Back-calculation of consolidation parameters from field measurements at a reclamation site

A pilot test was carried out at a land reclamation project site to study th e effect of vertical drains on the rate of consolidation of a marine clay d eposit in Singapore. Theoretical and numerical analyses were conducted to i nterpret the field measurements of pore pressure and settlement, and consol idation parameters were back-calculated. The back-calculated preconsolidati on pressure is similar to that obtained from the laboratory consolidation t est on undisturbed samples, but the field-deduced compression index is gene rally larger than that measured in the laboratory. The coefficient of conso lidation back-calculated from the settlement measurement is larger than tha t from the pore-pressure measurement. The coefficient of consolidation for horizontal flow obtained from the Rowe cell test, which is comparable to th at back-calculated from the field settlement measurement, is recommended fo r the preliminary design of vertical drains without the need of considering the smear effect.