Cyclic Behaviour and Dynamic Properties of Soils Under Simple Shear Loading

An experimental study was carried out on sensitive clays obtained from Eastern Canada and sand obtained from the Fraser Delta. Large strain tests were conducted to investigate the monotonic and cyclic behaviour of clays. Small strain tests were carried out at different consolidation stress levels to investigate the dynamic properties of soils. Tests were performed using the Carleton University simple shear device, which was modified to enable confident measurements at small strains.Results show that shear strength of clays is influenced by consolidation stress, OCR and clay content. Tested clays have relatively strong cyclic resistance at in-situ stress, but resistance decreased significantly if clays are normally consolidated.Site-specific modulus reduction and damping curves are proposed for Ottawa-Quebec area clays and sand. These site-specific curves are unique for sensitive clays and curves generated for sand are close to the average and lower bound curves reported in the literature.