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.