Experiment Investigation On The Evolution Of Anti-Dip Rock Slope-Anchor System

Slope is a geological mass which is in the process of evolution.The anchoring mechanism and evolution characteristics of the slope-anchor system are the theoretical basis for the design,evaluation,and optimization of anchoring based on the evolution process.Based on the slope engineering of the cable carne on the right bank of the Huangdeng Hydropower Station,this paper focuses on the stress evolution characteristics of the anti-dip rock slope,the anchoring mechanism of the anti-dip rock slope-anchor system and the evolution characteristics of the anti-dip rock slope-anchor system.The problem was studied through geological survey,scale model test,theoretical analysis and on-site monitoring.Based on the research results,a method for evaluating the stability of the anti-dip rock slope-anchor system based on the evolution process is proposed.The thesis draws the following main conclusions.In the anti-dip rock slope,the single point stress evolution process under undisturbed conditions can be divided into three stages: stress relaxation,stress accumulation and failure.During the stress relaxation stage,the single-point stress decreases at a slow rate,indicating the deterioration of rock mass properties.During the stress accumulation phase,the single-point stress gradually rises,resulting in elastic deformation.When the stress exceeds the strength limit of this point,failure will occur and enter the failure stage.In the anti-dip rock slope-anchor system,the anchor reinforcement is mainly achieved through axial reinforcement and radial reinforcement.Axial reinforcement includes active reinforcement of prestress and passive reinforcement after axial tension of the bolt;radial reinforcement includes obstruction of stress transmission and restraint of radial deformation in the slope-anchor system.Anchor bolts affect the stress and strain distribution characteristics of the slope-anchor system.A stress increase zone and a high compressive strain zone are formed on the upper side of the bolt,and a stress reduction zone and a low compressive or tensile strain zone are formed on the lower side.This is the internal reason for the radial reinforcement effect.In addition,the bolt also affects the failure mode of the slope-anchor system,which enhances the integrity of the deformation and reduces the cracks during the failure,reflecting the enhanced effect of the bolt on the slope integrity.In the anti-dip rock slope-anchor system,the stress evolution characteristics are similar to the original anti-dip rock slope,but due to the anchoring effect of the anchor bolt,the stress evolution process is slower.The evolution characteristics of the stress along the anchor bolt are highly synchronized with the evolution characteristics of the slope-anchor system.When the stress along the anchor bolt rises,the stress of surrounding rock and soil also rises,and when the stress along the anchor rod decreases,failure appears in the surrounding rock and soil,indicating the co-evolution of bolt and slope-anchor system.The anchoring force shows increasing characteristics during the evolution of the slope-anchor system.The stability safety factor,which based on the anchoring force,of the slope-anchor system is proposed as an evaluation of its evolution process.This method achieves good results while comparing the results of on-site monitering and model test.