Shear Strain Accumulation and Stiffness Degradation in Coal Ash under Cyclic Simple Shear Loading Conditions

The coal ash collected from the disposal site contains majorly silt size particles that are highly prone to liquefaction under seismic loading conditions. The current study investigates the cyclic and post cyclic shear response of coal ash under different densities (86%, 90%, and 95% MDD). Additionally, the influence of overburden stresses (50 kPa, 100 kPa, and 150 kPa) has been investigated for the coal ash specimens prepared at 95% MDD. The results concluded that the cyclic resistance ratio (CRR) was found to be increased with an increase in the density of the specimen. However, CRR was obtained to be decreasing with an increase in the overburden stresses due to higher positive pore pressure evolution at large overburden stresses. The rapid shear strain accumulation was observed at a lower number of loading cycles for specimens subjected to higher overburden stresses. The post cyclic shear strength was obtained to be higher as compared to the specimens with no cyclic history (never experienced earthquake loading in the past).