Experimental analysis on the influence of freeze-thaw cycle on the dynamic deformation characteristics of silty clay on the Qinghai-Tibet Railway

Dynamic triaxial test at room temperature is performed and the influence of the joint action of freeze-thaw cycle and train load is analyzed. This article studied the influence of the number of freeze-thaw cycles, the melting temperature and amplitude of dynamic stress on the resilient deformation and accumulated permanent deformation of the silty clay along the Qinghai-Tibet Railway. According to the analysis results, (1) As the number of freeze-thaw cycles increases, the accumulative plastic strain of the silty clay on the Qinghai-Tibet Railway grows with the increase of the number of vibration. Meanwhile, its failure mode slowly evolves from brittle failure to plastic failure; (2) Resilient strain shows a growing trend with the increase of the number of freeze-thaw cycles and the corresponding resilient modulus is declining, but the effect of freeze-thaw cycles is larger than that of the last two factors, both showing only mild changes; (3) As the temperature during thawing rises, the accumulative plastic strain increases, which causes the rise of resilient strain and the drop of the corresponding resilient modulus; the larger the dynamic strain amplitude, the greater the influence of temperature during thawing on accumulative plastic strain is.