Study of cone penetration rate effects in the Yellow River Delta silty soils with different clay contents and state parameters

Abstract

The penetration rate effect is a critical factor in the properties assessment of silty soils in the Yellow River Delta using CPTu. This paper discussed the factors affecting penetration rate effect of silty soils in the Yellow River Delta through variable penetration rate tests in a pressure chamber, a series of supplementary soil element tests and FE calculations. Samples, consisting of varying proportions of Yellow River Delta silt and kaolin clay that produce three clay contents of 13%, 20% and 30%, are mixed as slurry and consolidated to five state parameters of −0.27, −0.17, −0.1, 0 and 0.03. In the Yellow River Delta silty soil layers, clay content has a significant effect on the soil's drainage characteristics, and state parameters have a significant effect on viscous effects. With the increase of clay content, the Bq value increases, and a Bq value of close to zero at any penetration rate is a sign of silt. A normalized partial drainage influence equation is proposed. A practical recommendation is that Nkt(u) in the shallow silty soil is 9.5–9.9, and Bq can be used to judge drainage conditions. The partial drainage equation and Nkt(u) provide insight into the inversion of silty clay strength.