Theoretical Analysis And Test Research On Rushed Stone Pile Composite Foundation

Zhao MingSupervised by Prof. Zhao minghua & adjunct Prof. Chen changfuRushed stone pile composite foundation has been widely used to treat the soft soil in the construction building > traffic civil engineering ^ aerodrome engineering, port engineering and etc, but the theory and practice studies are under developing. The application of rushed stone pile to the treatment of soft roadbed is studied by means of theoretical analysis and field test in this paper. Firstly the property of the composite foundation under load is discussed, a new pile element stress-strain model is establish-hed by considering the different deformation in the vertical and horizontal and the pile-soil interaction, as a result, a new pile-soil stress ratio expression is established based on the Vesic expansive theory. Secondly, the application of the heavy dynamic penetration and static load test to inspect the composite foundation is discussed, and the pattern of the change of the stress ratio was analyzed, the results show that the messured data and the theoretical value are consistent. Based on the field test, the formula for calculation of composite foundation bearing capacity in the criterion are revised, and the reasonable method to detertemine the correction coefficient is also discussed. The visual VB program is work out to analyze the stress ratio, and the p-n curve method to determine rushed stone pile composite foundation is proposed. Finally, the strain composed method to calculate the settlement of the composite foundation was put forward when the pile-soil deformation harmony is discussed in the process of analysis of deformation modulus. The comparision between experimental and analytical results indicates that it is more reasonable to take the strain difference between pile and soil into account, and the theoretical analysis accords fairly well with experimental results.