上海市第四系的工程地质研究

通过２０余项工程代表性的钻孔岩芯分析，对比了上海市１２０ｍ以浅晚第四纪各沉积层的成因类型，形成时代，岩性及其物理力学性质，并按地基工程要求。编制了“地基土层次名称表”。表中将沉积层划分为１２个工程地质层及众多亚层。在此基础上，参照已有２０００多项工程勘察资料，编制成多时段１：５万古地理图，从而摸清了本区各土层的空间分布规律及其结构变化特征。根据地层结构差异，编制了 桩基工程地质分区图”，阐述了天然地基和三个不同桩基区岩土工程地质条件及应用中需注意的事项，为上海市工程勘察、设计和麓工提供了可靠的科学依据。

STUDY ON ENGINEERING GEOLOGY OF SHALLOW QUATERNARY SYSTEM IN URBAN AREA OF SHANGHAI

The Shanghai City is located in the south bank plain of Yangtze River. With a thickness about 130m, the Late Quaternary loose sediments in the Shanghai area have a complicated three dimensional distribution. Their lithological and mechanical properties are affected by sedimentation dynamics, sea level fluctuation, paleoclimate and paleo environment. As the foundation soil, the Late Quaternary sediments play an important role in the cost and safety of engineering construction in the Shanghai urban area. In this paper, the authors will present the engineering data derived from 20 typical bore cores. The Late Quaternary strata in the area were divided into 12 engineering layers and a series of sub layers according to their types of formation, chronology, lithology and mechanics. The authors also made a comprehensive study on the spatial distribution of soil, engineering geology and geotechnical changes of the foundation soil(less than 100 deep), as well as the paleo geography of different areas of engineering geology. The geotechnical and geological conditions of natural areas and three stub foundation areas are also discussed. The results of this study could provide reliable scientific data for the engineering survey, designing and construction in the Shanghai area.