Abstract
In the cold region of Japan, many roads constructed under steep slopes are in danger of rock falls. In thiswork, the occurrence mechanism of rock fall was considered theoretically to find the proper prevention measure.
Practically, the thermal deformation of a rock plate on slope was calculated on the basis of the mechanicalmodel. In this model there was a cohesive joint between the rock plate and the slope, and a length of crack propagatedalong the joint from the upper end. There was no or a piece of rock in the crack. Next, the energy releaserate was calculated by applying the method of linear fracture mechanics, and the stress intensity factor was investigatedby changing a temperature gradient, an angle of slope and a thickness of the rock plate as a parameter.
Consequently, it was proved that the occurrence condition of rock fall was satisfied more easily correspondingto an increase of the above parameters. Furthermore, it was clarified that the occurrence frequency of rockfall became highest at the term when the temperature gradient became steepest.
