全景钻孔摄像技术勘测精度分析

SURVEY PRECISION ANALYSIS OF PANORAMIC BOREHOLE CAMERA TECHNOLOGY

钻孔摄像技术已逐渐被广泛地应用到各种地下勘测领域,而实际勘测环境往往受到各种外界因素的制约,与理论勘测环境存在偏差,导致实际勘测值与理论值存在误差。为此,根据钻孔摄像技术的基本原理,开展从理论上对2种钻孔电视在实际勘测工程中可能存在的误差进行分析,着重对探头处于非正中心位置勘测时产生的误差进行系统的分析研究,计算出钻孔壁的裂隙宽度,结构面的倾向、倾角和宽度的误差,此外,对因钻孔摄像勘测速度带来的误差影响进行分析,并给出建议勘测速度。通过以上研究,可以得出的结论:(1)数字全景钻孔摄像系统的探头处于非钻孔正中心勘测时,所产生的误差非常小,几乎不影响勘测精度;(2)数字钻孔摄像系统的勘测精度高于前视全景钻孔电视;(3)数字全景钻孔摄像系统更适合对结构面进行勘测;(4)钻孔摄像的勘测速度通常为1.5 m/min。

Borehole camera technology has been widely applied to various underground survey field,however,actual survey environment is often restricted by external factors and there is a difference between actual survey environment and theory survey environment,resulting in errors of the actual survey value. Therefore,according to the basic principle of borehole camera technology,we carry out the theoretical error analysis of two kinds of borehole television which may exist in the actual survey engineering and scientific research,and focuses on the systematical study when the probe is in no central of the borehole,calculating the error of fracture width,structural plane tendency,inclination and the width of structural plane on borehole wall,besides,analyzing the error influence brought by the survey speed,and giving recommendations of the survey speed. Through the above study,the conclusion can be drawn:(1) It is very small error when the probe of digital panoramic borehole camera is not in the drilling center and almost does not affect the survey accuracy and precision of the system;(2) The digital borehole camera is more accurate than axial view panoramic borehole TV;(3) The digital panoramic borehole camera system is more suitable for the investigation of structural plane;(4) The survey speed of borehole camera is suggested to be 1.5 m/min.