Volume 3, Issue 1 (January 1975)
Inverse Method for Determining Approximate Stress-Strain Behavior of Soils
A new approach is advanced to analyze and interpret experimental data from a compression test on a cylindrical soil specimen. With a knowledge of the applied axial and radial pressures, the overall axial deformation, and radial deformations at several discrete points on the boundary, a piecewise linear continuum model is used to calculate approximate secant and tangent values for the modulus and Poisson's ratio of two different soils. Although soil moduli are found to be highly stress dependent and significantly influenced by the dry density of the specimen, values of Poisson's ratio are relatively insensitive to these variables. Results obtained by use of this new approach can be used to evaluate the assumptions that are frequently incorporated into simpler interpretation procedures. In particular, a comparison of secant and tangent moduli determined by the proposed method with other modulus values determined by commonly used procedures reveals substantial differences and suggests the use of extreme caution when selecting values of soil parameters for use in mathematical models of soil mechanics problems.