A RAPID METHOD FOR ESTIMATING SOIL SHRINKAGE

The Coefficient of linear extensibility (COLE(std)) is often used by soil survey agencies to characterize the shrink-swell behaviour of soil. Undisturbed clods or cores are required but these are rarely collected during routine survey in Australia. The standard linear shrinkage test (LS(std)) uses sieved soil and is often used as an alternative. However, the natural soil fabric is destroyed and the results can be difficult to relate to field behaviour. We have developed a modified linear shrinkage test (LS(mod)) in which disruption to the natural soil fabric is minimized. The LS(mod) was found to be a good predictor of COLE(std) (r2 = 0-88) with the slope of the regression line close to unity. LS.td was a weaker predictor of COLE(std). LS(mod) and LS(std) were more precise measures than COLE(std). The modified method has been tested on a limited range of soils but a more comprehensive evaluation is required. This can be performed wherever COLE(std) measurements have been made and sieved material is still available.