Laboratory tests were conducted on selected granular materials to determine the velocities of propagation of the shear and compression waves and to evaluate the internal damping. Test variables included the confining pressure, amplitude of vibration, void ratio of the material, saturation, and grain size. Resonant column tests were used for wave velocity evaluation, and the vibration decay method and static torsion tests were used to determine damping. The granular materials used were Ottawa standard sand, two sizes of glass spheres, and a crushed quartz. Confining pressure had the most significant effect on velocities of wave propagation, with velocities increasing about with the 1/4 power of the confining pressure. Damping determined from the decay o steady state vibrations behaved like viscous damping. The values of logarithmic decrement varied from about 0.02 to 0.20 for these materials and test conditions. Higher values of logarithmic decrement were found in the static torsion tests because tresses up to 75 per cent of the failure conditions were used. (Author).

Sponsored by the Geo-Institute of ASCE This collection of 78 historical papers provides a wide view of the rich body of literature that documents the development of fundamental concepts geotechnical engineering and their application to practical problems. From the highly theoretical to the elegantly practical, the papers in this one-of-a-kind collection are significant for their contributions to the geotechnical engineering literature. Among the writings of more than 60 geotechnical engineering pioneers are several by Karl Terzaghi, widely known as the father of soil mechanics, R.R. Proctor, Arthur Casagrande, and Ralph Peck. Many of these papers contain information as useful today as when they were first written. Others provide great insight into the origins and development of the field and the thought processes of its leaders.