This paper describes ground response analyses carried out for a major landfill in Washington State, USA, to assess the behavior of "refrigerator size" voids, their potential for propagation within the landfill, and the resulting forces that could develop in the geomembrane liner. The analyses considered the interaction of the liner with its bedding materials and the surrounding landfill materials. Although the problem is three-dimensional in nature, the analyses presented here were carried out assuming two-dimensional conditions. Parametric studies were undertaken to assess the liner forces as a function of (a) the depth between the top of the void and the landfill liner and (b) the type of material surrounding the cavity (i.e., cohesionless or cohesive). The 2,475-year seismic loading (10% probability in 250 years) was used for the design of the landfill liner system. The results of the numerical simulations indicate that the risk of propagation of the voids under seismic loading conditions is low, and that static loading conditions control the forces that develop in the liner. The forces in the liner were very sensitive to the assumed properties of the material surrounding the cavity, increasing by a factor of almost 10 if the waste material had no cohesion.
展开▼
