The Study Of Rigid-flexible And Long-short Piles Composite Foundation And Its Application In Deep Thick Soft Soil Ground

In this paper, the fundamental theories and general development situation of composite foundation had been summarized at first. By comparing the application effectiveness and economical efficiency of several major piles types used in soft soil area, it was been indicated that these piles types were all defectively on bearing capacity or economical efficiency, while the rigid-flexible, long-short pile composite foundation could make full use of its bearing capacity, reduce the quantity of piles, and satisfy settlement and bearing capacity requests.Researches on the calculation theories, design methods and example analysis of this kind of composite foundation indicated that:1. By replacing short flexible pile using long rigid one, the settlement of building had been reduced significant, and could approximately meet the requirement. But, while using too high rate of replacing or too long pile, the bearing capacity might be too high, leading to greater execution difficultly and lower economical efficiency.2. In large span multi-layer factory building structure, Because the loads were too large, the quantity of short pile should obviously increased, so the design method presented in this paper was not effective.3. In multi-layer residential construction and office building, the rigid-flexible long-short pile composite found was feasible, and its economical efficiency was also significant.Finally, a practical example has been given, to illustrate the potential benefits of this kind of composite found.