Considering the applicability of Kuz-Ram model, which has been used extensively for predicting rock fragmentation size distribution by blasting, to domestic open-pit limestone mine, a total of 21 blasting tests have been executed at an open-pit limestone mine in eastern Gangwon of South Korea. A comparative analysis of field measured value and Kuz-Ram predicted value showed that there are a considerable amount of error in the predicted values regardless of application of various correction parameters for rock factor and uniformity factor; up to 56.45% in mean fragmentation size and 37.52% in uniformity index. Also the problem of applying different correction parameters has been derived even though a similar blasting pattern has been adopted for a same blasting bench. The authors therefore suggest that Kuz-Ram model needs to be modified for a proper application to domestic open-pit limestone mine.

Prior to the huge reclamation work for constructing Kobe Airport, the sea-wall structure resting on a 30m-thick soft Holocene clay layer in the 16m-deep sea was constructed at stages over the period of three years. Regarding the design of short-term stability of the sea-wall structure, the ratio of undrained shear strength of the normally-consolidated seabed clay to in-situ yield stress was estimated to take the value of 0.35 in order to satisfy the factor of safety in excess of 1.3. This design strength in the clay foundation was checked with the unconfined compression strength of the fresh clay samples retrieved from boreholes during the construction. In this paper, the short-term stability of the embankment in this well-documented case history was re-evaluated after-the-event with the results of comprehensive series of constant-volume direct shear box tests in which the effects of strength anisotropy as well as the shearing rate on undrained shear strength were both examined. Discussion is made how to estimate the short-term stability of the embankment by considering the effects of strength anisotropy and shearing speed on undrained shear strength and how it is linked with the current design method in Japan in which a half of the undrained compression from unconfined compression test is employed.

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This study describes the results of blasting overbreak analysis using the stereo photogrammetry method in an underground mine. For comparing its quantitative measurements, LIDAR system was applied to the test site and blasting overbreak was analyzed for 4 test blasting operations. The difference in values obtained from the two methods showed only 0.81% in volume and 1.05% in area, respectively, therefore authors verify the field applicability of stereo photogrammetry method on underground mine. The volumes of overbreak measured from 4 test blastings were 29.84 m , respectively, in photogrammetry analysis on excavation surface, and it was shown that the volume of overbreak decreases with blasting sequence. From these measurements, it is concluded that the stereo photogrammetry method can describe the underground excavation surface effectively and the its quantitative data can be used for analysis of volume, area and overbreak of excavation zone. Key words

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