Measurement have been made by two methods, one is the resonance method of the longitudinal bar velocities and the other the high frequency pulse method. Saturating the rock specimens with water were found to results in a decrease of their resonance bar velocities and an increase of their pulse velocities, a change of wave velocity of rock shows that the elastic properties of rock are affected by the pore water.
Cohesive soils give rise to difficulties concerning the stability of slopes and no effective preventive measure has yet been found. In the recent years the thermal treatment of soils for im-proving the stability of cohesive soil was attempted in U. S. S. R. The procedure of thermal treatment aims to strengthen the soil around the boring hole by burning the oil for long time. The aim of our experiment is due to determine the transient temperature and moisture distribution around a hollow cylinder in which the temperature is kept constant and to estimate the effective range of strengthening of soil by thermal treatment. Using the thermal diffusivity, rate of drying and moisture diffusivity at a given temperature, the moisture and temperature distribution corresponding to a given time can be calculated. Concerning the field procedure, several examples are explained.
The Rebun tunnel passes through a thick section of Pliocene agglomerate with a layer of altered tuff breccia and the Obira tunnel passes through a zone of Miocene decomposed mudstone. In these rocks the altered tuff breccia and the decomposed mudstone were so swelling that the support or the lining of these tunnels were squeezed. The authors measured the rate of swelling and the swelling force of these rocks and analysed clay minerals in these rocks by X-ray diffraction method. The relation between the clay mineral and the swelling, and the amount of water absorption, the rate of swelling and swelling force are discussed.