• Journal of Korean Tunnelling and Underground Space Association
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• v.2 no.2
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• pp.41-49
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• 2000

Rock Mass Rating has been widely applied to the underground tunnel excavation and many other practical problems in rock engineering. However, Rock Mass Rating is hard, even by the experts of tunnel assessment owing to lack of investigation system. In this study, using multivariate analysis we presented rock mass rating system that is objective and easy to use. The constituents of RMR are decided to RQD, condition of discontinuities, groundwater conditions, intact rock strength, orientation of discontinuities, spacing of discontinuities in important order. In each step, we proposed the best multiple regression model for RMR system.

• The Journal of Engineering Geology
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• v.31 no.4
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• pp.719-730
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• 2021

An improved packer and injection system was developed to improve the efficiency of excavation by hydraulic rock splitting by reducing vibration and noise. Field testing of the system found hydraulic fractures limited in expansion and extension due to the loss of injection pressure by leackage from the cracks, and then the single packer applied to injection hole allowed to produce a sufficient tensile displacement for rock excavation. Numerical analysis based on the field test data could explain the development of cracks in the field experiments.

• Journal of the Korean Geotechnical Society
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• v.23 no.1
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• pp.13-21
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• 2007

Rock socketed drilled shafts are used as foundations for bridges and other transportation structures because of their load carrying capabilities. However, only limited information is available in the literature on the effects of roughness on the unit side resistance of rock socketed drilled shafts. The objective of this study is to investigate the effect of drilling tools on the socket roughness in soft clay shale in Texas. Field study showed that the drilling tools, auger and core barrel, produced different roughness in the boreholes.

• Journal of the Korean Geotechnical Society
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• v.23 no.9
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• pp.51-63
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• 2007

Behavior of rock-socketed drilled shafts subjected to axial load was investigated on the basis of pile load tests. The emphasis was laid on analyzing the shear load transfer characteristics from the shafts to surrounding rock. Field load tests were performed on nine test shafts under various conditions such as weathering of rock mass, borehole roughness, pile diameters, and loading directions. The borehole roughness at each test site was profiled using a laser borehole profiler. In order to evaluate and to propose ultimate shaft resistance($f_{max}$) of drilled shafts in rock of Korean peninsular, also, database of pile load tests was developed by reviewing various literature and technical reports.

• Geotechnical Engineering
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• v.6 no.4
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• pp.89-129
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• 1990

• Geotechnical Engineering
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• v.4 no.3
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• pp.69-73
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• 1988

• Tunnel and Underground Space
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• v.7 no.2
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• pp.158-162
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• 1997

• Magazine of the Korean Society of Agricultural Engineers
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• v.2 no.2
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• pp.342-350
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• 1959

• Geotechnical Engineering
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• v.3 no.2
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• pp.71-82
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• 1987

• Geotechnical Engineering
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• v.3 no.3
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• pp.75-96
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• 1987