Water-enriched tunnel noise sound excitation type energy capture advanced cavity geological inversion device and method

Abstract

The application discloses a water-rich tunnel noise sound excitation type energy trapping advanced cavity geological inversion device and method, which comprises a sound collecting unit, a resonant cavity, a beam forming unit and a sound wave transmitter and receiver. The sound collecting unit is used for gathering multi-source noise in a tunnel environment. The resonant cavity is connected with the sound collecting unit and has adjustable resonant frequency, and is used for frequency selection and sound pressure amplification of the multi-source noise. The beam forming unit is connected with the resonant cavity and is used for spatial directivity regulation and frequency spectrum reconstruction of the amplified sound wave, so as to form a directional sound wave. The sound wave transmitter is connected with the beam forming unit and is used for radiating the directional sound wave to a rock mass to be measured in front of a tunnel face. The sound wave receiver is used for receiving echo signals scattered by the rock mass. The signal processing unit is connected with the sound wave receiver and is used for inverting three-dimensional distribution of the cavity in front of the tunnel face according to the echo signals and generating early warning information. The application realizes efficient energy trapping and sound wave conversion of the noise in the water-rich tunnel environment, and improves noise utilization efficiency.

Description

Technical Field

[0001] This invention relates to the field of detection and risk warning technology for defects in water-rich tunnels, and in particular to a noise-induced energy-harvesting advanced cavity geological inversion device and method for water-rich tunnels. Background Technology

[0002] During operation and construction, water-rich tunnels are subjected to high hydrostatic pressure and dynamic water erosion for extended periods, making them highly susceptible to hidden defects such as cavities, solution cavities, and loose zones. Once these defects become unstable, they can cause sudden water and mud inrushes, tunnel face collapses, or even ground subsidence within hours, seriously threatening construction safety and subsequent operation.

[0003] Current advanced geological forecasting methods mainly rely on transient electromagnetic, ground-penetrating radar, or artificial blasting sonic wave methods. Transient electromagnetic and ground-penetrating radar signals attenuate drastically in water-rich and high-conductivity environments, and their resolution decreases sharply with increasing water content. Artificial blasting sonic waves require the placement of explosives or heavy hammers, which is a complex process with high safety risks and consumes a large amount of additional electrical energy. Traditional sonic wave equipment requires an external high-power transmitter, which makes cable laying difficult, resulting in high energy consumption and carbon emissions, making it difficult to meet the requirements of green and low-carbon construction.

[0004] As tunnel construction progresses, low carbon has become a core keyword and a competitive advantage for high-quality development in tunnel engineering. How to conduct advanced detection of cavities in water-rich environments using a method that requires "zero artificial seismic sources and zero additional energy consumption" has become a critical technical bottleneck that the industry urgently needs to overcome.

[0005] Therefore, there is an urgent need to provide a solution for a noise-induced energy-harvesting device and method for advanced geological inversion of water-rich tunnels. Summary of the Invention

[0006] To address the above issues, the present invention provides a noise-induced energy-harvesting advanced cavity geological inversion device and method for water-rich tunnels. This device directly purifies and amplifies multi-source noise, such as blasting impact, cutterhead roar, and water flow whistling, into controllable acoustic pulses, achieving millisecond-level closed-loop inversion and early warning. This significantly reduces system energy consumption and carbon emissions, providing key technical support for green construction and risk management of water-rich tunnels.

[0007] According to a first aspect of the present invention, a noise-induced energy-harvesting advanced cavity geological inversion device for water-rich tunnels is provided, comprising: A sound-gathering unit is used to collect multi-source noise in the tunnel environment; A resonant cavity, connected to the sound collecting unit, has an adjustable resonant frequency and is used for frequency selection and sound pressure amplification of the multi-source noise; A beamforming unit, connected to the resonant cavity, is used to spatially directively modulate and reconstruct the spectrum of the amplified sound wave to form a directional sound wave. A sound wave transmitter, connected to the beamforming unit, is used to radiate the directional sound waves to the rock mass to be tested in front of the tunnel face; A sound wave receiver is used to receive echo signals backscattered by the rock mass; The signal processing unit, connected to the acoustic receiver, is used to invert the three-dimensional distribution of the cavity in front of the tunnel face based on the echo signal and generate early warning information.

