软岩地区大直径灌注桩桩基设计探讨

Discussion on Pile Foundation Design of Large Diameter Cast-in-Place Pile in Soft Rock Area

长沙地区泥质粉砂岩、泥岩类软质岩石分布广泛,其具有“非土非岩”的特点。对于软岩地区桩基选型,常有嵌岩桩和摩擦桩的讨论。文章结合工程实际,分别采用嵌岩桩、摩擦桩对桩长进行计算,确定大直径软岩灌注桩采用嵌岩桩更为合理。通过分析岩石强度、桩侧土的摩阻力、岩体完整程度对桩长和单桩承载力的影响,为桩基设计提供建议。

Argillaceous siltstone and mudstone soft rocks are widely distributed in Changsha area,which have the characteristics of“neither soil nor rock”.For the selection of pile foundation in soft rock area,rock-socketed pile and friction pile are often discussed.In this paper,rock-socketed pile and friction pile are used respectively to calculate the pile length,and it is more reasonable to use rock-socketed pile for large-diameter soft rock cast-in-place pile.The influences of rock strength,soil friction resistance and rock integrity on pile length and bearing capacity of single pile are analyzed to provide suggestions for the design of pile foundation.