抗弯功能微型桩试验研究与应用

Experimental Study and Application on Micro Piles with Anti-Bending Function

通过Φ89钢管微型桩的试验,对其基本静力性能进行分析。结果表明,荷载—跨中挠度曲线可以分为弹性阶段、弹塑性阶段和强化阶段三个阶段;环向应变沿圆周分布不均匀;从加载之初至0.7Pu基本符合平截面假定;同一点的环向应变与纵向应变符号相反。比较分析可以看出,仅考虑加强体强度而未考虑桩体水泥浆强度的方法过于保守,桩体水泥浆对提高微型桩抗弯能力效果非常显著,该研究成果值得工程推广应用。

Several basic static performances about the 089 steel-pipe micro pile were analyzed based on the tests. It was found that load-middle span deflection curve could be defined as following stages： elastic stage, elasto-plastic stage and hardening stage; the circumferential strain does not distribute uniformly; longitudinal strain distribution obeys the plane cross-section assumption from 0 load till about70 percent the ultimate load of bearing capacity. For the same point, if it is compressed longitudinally, then must be tensioned eircumferentially; if it is tensioned longitudinally, then must be compressed circumferentially. By comparation and analysis, we can see that the way only considering the enhanced intensity without consideration of pile cement slurry intensity is too conservative. The improvement on the flexural capacity of micro-pile due to the pile cement slurry is very significant, which could be widely applied in projects.