[0008] In the above scheme, the resonant cavity is a Helmholtz resonant cavity, and the ratio of its neck length to its cavity volume is continuously adjustable between 1:8 and 1:12, which is used to lock the dominant frequency noise in the water-rich tunnel environment.

[0009] In the above scheme, the beamforming unit is an acoustic rainbow scatterer. The acoustic rainbow scatterer has a scattering ridge with a radially varying height inside, which is used to decouple the amplified sound wave spatially and directionally. The beamforming unit is connected to the resonant cavity through a first acoustic guide rod.

[0010] In the above scheme, the acoustic wave transmitter and the beamforming unit are rigidly connected by a second acoustic guide rod. The acoustic wave transmitter includes an acoustic reflector to adapt to the working face with different inclination angles.

[0011] In the above scheme, the sound wave receiver includes an echo receiving module and a signal processing module. The echo receiving module has a waterproof acoustic window, and the signal processing module is used to perform real-time conditioning and conversion of the echo signal.

[0012] The above solution also includes a device housing, the resonant cavity is encapsulated inside the housing, the beamforming unit is embedded around the device housing, the acoustic wave transmitter is hinged to the housing via a quick-release structure, and the acoustic wave receiver is embedded in the back plate of the device housing.

[0013] In the above scheme, the signal processing unit includes an interface for connecting an external data processing unit to perform three-dimensional inversion imaging of holes and risk warning.

[0014] In the above scheme, the signal processing unit is configured to: invert the three-dimensional density distribution of voids based on the total variation regularization model, and calculate the risk index based on the distance and density of voids from the working face to achieve risk zoning early warning.

[0015] The above scheme also includes a control platform, which is used to realize the device's self-test, parameter initialization and early warning trigger control.

[0016] According to a second aspect of the present invention, a method for advanced geological inversion of water-rich tunnels using noise-induced energy harvesting is provided, utilizing the apparatus described in any one of the above schemes, the method comprising: S1. Fix the device in front of the working face, turn on the device power, and perform self-test and parameter initialization settings. S2. The sound collection unit collects noise and transmits it to the resonant cavity. After the sound waves are processed by the resonant cavity and the beamforming unit, they propagate to the rock mass in front of the tunnel face and are reflected back to the sound wave receiver. The processed echo signal is then saved to the platform. S3. The data processing unit access device transmits the collected data to the data processing unit, processes the data using a preset cavity inversion algorithm, and generates a three-dimensional density distribution map (x, y, z) of cavities in the rock mass in front of the tunnel face. S4. According to the density distribution map Calculate the warning distance d and monitor the change of d in real time. When d is less than the set threshold, trigger the warning mechanism. S5. Back up and analyze the collected data and the generated three-dimensional density distribution map of cavities to provide geological basis for tunnel engineering.

[0017] Compared with the prior art, the present invention has the following advantages: (1) It realizes efficient energy capture and sound wave conversion of environmental noise in water-rich tunnels, enriches the technical means of tunnel advanced geological prediction, and improves the efficiency of noise utilization. (2) The acoustic energy-harvesting advanced cavity geological inversion device, combined with the improved total variation inversion method, can accurately measure the density of the cavity area in water-rich tunnels, improve the ability to extract regional features of cavity hazards, and avoid the phenomenon of misjudgment of cavity morphology caused by single frequency sound waves. (3) A real-time monitoring and early warning mechanism can promptly detect potential geological disasters, effectively ensure the safety of tunnel construction, and reduce economic losses and casualties caused by geological disasters. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of the acoustic excitation energy-harvesting advanced cavity geological inversion device of the present invention. Figure 2 This is a schematic diagram of the Helmholtz resonant cavity structure of the present invention; Figure 3 This is a schematic diagram of the acoustic rainbow scatterer structure of the present invention; Figure 4 This is a schematic diagram of the acoustic wave receiver structure of the present invention; Figure 5 This is a schematic diagram of noise energy harvesting in this invention.

