A New Method for Settlement Calculation of Long-Short Piles Combined Composite Foundation

Abstract

In the past ten years, China has seen great development of infrastructure construction, most of which are built on soft ground. Infrastructure constructions such as road and railway embankments, bridge approach and flood protection dam on soft soils have raised several concerns related to excessive total and differential settlements, bearing capacity failures, lateral pressure and movement and stability of the foundation These challenges have led to a significant development of soil improvement, which show economic solutions for the constructions on soft soils. One of the techniques is long-short piles combined composite foundation. Long-short piles combined composite foundation is referred to as a composite foundation supported by long piles and short piles. The composite foundation system utilizes the advantages of long piles and short piles individually, which is already applied in ground improvement widely in China. Nevertheless, there is no good method to calculate the settlement of this foundation. On basis of the performance of ground compression of the long-short piles combined composite foundation , a new settlement calculation method is presented. The method takes the different work condition of different part of the foundation into account, simplifies the additional stress distribution versus depth and presents the compression index . Finally, this new method is applied to investigate the settlement of one case. The computed results have good agreements with measured data, which shows the advantage over other existing methods in calculating the settlement of long-short piles combined composite foundation.