风化岩地基GFRP抗浮锚杆力学与变形特性现场试验

Field tests on mechanics and deformation properties of GFRP anti-floating anchors in decomposed rock foundation

利用光纤光栅传感技术,对10根GFRP抗浮锚杆进行现场拉拔破坏性试验,研究了风化岩地基中GFRP抗浮锚杆的承载性能与变形特性。试验结果表明:发生滑移破坏的锚杆杆体、锚固体荷载-位移差曲线高于同型号发生断裂破坏的锚杆;锚固长度接近临界锚固长度的试验锚杆荷载-位移差曲线上升较平稳;增加杆体直径有助于提高锚杆承载能力、限制杆体位移并且降低杆体、锚固体的位移差。此外,杆体横截面轴应力沿锚固深度呈“反S型”分布,由孔口沿锚固深度方向递减;锚杆轴向界面剪应力沿锚固深度呈先增大后减小的趋势,且剪应力在锚固体内按斜向上方向由第一界面传递至第二界面。最后,利用剪应力分布简化模型求得杆体、锚固体位移差与发生滑移破坏的锚杆试验结果较为一致,可为GFRP锚杆的推广应用提供理论基础。

Through the field pullout destruction tests on 10 GFRP anti-floating anchors using the fiber bragg grating sensing technology, the bearing capacity and deformation properties of the GFRP anti-floating anchors in decomposed rock foundation are investigated.The test results show that the load-displacement difference curve of the anchor body and anchorage body of the GFRP anchors in the slip failure model is higher than that in the rupture failure model.The load-displacement difference curve of the anchor body and anchorage body with the anchorage length which is close to the critical one rises steadily. Increasing the diameter of the anchor body is beneficial for improving the bearing capacity of anchors, limiting the displacement of the anchor body and reducing their displacement difference.Additionally, the distribution of the axial stress on the cross-section of the anchor body, which decreases along the anchorage length, shows a reversed S form along the direction of anchorage length.The shear stress of the axial interface increases firstly and then decreases along the direction of anchorage length, and it transfers from the first interface to the second interface with an oblique upward direction.Finally, the displacement difference of the anchor body and anchorage body, calculated by the simplified model for the distribution of the shear stress, is similar to that of the GFRP anchors in the slip failure model.The research results may provide the theoretical foundation for the application of GFRP anchors.