Wave Propagation Attenuation and Threshold Strains of Fully Saturated Soils with Intraparticle Voids

The prediction of ground response against wave propagation is essential for construction materials and the safe design of civil engineering infrastructures, such as, embankments, retaining walls, or foundations subjected to machine vibrations. For ground response analysis studies, the shear modulus and material damping, which are expressed as a function of shear strain, are the important properties of soils. The volumetric threshold strain is also a key property in order to evaluate possible permanent deformations or substantial increase in pore water pressure in saturated soils during dynamic loading. The paper presents dynamic test data derived from resonant column experiments on volcanic granular soils which are characterized by low unit weight and weak grains of intraparticle voids. These materials can be used as potential lightweight backfill in retaining walls or other applications with a demand in reduction of vertical or horizontal stresses to the ground and structural facilities. Additional experiments on quartz sands were conducted for comparison. The volcanic soils had much lower small-strain shear modulus than that of quartz sands and higher linearity in the range of medium strains, by means of normalized stiffness and material damping curves. The elastic and volumetric thresholds were shifted to larger strains for the volcanic soils in comparison to the quartz sands. Different prevailed micromechanisms possibly contributed to these observed trends. (c) 2015 American Society of Civil Engineers.