FIELD-EXPERIMENTAL STUDY OF SHEAR WAVE AND THE RELATED PROBLEMS

Abstract

The author has been engaged in field-experimental studies of S waves since 1957. In this paper, he discusses fundamental aspects of the S wave from field-experimental point of view, giving systematic form to his previous works. In an earlier part of this paper, problems of detection and generation of S waves are discussed, and they are connected to the methods of S wave logging in the later part. Significance of tube wave velocity and resistivity logging are emphasized as an indirect method of S wave logging. Results of experiments suggest that both are favourable for the purpose of S wave logging. From the resistivity logs void ratios are deduced, and the relation between S wave velocity and void ratio are compared with Hardin's relations obtained by laboratory experiments. Both agree in the main essentials. Velocity variation of weathered granite, obtained in field experiment, is dicussed in connection with sample tests by other authors. Empirical relations between P and S wave velocities are presented to the system covering granular soil and siliceous rock. In the final section, significance and methods of S wave logging are discussed in connection with earthquake engineering.