摘要
目前岩石力学参数测定,受限于探头及数据采集设备,多在实验室环境完成,同时,传统超声收发探头对接触面平整度要求较高,需要对岩石表面打磨处理,且需要涂抹导声糊。这些都极大限制了超声测量系统的应用范围。为实现对岩石钻孔内的长效监测,对声波发射、接收机制及岩石内超声信号的频域特性进行分析,通过AIC算法拾取波前初至,利用小波去噪和改进AIC法(NAIC)求波初至到达精确时间,研究了基于干耦合岩石内部参数测量系统,在岩石内部实现了超声信号的发射接收、信号瞬态触发、高速采集,并将最终结果通过无线方式传输至数据记录仪。分别对Φ50 mm×100 mm花岗岩及砂岩岩样进行了超声波传输参数测量,Φ114mm×280mm花岗岩岩样测量距离分别为150、200mm,利用NAIC、STA/LTA、MER、ETA 4种算法对该数据进行处理,并与第三方仪器测定结果进行比较。结果表明:基于干耦合声波测速采集系统,对不同工作接触面适应性较好,数据误差在规范允许范围内。小波降噪适用于背景干扰少、频率范围集中的超声接收信号,在到时拾取方面,除STA/LTA外其余3种算法在去噪后的到时拾取精度均得到有效提高,其中尤以NAIC法最为明显,到时平均误差由1.21?s锐减至0.19?s。
At present,the determination of rock mechanical parameters is limited to the probe and data acquisition equipment,which can only be used in the laboratory environment.At the same time,the traditional ultrasonic transceivers have high requirements for the contact surface roughness.Therefore,there is a need to polish the rock surface,and to apply sound guide paste before the analysis.The aforementioned issues have greatly limited the scope of the application of ultrasonic measurement systems.In order to achieve long-term monitoring in rock boreholes,the sound wave emission and reception mechanism and the frequency domain characteristics of the ultrasonic signals in the rock were analyzed in this study.The wavefront first arrival was picked up by the AIC algorithm,and the wavelet denoising and the improved AIC method(NAIC)were utilized to find the exact wave arrival time,and the internal parameter measurement system based on dry coupling rock was studied.The ultrasonic signal transmission and reception,signal transient triggering,and high speed acquisition were achieved inside the rock,and the final result was wirelessly transmitted to the data recorder.Ultrasonic transmission parameters were measured forΦ50 mm×100 mm granite and sandstone rock samples.The measurement distances ofΦ114 mm×280 mm granite rock samples were 150 mm and 200 mm with the use of NAIC,STA/LTA,MER and ETA algorithms.The data was processed and compared to the results of third party instrument measurements.The results show that the system based on dry coupling acoustic wave velocity measurement has good adaptability to different working contact surfaces,and the data error is within the allowable range of the specification.Wavelet denoising is suitable for ultrasonic receiving signals with less background interference and concentrated frequency range.In terms of picking-up,the other three algorithms except STA/LTA can effectively improve the pick-up accuracy after denoising.NAIC is the method with the most significant error reduction,and the
作者
刘媛
马祥华
刘洋
肖飞
陈玉海
LIU Yuan;MA Xiang-Hua;LIU Yang;XIAO Fei;CHEN Yu-hai(School of Mechanical Engineering,University of Science and Technology Beijing,Beijing 100083,China;School of Civil and Resource Engineering,University of Science and Technology Beijing,Beijing 100083,China;Korla Drilling Engineering Company,CNPC Bohai Drilling Engineering Company Limited,Bayinguoleng,Xinjiang 841000,China;Tubular Ware and Tools Technology Service Branch Company,Bohai Drill Engineering Company Limited,Cangzhou,Hebei 062552,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2020年第4期1455-1464,共10页
Rock and Soil Mechanics
基金
国家重点研发计划项目(No.2016YFC0600703)。
关键词
干耦合
数字化采集
小波降噪
改进AIC法
到时拾取
dry coupling
digital acquisition
wavelet denoising
improved AIC algorithm
arrival time picking
