Offshore Quaternary sediments and their engineering significance in Hong Kong

Abstract

Yim, W.W.-S., 1994. Offshore Quaternary sediments and their engineering significance in Hong Kong. In: E.F.J. de Mulder (Editor), Engineering Geology of Quaternary Deposits. Eng. Geol., 37: 31-50. Investigation works undertaken for coastal engineering projects in Hong Kong has provided abundant information on the Quaternary sedimentary sequence beneath the sea floor. Although the significance of such information may not have been realized at the time of these projects, valuable lessons have often been learnt afterwards. Some examples of the important engineering applications concerning offshore Quaternary sediments include: 1. (1) The provision of information on water movement, sediment transport and sedimentation rates during the Holocene period. 2. (2) The identification of exploitable offshore sand and gravel resources. 3. (3) The interpretation of marine geophysical data through the availability of reliable borehole descriptions. 4. (4) The enhancement of engineering soil testing results and their interpretation. 5. (5) The prediction of rates of long-term ground settlement in coastal land reclaimations. 6. (6) The selection of offshore sites for waste disposal. 7. (7) The reduction in cost of coastal engineering projects through choosing the most cost-effective site. 8. (8) The provision of baseline data to assist environmental impact assessment. A new geological model is proposed for the offshore Quaternary sedimentary sequence of Hong Kong. The engineering properties of the sediments are found to be closely related to the palaco-environmental changes. © 1994.