Study on the creep characteristics and modified burgers model of silty fine sand under seepage conditions

The soil's creep characteristics significantly impact both the effectiveness of the support system and the enduring stability of the engineering structure. During construction, dewatering is often carried out, which results in seepage within highly permeable soils. To scrutinize the creep behavior of silty fine sand under seepage conditions, triaxial compression tests and triaxial creep tests were conducted on the silty fine sand, subject to three distinct seepage flow rates: 0.5 ml/min, 1.0 ml/min, and 1.5 ml/min. The test results indicate that seepage reduces the maximum stress capacity of the soil and increases its creep deformation. Particularly under relatively high deviatoric stress and seepage flow rates, the specimens exhibit three stages: transient creep, stationary creep, and acceleration creep. Notably, the axial creep deformation rate shows a positive correlation with both seepage flow rates and deviatoric stress. Concurrently influenced by seepage and creep, fine particles within the specimen accumulate in the central and upper regions, whereas the lower section is characterized by larger particles. The progressive increase in pore water pressure, intricately linked to the impeding effect of fine particles on permeation pathways, catalyzes the creep-induced deformation of the specimen. Based on the experimental results, a modified Burgers model has been established. This model takes into account seepage, sliding damage, and particle fragmentation. A comparative analysis, contrasting the modified Burgers model against calculated values derived from the traditional Burgers and Kelvin-Voigt models, underscores the effectiveness of the proposed model. Specifically, the modified Burgers model adeptly captures the transient creep, stationary creep, and acceleration creep stages of silty fine sand, especially under varying seepage flow rates.