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http://dx.doi.org/10.7474/TUS.2018.28.3.258

Development of Integrated Type Main Frame and Downhole Sonde Apparatus for Hydraulic Packer Testing in Seabed Rock under High Water Pressure  

Bae, SeongHo (GeoGeny Consultants Group Inc.)
Kim, Jangsoon (GeoST Consultant Co.)
Jeon, Seokwon (Department of Energy Systems Engineering, Seoul National University)
Kim, Hagsoo (GeoGeny Consultants Group Inc.)
Publication Information
Tunnel and Underground Space / v.28, no.3, 2018 , pp. 258-276 More about this Journal
Abstract
The accurate and quantitative ground information on the hydraulic conductivity characteristics of rock mass is one of the key factors for evaluation of the hydro-geological behaviour of rock mass around an excavated opening under high water pressure. For tunnel and rock structures in seabed, where the sea acts as an infinite source of water, its importance become greater with increasing construction depth below sea level. In this study, to improve the problems related with poor system configuration and incorrect data acquisition of previous hydraulic packer testing equipment, we newly developed an integrated main frame and 30 bar level waterproof downhole sonde apparatus, which were optimized for deep hydraulic packer test in seabed rock mass. Integration of individual test equipment into one frame allows safe and efficient field testing work on a narrow offshore drilling platform. For the integrated type main frame, it is possible to make precise stepwise control of downhole net injection pressure at intervals of $2.0kg_f/cm^2$ or less with dual hydraulic oil volume controller. To ensure the system performance and the operational stability of the prototype mainframe and downhole sonde apparatus, the field feasibility tests were completed in two research boreholes, and using the developed apparatus, the REV(Representative Elementary Volume) scale deep hydraulic packer tests were successfully carried out at a borehole located in the basalt region, Jeju. In this paper, the characteristics of the new testing apparatus are briefly introduced and also some results from the laboratory and in-situ performance tests are shown.
Keywords
Hydraulic conductivity characteristics; Integrated type main frame; Waterproof downhole sonde; Deep borehole packer test; REV(Representative Elementary Volume);
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  • Reference
1 Bang, S.H., Jeon, S.W., Choe, J., 2003, Determination of Equivalent Hydraulic Conductivity of Rock Mass Using Three Dimensional Discontinuity Network, Tunnel and underground space, 13.1, pp 52-63.
2 Han, J., Um, J.G., 2015, Characteristics of Block Hydraulic Conductivity of 2-D DFN System According to Block Size and Fracture Geometry, Tunnel and underground space, 15.4, pp 450-461.
3 Hong, E.S., Park, E.S., Shin, H.S., Kim, H.M. and Ryu, D.W., 2008, A Numerical Analysis: Effect of Hydraulic Characteristics of a Hazardous Zone on the Face Stability in Subsea Tunnelling, Tunnel and underground space, 18.5, pp. 366-374.
4 Jeju Provincial Government, 1998, Geoligical report of the Cheju-Aewol sheet(scale 1: 50,000), pp.17-21.
5 Kim, K.S., Park, K.W. and Ji, S.H., 2010, The Development of Straddle Hydraulic Testing Equipment to Characterize Permeability in Deep Boreholes, The Journal of Engineering Geology, 20.2, pp.213-220.
6 Singhal, B.B.S, Gupta, R.P., 2010, Applied Hydrogeology of Fractured Rock, Springer, Dordrecht.
7 Zhou, Z., Zhang, L. and Liu, X., 2015, Determining Representative Elementary Volume of Fractured Rock Mass Considering Hydro-Mechanical Effect, The Electronic Journal of Geotechnical Engineering, 20.25, pp. 12647-12655.