Geotechnical characterization of Macau marine deposits

Samples of marine deposits retrieved at an onshore old reclamation site on the north coast of Taipa, Macau were studied. Samples located from 6 m to 17 m below the existing ground were retrieved from three boreholes where field vane shear tests were performed close to one of them. The soil is very soft and the results reveal that the deposits are normally consolidated. In addition to common geotechnical classification tests, X-ray diffraction and scanning electron microscope analyses were carried out. Oedometer tests, K0-compression and undrained triaxial shear tests were performed on intact as well as laboratory remolded specimens. The deposits resemble typical soft clay behavior in terms of compressibility and permeability. However, the soils exhibit a surprisingly high K0-value which is believed to be caused by the presence of salts during the sedimentation process. Critical state of the soil is presented and two unique critical state lines in the e − ln p′ space are found for the deposits at different depths.