桩端岩土强度提高对超长桩桩身总侧阻力的强化效应研究

基于5个场地中共15根超长桩的现场对比试验和2根超长桩的对比弹塑性数值模拟，分析了超长桩桩端岩土强度提高对桩身总侧阻力的影响。发现桩端沉渣厚度减小或无沉渣，超长桩桩身总侧阻力提高29.86 %～112.17 %；桩端注浆后，超长桩桩身总侧阻力提高33.07 %～66.95 %；桩端入硬层或基岩后，超长桩桩身总侧阻力提高23.34 %～235.65 %。结果表明，和一般桩（即短桩和中长桩）一样，桩端岩土强度提高同样能使超长桩的桩身总侧阻力得到强化。

Strengthening effect of total pile lateral friction by improving rock or soil strength at pile tip

Based on comparative field tests of 15 super-long piles in 5 sites and comparative elastoplastic FEM numerical simulation of 2 super-long piles, the effect of the improvement of rock or soil strength at pile tip on total super-long pile lateral friction is studied. It is found that the total lateral friction of super-long pile increases 29.86 % ?112.17 % after reducing the thickness of residue at pile tip, or there is no residue at pile tip; the total lateral friction of super-long pile increases 33.07 % ? 66.95 % after grouting at pile tip; the total lateral friction of super-long pile increases 23.34 % ?235.65 % after penetrating pile tip into harder soil or rock stratum. It is concluded that, like general piles (short piles and middle-long piles), the improvement of rock or soil strength at pile tip can strengthen the total lateral friction of super-long pile.