Dynamic Behavior of Granulated Coal Ash during Earthquakes

Coal ashes discharged from coal-fired power plants have recently been gaining attention as a new form of geomaterials. They have been popularly used as ground materials for the improvement of unsuitable soil and for foam-mixed solidified soil. However, development of more applications is needed in light of the enormous amount of coal ash generated. The current study was performed to confirm the applicability of granulated coal ash (GCA) as reclamation material with adequate resistance against liquefaction during an earthquake. In this study, the liquefaction characteristics of GCA were investigated through cyclic triaxial tests and online pseudodynamic response tests, and the results were compared with those of natural sands to examine the cyclic shear properties of the material. The triaxial test results revealed that the slope of the cyclic shear strength curve of GCA was gentle under high confining pressure, but it was still higher than those of natural sands. It was observed that GCA underwent remarkable particle crushing, resulting in higher cumulative dissipated energy, and this accounted for the higher cyclic shear strength when compared with natural sand. Moreover, the online pseudodynamic response tests performed using a hollow torsional shear test apparatus showed that GCA exhibited slower excess pore water pressure buildup when compared with Toyoura sand for the same level of input motion. The presence of a GCA layer in a saturated sandy ground had beneficial effects on the earthquake response.