Study On Dynamic Response Of Frozen Embankment Under Train Vibration Load

In this paper, the vibration responses of frozen soil embankment caused by trains travel are studied by means of combining experiment research and theoretical analysis. On the basis of low temperature dynamic triaxial tests, the dynamic performance of frozen soil and its main influence factors, which are necessary to research the vibration response of frozen soil embankment caused by trains travel, are analyzed. Combined with the basic design principles of frozen embankment, traditional structure types, real situations of frozen site embankment and several representative sections, the subsystem analysis method of soil-structure interaction is introduced to build the sleep-ballast-embankment-ground dynamic system. FLAC is used to build a two-dimensional model of frozen ground-embankment and execute numerical simulation which has field testing data on the DaQing spot in winter as dynamic inputs. Some fundamental researches on the vibration response of frozen soil embankment caused by trains travel and its main influence factors have been done on the basis of numerical simulation. Low temperature dynamic triaxial tests show the maximum dynamic shear modulus of frozen soil has close correlation with its ice crystal content, and rises along with the increase of confining stresses and with the decrease of temperature; the maximum dynamic shear modulus may occurs by adjust frequency of axial dynamic loads, the times of vibration and water content; damping ratio is remarkably influenced by confining stresses, temperature and water content, and it rises along with the increase of amplitude of dynamic shear strain; the ratio of dynamic shear modulus is influenced mainly by fatigue effect, unfrozen water content, temperature, axial dynamic loads and the times of vibration, and it drops along with the increase of amplitude of dynamic shear strain; stress-strain relations of frozen soil can be approximated to hyperbolic constitutive mode, but the late plastic deformation increases remarkably, especially for higher temperature or low water content frozen soil. FLAC Numerical similation shows the ground dynamic response mostly caused by vertical vibration; velocity and acceleration declines rapidly along the depth direction; the...