含有水分による岩石の縦波速度の変化と組織との関係

抄録

Variation of longitudinal wave velocity with respect to water content was measured for various rock types by ultrasonic method, and the relation between rock texture and longitudinal wave velocity was investigated.
The experimental results show that the variation of longitudinal wave velocity is characterized by the indices of velocity difference in dry and saturated states and hysteresis phenomenon, which means here the velocity difference between evaporation and suction processes.
Comparing crystalline rocks with other rock types, the indices (Is) of velocity difference in saturated state of crystalline rocks are extremely larger than those of other rock types.This is mainly caused by the difference in rock texture.Namelyth e shape of pores in crystalline rocks is in the form of cracks. On the other hand the large indices (Id) of velocity difference in dry state are obtained by the cases of rock specimens which consist of clay minerals in matrix. From this result it is suggested that the degree of velocity increase in dry state depends on clay minerals.