堆積岩の弾性波伝播速度, 圧縮強さと含水比の関係

Abstract

Rock specimens curred at various curring circumstances were prepared for this experiment. Dilatational wave velocity measured by ultrasonic pulse method, longitudinal vibration velocity measured by resonance frequency method and uniaxial compressive strength of the rock specimens were investigated and described to water content of them.Results obtained in this paper are summarized as follows:(1) The uniazial compressive strength varies in the form of following exponential relation as a function of the water content of rocksσc=αe-bω+cWhere, σc; uniaxial compressive strength (kg/cm2), w; water content (%) and a, b and c; constants.(2) It was found that the rocks have a specific water content value which dilatational wave velocity becomes minimum. In the range of specific water content from this point to saturated state the dilatational wave velocity increases as the water content increases, and it increases again as the water content decreases in the range from the point to dry state.(3) The longitudinal vibration velocity does not increase just as the dilatational wave velocity does. The velocity does not vary or tends to decrease slightly, as the water content approaches to saturation.(4) At a certain specific water content, there is a point of inflection on this experimental curve relating of compressive strength, dilatational wave and longitudinal vibration velocity to water content of rocks. At the point of a certain specific water content, the action of the pore water is considered to divide into two stages, the one acts chiefly in free water the other acts chiefly in capillary water.