Strain-rate sensitivity in sands

strain_rateAn understanding of the behaviour of soils over a wide range of strain rates and ground conditions is of interest in a variety of engineering applications, particularly in predicting soil response during blast and impact events. While the response of materials such as concrete and metals at high loading rates is increasingly well understood, a detailed understanding of the behaviour of soils is currently lacking.

This project seeks to identify whether a strain-rate effect exists in a fine quartz sand, and if so how it is mobilised, by comparing the response in a series of high-pressure one-dimensional compression tests at quasi-static and intermediate strain rates (0.001-1000 /s). The effect of moisture content on any observed effects will also be analysed, and in both test series the axial and radial stresses will be measured carefully so that the development of the specimens' three-dimensional stress state can be investigated. This is of particular importance in understanding the inertial effects which are present at higher strain rates.

Simulation of the quasi-static and dynamic experiments using LS-DYNA will provide further insight into the physics of any observed rate effects, and could form the basis of a numerical model which could be adapted to predict the response of other granular soils to loading at high strain rates.