Research on Dynamic Shakedown Critical Threshold of High-speed Rail Subgrade Filler Based on Dissipated Energy
Scientific evaluation of the stability characteristics of high-speed railway subgrade during service is an impor-tant theoretical means to ensure the durability and stability of the subgrade during its hundred year service period in com-plex environments.By conducting long-term cyclic loading dynamic triaxial tests on typical coarse grained soil fillers for high-speed railway embankments,this paper revealed the effects of different confining pressures and dynamic load ampli-tudes on the deformation development law of the fillers.Based on three shakedown states:A.plastic shakedown,B.plastic creep,and C.incremental failure,the long-term deformation convergence trend and dissipation energy change were analyzed.On this basis,the correlation between the unit volume dissipated energy and shakedown states under cy-clic loading conditions was constructed.A criterion for determining the shakedown critical state based on equivalent unit volume dissipated energy was proposed,along with the determination of the critical thresholds of dynamic stress and strain.In the case of the typical high-speed railway subgrade filling studied in this paper,the critical dynamic strain that causes the high-speed railway subgrade filling to transition from a stable shakedown state to an unstable incremental fail-ure state is within the range of 0.8×10-3～1.3×10-3.The results can provide theoretical reference for the shakedown analysis and long-term stability evaluation of high-speed railway subgrade under long-term dynamic train loads.
high-speed railwaysubgrade fillershakedown theorydissipated energylong-term deformationcritical state
万方数据
维普