[0020] In the diagram: 1-Acoustic enclosure, 2-Device housing, 3-Helmholtz resonant cavity structure, 3-1 Support, 3-2 Vibrating diaphragm, 3-3 Dustproof grid, 3-4 Sound wave output end, 4-Acoustic rainbow diffuser, 4-1 Pre-processing noise inlet, 4-2 Fixing ring, 4-3 Scattering ridge, 4-4 Dustproof enclosure, 4-5 Sound wave outlet, 5-Sound wave transmitter, 6-Sound wave receiver, 6-1 Echo receiver module, 6-2 Signal processing module, 6-3 Connecting cable, 7-USB interface, 8-Computer, 9-First acoustic guide rod, 10-Control platform, 11-1 Explosion vibration noise, 11-2 Mechanical vibration noise, 11-3 Airflow noise, 11-4 Processed sound wave, 11-5 Echo.

[0021] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0022] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0023] The terms "first," "second," etc., used in this disclosure are for distinguishing similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that the embodiments of this disclosure described herein can be implemented, for example, in orders other than those illustrated or described herein.

[0024] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0025] Multiple, including two or more.

[0026] And / or, it should be understood that, for the purposes of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0027] One embodiment of the technical solution of the present invention provides a noise-induced energy-harvesting advanced cavity geological inversion device for water-rich tunnels, such as... Figure 1 and Figure 5 As shown, the system includes: a sound-gathering unit for gathering multi-source noise from the tunnel environment; a resonant cavity connected to the sound-gathering unit, whose resonant frequency is adjustable for frequency selection and sound pressure amplification of multi-source noise; a beamforming unit connected to the resonant cavity for spatial directional control and spectrum reconstruction of the amplified sound waves to form directional sound waves; a sound wave transmitter 5 connected to the beamforming unit for radiating the directional sound waves, i.e., processed sound waves 11-4, to the rock mass to be measured in front of the tunnel face; a sound wave receiver 6 for receiving the echo signal backscattered by the rock mass; and a signal processing unit connected to the sound wave receiver 6 for inverting the three-dimensional distribution of cavities in front of the tunnel face based on the echo signal and generating early warning information. The tunnel face refers to the working face that advances during tunnel excavation, i.e., the rock and soil wall that is being excavated and continuously moving forward in the tunnel.

[0028] The sound collection unit includes a sound collection cover 1, which is a trapezoidal body made of metal. Its larger diameter end faces the tunnel environment, while its smaller diameter end connects to the subsequent resonant cavity. In this embodiment, the sound collection cover 1 is used to collect blast vibration noise 11-1, mechanical vibration noise 11-2, and airflow noise 11-3. This trapezoidal structure can efficiently collect blast vibration noise 11-1, mechanical vibration noise 11-2, and airflow noise 11-3 from different directions, achieving wide-angle noise convergence and providing sufficient sound source input for subsequent sound energy conversion.

[0029] The device also includes a housing 2, which is made of waterproof metal and is used to encapsulate the internal components and provide waterproof and dustproof protection. The resonant cavity is encapsulated inside the housing, the beamforming unit is embedded around the housing 2, the acoustic transmitter 5 is hinged to the housing via a quick-release structure, and the acoustic receiver 6 is embedded in the back plate of the housing 2.

[0030] like Figure 2As shown, the resonant cavity is a Helmholtz resonant cavity. One opening of the Helmholtz resonant cavity is connected to the inner side of the sound collecting cover 1. The Helmholtz resonant cavity structure 3 includes the resonant cavity, a bracket 3-1 fixed to the device housing 2, a fixed diaphragm 3-2 at the input end of the resonant cavity, a dustproof grille 3-3 at the input end of the diaphragm 3-2, and a sound wave output end 3-4 at the output end of the resonant cavity. The resonant cavity contains 30 resonant chambers. The bracket 3-1 is fixed to the inner wall of the device housing 2 and has a frame-like structure. The diaphragm 3-2 is a square thin film, and each diaphragm 3-2 is pressed and fixed by adjacent brackets 3-1. This multi-layered diaphragm 3-2 and chamber structure can perform preliminary screening and amplification of broadband noise, while the dustproof grille 3-3 effectively protects the internal precision structure, improving the reliability of the device in harsh tunnel environments.

