The Japanese Committee for Rock Mechanics (JCRM) is the ISRM national group of Japan, and is formed of researchers and engineers in the rock mechanics / rock engineering field and corporate members. JCRM has, as one of its most active operations, hosted the International Symposium on Weak Rock (1981), ISRM 8th International Congress on Rock Mechanics (1995), and the 2004 ISRM International Symposium: 3rd ARMS (2004) in addition to domestic symposiums. Research and development works in this field are very active and at a high-level in Japan. About one thousand papers are published annually in domestic journals and symposiums related to rock mechanics / rock engineering. However, not much of that information has been in circulation in the world. We often hear from overseas colleagues that Japan seems reluctant to dispatch information. We also hear that they want Japanese researchers / engineers to dispatch their informative work to the world. Against this background, JCRM has decided to publish its own English journal to help disseminate the Japanese research work. Nevertheless, contribution to the Journal is open not only to Japanese members. Asia in general has significant activity in rock mechanics / rock engineering, with an increasing number of rock projects being given impetus by its economic growth. It is our pleasure that the Journal could share in such a high level of activity and help disseminate this research work to the world. Contribution to the Journal is open to all ISRM members. The purpose of the Journal is, by dispatching high-level research and development papers, to promote rock mechanics / rock engineering and to contribute to academic and technical exchange internationally. To achieve the elevated goals of the Journal, the editorial advisory board counts among its members Professor Chung-In Lee from Seoul National University, in addition to several eminent Japanese professors. And in this era of information and communication technology in a globalized world, we have opted for an electronic journal. The Journal will be published in the JCRM website. All the related information such as editorial policy and instruction for authors will be found in the website. I sincerely hope that many researchers and engineers in the field of rock mechanics and rock engineering will contribute to the Journal and thus assist in making it a highly respected publication.

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On behalf of the Japanese Committee for Rock Mechanics, we are very pleased to be able to issue the first electronic journal as International Journal of the JCRM. The overall objective to issue the electronic journal is to exchange quickly new ideas, new technologies and advanced development in problem solving in rock mechanics theory and practice, to provide an opportunity to strengthen academic relation among experts from home and abroad, thereby to promote the development of practical science covering a wide field of rock engineering. Especially, unlike general journals published, we are able to see colorful illustrations and pictures in detail through the electronic journal. The Founding Committee on Electronic Journal, JCRM was founded in 2003. The members of the committee were as follows: Yoshiaki MIZUTA, Sojo University Shunsuke SAKURAI, Construction Engineering Research Institute Foundation Tsutomu YAMAGUCHI, National Institute of Advanced Industrial Sci. & Tech. Atsuo HIRATA, Sojo University, Masaru SATO, Geoscience Research Laboratory Yoshitada MITO, Kyoto University Masashiko OSADA, Saitama University Kiyotoshi SAKAGUCHI, Tohoku University After they made all sorts of preparation for issue of the electronic journal, the committee was dissolved in 2005 and they left editorial work to the Committee on Electronic Journal, JCRM, newly founded in 2005. The chairman of the committee is Katsuhiko KANEKO, Hokkaido University. We are extremely grateful to the many people who will join us to exchange scientific information. In particular, we should like to thank everyone who submits articles as Review Paper, Issue Paper, Technical Notes, Discussion, or Others. We should like to extend our thanks to everyone who has helped in issue of the first electronic journal. We are especially indebted to Prof. J. A. HUDSON, ISRM President-elect 2007-2011, who encouraged us to create electronic journal. We can promise that you will find a great deal of useful information in the following electronic journals.

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I am pleased to be able to introduce this first issue of the electronic International Journal of the JCRM (Japanese Committee for Rock Mechanics). The start of the Journal is a most constructive initiative – illustrating the dynamism of the Japanese rock mechanics community. It is also a timely initiative because we are moving rapidly towards an electronic future in rock mechanics. In 1984, when I first visited Japan for a rock mechanics conference in Kyoto, in order to arrange the visit, it was necessary to communicate by air-mail letter, i.e. snail mail, and the turnaround communication time for the letters was about two weeks. In 2004, when I made my most recent visit to Japan for a Workshop, also in Kyoto, everything could be rapidly arranged by email and the turnaround time for communication was just minutes if both people were at their computers. But it is not only email: we can now send pictures, documents, etc. and visit websites for information, all at high speed. It is difficult for us to remember how we operated before these facilities were available.

