重载列车荷载作用下路基夹层现象的分析OA北大核心CSTPCD

Problems of subgrade interlayer,ballast pockets,and mud pumping frequently occur under heavy-haul train loads,which seriously affect the safe operation of trains.To investigate the phenome-non of subgrade interlayer under heavy-haul train load,the cyclic loading tests of subgrade soil(silty clay)and ballast were carried out by a self-developed test apparatus,the deformation characteristics of the sample and the development of subgrade interlayer under the heavy-haul train load were analyzed.Furthermore,two characterizing indexes of subgrade interlayer,thickness of subgrade interlayer and migration quality of fine particles,were proposed.The results show that:1)the axial deformation of the sample increases nonlinearly with the increase of loading times under heavy-haul load.The develop-ment of subgrade interlayer is obvious in the initial stage of loading,but not noticeable in the later stage of loading.2)The thickness of the subgrade interlayer and the migration quality of fine particles can be used to characterize the features of the subgrade interlayer.The thickness of the subgrade inter-layer and migration quality of fine particles are negatively correlated with the initial dry density of sub-grade soil,and positively correlated with cyclic loading amplitude.The influence of loading frequency on the thickness of the subgrade interlayer and the migration quality of fine particles is relatively small.