[0031] Preferably, the Helmholtz resonator employs a neck-to-cavity ratio adjustable structure, with the neck length to cavity volume ratio continuously adjustable between 1:8 and 1:12. This is used to lock onto the dominant frequency noise of water-rich tunnels, achieving noise gain and output. Therefore, it can dynamically match the dominant frequency noise characteristics according to different tunnels and different construction stages, realizing the transformation from "broad-spectrum collection" to "precise locking," greatly improving noise capture and conversion efficiency. The resonant frequency of the Helmholtz resonator... Uniquely determined by equation (1): In the formula: c is the speed of sound, S is the cross-sectional area of ​​the neck, and V is the volume of the cavity. For neck length, Δ =0.85r1 is the end correction amount, and r1 is the neck radius.

[0032] like Figure 3As shown, the beamforming unit is an acoustic rainbow scatterer 4, which has a barrel-shaped structure. The acoustic rainbow scatterer 4 includes a pre-processing noise inlet 4-1, a fixing ring 4-2, a scattering ridge 4-3, a dust cover 4-4, and an acoustic wave outlet 4-5. The acoustic rainbow scatterer 4 is fixed to the outer wall of the housing by the fixing ring 4-2. The pre-processing noise inlet 4-1 and the acoustic wave outlet 4-5 are located at the inner end of the acoustic rainbow scatterer 4. The dust cover 4-4 is located at the outer end of the acoustic rainbow scatterer 4. The scattering ridge 4-3 is located inside the acoustic rainbow scatterer 4 and is used to reprocess the pre-processed noise from the Helmholtz resonator and achieve beamforming. The dust cover 4-4 has an arc-shaped mesh structure and is used to block... Dust and other particulate matter are prevented from entering the diffuser. The scattering ridge 4-3 is a sealed metal sound guide tube that is spirally distributed along the inner wall of the acoustic rainbow diffuser 4. The inlet end of the scattering ridge 4-3 is sealed to the pre-processed noise inlet 4-1, and the outlet end of the scattering ridge 4-3 is sealed to the sound wave outlet 4-5. The pre-processed noise inlet 4-1 is a short tube sound guide, and the diameter of the pre-processed noise inlet 4-1 matches the end of the first sound guide rod 9. One end of the pre-processed noise inlet 4-1 is connected to the Helmholtz resonant cavity through the first sound guide rod 9. The sound wave outlet 4-5 is connected to the sound wave transmitter 5 through the second sound guide rod, so that the pre-processed noise is reprocessed and shaped inside the acoustic rainbow diffuser 4 and then directionally output to the sound wave transmitter 5 through the sound wave outlet 4-5.

[0033] Because the noise sources in the tunnel are numerous, with mixed frequencies and random directions, directly using existing materials would not be sufficient to form an effective detection beam. The Helmholtz resonator first extracts and amplifies the energy of the main frequencies. Then, the acoustic rainbow scatterer 4, through its spatial structure, reorganizes these sound waves into a directional, wavefront-aligned detection beam. This allows the entire device to form a complete acoustic wave manipulation chain without relying on an external power source. From the frequency-selective amplification of the resonator to the spatial shaping of the scatterer, and finally to the directional output of the transmitter, the entire process is a purely acoustic path, without any "sound-to-electricity-to-sound" conversion losses. This structural coordination enables the device to truly achieve zero additional energy consumption. The acoustic rainbow scatterer 4 plays a crucial role in this chain, receiving the energy from the resonator and preparing a high-quality signal for the transmitter. Furthermore, the design fully considers the harsh environment of the tunnel site. The acoustic rainbow diffuser 4 employs a barrel-shaped sealed structure, rigidly connected to the pre- and post-amplifier stages via a short tube sound inlet. This ensures both the airtightness of sound wave transmission and prevents energy leakage. A dust cover at the inlet also blocks rock debris and water mist. This design allows a relatively delicate acoustic structure to operate stably for extended periods in the dusty, humid, and vibrating environment of a tunnel, truly demonstrating its engineering practicality.

