Study On Bearing Characteristics Of Pile Foundation With End Grouting In Deep Soft Soil

With the rapid development of Pile Foundation engineering technology, the technique of pile with end grouting has demonstrated its strong momentum, the pile group foundation with end grouting not only strengthened the pile end soil, but also eliminate the adverse effects of the pile bottom sediment in the grouting process, which made pile end resistance better play, the upward flow of grouting can improve the limit friction of pile side, the bearing capacity of the end grouting is greatly increased compared with non-grouting pile。The research of this paper is conducted under the Experimental Study of Bridge Pile Foundation with Post Grouting Techniques of Beijing-Shanghai High-speed Railway, which is a major subject of science and technology R&D program of China's Ministry of Railways(2008G032-3), which mainly studied the technique of pile end pressure grouting and its mechanism and the pile bearing capacity of pile end pressure grouting in deep soft soil, analysis the deformation characteristics of non-grouting and end grouting foundation. adopts FLAC3D calculated the end grouting of pile group foundation by numerical simulation, which provide another idea for the bearing capacity calculative method of pile group foundation with post grouting. This paper also studied three bearing capacity calculative method of pile group foundation, the pile group effect calculation method which used ultimate bearing capacity of pile for parameter, the limit equilibrium method which used the strength of soil for parameter, the method in "Technical Code for Building Pile Foundations", and calculated the capacity of pile end pressure grouting in the deep soft soil, and compared with the test results. Analysis results show:the method in "Technical Code for Building Pile Foundations" is recommended as the suitable method for calculating the maximum bearing capacity of frictional pile foundation with end grouting in deep soft soil, which fully considers the caps, piles and soils interaction characteristics, its calculative method was accord with the actual conditions.