南海珊瑚岛礁水域浅层地震反射波勘探

Investigation of seismic reflection in shallow waters of coral island and reef in South China Sea

在南海某珊瑚岛礁的工程勘察中,采用快速高效的浅层水域地震反射波勘探方法配合钻探进行联合勘察,将钻孔的"点"与物探的"线"结合起来,相互对比、佐证,进行综合解释,查明了岛礁珊瑚松散沉积物的厚度、基岩起伏形态及大范围内的连续地质剖面。勘探结果为岛礁岩土工程性状调查、水文地质调查以及工程建设提供了可靠的地质依据和设计参数,取得了理想的效果。水域地震反射波对岛礁的不同地貌单元内礁坪、向海坡、潟湖、外海的沉积层界面反映清晰,但在外礁坪区域由于现代海滩岩的发育,声波较难穿透。

The quick and effective seismic reflection in shallow waters and the geological drilling are combined in the investigation of a coral and reef island in South China Sea. The thickness of loose coral deposits,undulating bedrock and continuous geological profiling in a large scale are obtained by the comparison,corroboration and comprehensive interpretation of borehole point results and the geophysical survey line results. The prospecting results provide solid geological basis and design index for the geotechnical investigation of coral island and reef rock,hydrogeology survey and engineering construction. The reflection of the deposit interface in different geomorphic units,such as the reef flat,seaward slope,lagoon and sedimentary deposit interface is clear while the reflection in outer reef flat area is unclear due to the development of hard modern beach rock.