Intelligent Rock Acoustic Spectrum Feature Recognition System And Its Application

As an important part of engineering geological structure,rock plays a fundamental role in various engineering constructions.The instability and destruction of the rock mass will have a catastrophic effect on the project.Among these detection methods,acoustic wave nondestructive testing is an important technical means for rock quality evaluation by testing the acoustic properties of the rock,which obtained the physical and mechanical properties of the rock.The vibration signal of rock contains rich lithology information,and the spectrum signal can reflect the characteristics of the tested rock.By extracting the characteristic signal of the vibration characteristics in the sound wave spectrum of the rock,the lithology characteristics of different rocks can be identified.Since the extraction of the characteristic signals of the sound wave spectrum depends on the analysis of professionals,there is a practical engineering need to develop intelligent detection instruments that can quickly and automatically identify the characteristics of rocks.The research content and results of the thesis are as follows :(1)An intelligent rock acoustic spectrum feature recognition and analysis software has been developed.According to the spectrum characteristics of acoustic wave in the rock propagation system,based on LabVIEW development integrated environment and lithological feature identification method,an intelligent rock acoustic spectrum feature identification software have been developed.Software mainly have the waveform acquisition,data processing analysis of the rock,rock characteristics identification and data capture and storage module,realizes the acoustic signal waveform in time domain into frequency domain,frequency spectrum and signal data obtained by frequency domain signal analysis of various kinds of characteristics in the frequency domain,which can make quantitative analysis on acoustic signal.(2)The system integration of the rock intelligent acoustic wave spectrum feature identification software and application devices has been realized.Integrating software and hardware applications into a complete test system.Transducer design and improvement are carried out for rock specimens with curved test surfaces.A sound-receiving device have been developed according to the characteristics of rock acoustic wave signals.The design used multi-stage narrow-band high-frequency and intermediate-frequency filters,sound quality compression and expansion techniques to eliminate The interference of noise signals in a noisy environment improves the stability of collecting sound wave signals.After the integration of the rock sound wave acquisition test software and the hardware device system,after multiple tests and analysis,the overall application results show that different rock characteristics can be analyzed and identified better.(3)The acoustic propagation characteristics of standard specimens of five rock bodies has been tested.Through the rock acoustic attenuation frequency characteristic test,different rock waveforms,acoustic attenuation and frequency variation rules are obtained,and the acoustic attenuation coefficients of different rocks are determined.The attenuation coefficient of basalt is 0.0011,granite is 0.0236,marble is 0.0457,grey sandstone is 0.0176,red sandstone is 0.0071.According to the acoustic attenuation degree of different rocks,the rock types are identified.In this paper,the acoustic wave attenuation coefficients of different rocks has been determined through the acoustic test of typical rocks,and the rock types are judged according to the acoustic wave attenuation degree of the rocks.According to the actual needs,a rock feature recognition system based on the characteristics of the acoustic spectrum has been designed and developed,which has certain application value for the identification of rock lithology.