Abstract
The effects of compaction conditions in terms of dry density, water content and compaction energy on the strength and deformation properties of backfill were evaluated by performing triaxial compression test and plane strain compression tests on six types of sand/gravel backfill materials. The results of these laboratory stress-strain tests revealed that the compressive strength was controlled rather uniquely by compacted dry density irrespective of water content during compaction. However, the pre-peak stiffness, creep deformation and dilatancy characteristics were controlled not only by compacted dry density but also water content during compaction as well as compaction energy on granular materials. The effects of the degree of compaction Dc on the strength and stiffness of all backfill materials for Dc higher than 90% were significant while the material was very weak and soft when Dc was 90%. Furthermore, rational compaction control method of backfill discussed based on the results of laboratory stress-strain tests in the present study.
