岩盤内の地山応力と地学的に推定される地殻応力との関連について

抄録

On designing and performing underground excavation works it is desirable to measure the initial rock stress as one of fundamental data. Recently in the field of mining and civil engineering the rock stress is being measured by the stress relief technique. On the other hand, the tectonic movements, particularly the direction of stress and the strain rate, have been clarified by geological and geophysical investigations. The present paper first describes the method for estimating the tectonic stress. Subsequently, it mentions the fact that the initial rock stresses measured at the sites of Shintakasegawa and Okutataragi underground power stations are connected closely with the tectonic stresses in the respective districts.
From these investigations, it has been found that the axis of the maximum rock stress nearly coincides with that of the maximum tectonic stress. Though the experiences in determining rock stress have revealed that the stress obtained varies from one point to another and that the accuracy is not high, it may be concluded that the rock stress measured is reliable to some extent.