Some effects of rate of loading, method of loading, and applied total stress path on the critical void ratio of a fine uniform sand

Abstract

This investigation consists of four series of anisotropically consolidated undrained triaxial compression tests with pore pressure measurements on 1.4-in.-diam specimens of a fine uniform and derived from a Mississippi River pointbar deposit. The four test series are delineated on the basis of rate of loading, method of loading, and applied total stress path. Three rates of loading were very slow, medium, and very fast; methods of loading were manually applied step function and automatically applied ramp function; applied total stress paths were axially increasing stress under constant confining stress and laterally decreasing stress under constant axial stress. Test data reduction was facilitated by computer code calculations and cathode ray tube plot routines. The critical void ratio relationships resulting from the four test series are compared along with other pertinent parameters which illustrate the observed differences in specimen responses. In addition, the distinctly different critical void ratio characteristics of another similar Mississippi River pointbar sand are compared to those of the selected test material. It is concluded that all investigated parameters exert an influence on the stress-strain and pore pressure response of the soil and to a less general extent on the relative position of the critical void ratio relationship.