Abstract: Gray clay of Zhanjiang Formation which widely distributes in Zhanjiang area have caused a series of geotechnical engineering problems in actual projects due to their strong structural characteristics which aroused great interest among Chinese scholars in 80 s of 20 century. It is difficult to understand the distribution of the Zhanjiang Formation, because different sedimentary environment shows different spatial distribution of the Zhanjiang formation in Leizhou peninsula. According to the data from site geology survey, 27 geological drillings had been done for the gray clay samples in different regions considering lots of factors such as topography, geological structure at Leizhou Peninsula as well as the sedimentary environment of Zhanjiang Formation. The typical profiles of different areas showed that gray clay had different sedimentary cycles, buried depth and thickness in different sedimentary environment. Its distribution is regional. The influences of gray clay on real projects were studied based on its buried depth and thickness. Additionally, a 3D geological model of spatial distribution of gray clay was established by using MAPGIS based on drilling survey data. This geological model can be used to study the spatial distribution of Zhanjiang Formation gray clays, and realized the visualization of gray clay spatial distribution. Finally, some basic applications of the proposed model are introduced.

Key words: Zhanjiang Formation gray clay, spatial distribution law, 3D geological modeling