Statistics and Analysis of Compression Index of Marine Soft Soil in Lianyungang, China

There is shallow-buried thick soft soil in Lianyungang area, and post-construction settlement is serious. Compression index (Cc) is an important parameter for calculating engineering settlement. This paper aims to systematically study the influencing factors of Cc of soft clay, as well as the correlation between Cc with physical and mechanical indices. 435 specimens were collected for consolidation tests. Pearson correlation analysis and binary linear fitting were used to resolve the correlation between Cc and physical mechanics indices. The results show that the Cc value is close to a certain value when the consolidation pressure is greater than the yield stress (σk) of soft soil. The Cc value of undisturbed soil samples is 1.14 times that of the remolded soil samples. The linear correlation coefficient of Cc with natural porosity is the highest. The next is Cc with natural water content (wn) correlation coefficient, which is different from other regions with the highest Cc-wn correlation coefficient. The correlation coefficient of Cc value with coefficient of compressibility is the highest. The fitting relationship between Cc with silt content and clay content is given for the first time, and the correlation coefficient is good. Six typical soft soils of different soft soils were selected for comparative analysis. The fitting slope of Cc-wn is higher in Jiangsu coastal and Shanghai, and the overall fit is linear fitting. Cc-wn fitting correlation of mud is slightly better than that of mucky soil in the study area. The average Cc of soft soil is relatively large in the study area, which is related to the sedimentary environment, sediment source, stress history, and clay mineral activity of the soft soil.