Study Of Pile-Plank Subgrade On Ballastless Track Railway By Big Scale Dynamic Model Test

Ballastless truck on soil subgrade has been already widely used on high-speed railway abroad, but it is just at the starting stage in china, the pile-plank structure is a new-type structure of ballastless truck on soil subgrade , the design and calculation of the pile-plank structure are still immature. Based on the design of the pile-plank structure in the ballastless truck test sections in Suining-chongqing railway, the design of this kind of structure is studied by big scale dynamic model test, According to the theorem of Bockinghamπ, the dimensional analysis method is used, the model was established with a geometry scale of l:12,confirmed the dynamic model similitude constant of pile-plank structure roadbed, use to shot flap the arouse-machine to emulation railroad again and again to carry, pass change the frequency to emulation different velocity effect on pile-plank roadbed during the side-ascent soak in water in front and back ,received the acceleration and dynamic stress change rule, test result indicated, The test results indicate that after 10000 times of vibrant loading, the dynamic response of the embankment remains constant. Dynamic stress is significantly affected by the loading position, but less affected by the loading frequency, after the roadbed side-ascent soak in water, at the same shot flap frequency, dynamic stress compare to before soak in water is enlarge, the piles deepen dynamic influence scope of roadbed and improve the stress of the roadbed soil, Amplitude of acceleration is significantly affected by loading frequency and loading position, its value decreases with the vertical depth increase. The subgrade settlement after constuction is small,which can satisfy the requirement of design. Carry on the indoor great scale dynamic model test research for the pile-plank structure roadbed,hope to offer reference for the design and the fact that the project is used.