GFRP筋及钢筋抗浮锚杆与基础底板锚固性能试验研究

Experimental Study on Anchorage Characteristics of GFRP and Steel Anti-floating Anchor Embedded in Foundation Slab

采用倒置锚杆-基础底板体系,通过现场拉拔破坏性试验,研究GFPR筋和钢筋两种材质抗浮锚杆与基础底板的黏结锚固性能.试验结果表明:GFRP筋和钢筋抗浮锚杆均产生两种破坏形态-滑移破坏与拔断破坏;弯曲处理对两种材质锚杆极限承载力影响效果相反,钢筋锚杆极限承载力随拉拔荷载增大而增大,GFRP锚杆极限承载力随拉拔荷载增大而减小;钢筋抗浮锚杆的Q-S曲线为双折线型,存在明显的拐点,产生拐点的原因是拉拔荷载达到材料屈服强度,而GFRP锚杆无明显屈服阶段,故其Q-S曲线近似线性分布;在分析比较3种描述锚杆Q-S曲线的数学模型的基础上,发现指-幂函数模型能较好地拟合两种不同材质抗浮锚杆的Q-S曲线,能够精准预测GFRP筋及钢筋抗浮锚杆与基础底板的极限抗拔力和滑移变形.研究成果将为GFRP筋在抗浮工程中推广应用奠定基础.

The anchorage properties of the GFRP and steel anti-floating anchors embedded in the foundation slab were researched based on the failure field pull-out tests conducted by an inverted anchor-foundation slab system.The results show that both the sliding failure and pull-out failure occurs to GFRP and steel anchor.The influence of bend for the bearing capacity of two types of the anchor is opposite.With the increase of the pullout load,the bearing capacity of the steel anchor will be promoted and that of the GFRP anchor will be decreased.For steel anchors,the Q-S curves are double broken line with an obvious inflection point,which due to the pullout load reach to the material yield strength.While the GFRP anchor does not have a material yield strength,which contributes to a linear Q-S curve.Compare with three mathematical models used to describe Q-S curve and found that exponential-power function model can well fit the Q-S curve and provide accurate ultimate pull-out capacity and slippage of GFRP and steel anchor.All these researches lay a foundation for further application of GFRP anchor in anti-floating projects.