Underground cavern event location system and method based on audible sound wave monitoring

Abstract

The application relates to an underground cavern event positioning system and method based on audible sound wave monitoring, which is suitable for the field of geotechnical engineering. The technical scheme of the application is as follows: an underground cavern event positioning system based on audible sound wave monitoring is characterized in that: a plurality of microphones are arranged at each measuring point in the cavern and are used for collecting sound signals and converting the sound pressure signals into voltage signals; a data acquisition system is connected with the microphones at each measuring point through a data transmission cable circuit and is used for recording and saving the voltage signals transmitted by each microphone; a sound signal positioning and analyzing system is connected with the data acquisition system through a circuit and is used for identifying target sound from the voltage signals transmitted by each microphone based on amplitude and frequency, determining the wave time of the target sound, and calculating the spatial position coordinates of the sound based on the wave time corresponding to each measuring point and the three-dimensional spatial position coordinates of the measuring point.

Description

TECHNICAL FIELD

[0001] The application relates to an underground cavern event positioning system and method based on audible sound wave monitoring. BACKGROUND

[0002] For concealed engineering such as underground caverns, due to the complex geological conditions (such as faults, karst caves, underground rivers, etc.), accidental geological structure movements or human actions (such as plate movement, earthquake, construction blasting, etc.) are affected, thereby causing sound in underground space, causing great psychological pressure on personnel in underground space or related areas. At present, the monitoring means for such problems basically adopts a microseismic monitoring system, but the monitoring range of the microseismic monitoring system is basically several Hz to several thousand Hz, and does not cover the entire audible sound wave band (20 Hz-20 kHz), and the microseismic signal cannot be accurately captured for some events with small energy. In addition, the current sound monitoring positioning equipment is only suitable for open areas, and sound signal collection and analysis are carried out through a multi-sensor array, and the equipment cannot be used for underground space or cavern group type concealed or scattered space. SUMMARY

[0003] The technical problem to be solved by the application is to provide an underground cavern event positioning system and method based on audible sound wave monitoring in view of the above problems.

[0004] The technical scheme adopted by the application is: an underground cavern event positioning system based on audible sound wave monitoring, characterized by:

[0005] A plurality of microphones are arranged at each measuring point in the cavern for collecting sound signals and converting sound pressure signals into voltage signals;

[0006] A data acquisition system is connected to the microphones at each measuring point through a data transmission cable circuit, and records and saves the voltage signals transmitted by each microphone;

[0007] A sound signal positioning analysis system is connected to the data acquisition system through a circuit, used for identifying target sound from the voltage signals transmitted by each microphone based on amplitude and frequency, determining the wave arrival time of the target sound, and calculating the spatial position coordinates of the sound based on the wave arrival time of each measuring point and the three-dimensional spatial position coordinates of the measuring point.

[0008] The measuring points are distributed in a three-dimensional space, and all the measuring points cannot be located on the same plane or hyperboloid.

[0009] The data transmission cable adopts a coaxial cable.

[0010] An underground cavern event positioning method based on audible sound wave monitoring, characterized by:

[0011] The present application is directed to the abnormal sound occurred in the underground space or cave group type hidden or scattered space, the approximate direction of the abnormal sound is preliminarily judged by artificial discrimination, and a three-dimensional monitoring network is designed according to the approximate direction and the arrangement scheme of the cave group.

[0012] The three-dimensional monitoring network has a plurality of microphones arranged at each measuring point in the cave, the microphones at each measuring point are connected to the same data acquisition system through a data transmission cable circuit, and the data acquisition system is connected to a sound signal positioning analysis system through a circuit.

[0013] The microphone collects the sound signal and converts the sound signal into a corresponding voltage signal, the microphone transmits the voltage signal converted from the sound signal to the data acquisition system through the data transmission cable, the data acquisition system records and stores the voltage signal transmitted by each microphone, the sound signal positioning analysis system identifies the target sound from the voltage signal transmitted by each microphone based on the amplitude and frequency, and then determines the target sound arrival time, and calculates the spatial position coordinates of the sound based on the corresponding arrival time of each measuring point and the three-dimensional spatial position coordinates of the measuring point.

