拉拔工况下全长粘结锚杆工作机理

来源期刊：中南大学学报(自然科学版)2006年第2期

论文作者：贺若兰 张平 李宁 刘宝琛

文章页码：401 - 407

关键词：拉拔;锚杆;界面单元;数值分析;机理

Key words：pull-out; bolt; interface element; numerical analysis; mechanism

摘    要：采用一种能够真实模拟锚杆和岩土体界面闭合、滑移及张开等实际变形性能的摩擦接触型界面单元,对照实测工程,建立拉拔工况下全长粘结锚杆的数值模型,并验证了模型的精度;对拉拔工况进行全过程仿真分析,再现锚杆、界面以及岩土体的力学特性随施工全过程发展的变化规律,定量揭示这一工况下全长粘结锚杆的工作机理;对典型岩土介质中的拉拔锚杆进行数值对比试验,由锚杆轴力和界面剪应力不同的衰减速度反映岩锚和土钉不同的有效锚固长度,得出:岩体锚杆长度为1.5~2.0 m,而土钉长度达到10.0 m左右。所以,土体中采用较 长的土钉可以充分发挥作用,而岩体中选取适当有效锚固长度的锚杆可充分发挥锚杆作用,又节省成本。

Abstract: A new friction-contacting interface element was used, which can simulate factually the interface′s working status such as closing, slipping and breaking. A numerical model of fully grouted bolt for the pull-out test was built, whose credibility and precision were validated after being compared with a field-measured project. With the detailed reappearance of the development of mechanical characters for bolt, interface and rock or soil medium, the working mechanism for bolt pull-out test was revealed quantitatively by the overall course simulating analysis. The numerical comparative tests between rock and soil medium were implemented with the results showing quantitatively the different attenuation speed of bolt axial force and interface shear stress, and giving the different effective bolting length, 1.5~2.0 m for rock bolt and 10.0 m for soil nail.