• The Journal of Engineering Geology
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• v.32 no.4
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• pp.725-733
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• 2022

This study applied a hydraulic rock splitting system equipped with a hybrid packer to the bench-cut method. The hybrid packer system is an improvement of the packer developed in previous studies; it is designed efficiently to reduce vibration and noise during rock excavation by combining the two functions of inducing hydraulic fractures using injection pressure and then expanding and extending them using a rubber packer. Field experiments assessed the efficiency of rock excavation with respect to the injection conditions; the adjusted experimental conditions included the distance from the free surface and the test holes drilled at the top of the slope and the injection settings. Using a separation of 5 m left some unexcavated parts, but using a separation of 1 m left no unexcavated parts. The hydraulic fractures generated by the injection pressure developed generally parallel to the free surface and expanded and extended as the rubber packer expanded, thus facilitating bench-cut excavation. For hydraulic rock splitting to be broadly applicable to bench-cut rock excavation, it is important to accumulate results from many field experiments conducted under varying experimental conditions for various types of rockmass.

• Journal of the Korean Geosynthetics Society
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• v.16 no.2
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• pp.149-158
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• 2017

Permeating injection is commonly known as an ideal type of injection in grouting reservoir embankment, yet often-combined permeating and fracturing injection grouting operation can disturb the original soil. A grouting method has been regarded as effective and developed to ameliorate the possible disturbance problem. It involves compaction grouting with low expansive pressure near the injection hole and repetitive injection and compaction with grout material that allows ideal permeating injection. This thesis develops Hybrid Grout (ie. HG grout) that allows various application in any ground condition combined together, has high fineness and low viscosity, and expands permeation injection to silty sand. It researches on the injection effect of permeable compaction grout which is done with PC packer and is a combination of HG grout and expansion agent to obtain permeation compaction effect on the area near grout injection spot by developing Permeable Compaction Type Packer(ie. PC packer). As the developed PC packer, HG grout, and and expansion agent (HI-E) are applied to reservoir embankment reinforcement grouting, possibile permeation compaction effect that satisfies reservoir embankment grouting standard is confirmed according to the research.