Orthogonal experimental study on the compressibility characteristics of bank sandy silt based on freeze-thaw effects

The compressibility of bank soils is a critical consideration in t riverbank protection project, construction. In the Inner Mongolia section of the Yellow River, a seasonal frozen soil region, the impact of F-T cycles on soil compressibility cannot be overlooked. This study, based on F-T cycle tests, conducted orthogonal consolidation tests on embankment sandy silt from the Inner Mongolia section of the Yellow River, considering varying initial w and rho(d). It investigated the effects of different initial w, rho(d), and F-T cycles on soil compressibility, ranked and assessed the significance of influencing factors, and established a predictive model for the compressibility of Inner Mongolia section Yellow River embankment sandy silt. The results show that: the embankment sandy silt is medium-high compression soil, with a between 0.1 and 0.74 MPa-1, E-s between 2.65 and 18.47 MPa, and C-c between 0.04 and 0.24 MPa. The greater the rho(d) of soil, the smaller the initial w, the smaller the a and C-c, and the greater the E-s of soil. The F-T effect affects soil compressibility, and soil a, E-s and C-c are linearly related to the number of F-T cycles. The ranking of factors influencing soil compressibility is rho(d) > w > F-T cycles. The initial rho(d) and w are decisive factors affecting soil compressibility, while the impact of F-T cycles is relatively minor. Additionally, a regression predictive model based on the initial rho(d) and w of the soil demonstrates good performance in predicting soil compression indices. This model can be utilized for predicting the compressibility indices of embankment soil in the Inner Mongolia section of the Yellow River.