Soil modification is an effective method for enhancing the mechanical properties, including its strength, deformation capacity, and dynamic mechanical stability. Nanomaterials have broad prospects in soil modification due to their small particle size, large specific surface area, and non-toxic and harmless properties. Using the laboratory dynamic triaxial test method, this paper presents a scientific evaluation on the dynamic stability and freeze-thaw resistance of loess modified with nano-silica. This study has investigated the effects of nano-silica content, dynamic stress amplitude, confining pressures, and freeze-thaw cycles on the cumulative deformation behavior of nano-silica modified loess subjected to cyclic loading. Based on the shakedown theory, the shakedown state of 60 samples was evaluated, and an equation for the critical dynamic stress of modified loess was established under the shakedown limit state. The experimental results show that nano-silica can effectively fill the micropores in soil and form a cohesive gel that enhances the bonding between soil particles, significantly increasing the cohesion of the loess due to its nanoscale (10- 9) small size. The 2.5 % content of nano-silica is the optimal dosage for reinforcing loess. Under the same confining pressure condition, the failure strength of the 2.5 % nano-silica modified loess is about 1.4-2.1 times that of the loess, and the residual strength is about 1.2-1.5 times that of the loess. The incorporation of nano-silica significantly improves the dynamic stiffness and freeze-thaw resistance of loess, increasing the reinforcement factor by 51 %-69 % under unfrozen conditions and still increasing it by 43 %-64 % after experiencing one freeze-thaw cycle. Similarly, nano-silica significantly enhanced the dynamic strength and strength parameters of loess. Nano-silica exerts an influence on the shakedown state of the soil, wherein the impact becomes more significant with increasing dynamic stress amplitude.

来源平台：CONSTRUCTION AND BUILDING MATERIALS