冻损胶结粗粒填料累积塑性变形特性与预测模型OA

The cumulative deformation effect of freeze-thaw damaged cemented coarse-grained fillers under dynamic loading is greater,and it is significantly affected by material structure characteristics and load conditions.The effects of gradation,compaction degree,confining pressure,and loading frequency on the development of cumulative plastic deformation of freeze-thaw damaged cemented coarse-grained fillers are studied by cyclic loading-unloading tests in the laboratory.The results are as follows:①The cumulative plastic strain of cemented coarse-grained fillers increases with increasing block stone content under the same degree of compaction.②The cumulative plastic strain of freeze-thaw damaged cemented coarse-grained fillers increases with decreasing compaction degree,and the strain growth rate of fillers with lower block stone content is faster at the same compaction degree level.When the compaction degree decreases from 95%to 89%,the cumulative plastic strain of group B fillers increases from 1%to 2.8%,while that of group A fillers increases from 0.4%to about 1.8%under the same compaction degree change.③Under high confining pressure,the initial cumulative plastic deformation is larger than that under low confining pressure;however,as the number of loading cycles increases,the strain rate of freeze-thaw damaged cemented coarse-grained fillers decreases and reaches plastic shakedown first.④At low frequency,the cumulative plastic deformation of the fillers develops slowly,but the cumulative plastic strain of the fillers accelerates with the increase of frequency under repeated loading.Based on the test results and plastic shakedown analysis,a prediction model of the cumulative plastic deformation of freeze-thaw damaged cemented coarse-grained fillers based on dynamic stress confining pressure ratio and number of loading cycles is proposed.The research provides solid theoretical support for the application and popularization of cemented coarse-grained fillers in railway subgrades in cold regions.