Analysis on Settlement Properties of Soft Ground Improved by Sand Piles

摘要

The key to the safe operation of high-speed railway lies in the control technology of post-construction settlement. Soft ground improved by sand piles has been regarded as composite ground all the time, but it is found in the large-scaly synthetical tests of Railways Ministry that the settlement of sand-pile ground has the characteristics of both composite ground and drainage and consolidation. So, it is very necessary for high-speed railways, whose post-construction settlement is strictly limited, to research on the settlement properties of soft ground improved by sand piles. Based on Jing-Hu high-speed railway trial embankment project, settlement, excess pore pressure, lateral displacement, earth pressure below the embankment and stress in geogrid, etc. have been observed for 2 years. By analyzing the performance of surface settlement and pile-soil stress ratio, it is found that: sand piles mainly act as drainage channels in the initial stage, but its drainage and consolidation function is gradually weakened by time, meanwhile, the function of composite ground is developing step by step. This conclusion can be the basis of farther research on settlement calculation methods of sand-pile ground in the future.