Effect of Particle Characteristics on Wave Velocity

Abstract

In an effort to establish a quantitative evaluation of the effect of the variables of particle size, shape and distribution on the compression wave velocity in a variety of different sands, the propagation velocity was determined of a rod wave under 112 different conditions i.e. 24 different dry sands plus four different damp sands, each at four different confining stresses. As used herein. A rod wave is a special form of compression wave that appears only in a rod like specimen subjected to particular boundary conditions where the confining stress is held constant and lateral strains are allowed to occur. The tests were divided into 4 series and details are given of sands. The test results are summarized in a table. Specimen geometry and confining stress are discussed and test equipment and procedure are described. The rod wave velocity was measured with a commercial electronic system which combines a pulse generator, source and receiver transducers, and an oscilloscope into one unit. The data obtained is reviewed. When plotted on a log-log scale, the data for any given test sequence exhibit a straight line relationship between the wave propagation velocity and confining stress. The relationship between the propagation velocity of a rod wave and the confining stress is given by a power law. It was also found that the void ratio exerts some influence on the wave propagation velocity, but the range of data is too limited to deduce any specific relationship. The effect of particle size, shape and distribution on the rod wave velocity is negligible, except insofar as they affect the void ratio.