| Summary: | 碩士 === 國立中山大學 === 海洋環境學系 === 86 === The sediments are in a state of metastable in estuary, delta, and its* nearby areas. Extensive instability of sediments could be easily caused by the addition of environmental forces. This paper was dedicated to discuss the stability and transport processes of sediments in the Tseng-wen River estuary and it*s surrounding areas. This research incorporated the knowledge and techniques of several professional fields which include marine geotechnical engineering and underwater acoustics surveying.
Based on the physical and engineering properties of sediments: the major textures of sediments were sandy silt, the sediments were transported downslope by means of suspension, the sorting of sediments was extremely poor, and the sediments were in a stress state of overconsolidation. Slumping of sediments at relative steep slopes could be easily activated by an earthquake with horizontal acceleration of 0.038 g. Under the actions of typhoon waves, the sediments with water depth shallower than 30 m were in an unstable state.
Due to underwater acoustics surveying: a series of V-shaped submarine channels were detected. These channels were perpendicular to the contour of depth and cut through the delta slope and prodelta in the Tseng-wen River estuary areas. The relief of these channels could approach 50 m. These submarine channels could be the conduits for the sediments transported from shallow to deep areas.
The conclusions of this research, especially the topic regarding the mass wasting processes of marine sediments, could offer valuable information for the development of offshore facilities in this area.
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