多支盘锚杆的原型试验与荷载传递特征分析

Prototype test and load transfer characteristic analysis of multi-disk anchor rod

多支盘锚杆是新近研发的新型锚固结构,与普通锚杆相比具有优良的工程特性。在多支盘锚杆室内模型试验研究的基础上,通过极限平衡理论推导出多支盘锚杆极限承载力理论计算公式,计算模型结果与室内实测数据基本一致,验证了计算公式的有效性。为了进一步掌握多支盘锚杆的荷载传递特性,开展了现场边坡锚固原型试验,利用现场多支盘锚杆拉拔测试所得数据研究了多支盘锚杆的支盘直径、支盘间距和支盘个数对多支盘锚杆极限承载力和变形控制能力的影响。试验结果表明:在粉质黏土中,当支盘间距大于等于4倍支盘直径时,可认为各支盘能独立工作,充分发挥多支盘锚杆的承载力;在相同条件下,与普通锚杆相比,随着多支盘锚杆的支盘直径从300 mm增大到500 mm以及支盘个数从1个增加到3个,多支盘锚杆的抗拔承载力提高非常明显,其变形控制能力也大幅度增强;多支盘锚杆的轴力传递曲线在支盘位置发生突变,呈陡降型,充分体现支盘在抗拔方面的贡献作用。该研究成果为多支盘锚杆的工程应用奠定了良好的理论基础。

Multi-disk anchor rod is a newly developed anchoring structure,which has excellent engineering characteristics compared with ordinary anchor rod.On the basis of the laboratory model test research of the multi-disk anchor,a theoretical calculation formula for the ultimate bearing capacity of the multi-disk anchor is deduced through the limit equilibrium theory.It’s validity is verified by the correspondence between the calculation result and the measured data.To further grasp the load transfer characteristics of the multi-disk anchor,an on-site slope anchoring prototype test is carried out.The data obtained from the on-site multi-disk anchor pull-out test are used to study the influence of the diameter of support disks,the spacing of support disks and the number of support disks on the ultimate bearing capacity and deformation control ability of multi-disk anchors.The test results show that in silty clay,when the distance between the support disks is greater than or equal to 4 times the diameter of the support disks,it can be considered that each support disk can work independently,giving full play to the bearing capacity of the multi-disk anchor;under the same conditions,compared with ordinary bolts,as the disk diameter increases from 300 mm to 500 mm and the number of disks increases from 1 to 3,the pull-out capacity of the multi-disk anchor increases significantly,and its deformation control ability is also greatly enhanced.The test results also show that the axial force transmission curve of the multi-disk anchor rod has a sudden change at the position of the support disk,presenting a steep drop,which fully reflects the contribution of the support disk in the uplift resistance.The research results have laid a good theoretical foundation for the engineering application of multi-disk anchor rods.