[0034] The core advantage of this beamforming unit lies in its spirally distributed scattering ridge 4-3 structure, which can generate different phase delays for sound waves of different frequencies, thereby achieving two-dimensional modulation of space and frequency. This allows the originally diffuse noise energy to be reconstructed into a highly directional acoustic beam, significantly improving the penetration depth and detection resolution of sound waves in rock masses. Specifically, addressing the inherent characteristics of broadband, multi-source, and chaotic incident direction noise in tunnel environments, this device abandons the traditional design path of relying on narrowband signals with a single phased array or single reflector. Instead, it adopts a radially height-gradient scattering ridge structure to form a gradient refractive index acoustic lens effect, achieving spatial decoupling and wavefront reconstruction of broadband sound waves, significantly improving energy focusing efficiency and beam directivity. Simultaneously, the spirally distributed sealed metal sound guide tube and the aluminum-magnesium alloy sound guide rod are rigidly coupled, ensuring low-loss sound transmission. Through modular packaging and dustproof and corrosion-resistant structures, it effectively adapts to the complex working conditions of high dust, high humidity, and strong vibration in tunnels, ensuring the acoustic stability and engineering reliability of the beamforming unit under long-term service conditions.

[0035] The height h(r) of the scattering ridge 4-3 of the acoustic rainbow diffuser 4 along the radial direction r2 satisfies equation (2): In the formula: h0 is the minimum ridge height, R is the curvature coefficient, R1 is the outer radius of the scatterer, and 0 ≤ r2 ≤ R1.

[0036] Among them, the first acoustic guide rod 9 and the second acoustic guide rod are aluminum-magnesium alloy rods, which are used to transmit sound waves along the rods with low loss.

[0037] The acoustic wave emitter 5 includes an acoustic reflector, preferably a fan-shaped metal acoustic reflector that can be finely adjusted within ±15° pitch angle to adapt to different tunnel face inclination angles. This allows the device to flexibly adapt to the complex and ever-changing geometry of the tunnel face, ensuring that directional sound waves always incident at the optimal angle and minimizing energy loss. The far-field sound pressure level gain G of the acoustic wave emitter 5 is given by equation (3): Where R2 is the radius of the funnel, r0 is the reference distance, and S2 / S1 is the ratio of the outlet area to the inlet area.

[0038] like Figure 4As shown, the acoustic receiver 6 includes a cylindrical housing, several echo receiving modules 6-1, a signal processing module 6-2, and connecting lines 6-3. The echo receiving module 6-1 is a stainless steel grid substrate acoustic window mesh coated with a polyurethane protective coating. The echo receiving module 6-1 is located at the wave-facing end of the cylindrical housing and is used to receive the echoes 11-5 backscattered by the rock mass. This multi-layer grid structure combined with the polyurethane coating can achieve highly selective coupling reception and low-loss transmission of weak echo signals, while effectively resisting the erosion of rock debris and water mist, ensuring the sensitivity and long-term stability of the receiver. The signal processing module 6-2 and the echo receiving module 6-1 are installed inside the cylindrical chamber. The signal processing module 6-2 and the echo receiving module 6-1 are connected. The signal processing module 6-2 is used to receive the backscattered echo 11-5 from the rock mass and process it in real time. The signal processing module 6-2 is electrically connected to the control platform 10 through the connecting line 6-3 and saves the processed echo signal to the control platform 10. The echo signal received by the acoustic receiver 6 is processed by the three-dimensional inversion model of the cavity in equation (4): In the formula: The three-dimensional coordinates of any point within the rock mass; Let A be the three-dimensional density distribution of the cavity to be determined, and let b be the sound wave propagation operator and b be the measured echo vector. The regularization coefficient is . Here, b is the total variation regularization term, and b is the calibrated frequency domain echo amplitude vector. It is a frequency domain signal amplitude, This is the system gain, used to normalize the amplitude to eliminate the effects of the transmitter and receiver frequency responses. The time-domain signal recorded by acoustic receiver 6 includes the rock mass echo sound pressure. and environmental noise The convolution result is simultaneously affected by the receiver impulse response. The impact.

