Abstract
Using the silty clay specimens that were compacted in the constant energy under various water contents, unconfined compression test, in which suction and volume change of specimen were measured, was carried out. The obtained stress-strain relations showed the tendency that depends on the initial degrees of saturation of the specimens. The measured relation between the suction stress and suction at failure showed similar tendency with the predicted ones based on the water content characteristic curve. This result means the possibility of estimating the suction vs. the adhesive force relation by unconfined compression test. And. when the suction stress was taken into account as a confining net stress, the stress state at failure followed the failure criterion for unsaturated soil proposed by Fredlund, Morgenstern & Widger. This result of silty clay means that the undrained strength follows the failure criterion based on the test results test under drained condition.
