Within the coming years a doubling of the container handling in the ports of Hamburg, Germany, is estimated. As a consequence, a significant increase in required space for the new logistic areas is expected. To meet that demand a number of unused canals are backfilled using dredged material from the port or from the Elbe River. The sediments are backfilled in a quasi liquid state, so that they experience one-dimensional consolidation under saturated conditions. In order to study the behaviour of these fills, several laboratory long-term consolidation tests were carried out on soft organic sediments coming from the ports of Hamburg and Bremerhaven. Results show an increase in settlement rate during the secondary compression, the so called tertiary compression. The variation of the tertiary compression coefficient and start-time are investigated in relation to loading, temperature, fibre content, organic content, salinity and gas formation.
