This report is an analysis of the unconfined compressive stress-strain-time behavior of a remolded plastic clay and the formulation of this response into a mathematical model or response spectra. The concept of a compliance function is employed to represent soil response over approximately nine decades of the time spectrum. Experimental data within this time range are obtained from both transient and dynamic steady-state testing techniques and formulated in terms of the Gaussian Error Integral. This integral permits the unified presentation of observed soil response by a coherent phenomenological expression and suggests the feasibility of anticipating dynamic behavior from quasi-static response characteristics. (Author).

The motivating philosophy for a rheologic study of the dynamic response spectra of soils is pre sented. Basic concepts regarding the method of approach, equipment development, experimental techniques, preparation and control of soil specimens and preliminary results of the soil response under various loading conditions in uniaxial compression are given. Dynamic visco elastic techniques are utilized and the linear and nonlinear aspects of soil response under dynamic and static loading conditions are studied. The variables considered include dynamic stress level, dynamic strain level, strain rate, static stress level, tim of loading, frequency of load application, phase angle, quasi-static strains, strain recovery, moisture content, density, un confined compressive strength and specimen geometry. (Author).

The results of an investigation of the energy storage and energy dissipation properties of a cohesive soil are presented. Major emphasis is directed at energy dissipation as well as phenomena associated with energy dissipation. Soil response is represented in terms of viscoelastic parameters. Both direct and indirect methods of determining energy dissipations are considered. Damping capacity as a function of frequency is determined directly by measuring the phase angle, delta, between applied and resulting waveforms in uniaxial (unconfined) compression with controlled sinusoidal vibration. The results are given in terms of the loss tangent, tan, delta. The loss tangent is dependent on moisture content, frequency, and amplitude of dynamic stress-strain; but specimen geometry and static stress level, within the range considered seem to have no definite effect on the results. The experimental response is definitely nonlinear. Energy dissipation is also obtained by indirect methods through the application of Fourier transformation techniques to experimental data obtained from creep and stress relaxation tests. The loss tangent relations obtained using the Fourier Transforms are comparable to those obtained by the direct stress-strain-phase angle method.