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Open AccessArticle

Investigation of Key Parameters of Rock Cracking Using the Expansion of Vermiculite Materia

Korea Railroad Research Institute (KRRI), Uiwang-si, Gyeonggi-do 437-757, Korea
Department of Civil and Environmental Engineering, Incheon National University, Incheon 406-840, Korea
Incheon Disaster Prevention Research Center, Incheon National University, Incheon 406-840, Korea
Author to whom correspondence should be addressed.
Academic Editor: Jorge de Brito
Materials 2015, 8(10), 6950-6961;
Received: 15 July 2015 / Revised: 13 September 2015 / Accepted: 28 September 2015 / Published: 12 October 2015
PDF [5557 KB, uploaded 12 October 2015]


The demand for the development of underground spaces has been sharply increased in lieu of saturated ground spaces because the residents of cities have steadily increased since the 1980s. The traditional widely used excavation methods (i.e., explosion and shield) have caused many problems, such as noise, vibration, extended schedule, and increased costs. The vibration-free (and explosion-free) excavation method has currently attracted attention in the construction site because of the advantage of definitively solving these issues. For such reason, a new excavation method that utilizes the expansion of vermiculite with relatively fewer defects is proposed in this study. In general, vermiculite materials are rapidly expanded in volume when they receive thermal energy. Expansion pressure can be produced by thermal expansion of vermiculite in a steel tube, and measured by laboratory tests. The experimental tests are performed with various influencing parameters in an effort to seek the optimal condition to effectively increase expansion pressure at the same temperature. Then, calibrated expansion pressure is estimated, and compared to each model. After analyzing test results for expansion pressure, it is verified that vermiculite expanded by heat can provide enough internal pressure to break hard rock during tunneling work. View Full-Text
Keywords: key parameters; rock cracking; thermal expansion; vermiculite key parameters; rock cracking; thermal expansion; vermiculite

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Ahn, C.-H.; Hu, J.W. Investigation of Key Parameters of Rock Cracking Using the Expansion of Vermiculite Materia. Materials 2015, 8, 6950-6961.

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