岩芯力学实验的面应变耦合系数及其差值的阈值研究  

Study on the Borehole Coupling Coefficients and the Threshold of Their Difference Base on Core Mechanical Tests

作　　者：何斌[1] 李锋[1] 田韬[1] 江昊琳[1] 章东 HE Bin;LI Feng;TIAN Tao;JIANG HaoLin;ZHANG Dong(Jiangsu Earthquake Agency,3 Weigang,Nanjing 210014,China)

机构地区：[1]江苏省地震局,南京市210014

出　　处：《大地测量与地球动力学》2023年第9期931-935,共5页Journal of Geodesy and Geodynamics

基　　金：中国地震局震情跟踪定向工作任务(2022010217);江苏省地震局青年基金(202107)。

摘　　要：通过单轴压缩实验获取江苏省体应变仪钻孔岩芯的弹性模量和泊松比,利用面应变理论,计算钻孔应变仪器的理论耦合系数和实测耦合系数,探讨两者的相关性。在此基础上,引入观测精度,研究仪器的观测精度、耦合系数和数据质量的关系,确定耦合系数差值的阈值。结果显示:1)钻孔应变仪的观测精度与理论耦合系数和实测耦合系数呈正相关,钻孔应变仪的理论耦合系数和实测耦合系数一致性越好,仪器的观测精度越高,数据质量越好。2)江苏省各台站面应变的理论耦合系数和实测耦合系数差值的阈值为0.1。差值小于0.1时,观测数据质量较高;差值在0.1~0.2之间时,井下耦合对观测精度有一定影响,但不显著;差值超过0.2时,井下耦合存在问题,仪器的观测精度较低,数据的观测质量较差。Through uniaxial compression test,we obtain the elastic modulus and Poisson’s ratio of the drill core of the borehole strainmeters in Jiangsu province.We calculate the theoretical coupling coefficient and the measured coupling coefficient of the borehole strainmeters using surface strain theory,and discuss their correlation.On this basis,we introduce the observation accuracy,study the relationship between the observation accuracy of the instrument,the coupling coefficient and the data quality,and determine the threshold of the difference of the coupling coefficient.The results show that:1)The observation accuracy of the borehole strainmeter is positively correlated with the theoretical coupling coefficient and the measured coupling coefficient.The better the consistency between the theoretical coupling coefficient and the measured coupling coefficient,the higher the observation accuracy of the borehole strainmeters and the better the data quality.2)The threshold of difference between the theoretical coupling coefficient and the measured coupling coefficient of the surface strain at each station in Jiangsu province is 0.1.When the difference is less than 0.1,the observation data quality is higher.When the difference is between 0.1 and 0.2,the downhole coupling has a certain,but not significant,effect on the observation accuracy.When the difference exceeds 0.2,downhole coupling problems occur,resulting in low instrument observation accuracy and poor data observation quality.

关 键 词：体应变仪 岩石力学 耦合系数 阈值 

分 类 号：P315[天文地球—地震学]