Determination of consolidation behaviour of clay slurries

The main objective of this study was to determine the consolidation behaviour of clay slurries. A fine-grained clay with high consistency limits (wL = 180%, wP = 120%) was investigated using conventional oedometer and bench-top centrifuge tests. Results indicated that the slurry had an apparent preconsolidation (due to initial conditions, electrochemical interactions, tortuous drainage, and thixotropic strength) from e = 5.7 to e = 5.5 followed by virgin compression. Likewise, the low hydraulic conductivity (10−10–10−12 m/s) was due to low porosity (small pore throats) and high tortuosity (long flow paths). Unlike consolidation of soils, the cv and mv decreased with increasing σ′ but increased with increasing e and k. The data from the two tests correlated well in the range of σ′ = 10–65 kPa, e = 5.5–3.86, k = 1.7 × 10−10–5 × 10−11 m/s, Fc = 1–40 MN. New equations were developed to correlate the consolidation parameters (e, σ′, k) with Fc. The deviation of k beyond 40 MN (e = 4.65) was due to deviation from the initial straight line portion of the settlement curve in the centrifuge test.