through the wireless charging transmitter system (12) and charge it in an emergency. At the same time, receive the temperature data sent by the monitoring terminal, including the surrounding rock temperature, point number and timestamp, through the data receiving system (13). Step 4: Store and analyze the temperature data through the data storage and analysis system (15), and issue an early warning of temperature anomalies based on preset rules.

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