端头自锚型锚索自锚器结构研制及应力分析

Structure Development and Stress Analysis of Self-anchored Machine of End Free Segment Self-anchored Cables

端头自锚型锚索的作用机理是在张拉段设置自锚器,将锚固段和张拉段有效隔离,通过约束锚筋材料不同方向的变形,将全部或部分锚固荷载转化为锚筋注浆体与岩土层之间的黏聚力。这种锚索将传统预应力锚索的"锚固荷载等于外锚头锁定荷载"的受力模式改为"锚固荷载等于自锚荷载与外锚头锁定荷载之和"。本文介绍了基于锚筋体材料等强度条件下自锚器的结构设计,并对采用45Mn2钢制作的自锚器进行了应力分析与试验研究。结果表明:在预应力锚索极限荷载作用下,自锚器平均应力为731. 97 MPa,最大应力为1 441. 5 MPa;限位荷载为40 kN/孔,自锚荷载能达到钢绞线屈服强度442. 68 kN。所研制的锚器具备可重复张拉、锚固荷载完全自锚的优点。

The mechanism of end free segment self-anchored cables is setting self-anchored machine on pulling section to seclude pulling section from anchoring section,the whole or part of anchoring load is transformed into cohesion between anchorage grouting body and rock soil layer by constraining the deformation of anchor bars in different directions.This kind of anchor cable changes the stress mode of traditional prestressing anchor cable from“anchoring load equals locking load of external anchor”to“anchoring load equals the sum of self-anchoring load and locking load of external anchor”.The structure design of self-anchored machine based on the material of anchor bar under the condition of equal strength was introduced in this paper,and the stress analysis and experimental research on self-anchored machine made of 45Mn2 steel were carried out.The results show that the average stress is 731.97 MPa and the maximum stress is 1 441.5 MPa under the ultimate load of self-anchored cables.The limit load of self-anchored machine is 40 kN/hole,and the self-anchoring load can reach the yield strength of steel strand 442.68 kN.The developed self-anchored machine has the advantages of repeated tension and self anchoring.