不同肋间距锚杆锚固性能实验室试验研究

摘要

为确定右旋螺纹钢锚杆肋间距与锚固性能的关系,对锚固于壁厚5.5和7.0 mm刚性套筒的肋间距分别为12,24,36,48 mm锚杆锚固试件进行拉拔试验,测定和计算拉拔力、剪胀位移量、耗能值、套筒周向应变等.试验结果显示,拉拔力、剪胀位移量、耗能值随肋间距的增加呈近似线性增长趋势;壁厚5.5和7.0 mm套筒拉拔试验中,肋间距48 mm试件相较肋间距12 mm试件的拉拔力分别增加了27.4％,50.43％,剪胀位移量分别提高了379.18％和813.55％,耗能值相比提高了52.06％和124.32％.周向应变量随肋间距增加呈现先增加后减小,其最大值出现在肋间距36 mm,与肋间距12 mm相比分别增加95.14％和112.84％.分析表明随着杆体肋间距的增加,嵌入锚固杆体相邻肋间距内的树脂长度增加,树脂的受剪面积增大,因而抗剪力、拉拔力在增加;树脂破坏后体积膨胀以及轴力在径向的分力增加,使得套筒周向产生应变,直接引起树脂剪胀破坏后的位移量增加.肋间距的增加可以提高锚固性能,肋间距为48 mm时右旋螺纹钢锚杆的锚固性能最好.%To determine the relationship between rib spacing and anchorage performance of right-screwing rebar bolt,the pull-out test was conducted with the rib spacing of 12 mm,24 mm,36 mm,48 mm and wall thickness of 5.5 mm and 7 mm.Four parameters including pulling force,shear expansion displacement,energy dissipation,and circumferential strain were monitored and calculated.The test results show that the pulling force,dilatancy displacement,and energy dissipation increased with the increase of rib spacing;in the pull-out test with sleeve wall thicknesses of 5.5 mm and 7 mm,the rib spacing of 48 mm specimens compared with the 12 rib spacing of MM specimen the pulling force were increased by 27.4％ and 50.43％,the shear displacement amounts were increased by 379.18％ and 813.55％,the energy dissipations were increased by 52.06％ and 124.32％.The circumferential strain increases first at the rib spacing of 24 mm and 36 mm and then decreases at the rib spacing of 48 mm,and the maximum value is 36 mm,which is increased by a factor of 95.14％ and,112.84％ respectively,compared with the rib spacing of 12 mm.The increase of the rib spacing can improve the anchorage performance,and the best rib spacing is 48 mm.