Cone Penetration Testing for Characterizing Landfilled Municipal Solid Waste

The cone penetration test (CPT) was evaluated as a tool for characterizing landfilled municipal solid waste (MSW). Cone penetration test soundings were performed at 16 locations in a closed MSW landfill in Florida, United States, where tip resistance ($q_t$), sleeve friction resistance ($f_s$), and friction ratio ($f_r$) data were collected up to a depth of 10 m, and compared to waste properties from borings in the same location as five of the CPTs. The delineation of cover soil, waste, and subgrade soil was readily identifiable from the CPT data, but intermediate cover layers could not be discerned. At greater depths in the landfill, waste generally exhibited greater degradation with an average biochemical methane potential of $0.044\mathrm{L}{\mathrm{CH}}_4/\mathrm{g}$ volatile solids versus shallower waste that was less degraded with an average BMP of $0.200\mathrm{L}{\mathrm{CH}}_4/\mathrm{g}$ volatile solids. More degraded waste tended to have lower tip resistances of 3.6–3.7 MPa than less degraded waste that exhibited 5.0–5.4 MPa. The friction ratio tended to be greater for more degraded waste (2.8–3.2%) than less degraded waste (2.3–2.4%). The CPT data collected from the MSW landfill were also compared to conventional correlations to soil classification systems. The CPT data for more degraded waste generally correlated with finer soil classifications while CPT readings of less degraded waste corresponded to more coarse soils.