花こう岩分離面のせん断強度特性

抄録

In this paper we describe an experimental study of the joint shear strength of granite. The specimens used were chosen from fresh rocks (0.9% in porosity) to weathered rocks (5.6% in porosity). The area of shearing plane was about 24-46 cm². Two kinds of joint planes were prepared, the one was “rough surface” split by Brazilian tensil test, the other was “smooth surface” sawcut with a diamond blade. The result obtained with a series of direct shear tests may be summarized as follows:(1) the shear strength on both surfaces can be expressed by Coulomb's friction law within applied normal stress range shown in Figs. 3 (a)-(e), (2) friction angles of rough and smooth surfaces were measured about 35°(30°-40°), 25°(23°-28°), respectively, (3) there is no effect of weathering of rock on shearing strength as shown in Fig. 6, and (4) the amount of shearing strein to peak or maximum strength was mainly influenced by the magnitude of normal stress, shown in Figs. 4, (a), (b).