Monotonic, Cyclic, and Postcyclic Simple Shear Response of Three Uniform Gravels in Constant Volume Conditions

This paper presents the results of large-size cyclic simple shear testing on three uniform gravels (Pea Gravel, 8-mm Crushed Limestone, and 5-mm Crushed Limestone), which varied in particle size and angularity. Monotonic, cyclic, and postcyclic shear response was assessed for these materials at two relative densities and initial vertical effective stresses up to 400 kPa. Shear wave velocity was measured in each specimen so that laboratory and field conditions could be compared. Particle angularity was shown to be an important parameter that affects peak, phase transformation (PT), and ultimate state (US) response of uniform gravels. As particle angularity increased peak, PT, and US friction angles increased. Particle size was shown to have a lesser impact on these friction angles. Peak and US friction angles were dependent on relative density, while the PT friction angle was unique for each material. Results of cyclic tests on uniform gravels in this study showed that gravels will liquefy at normalized shear wave velocities (V-S1) of up to approximately 230 meters per second (m/s). Increasing particle size, angularity, and relative density led to an increase in postcyclic shear strength. (C) 2017 American Society of Civil Engineers.