Physical and Mechanical Characteristics of Soft Soil in Lower Reaches of Yangtze River

Based on large numbers of geotechnical tests, the physical and mechanical characteristics of soft soil (including clay and silty clay) in the foundation of Sutong large bridge in lower reaches of Yangtze River, Jiangsu province, China, is studied. The following conclusions can be drawn. Firstly, the variation coefficient of natural density, dry density, specific gravity of soil grain, saturation are small; the variation coefficient of natural water content, natural hole ratio, liquid limit, plastic limit are generic; and the variation coefficient of plasticity index, compress module, compress coefficient, coherent strength, inner friction angle, the standard penetration test (SPT) are big. Secondly, there exist good linear correlativity between natural density, hole ratio and natural water content, their correlativity coefficients are over 0.95. Thirdly, there is not linear correlativity between plastic limit and liquid limit, but there is better linear correlativity between plastic limit and liquid limit to clay. And the correlativity between plasticity index and liquid limit is good, and the correlativity coefficient is 0.90056. Fourthly, there exist good linear correlativity between compress coefficient and natural hole ratio, natural water content, their correlativity coefficients are over 0.90. There exist good exponential correlativity between compress module and natural hole ratio, natural water content, their correlativity coefficients are over 0.85. Finally, there exist better exponential correlativity between coherent strength and natural density, natural hole ratio; the relativity between inner friction angle and natural density, natural hole ratio are not obvious.