干耦合超声波测试技术及其岩石动静参量测试应用
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摘要
岩体非线性特征随深度增加不断凸显,其力学参量现场实时精确测量及长期监测,为地应力解除过程中岩体变化特征及应力监测提供了必要的基础。然而目前岩石力学参量测定多基于室内力学试验,时效性及拟合方法都会对测试结果带来误差。传统耦合超声波发射、接收探头对接触面平整性要求高,无法实现布置于现场钻孔内的长效监测。基于干耦合点接触声波探头测速技术,通过对声波发射、接收探头设计,电路板稳定性及去噪算法研究,研发出具有瞬时采集、无线传输功能的数字化波速采集系统。通过对同一区域取自现场加工的?50 mm×100 mm花岗岩岩样及地应力解除岩芯,分别进行室内力学试验及波速测定,以计算获取相应静态、动态弹性模量。结果表明:首先,自研发基于干耦合点接触声波测速采集系统,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。其次,对于同一区域相同岩性不同尺度、形态的岩样,其动态、静态弹性模量关系彼此间具有适用性。这就为现场基于干耦合点接触声波测速计算获得的岩体动态弹性模量,推算其静态弹性模量提供了依据。进一步的,基于干耦合点接触声波测速数字化采集系统,岩体动、静态力学参数在现场地应力岩芯解除过程及岩体长期监测过程中的实时采集及分析研究,具有一定的可行性。
The nonlinear characteristics of rock mass become increasingly prominent with the increase of depth,and its mechanical parameters can be accurately measured and monitored in real-time,which provides a necessary basis for rock mass change characteristics and stress monitoring in the process of in-situ stress relief. At present,however,rock mechanics parameter measurement is mostly based on laboratory mechanics test. Timeliness and fitting method will bring errors to test results. Conventional coupled ultrasonic transmitting and receiving probes have high requirements for the flatness of the contact surface,so it is impossible to achieve long-term monitoring in the field borehole. Based on the dry-coupled point-contact acoustic probe velocity measurement technology,through the design of acoustic emission and reception probes,the stability of the circuit board and the research of denoising algorithm,a digital wave velocity acquisition system with instantaneous acquisition and wireless transmission functions has been developed. Based on the same area taken from the scene processing?50 mm×100 mm granite rock and ground stress relieve core,the laboratory mechanics test and the determination of wave velocity were conducted,respectively,to obtain corresponding static and dynamic modulus of elasticity. The results show that firstly,the self-developed acoustic velocity acquisition system based on dry coupling point-contact has a good adaptability to different working contact surfaces,and the data error is within the allowable range of the specification. Secondly,for rock samples with the same lithology and different scales and forms in the same region,the dynamic and static elastic modulus relationship is applicable to each other. This provides a basis for calculating the dynamic elastic modulus of rock mass based on dry coupling point-contact acoustic velocity measurement and calculating its static elastic modulus. Furthermore,based on the digital acquisition system of dry-coupled point-contact acoustic velocity measurement,it is feasible to collect and analyze the dynamic and static mechanical parameters of rock mass in real time during the process of in-situ stress core relief and long-term monitoring of rock mass.
The nonlinear characteristics of rock mass become increasingly prominent with the increase of depth,and its mechanical parameters can be accurately measured and monitored in real-time,which provides a necessary basis for rock mass change characteristics and stress monitoring in the process of in-situ stress relief. At present,however,rock mechanics parameter measurement is mostly based on laboratory mechanics test. Timeliness and fitting method will bring errors to test results. Conventional coupled ultrasonic transmitting and receiving probes have high requirements for the flatness of the contact surface,so it is impossible to achieve long-term monitoring in the field borehole. Based on the dry-coupled point-contact acoustic probe velocity measurement technology,through the design of acoustic emission and reception probes,the stability of the circuit board and the research of denoising algorithm,a digital wave velocity acquisition system with instantaneous acquisition and wireless transmission functions has been developed. Based on the same area taken from the scene processing?50 mm×100 mm granite rock and ground stress relieve core,the laboratory mechanics test and the determination of wave velocity were conducted,respectively,to obtain corresponding static and dynamic modulus of elasticity. The results show that firstly,the self-developed acoustic velocity acquisition system based on dry coupling point-contact has a good adaptability to different working contact surfaces,and the data error is within the allowable range of the specification. Secondly,for rock samples with the same lithology and different scales and forms in the same region,the dynamic and static elastic modulus relationship is applicable to each other. This provides a basis for calculating the dynamic elastic modulus of rock mass based on dry coupling point-contact acoustic velocity measurement and calculating its static elastic modulus. Furthermore,based on the digital acquisition system of dry-coupled point-contact acoustic velocity measurement,it is feasible to collect and analyze the dynamic and static mechanical parameters of rock mass in real time during the process of in-situ stress core relief and long-term monitoring of rock mass.
引文
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[16]刘允芳,刘元坤.围压试验在空心包体式应变计地应力测量中的作用[J].岩石力学与工程学报,2004,23(23):3932-3937.LIU Yunfang,LIU Yuankun.Function of confining pressure test on Hollow inclusion triaxial strain gauge for geostress measurement[J].Chinese Journal of Rock Mechanics and Engineering,2004,23(23):3932-3937.
[17]冀东,任奋华,彭超,等.地应力弹性参数计算的应力区间分级方法研究[J].岩石力学与工程学报,2014,33(S1):2728-2734.JI Dong,REN Fenhua,PENG Chao,et al.A stress interval classification method for calculating rock elastic parameters in in-situ stress measurement[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(S1):2728-2734.
