The characteristic of deep rock joints affects the mechanical behavior of rock mass in underground rock engineering, especially underground oil storage caverns. Borehole Television (BHTV) is used to investigate lithology and deep rock joints characteristic, which is dip direction, aperture and roughness, in the largest underground oil storage caverns in China. Based on the geometry relationship between inclined borehole and joints, the dip angle and dip direction has been identified by 3 points' depth and orientation, and the real aperture has been figured out by depth and orientation of 2 points of the joints trace in the BHTV image. A sinusoid ruler was proposed to measure the fluctuating quantity of the joints in images, and projected the oval roughness of borehole wall to straight line. The joints roughness was estimated by Joint Roughness Coefficient (JRC) through the relationship of Fractal Dimension and Barton's 10 standard profiles.
The characteristic of deep rock joints affects the mechanical behavior of rock mass in underground rock engineering. Generally, the characteristic of joints means the dip angle and dip direction, aperture and roughness. Those are the key parameters for rock engineering works, especially for the underground water sealed oil storage caverns because of the effect of mechanical and flow behavior of rock mass.
For investigating the deep joints, Borehole Television (BHTV) as a new technology was introduced to underground rock engineering. The image of lithology and rock discontinuous can be gained by highresolution BHTV. With the development of the BHTV technology, it has been applied to investigate joints direction (Genter et al. 1997, Williams & Johnson 2004, Glover et al. 2007, Wu et al. 2011, Li et al. 2012a), aperture (Li et al. 2012a), main flow path of rock mass (Lofi et al 2012), Excavation Damaged Zone (Li et al. 2012b), connectivity of discontinuous (Wang et al. 2009), and so on.
However, the identified method of joints direction in inclined borehole is different and more complex to the vertical one. The aperture of joints in the BHTV image is not the real one and it should be transformed. In this paper, we proposed the methods to identify joints dip angle and dip direction in inclined borehole, real aperture and roughness from BHTV image.
