Research On Influencing Character Of Structural Materials Of Pile Supported Reinforced Embankment

Pile supported reinforced embankment has been commonly employed in the foundation treatment of soft soils. and it has been increasingly employed in the construction of high-speed railway and highway in china. It has many advantages including fast construction, small after-construction settlement and small differential settlement and high stability. The structural layers of pile-supported embankment are very complicated including embankment, reinforced cushion, pile and substratum. Since it has many interface and many characters of the structural layers, the work mechanism of the pile-supported reinforced embankment is very complicated. Soil arching and lateral displacement of the pile are the key indicator for evaluating the performance of the pile supported reinforced embankment, and these two indexes are influenced by many parameters. A FEM model of pile supported reinforced embankment is founded based on Plaxis to research the behavior of the embankment under different conditions. Based on the calculated results, the influence of the geogrid stiffness, layers of geogrid.characters of embankment soil, and layout of pile on the performance of the embankment is analyzed in detail. And several study results are summarized as follow:The increment of the geogrid stiffness could increased the ratio of pile and soil’s stress.Especially, when the height of the embankment is 4.12-5.25(s-b), the geogrid stiffness has greatest influence on the pile-soil stress ratio. The improve of layer number of geogrid could evidently increased the pile-soil stress radio, and the increment is hardly related to the height of embankment. And it also could evidently decrease the lateral displacement of the pile. The increment of the friction angle and cushion of the embankment fill could effetely improve the pile-soil stress ratio, and slightly reduce the lateral displacement of the embankment pile. Both the increment of the embankment friction angle and cushion improve the pile-soil stress ratio through improving the shearing stress between soil interface over the pile and subsoil between piles. And it could also reduce the lateral displacement of the embankment pile through improve the strength of the embankment fill. The influence of the pile cap size and the displacement between the piles on the pile-soil stress ratio is very evident. The smaller the displacement between the piles is and the bigger the pile cap’s size is, the bigger the pile-soil stress is. however the size of the pile cap has little influence to the lateral displacement of the embankment pile. And the decrease of the distnce between the pile caps could evidently reduce the lateral displacement of the embankment pile and improve the stability of the embankment.