[18]聂运钧,肖国强,王法刚.声波法在三峡坝基岩石力学试验中的应用[J].岩土力学,2003,24(S1):175-177.NIE Yunjun,XIAO Guoqiang,WANG Fagang.Application of acoustic wave method to rock mechanical tests in Three Gorges Project dam area[J].Rock and Soil Mechanics,2003,24(S1):175-177.
[2]康红普,林健,张晓.深部矿井地应力测量方法研究与应用[J].岩石力学与工程学报,2007,26(5):929-933.KANG Hongpu,LIN Jian,ZHANG Xiao.Research and application of in-situ stress measurement in deep mines[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(5):929-933.
[3]任重阳,唐爱松.岩体工程质量分级应用研究[J].岩土力学,2003,24(S1):53-57.REN Chongyaug,TANG Aisong.Classification application research of quality of engineering rock[J].Rock and Soil Mechanics,2003,24(S1):53-57.
[4]赵航,李新平,罗忆,等.裂隙岩体中弹性波传播特性试验及宏细观损伤本构模型研究[J].岩土力学,2017,38(10):2939-2948.ZHAO Hang,LI Xinping,LUO Yi,et al.Characteristics of elastic wave propagation in jointed rock mass and development of constitutive model by coupling macroscopic and mesoscopic damage[J].Rock and Soil Mechanics,2017,38(10):2939-2948.
[5]王贵宾,杨春和,郭应同,等.川东北地区岩石纵波速度分布特征和响因素的试验研究[J].岩石力学与工程学报,2011,30(S1):2834-2842.WANG Guibin,YANG Chunhe,GUO Yingtong,et al.Experimental research on distribution characteristics and influential factors of pwave velocity for rocks in northeast region of sichuan province[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(S1):2834-2842.
[6]李楠,张新,王达轩,等.煤样吸水全过程纵波波速变化规律及波形特征实验研究[J].岩石力学与工程学报,2017,36(8):1921-1929.LI Nan,ZHANG Xin,WANG Daxuan,et al.Experimental study on the variation of P-wave velocity and waveform characteristics during the whole process of water absorption of coal samples[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(8):1921-1929.
[7]朱合华,周治国,邓涛.饱水对致密岩石声学参数影响的试验研究[J].岩石力学与工程学报,2005,24(5):823-828.ZHU Hehua,ZHOU Zhiguo,DENG Tao.Acoustic parameters of lowporosity rock under dry and saturated conditions[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(5):823-828.
[8]徐晓炼,张茹,戴峰,等.煤岩特性对超声波速影响的试验研究[J].煤炭学报,2015,40(4):793-800.XU Xiaolian,ZHANG Ru,DAI Feng,et al.Effect of coal and rock characteristics on ultrasonic velocity[J].Journal of China Coal Society,2015,40(4):793-800.
[9]陈宇龙,张玉.不同温度热处理石灰岩的物理力学性质试验研究[J].岩石力学与工程学报,2017,36(S2):3732-3739.CHEN Yulong,ZHANG Yu.Experimental study of physical and mechanical behavior of limestone subjected to different heat treatment temperatures[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(S2):3732-3739.
[10]司文朋,杨勤勇,王辉明,等.耦合方法对岩样声波速度测试影响的实验分析[J].地球物理学进展,2018,33(5):1951-1955.SI Wenpeng,YANG Qinyong,WANG Huiming,et al.Experimental analysis of the influence of coupling methods on rock samples acoustic velocity measurement[J].Progress in Geophysics,2018,33(5):1951-1955.
[11]SHEVALDYKIN V G,SAMOKRUTOV A A,KOZLOV V N.Ultrasonic low-frequency transducers with dry dot contact and their applications for evaluation of concrete structures[P].Ultrasonics Symposium,Proceedings,2002 IEEE,2002.
[12]尤明庆,苏承东.利用纵波探头测量横波速度的试验[J].岩石力学与工程学报,2003,22(11):1841-1843.YOU Mingqing,SU Chengdong.Measurement of s-wave velocity with probes for p-wave[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(11):1841-1843.
[13]柳建新,刘文劼,童孝忠,等.超声波单面平测法检测中的若干问题及改进方法[J].水资源与水工程学报,2011,22(5):20-23,28.LIU Jianxin,LIU Wenjie,TONG Xiaozhong,et al.Some problems in one-side way of ultrasonic wave method and improving measures[J].Journal of Water Resources&Water Engineering,2011,22(5):20-23,28.
[14]晏露超.混凝土结构裂缝的超声波平测法研究[D].长沙:中南大学,2010.YAN Luchao.Research on crackdetecting in concrete structure with ultrasonic single plane detecting method[D].Changsha:Central South University,2010.
[15]HARDYJHR.Acoustic emission/microseismic activity[M].Pennsylvania,USA:A.A.Balkema Publishers,2003:29-33.
[16]刘允芳,刘元坤.围压试验在空心包体式应变计地应力测量中的作用[J].岩石力学与工程学报,2004,23(23):3932-3937.LIU Yunfang,LIU Yuankun.Function of confining pressure test on Hollow inclusion triaxial strain gauge for geostress measurement[J].Chinese Journal of Rock Mechanics and Engineering,2004,23(23):3932-3937.
[17]冀东,任奋华,彭超,等.地应力弹性参数计算的应力区间分级方法研究[J].岩石力学与工程学报,2014,33(S1):2728-2734.JI Dong,REN Fenhua,PENG Chao,et al.A stress interval classification method for calculating rock elastic parameters in in-situ stress measurement[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(S1):2728-2734.
[18]聂运钧,肖国强,王法刚.声波法在三峡坝基岩石力学试验中的应用[J].岩土力学,2003,24(S1):175-177.NIE Yunjun,XIAO Guoqiang,WANG Fagang.Application of acoustic wave method to rock mechanical tests in Three Gorges Project dam area[J].Rock and Soil Mechanics,2003,24(S1):175-177.