摘要
Abstract
To investigate the dynamic stability of foamed lightweight concrete(FLC)as a railway subgrade filler,cyclic triaxial tests were conducted to systematically analyze the evolution of hysteretic loops and energy dissipation characteristics.The results show that:the dynamic deviatoric stress threshold is a key parameter governing the dynamic response of FLC,which can distinguish between two distinct modes of cumulative plastic strain:a"failure mode"and a"stable mode."Under the failure mode,the specimen undergoes three stages:initial compaction,steady development,and accelerated instability.The density distribution of hysteretic loops exhibits a non-monotonic evolution—initially scattered,then compacted in the mid-stage,and scattered again at the end,while the geometric shape evolves from broad to narrow and finally re-opens.In contrast,under the stable mode,the material rapidly transitions from an initial transient adjustment into a state of plastic shakedown,with hysteretic loops taking a closed spindle-like form.Dimensionless normalization analysis reveals the micro-mechanisms underlying the transition of hysteretic loops from"non-closed"to"closed spindle-or bow-shaped"patterns:during the early loading phase,energy dissipation is dominated by plastic work associated with skeleton reorganization;in the stabilization phase,it shifts to viscous damping within the matrix.Furthermore,FLC demonstrates superior engineering suitability compared to conventional backfill materials.关键词
铁路路基/路基填筑/泡沫轻质混凝土/滞回演化/循环荷载/微观机理/适宜性Key words
railway subgrade/subgrade filling/foamed lightweight concrete/hysteretic evolution/cyclic loading/microscopic mechanism/suitability分类
建筑与水利
