This paper describes an integrated study on sedimentary environments of Holocene deposits near Lake Jinzai in the Izumo Plain using CNS elemental analysis and its application to geotechnology. The weight ratios of total organic carbon to pyrite sulfur (C/S ratio) and total organic carbon to total nitrogen (C/N ratio) and total sulfur (TS) are useful for evaluating sedimentary environment. The geological processes of the Lake Jinzai area during the Holocene is also described.
In addition, the influence of variation of calcite (CaCO₃) content on observed strength-deformation characteristics with depth is investigated. Quantitative relationships between CaCO₃ content and strength-deformation characteristics for cohesive soils of the Lake Jinzai area have been developed as a result of this work, i. e, strength-defomation characteristics increase as the CaCO₃ content of the soils increases. Finally, this study emphasizes to geotechnical engineers the necessity of integrated evaluation for the refinement of construction technology.