ASSESSMENT OF EARTHQUAKE HAZARDS ON WASTE LANDFILLS

Earthquake hazards may arise as a result of: (a) transient ground deformation, which is induced due to seismic wave propagation, and (b) permanent ground deformation, which is caused by abrupt fault dislocation. Since the adequate performance of waste landfills after an earthquake is of outmost importance, the current study examines the impact of both types of earthquake hazards by performing efficient finite-element analyses.

These took also into account the potential slip displacement development along the geosynthetic interfaces of the composite base liner. At first, the development of permanent deformation caused by base fault dislocation is investigated, and the axial strains of the geomembrane liner are calculated. Three levels of damage associated with fault rupture were identified: (a) rupture of clay layer, (b) maximum stress at the geomembrane equal to its yield stress and (c) surface exposure of the fault rupture through the waste mass.

In addition the stability of the waste mass, the seismic slip deformations along low-shear-strength interfaces and the tension of the geosynthetics were estimated. Results indicate that the basic factors that designate the types of failure are the ratio of the shear strength of the interface to the maximum applied acceleration as well as the tuning ratio of the landfill.