Stress Propagation in Soils

Stress Propagation in Soils
Author: L. Seaman
Publisher:
Total Pages: 202
Release: 1963
Genre: Soil mechanics
ISBN:

A knowledge of soil motions resulting from nuclear explosions is necessary for the design of underground structures which are to survive a nuclear attack. In this project the authors studied wave propagation in soil and developed methods for predicting wave propagation phenomena based on data from laboratory compression tests on soil samples. The study was restricted to one-dimensional wave propagation in a sand and a clay. Extensive wave propagation tests were made on 5-meter columns of Monterey sand of various densities subjected to transient loads of different intensities and duration. Stresses and particle velocities were measured at various locations in the column to test the validity of theoretical models representing sand. The main feature of stress wave propagation--stress attenuation--can be predicted for sand on the basis of a rate-independent model. In addition, wave front development, wave velocity, particle velocity attenuation, and duration of the stress wave are described qualitatively by this model in combination with a second rate-independent model. The parameters of the models can be determined from static or dynamic compression test data on small samples of sand. (Author).

Study of the Dynamic Stress-strain and Wave-propagation Characteristics of Soils

Study of the Dynamic Stress-strain and Wave-propagation Characteristics of Soils
Author: James V. Zaccor
Publisher:
Total Pages: 160
Release: 1964
Genre: Sand
ISBN:

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).

One-dimensional Stress Wave Propagation in Soils

One-dimensional Stress Wave Propagation in Soils
Author: Lynn Seaman
Publisher:
Total Pages: 175
Release: 1966
Genre:
ISBN:

Soil behavior during stress wave propagation was studied on a sand and two clays by making one-dimensional wave propagation tests on 5-meter long columns of the soils. Attempts were made to predict this behavior by determining soil properties in dynamic compression tests on small samples and by using these properties in a variety of mathematical models for soils. In all the wave propagation tests, stress and acceleration records were very similar, showing that the three soils differ in degree, not in kind. Peak stress and particle velocity attenuated to 20-40% of the peak value in the length of the 5-meter column. Two theoretical soil models were analyzed: one to investigate the effect of combined time-dependent and time-independent dissipation, and one to study the effects of nonlinear stress-strain relations and geostatic stress. Comparison of the theoretical predictions from the first of these and two previously studied models (using properties obtained from compression tests on soil samples) with the wave propagation results shows: (1) For clays the arrival time of the wave at the column base was within 10% of that calculated from the tangent modulus, and for sand it was within 25%. (2) Attenuation of peak stress and particle velocity was predicted within plus or minus 50% at the base of the column (5-meter length). (Author).

Theoretical Studies of Stress Wave Propagation in Laterally Confined Soils

Theoretical Studies of Stress Wave Propagation in Laterally Confined Soils
Author:
Publisher:
Total Pages: 0
Release: 1999
Genre:
ISBN:

In order to overcome the mathematical difficulties in the solution of one-dimensional stress wave propagation in soils, real soil stress-strain relationships are often idealized by various simple mathematical models. A considerable body of scientific literature on one-dimensional stress wave propagation for such models has been published in recent years by various researchers, both in the United States and abroad. The pertinent literature applicable to one-dimensional stress wave propagation in soils are collected and studied in detail. Comparative studies are made with the various mathematical models for a wave propagation problem. Fortran computer programs for each of the analytical solutions are included as appendixes.