Wave propagation studies conducted on laterally confined columns of three granular materials which exhibit nonlinear stress-strain behavior are described. Under these conditions, axial and lateral stresses and strains, wave velocities, and particle velocities measured at points along the column are reported. A new technique for measuring free-field displacements without physically contacting the soil is also described. A correlation between the moduli computed from the stress wave velocity, particle velocity, and the secant drawn to the stress-strain curve is presented. Relationships between stress, strain, wave velocity, and particle velocity are shown to be such that if any two of the parameters are known, the other two may be determined. Comparison of the data is made with the Hertzian theory relating confining stress to wave velocity or constrained modulus. Several interesting though preliminary observations on stress precursors resulting from initial axial stresses are presented. Based on these observations, an explanation is presented for the disparity between moduli based on constrained compression tests and those back- figured from seismic velocities.

The general approach, physical concepts, and methods employed in the actual development of the equipment are discussed. The equipment and its capabilities are described. A brief summary of concurrent reports that describe results of studies of response in granular media is presented. The summary indicates that the significant parameters have been correctly identified from theoretical mechanics and suitably measured, since results demonstrate relationships between stress-strain behavior and propagating waves in laboratory devices. The report also summarizes the broad range of protective construction problems which lend themselves to study in this equipment. These include such studies as the effects of reflection phenomena, the effects of layered media, soil-structure interaction in a high-stress field, and the evaluation of disturbances in free-field conditions caused by the presence of a gauge. The latter is shown to be possible by virtue of the ability to measure soil response without placing a gauge in the soil or attaching one to the sample. (Author).

This report describes three types of constrained compression tests, and results thereof, on dry sands. In most tests, lateral confinement was provided by a ring boundary that inhibits radial displacements while offering little resistance to axial strains. In addition, comparisons are made between results of tests in this boundary and those in the United Research Service fluid boundary. Stress-time and displacement-time records obtained from interior points along the column, indicating shocking-up, are included. Predicted peak particle velocities and shock-wave propagation velocities based on the stress-strain data are presented and compared with measured values. (Author).