[0039] The signal processing unit includes an interface 7, which is connected to the connection line 6-3, used to implement the modular configuration of the interface 7, provide flexibility for the whole machine interface 7, and be used to externally connect a data processing unit 8 to perform void three-dimensional inversion imaging and risk warning. The signal processing unit integrates a total variation regularization inversion algorithm, and its advantage is that it can stably reconstruct the boundary and density distribution of the void under noise interference, significantly improving the accuracy and robustness of the inversion. The specific configuration of the signal processing unit is: inversely calculate the three-dimensional density distribution of the void based on the total variation regularization model, and comprehensively calculate the risk index according to the distance between the void and the heading face and the density, so as to achieve risk zoning warning.

[0040] Specifically, the data processing unit 8 can be connected to the device through the interface 7, used to reprocess and image the received echo signal, generate a three-dimensional density distribution map, and achieve void three-dimensional inversion and warning; when the distance d between the void and the heading face satisfies equation (5): In the formula: d is the warning distance, is the inversion calculation domain, is the density threshold for void determination; is the three-dimensional density distribution value of any point inside the rock mass obtained by inversion through the total variation regularization model, is the preset density threshold for void determination. The two establish a logical relationship through the inequality ≥ : If the density value of a certain point ≥ , then this point is determined to belong to the void area; if the density value of < the nearest point to the heading face reference point, and define this minimum distance as the warning distance d.

[0041] The comprehensive risk index is given by equation (6): In the formula: is the volume weight, is the distance weight, and the risk zoning is only determined by the size of R: R < R1 is the low-risk area; R1 ≤ R < R2 is the medium-risk area; R ≥ R2 is the high-risk area; where , is the theoretical maximum risk index, is an empirical constant and , , α < .

[0042] This risk warning mechanism comprehensively considers two key factors: the size and distance of the cavity, enabling quantitative assessment and graded early warning of geological disaster risks, and providing a more scientific and intuitive basis for construction decisions.

[0043] The device also includes a control platform 10, which is used to realize the device's self-test, parameter initialization and early warning trigger control.

[0044] In summary, this invention, through the synergistic effect of a sound-collecting unit, an adjustable resonant cavity, a beamforming unit, a sound wave transmitting and receiving unit, and a signal processing unit, constructs a complete technical chain from "environmental noise capture → acoustic energy purification and amplification → directional beamforming → rock mass detection → echo inversion → risk warning." Its advantages are: 1) It achieves advanced geological exploration with zero artificial seismic sources and zero additional energy consumption, significantly reducing construction energy consumption and carbon emissions; 2) Through frequency tunability and beamforming technology, it solves the problems of signal attenuation and low resolution in water-rich environments using traditional methods; 3) The integrated inversion and early warning mechanism directly transforms the detection results into operable engineering risk indicators, improving the safety and intelligence level of tunnel construction.

[0045] According to a second aspect of the present invention, a method and apparatus for noise-induced energy harvesting and advanced geological inversion of water-rich tunnel cavities are provided. Utilizing the apparatus of any of the above-described solutions, the method includes: S1. Fix the device in front of the working face, start the device power supply through the control platform, and perform self-test and parameter initialization settings; S2. The sound collector covers collect noise and transmit it to the Helmholtz resonant cavity. After the sound waves are processed by the acoustic rainbow scatterer and the Helmholtz resonant cavity, they are transmitted to the rock mass in front of the tunnel face and reflected back to the sound wave receiver. The processed echo signal is then saved to the platform. S3. The data processing unit access device transmits the collected data to the data processing unit, processes the data using a preset cavity inversion algorithm, and generates a three-dimensional density distribution map (x, y, z) of cavities in the rock mass in front of the tunnel face. Based on the density distribution map ρ(x,y,z), calculate the warning distance d and monitor the change of d in real time. When d is less than the set threshold, trigger the warning mechanism. S5. Back up and analyze the collected data and the generated three-dimensional density distribution map of cavities to provide geological basis for tunnel engineering.