[0014] The measuring points are distributed in three-dimensional space, and all the measuring points cannot be located on the same plane or hyperboloid.

[0015] The data transmission cable uses a coaxial cable.

[0016] The beneficial effects of the present application are: the present application collects sound signals through a plurality of microphones, identifies the target sound in the sound signal based on the amplitude / frequency spectrum characteristics, determines the target sound arrival time, and calculates the spatial position coordinates of the sound according to the arrival time and the corresponding three-dimensional spatial position coordinates.

[0017] The event positioning method based on sound signal monitoring proposed by the present application is suitable for underground space, cave group and other scattered spaces; the present application uses a coaxial cable as a data transmission medium, which can ensure long-distance, high-fidelity, low-attenuation and synchronous transmission of sound signals.

[0018] The event positioning method based on sound signal monitoring proposed by the present application can well monitor and locate the sound signals in the hidden and scattered space such as underground cave, and can provide a good solution to the abnormal sound and other situations that may occur in geotechnical engineering and affect the safety and normal operation of the project, and has a solving effect, which makes up for the defects of the general monitoring methods and equipment in the market. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a principle block diagram of the embodiment.

[0020] Figure 2 It is a structural schematic diagram of the embodiment.

[0021] Figure 3 A schematic diagram of microphone arrangement in the example.

[0022] Figure 4 A waveform diagram of measurement points in the example.

[0023] Figure 5 A schematic diagram of positioning results in the example. DETAILED DESCRIPTION

[0024] As shown in Figure 1 , Figure 2 , the embodiment is an underground cavern event positioning system based on audible sound wave monitoring, comprising a microphone, a data transmission cable, a data acquisition system, and a sound signal positioning analysis system. In this example, the microphone has several, which are respectively arranged at each measurement point in the cavern; the microphone is connected to the data acquisition system through the data transmission cable circuit; the data acquisition system is connected to the sound signal positioning analysis system through the circuit.

[0025] The microphone is a high-precision, high-sampling frequency, and good stability sound signal acquisition device, which can monitor the frequency range consistent with audible sound (20Hz-20kHz), and convert the sound pressure signal into a voltage signal through a transducer device to realize long-distance transmission of sound signals.

[0026] After the microphone collects the sound signal, the voltage signal is transmitted from the microphone to the data acquisition system through the data transmission cable (usually a coaxial cable). The coaxial cable has high conductivity and low impedance of the core material, which can meet the collection needs of the microphone without external power supply, and ensure the synchronization of signal acquisition and reception (the transmission delay can be ignored). In addition, the strong anti-interference ability of the double shielding layer of the coaxial cable can ensure the data stability of the signal during long-distance transmission.

[0027] The data acquisition system uses a general multi-channel vibration and sound (such as NI-9234, Chengke WebDAQ504, etc.), records and saves the sound signals collected by the multi-channel microphone, and ensures the absolute synchronization of multi-channel data acquisition time through the hardware / software settings of the acquisition system.

[0028] In the sound signal positioning analysis system, first, the original data is filtered, the amplitude / spectrum law of background noise is analyzed, and filtering is performed based on software development; then the waveform characteristics of the target sound are analyzed, the amplitude / spectrum characteristics are extracted, and they are used as the basis for determining the sound arrival time; finally, the sound signals of all microphones are analyzed, combined with their three-dimensional spatial position coordinates, based on spatial positioning algorithm, the spatial position coordinates of the sound source are calculated, which provides the basis for further analyzing the sound reason.

