One‐Dimensional Loading‐Rate Effects

Abstract

It has long been recognized that the one‐dimensional or uniaxial strain response of most soils subjected to high‐intensity transient loads (i.e., blast pulses) differs from the response measured under quasi‐static loading rates. Recent research has suggested that for submillisecond rise times, increases up to 10‐fold in the loading constrained modulus occur for some remolded partially saturated granular soils under undrained conditions. Parallel research has shown that, in contrast, loading‐rate effects can be ignored for a similar granular material tested under nearly identical boundary conditions. Stress‐strain curves from 60 uniaxial strain tests are summarized and presented herein depicting the behavior of three soils (two clean sands and a silty clay) to a variety of loading rates. Loadings are typically carried to 10,000 psi (69 MPa) with times to peak ranging from a few tenths of a millisecond to several minutes. These laboratory test results show that a dramatic increase in the loading constrained...