Site Characterization for Container Terminal Project at North Coast of Jakarta City by In-Situ Testing

New container port terminal is to be constructed in the Jakarta offshores. The seabed in the project location is generally very soft, and the thickness may vary. Undisturbed sampling is difficult, and disturbance cannot be avoided. Consequently, it is required to perform a set of in-situ soil testing. This paper presents site characterization of an offshore-container terminal by in-situ tests. Several types of insitu tests have been performed on the port area, which is drilling with SPT, mechanical CPT, CPTu (piezocone), and Vane Shear Test (VST). All of the test results are compared to investigate the variation of the ground condition, as well as to check the consistency between the tests. In general, the results show that the subsurface condition is soft clays with the thickness varies from 11.0 to 18.5 m, and with the cone resistance (qc) value of 0.2 – 0.4 MPa. Underneath is a dense sand layer with an average SPT N-value of 50 blows/0.3 m. Furthermore, interestingly it is found diluvium clays deposit below the sand layer, with an average of cone resistance (qc) of 2.0 MPa. Besides, interpretation of geotechnical parameters of the soft clay deposit is also presented. The use of Bq* parameter (Rahardjo, 2016) is introduced to interpret the results better, and it is mainly used for the detection of under-consolidation behaviour.