In order to study the dynamic characteristics and long-term dynamic stability of crushed stone interlayer struc-ture of foamed concrete subgrade of ballastless track,a full-scale test model for interlayer structure was established to carry out variable frequency loading and cyclic loading tests.The results show that the vibration acceleration,dynamic displacement and dynamic earth pressure of the interlayer structure increase without peak value under the action of varia-ble frequency dynamic load,indicating no resonance in the interlayer structure.Furthermore,to reduce the influence of the loading frequency on the ratio coefficient,it was suggested that the vibration displacement ratio coefficient between the base slab and the subgrade surface should be used as a criterion for the analysis of the supporting state of the ballast-less track structure by the subgrade bed or the graded crushed stone interlayer structure.Under the cyclic dynamic load,the vibration acceleration,dynamic displacement and dynamic earth pressure of the structure can be stabilized after being loaded to 1 million times.Compared with the traditional embankment filled with soil and rock,the foam concrete layer can better distribute the loads from above.After 2 million dynamic loads,the total cumulative settlement of the test model was 0.898 mm,with the compression deformation of the crushed stone interlayer accounting for 82.9％ of the total cumulative settlement.The results of the tests show that setting a graded crushed stone interlayer with a thickness of 0.7 m between the ballastless track structure and the foamed concrete layer can provide smooth and stable foundation for the line.
关键词
级配碎石夹层结构/足尺试验模型/变频加载试验/循环加载试验/动力响应/长期动力稳定性
Key words
graded crushed stone interlayer structure/full-scale test model/variable frequency loading test/cyclic loading test/dynamic response/long-term dynamic stability
维普
万方数据