DRAINED SHEAR STRENGTH OF LIME-CLAY MIXES

Lime-stabilized clay is being used for novel applications such as slope stabilization and appropriate proof tests are required. The testing of lime-stabilized clay is described in the context of different site applications and recommendations are made. Two British clays of different mineralogies have been tested in unconfined compression and in quick-undrained and slow-drained triaxial tests to examine the difference in both strength and stiffness. The results clearly demonstrate that lime-stabilized clay is a remarkably frictional material. Significant differences were found between the drained and undrained triaxial tests, whereas stiffnesses were approximately similar. In particular the frictional component of strength is shown to be more dominant in drained tests. Unconfined compression tests, which are unable to take account of frictional behavior, are shown to be of value only as index tests to establish whether lime treatment is feasible. The detailed results show that the clays can be treated with relatively low lime contents for use as bulk fill in drained applications. Atterberg Limits are reported for lime-clay mixes between 0 and 56 days after compaction and implications for reaction progress are discussed. The authors conclude that failure envelopes obtained for simulated site conditions should be used for design purposes and that other aspects, such as strain compatibility, should be considered.