Abstract: Jiaozhou Bay was formed through tectonic subsidence and Holocene marine transgression, resulting in the widespread distribution of soft marine clay—dominated by silty clayey mud—around the bay. Based on a comprehensive regional engineering-geological database, this study statistically analyzes the physical and mechanical properties of the representative soft-soil layers and summarizes their spatial distribution across the Jiaozhou Bay region, including the SCO Demonstration Zone and the Hongdao Economic Zone. The results indicate that soft soils are mainly distributed in Anzi Wharf, Qianwan Port, the Bonded Zone, and northern Hongshiya in Huangdao District; southeastern Jiulong in Jiaozhou City; Hetao, southern Shangma, and southern Jihongtan in Chengyang District; Bainidi Park in Licang District; and Huanle Binhaicheng and Dagang in Shibei District. Soft-soil thickness generally increases landward from the offshore margin, reaching a maximum of approximately 14.5 m. The soft soils exhibit water content of 20.0~99.5%, specific gravity of 2.68~2.77, natural density of 1.44~2.04 g/cm³, degree of saturation of 72.7~109.7%, void ratio of 0.650~2.591, plastic limit of 10.0~42.2%, liquid limit of 18.0~72.5%, plasticity index of 4.0~44.8, and liquidity index of 0.75~3.72. The compression index, compression modulus, cohesion, and internal friction angle range from 0.20~2.52 MPa^-1, 0.90~6.50 MPa, 1.0~19.9 kPa, and 1.0~19.0°, respectively.

Key words: Jiaozhou Bay, Soft Marine Soil, Engineering Geological Property, Spatial Distribution