Data collection by literature survey on rock physical properties in Japan (II)

Sato, Toshinori  ; Taniguchi, Wataru ; Fujita, Tomoo ; Hasegawa, Hiroshi

In order to understand the general thermal and mechanical properties of rock masses and initial stress of rock at depth, data were compiled from the published literature in Japan and collected from investigations carried out at Kamaishi mine and Tono mine. Statistical examinations derived the ranges, means and medians of the mechanical properties for the different rock types. It was confirmed that the correlations between the mechanical properties were in agreement with correlations determined previously in other similar surveys. The unconfined compressive strength of Neogene sedimentary rocks showed a tendency to increase with increasing depth ( 500 m). An examination of the measured initial stress data collected through literature surveys showed that the vertical stress can be approximated by the extent of gravitational loading at a particular point. There is an approximately linear relationship between the average stress in a horizontal plane and the depth. The lateral pressure coefficient tends to have a high value and large range at shallow depths, but tends towards 1 with increasing depth.