[0046] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0047] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0048] Through the above description of the embodiments, those skilled in the art can clearly understand that the above implementation methods can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0049] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A noise-induced energy-harvesting advanced cavity geological inversion device for water-rich tunnels, characterized in that, include: A sound-gathering unit is used to collect multi-source noise in the tunnel environment; A resonant cavity, connected to the sound collecting unit, has an adjustable resonant frequency and is used for frequency selection and sound pressure amplification of the multi-source noise; A beamforming unit, connected to the resonant cavity, is used to spatially direct and reconstruct the spectrum of the amplified sound wave through the scattering ridges set inside it, thereby forming a directional sound wave. A sound wave transmitter, connected to the beamforming unit, radiates directional sound waves to the rock mass to be tested in front of the tunnel face by adjusting the pitch angle; A sound wave receiver is used to receive echo signals backscattered by the rock mass; The signal processing unit, connected to the acoustic receiver, is used to invert the three-dimensional distribution of the cavity in front of the tunnel face based on the echo signal and generate early warning information.

2. The apparatus according to claim 1, characterized in that, The resonant cavity is a Helmholtz resonant cavity, and the ratio of its neck length to its cavity volume is continuously adjustable between 1:8 and 1:12, which is used to lock the dominant frequency noise in the water-rich tunnel environment.

3. The apparatus according to claim 1, characterized in that, The beamforming unit is an acoustic rainbow scatterer. The acoustic rainbow scatterer has a scattering ridge with a radially varying height inside, which is used to decouple the amplified sound waves spatially and directionally. The beamforming unit is connected to the resonant cavity through a first acoustic guide rod.

4. The apparatus according to claim 1, characterized in that, The acoustic wave transmitter is rigidly connected to the beamforming unit via a second acoustic guide rod. The acoustic wave transmitter includes an acoustic reflector to adapt to working faces with different inclination angles.

5. The apparatus according to claim 1, characterized in that, The acoustic receiver includes an echo receiving module and a signal processing module. The echo receiving module has a waterproof acoustic window, and the signal processing module is used to condition and convert the echo signal in real time.

6. The apparatus according to claim 1, characterized in that, It also includes a device housing, the resonant cavity is encapsulated inside the housing, the beamforming unit is embedded around the device housing, the acoustic wave transmitter is hinged to the housing via a quick-release structure, and the acoustic wave receiver is embedded in the back plate of the device housing.

7. The apparatus according to claim 1, characterized in that, The signal processing unit includes an interface for connecting an external data processing unit to perform three-dimensional inversion imaging of holes and risk warning.

8. The apparatus according to claim 7, characterized in that, The signal processing unit is configured to: invert the three-dimensional density distribution of cavities based on the total variation regularization model, and calculate the risk index based on the distance and density of cavities from the working face to achieve risk zoning early warning.

9. The apparatus according to claim 1, characterized in that, It also includes a control platform, which is used to realize the device's self-test, parameter initialization and early warning trigger control.

10. A method for advanced geological inversion of water-rich tunnels using noise-induced energy harvesting, characterized in that... The method, using the apparatus of any one of claims 1-9, comprises: S1. Fix the device in front of the working face, turn on the device power, and perform self-test and parameter initialization settings. S2. The sound collection unit collects noise and transmits it to the resonant cavity. After the sound waves are processed by the resonant cavity and the beamforming unit, they propagate to the rock mass in front of the tunnel face and are reflected back to the sound wave receiver. The processed echo signal is then saved to the platform. S3. The data processing unit access device transmits the collected data to the data processing unit, processes the data using a preset cavity inversion algorithm, and generates a three-dimensional density distribution map of cavities in the rock mass in front of the tunnel face. S4. According to the density distribution map Calculate the warning distance d and monitor the change of d in real time. When d is less than the set threshold, trigger the warning mechanism. S5. Back up and analyze the collected data and the generated three-dimensional density distribution map of cavities to provide geological basis for tunnel engineering.

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