基于荷载传递法的锚杆锚固段荷载变形分析

Analysis on Load Deformation of Anchorage Section Based on Load Transfer Method

基于荷载传递法,推导了锚固段的荷载传递基本微分方程;结合Kelvin问题的位移解,得到锚固段的应力分布的解析表达式,认为锚杆体的直径、外荷载及锚杆体弹性模量与岩体剪切模量的比值等因素影响着锚固段的应力水平。计算结果表明:锚杆体直径增加到一定程度会使锚杆所受的最大剪应力快速增加;在较高的初始力条件下,锚固段前端应力集中现象明显;较小的锚杆体弹性模量与岩体剪切模量比值有利于锚固段应力的均匀分布。

The basic equation of anchorage section is derived based on load transfer method. This paper derived the analytical expression of anchorage sections’stress distribution,combining the displacement solution to Kelvin problem. The results show that the bolt body diameter,external load and the ratio of bolt body’s elastic modulus and rock’s shear modulus affected the stress level of anchorage section. The calculation finds that： （i）when bolt diameter bolts up to a certain extent, anchorage section’s maximum shear stress has a rapid increase; （ii）under a higher initial force conditions,the front of anchorage section has a clear stress concentration;（iii） a smaller ratio of bolt body’s elastic modulus and rocks’shear modulus is conducive to uniform the stress distribution of anchorage section.