Abstract
The purpose of this study is to develop a method of measuring thermal diffusivity in rock core and rock mass by the optional heating method without the restriction of heating conditions. The conventional method of measuring thermal diffusivity in rock has many restrictions of heating conditions, such as form of specimen, adiabatic condition and so on. Therefore, we cannot easily measure thermal diffusivity in rock core and rock mass.
In the measurement method proposed in this paper, rock core is heated from its surface and the temperature in the core is measured. Then, its thermal diffusivity is calculated from the change in the temperature by the proposed method. Furthermore, this technique is applied to rock mass. In the in-situ measurement, holes are drilled in the rock mass, in which a cylindrical heater and thermocouples are inserted. By this method, it is possible to investigate an effect of discontinuity surface in rock mass.
The results of the experiments show that the appropriate thermal diffusivity of rock can be obtained by using the proposed method, and also reveal that the thermal diffusivity of rock mass tends to decrease remarkably owing to discontinuity in rock mass.
