Study on Creep Mechanical Properties and Constitutive Models of Silty Clay with Different Compaction Degrees

In order to ensure the smooth construction and long-term stable operation of silty clay sections in the Zhoukou–Pingdingshan highway project, this paper conducted one-dimensional creep tests on silty clay samples with different compaction degrees under different stress levels and studied the effect law of compaction degree on its long-term creep mechanical properties. By establishing the corresponding creep constitutive models, a theoretical basis was provided for the prevention and control of creep failure in silty clay subgrades in engineering practice. Research results show that: ① Under the same stress level, with the increase of compaction degree, the instantaneous strain, creep strain, and total strain of the samples all decrease significantly. Among them, the compaction degree has the most obvious inhibitory effect on the creep strain of the samples, followed by the total strain, and the inhibitory effect on the instantaneous strain of the samples is minimal; ② The variation laws of the void ratio‑logarithm of time (e-lg t) curves of samples with different compaction degrees are basically consistent, which can all be divided into three stages. At the same stress level, the total reduction in void ratio of the samples becomes smaller as the compaction degree increases; ③ Under the same stress level, with the increase of compaction degree, the parameters E1, E2, η1, and η2 in the Burgers model all show an increasing trend, indicating that the instantaneous elastic deformation, viscoelastic deformation, and the steady-state creep rate of the samples are all decreasing, while the duration of the samples in the stable-state creep stage is increasing.