Study On The Load Bearing Capacity Of Post-grouted Bored Piles

With the development of technology, the kinds of piles, the construct techniques and equipments has improved very much. And the theories of piles and design methods also have developed. Piles have been used widely in many structures, especially in high-rise buildings, factories and some special requirements buildings. And with the increase of high-rise buildings and bridges with big span, the application of piles with high bearing capacity have been adopt more and more, and much experience was gained from these practices.The post-grouting technology is one of the methods to increase the base areas and base resistance pressure. The piles, which are used abroad in the projects, will cause settled materials and some hidden troubles, and consider the release of strains and softening in the end of piles, the bearing capacity of the layer below the piles can not been exerted sufficiently, which will cause the resistance force in the end of piles and around piles reduced a lot. So the post-grouting technology will solve these problems. It could improve the situation of layers in the end of piles, and it also could increase the base areas and base resistance pressure.In this paper, it focuses on the mechanism of post-grouting pile increasing bearing capacity, analyze the influences of post-grouting. Then, the geological conditions and technical parameters are discussed, and a formula, which is examined and verified by the cases in Ningbo area, to calculate the bearing capacity for post-grouted pile is suggested to be a initiative base of design. Finally, with the help of finite element software, this paper analyze the load capacity, the force in the piles and frictional resistance around piles, which can offer some experience and be a consult to theses projects.