Abstract
Sand-non plastic fines mixtures show a transitional mechanical behaviour as the fines content increases from a low level to a high level. The transition fines content, which is the boundary between sand-dominated and fines-dominated behaviour, can be found by simple laboratory tests e.g. maximum/minimum void ratio or stress path tests e.g. location of the normal compression line. The small-strain stiffness of sand-fines mixtures is supposed to have a similar transitional trend when the fines content is high enough to reach the transition fines content. A series of tests with local LVDTs was performed on samples of Leighton Buzzard sand mixed with non-plastic silt. The tests were performed during isotropic compression and shear tests in a triaxial apparatus. The fines content range was large enough to determine how the small-strain stiffness changes with the fines content. The value of transition fines content found from the triaxial tests are compared with those found from the bender element test results. Possible similarities and/or differences are discussed.
