Consolidation characteristics of the turfy soil in seasonally frozen area

The turfy soil in seasonally frozen regions has very poor engineering properties, with high compressibility and obvious creep characteristics. The settlement of roadbed after construction is large. Therefore, it is urgent to conduct in-depth researches due to the lack of consolidation compression and creep characteristics researches of turfy soil in seasonally frozen regions, so as to provide parameters for the settlement prediction of the turfy soil roadbed in seasonally frozen regions. The typical turfy soil in seasonally frozen region near the Jiangyuan town of the city of Dunhua in Jilin Province is selected as the research object. Through 1D consolidation compression test and 1D consolidation creep test, the distribution range of the compression coefficient, consolidation coefficient and secondary consolidation coefficient of the turfy soil and the influence of fiber content on the primary and secondary consolidation characteristics of the turfy soil are obtained. The experimental results show that under graded loading, the greater the fiber content is, the stronger the compressibility of turfy soil is, showing a positive correlation. Consolidation coefficient (C_v) ranges from 1.00×10⁻³ to 8.39×10⁻³ cm²/s. C_v decreases with the increase of consolidation pressure. When the consolidation pressure exceeds 200 kPa, C_v is basically in a stable range. The secondary consolidation coefficient (C_α) ranges from 0.022 to 0.095. C_α increases with the increasing consolidation pressure, then decreases gradually after reaching the peak value when the corresponding consolidation pressure varies between 50 kPa and 100 kPa. When the consolidation pressure is constant, the higher the fiber content is, the more obvious the consolidation creep is, and the higher C_α is. There is a certain correlation between the secondary consolidation coefficient and compression index of the Dunhua turfy soil in Jilin Province. The C_α/C_c numerical values corresponding to the turfy soil with the fiber content of 21%, 34%, 48%, 59% and 73% are 0.0452, 0.0331, 0.0303, 0.0246 and 0.0245, respectively.