Determination of consolidation behaviour of clay slurries

Abstract

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 (10−10–10−12m/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′=10–65kPa, e=5.5–3.86, k=1.7×10−10–5×10−11m/s, Fc=1–40MN. New equations were developed to correlate the consolidation parameters (e, σ′, k) with Fc. The deviation of k beyond 40MN (e=4.65) was due to deviation from the initial straight line portion of the settlement curve in the centrifuge test.