CIVIL ENGINEERING 365 ALL ABOUT CIVIL ENGINEERING



AbstractA set of experimental data on the time-dependent oedometric compression behavior of sands is presented. The investigation focuses on the behavior of a clean quartz sand with respect to creep, strain-rate response, stress relaxation, and strain and strain rate history. The influence of different fine contents up to 25% by weight on creep, strain rate response, and stress relaxation are studied. The tests were conducted under vertical effective stress levels up to 7,500 kPa with specimens of medium dense and very dense relative density. The tests show a stress and density dependent creep behavior regardless of the fine content. Creep of sands with more than 14% by weight fine content can be described by a constant Cα/Cc ratio, whereas clean sand shows varying ratios. The response of the soils upon sudden changes in loading strain rate changes from clean sand, which exhibits only a temporary response of the stress-strain behavior, to the sands with more than 14% by weight fine content, which have a permanent response of the stress-strain behavior with continued straining. Stress relaxation tests show decreasing normalized stress relaxation σ/σ0 with increasing vertical effective stress. The behavior is independent of the density. It is described by the oedometric swelling index κ0. The tests on the influence of strain rate history show that the creep behavior of the sands is not dependent on it in the time scales studied.



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