Effect of Gradation and Particle Shape on the Limiting Compression Curves of Sand-Sized Siliceous Materials

The compressive behavior of soils at stresses high enough to induce particle breakage is relevant to several geotechnical applications. At these high stresses, compression curves become independent of initial density and define a limiting compression curve (LCC) that follows a power law and depends on particle characteristics. This study focuses on the effect of the particle size distribution (PSD) and particle shape on the LCC. Eleven siliceous, sand-sized mixtures were subjected to one-dimensional compression tests at vertical effective stresses ranging from 10 to 190 MPa. Because particle size affects breakage characteristics, all mixtures had a median particle size of 0.6 mm. This enabled a clear distinction between PSD and particle shape effects while minimizing particle size effects that may obscure trends. There is a direct and linear correlation between the slope and reference stress of the LCC that was previously unknown. Particle shape and PSD significantly affect particle breakage. Particle shape was the single most important predictor of the three parameters that define an LCC: slope, reference stress, and the merging stress at which the LCC begins. (C) 2021 American Society of Civil Engineers.