锚杆长度对边坡稳定性影响的数值分析

为了探讨边坡锚固及锚杆荷载传递机理,利用双弹簧单元,通过FLAC3D建立数值计算模型,分析锚杆长度变化对边坡安全系数和滑动面的影响以及锚杆的力学响应。表明:①锚杆加固边坡时,存在一有效锚固长度;随着锚杆长度的增加,边坡潜在滑动面逐渐往坡内移动,破坏模式由浅层滑动变为深层滑动;当锚杆长度达到有效锚固长度时,边坡的滑动面位置发生突变;②各层锚杆轴力沿杆体不均匀分布;当边坡岩土体受到外界扰动而劣化时,边坡下部锚杆轴力值最大;因此,对于永久性锚杆支护边坡,应适当加长底层锚杆长度。

Numerical analysis for effect of bolt length on stability of slopes

In order to study the reinforcement and load transfer mechanism of anchors in slopes,the dual-spring element is adopted to simulate the characteristics of anchors.A numerical model for slopes reinforced by anchors is founded by FLAC3D.The effects of anchors length on the safety factor and slip plane of slopes are analyzed as well as the mechanical response of anchors.The results show that,in the slope with anchors reinforcement,there exists an effective length;with the increase of anchors length,the potential slip plane moves towards the inside of slopes,and failure mode transfers from the shallow slip to the deep slip;when the length reaches the effective reinforcement length,the location of the slip plane changes abruptly;the axial forces at each layer distribute differently along the anchor;if the material of slopes becomes weaker after the disturbance of outer load,the anchors in the lower part of slopes exhibit the maximum axial force;so it is necessary to lengthen the anchors in these places for the slopes with permanent reinforcement of anchors.