1962 年 78 巻 893 号 p. 803-808
The stress conditions for fracture of rock around underground openings have been investigated experimentally as well as theoretically, and it has been found thct tension fracture took place where about a half the stress calculated by the theory of elasticity reached the tensile strength, while compression fracture took place where about 0.95 times the theoretical stress reached the compressive strength.
It is found, therefore, that calculation of stress by the theory of elasticity affords an effective material to foresee possible fracture of rock. Further it is shown that the state of stress around underground openings is, to some extent, inferred by investigating whether or not fractures occur around them, and if any, how they are.