Effect of Load Duration on Particle Breakage and Dilative Behavior of Residual Soil

This paper presents an experimental investigation of the effect of load duration on particle breakage and dilative behavior of a residual soil. To deepen the understanding of particle breakage subjected to load duration, the large-scale monotonic triaxial (TX) tests and creep TX tests were conducted on residual soil in saturated conditions. Values of particle breakage for the monotonic loading condition are compared with corresponding values for the creep loading condition calculated using a relative breakage index. For the creep TX tests, the load duration results in >1.5 times greater breakage index than the values of the monotonic TX test did. The obtained results suggest that load duration and stress level beneficially influence the particle breakage in the form of dilation suppression. The linearity is observed between the shear stress ratio and the dilation rate. A cycle with three phases is provided to help understand the creep behavior of coarse-grained residual soil: the concentration of contact stress, particle breakage, and rearrangement of crushed grains. The findings are expected to improve the understanding of the dilative behaviors of residual fills at subgrade sites. (C) 2016 American Society of Civil Engineers.