Abstract: Dredged material (DM) solidification technique was gradually put into engineering application in China, determination of the compressibility behavior cement-treated clays is of great importance to direct DM solidification engineering. Compressibility behaviour of cement solidified dredged material (SDM) was conducted through single factor experiment considering initial water content, cement content and curing time in the oedometer tests. Results show that the significant characteristics for the SDM compressibility is there exist a yield stress, when external load is below the yield stress; the compressibility is very low, however, once the external load exceed the yield stress, the compressibility of the SDM suddenly increases to more than 20 times at the post-yield state than that pre-yield state, and is also larger than that of the untreated dredged material. The untreated dredged material is belong to high compressibility soil according to criterion, and the cement treated dredged material transfers to medium or low compressibility soil. Yield stresses of SDM increase linearly with increased cement content; lower water content and longer curing time get larger yield stresses. The compressibility behaviour of SDM is similar to that of the natural sedimentary soils, double logarithm compression pattern is fitted to depict the sudden drop compressibility behaviour of SDM.

Key words: solidified dredged material, compressibility behaviour, compression index, consolidation yield stress