风化岩地基微型抗浮桩承载性能原位试验研究

微型抗浮桩具有地层适应性强、布置形式灵活、成孔快、施工占用场地小、施工机械小型化及经济环保等优点。基于中风化花岗岩地层8根微型抗浮桩现场静载荷试验,研究青岛风化岩地基微型抗浮桩的竖向抗拔承载性状。试验结果表明:试桩Q-s曲线为缓变型,极限荷载作用下桩长为4.2~5.1 m的微型抗浮桩总上拔量不超过7.0 mm,极限抗拔承载力高达1 700 kN,承载力较高,满足设计要求;单桩单位平均极限侧摩阻力为0.307~0.425 MPa;在其他条件均不变的情况下,微型抗浮桩的单位平均极限侧摩阻力随桩径的增加而减小。

IN-SITU TEST STUDY ON BEARING BEHAVIOR OF ANTI-FLOATING MICROPILE IN WEATHERED ROCK SITE

Anti-floating micropile has the virtue of strong strata adaptability,flexible layout,economical construction, quick hole forming,environmental protection and machinery miniaturization. Based on the static load test of eight anti-floating micropiles,the vertical pull-out bearing properties of anti-floating micropile in Qingdao weathered rock site have been studied. The test results show that the Q- s curves of the testing piles are of slow change type, ultimate uplift capacity of pile length with 4. 2 ~ 5. 1 m are 1 700 kN under the ultimate load,which can meet the design demands; the unit average ultimate side friction of single pile is 0. 307 ~ 0. 425 MPa under the ultimate load; with other conditions being unchanged,the unit average ultimate side friction of anti-floating micropile reduces with the increase in pile diameter.