[0029] The arrangement principle of the measuring points in the embodiment is as follows: for the abnormal sound occurring in the underground space or the hidden or scattered space of the cavern group, the approximate direction of the abnormal sound is first determined by artificial discrimination, and a three-dimensional monitoring network is designed according to the arrangement scheme of the cavern group. The design principle is as follows: ① the measuring points are distributed in three-dimensional space, and all the measuring points cannot be located on the same plane or hyperboloid; ② the number of measuring points is greater than or equal to 5, and if the number of measuring points is less than 5, a positioning equation set cannot be constructed, and considering the distributed design of the underground cavern group, it is impossible to ensure that the monitoring signal is captured by each measuring point, therefore, enough measuring points need to be arranged; ③ the spacing between the measuring points is determined according to the test accuracy requirement and the test range, if the spacing between the measuring points is too small, too many monitoring points and equipment are needed for large-scale monitoring, and too many data channels are also needed, which is not conducive to the construction of the monitoring platform, and if the spacing between the measuring points is too large, it is difficult to capture the same signal, and it is difficult to lay a super-long monitoring cable, and it is difficult to ensure signal attenuation, signal fidelity and safe operation of the equipment.

[0030] For the abnormal sound occurring in the large underground cavern group of a certain hydropower project during operation (about 1-2 times per month), the sound is loud and dull, and the duration is short, the audible sound wave monitoring and positioning system and method proposed in the embodiment are used to monitor and position the abnormal sound, according to the measuring point arrangement principle proposed in the embodiment, the measuring point arrangement scheme is designed as shown in Figure 3 , and the three-dimensional space coordinates of the measuring points are shown in Table 1.

[0031] Table 1

[0032] Microphone number X coordinate Y coordinate Elevation 1 340456.00 3513312.30 1356 2 340627.00 3513312.30 1364 3 340755.45 3513312.30 1364 4 340269.19 3513239.00 1354 5 340477.19 3513239.00 1344 6 340647.19 3513239.00 1335 7 340866.19 3513255.40 1358 8 340231.04 3513075.01 1354 9 340466.66 3513121.50 1361 10 340610.25 3513139.61 1361 11 340763.34 3513166.21 1361 12 340941.62 3513172.79 1355

[0033] For a certain abnormal sound, the main measuring point waveform is shown in Figure 4 . The monitoring data of all measuring points are analyzed to determine the abnormal sound signal arrival time, and then the three-dimensional space positioning of the abnormal sound source is carried out combined with the space coordinates of the measuring points, and the positioning result is shown in Figure 5 .

Claims

1. An underground cavern event location system based on audible sound wave monitoring, characterized in that: Several microphones are installed at various measuring points inside the cave to collect sound signals and convert sound pressure signals into voltage signals; The data acquisition system connects microphones at various measuring points via data transmission cable circuits, and records and saves the voltage signals transmitted from each microphone. The sound signal localization and analysis system is connected to the data acquisition system circuit. It is used to identify the target sound from the voltage signals transmitted from each microphone based on the amplitude and frequency, and then determine the arrival time of the target sound. Based on the arrival time of each measuring point and the three-dimensional spatial coordinates of the measuring point, the spatial coordinates of the sound are calculated. The measuring points are distributed in three-dimensional space, and all measuring points cannot coexist on the same plane or hyperboloid; the data transmission cable is a coaxial cable. Methods for locating events in underground caverns based on audible sound wave monitoring include: For unusual noises occurring in underground spaces or cavern clusters that are hidden or scattered, manual judgment is used to preliminarily determine the approximate location of the noise. Based on the approximate location and the layout plan of the cavern cluster, a surround three-dimensional monitoring network is designed. The surround three-dimensional monitoring network has several microphones set at various measuring points in the cave. The microphones at each measuring point are connected to the same data acquisition system via data transmission cable circuits. The data acquisition system circuits are connected to the sound signal positioning and analysis system. The microphone collects sound signals and converts them into corresponding voltage signals. The microphone transmits the converted voltage signals to the data acquisition system via a data transmission cable. The data acquisition system records and stores the voltage signals transmitted by each microphone. The sound signal positioning and analysis system identifies the target sound from the voltage signals transmitted by each microphone based on amplitude and frequency, and then determines the arrival time of the target sound. Based on the arrival time of each measuring point and the three-dimensional spatial coordinates of the measuring point, the spatial coordinates of the sound are calculated.

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