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Vision metrology using digital cameras has been used for accurately measuring the configurations of large industrial products such as ships, aircraft and automobiles. This paper refers to the application of this technique to measurement of engineering structures, mainly tunnels. Vision metrology is nearly established, but its use in civil engineering requires solution of numerous problems. A test was therefore conducted in an actual tunnel to verify its measurement accuracy for tunnel configurations to assess its applicability to convergence measurement in tunnels. The resulting measurements were as accurate as those obtained by Total Station instruments. This paper outlines the test and reports how the technique was applied to various objects on a trial basis.

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This paper presents the new classification system which identifies and designates rock masses based on their fundamental engineering characteristics. The system encompasses the stepwise procedural classification with three steps and a sub-step. The first-step is to classify rock mass into two types; (1) hard rock mass and/or its weathered or altered rock mass, and (2) soft rock mass that is not lithified enough. The second and third steps are to further classify the rock mass based on their inherent structural and physical parameters such as discontinuities, strength of rock material and others that govern the engineering properties. Most of identification items and description terms for classification parameters are adopted from internationally recognized standard (ISO14689-1), and expressed quantitatively. Since, examples on the applicability of this classification system to the actual rock mass of typical infrastructures showed well that this system is suitable for the engineering classification of rock mass.

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The authors developed a computer program for predictive calculation of transient underground climate. One can compute simultaneously the variations of flow rates, temperatures and humidities of air flow in the airways along one circuit with time passage, by using the program. They made a one simple circuit model in which heat sources are placed along the drift. The heat sources represent the metal casks in which the used nuclear fuel sticks are put. They approximated a field data set of seasonal cyclic changes of air temperature and humidity at the inlet to the sine curves. Then, they adopted those as the input data. In this paper, the variations of flow rate, temperature and humidity distribution along the model airway with time lapsed since natural ventilation started.

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Dynamic fracture process analyses for different waveforms of borehole pressure are conducted using a proposed numerical simulation method in order to verify the dynamic fracture mechanism related to blast-induced borehole breakdown. The fracture processes are affected more by the rise time increases than by the decay time. A higher stress-loading rate increases the number of radial cracks and leads to intense stress release around running cracks. The stress release caused by adjacent cracks interferes with crack extension and results in shorter crack propagation. At lower stress-loading rates, the number of cracks and the crack arrest caused by the stress released at adjacent cracks are reduced, leading to longer crack extension. These analyses reveal that the earlier preferential crack development occurs the greater the extension of the crack. The dynamic fracture process analyses are extended to investigate the influence of the waveform of applied pressure on the dynamic fracture process in a free face model. These fracture processes reveal that crack extension increases with the rise time increase.

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Mechanical behaviors of rock mass with discontinuities are of great concern. To find solutions to engineering problems such as a design of a large-scale cavern in jointed rock mass, a well-defined mathematical model must be settled. The number of joint involved in the rock mass is, however, so enormous that it is almost impossible to treat them individually. Hence, the jointed rock mass is replaced with an equivalent continuum. The point is how to ensure the equivalence between the two problems. “Micromechanics-Based Continuum (MBC) Modeling” provides a constitutive equation in the equivalent continuum problem with using an average operation of strain and stress over a representative volume element (R.V.E). In this article, the joints involved in the rock mass are regarded as microstructure and the MBC approach for the jointed rock mass is resented. To examine the performance of the proposed method, the excavation of the Shiobara powerhouse constructed by the Tokyo Electric Power Co., Ltd. is analyzed and it is demonstrated how successfully the MBC approach answers the engineering problems.

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