The Anchorage Technology Research Of CFRP Rock Anchor Blots

The rod body of traditional metal anchor is susceptible to corrosion,and this brings huge harm to the structure safety and durability.This paper replaces metal anchor rod body with Carbon Fiber Reinforced Polymer(CFRP),a reinforced material with high corrosion resistance,strength and other excellent performances.The method of combining finite element analysis and field test was used in the paper to solve the anchor connection problem of the CFRP material and mechanical anchor head、CFRP material and CFRP material,and study the anchorage technology of CFRP rock anchor blots,at the same time provide guidance for the engineering application.The main research contents and results were as follows:(1)The nonlinear finite element analysis method was carried out for establishing a three-dimensional finite element model to wedge-type anchorages for CFRP tendons.Furthermore,the effects of anchorage designed parameters on anchoring performance,such as the angle difference between barrel and wedge,the taper of anchor-ring,anchorage length and presetting load level were analyzed.Based on the numerical analysis,the best value ranges for the above mentioned parameters were confirmed;the static load test of anchorage was conducted under the same load using the anchorage on the basis of the predicted optimal parameters of the finite element model;the test result shows the good performance of the anchorage properties.The finite element method used can be referenced by the design and parameter optimization of new type anchorage of FRP tendons.(2)The pull-out tests of 28 new type of CFRP rock anchor bolts were carried out in the paper.The failure modes,bearing capacity of mechanical head,bearing capacity,critical anchorage length of the new type of CFRP rock anchor bolts were studied.Besides,the formulas of the bearing capacity and the critical anchorage length of the new type of CFRP rock anchor bolts were deduced;According to the results,several conclusions are drawn:the bearing capacity of mechanical head can account for 90 percent of the design load of the CFRP rock anchor bolt;the anchorage performance of the new type of CFRP rock anchor bolts is reliable;the formula of critical anchorage length is reliable.(3)Nonlinear finite element analysis method is used to carry out the numerical analysis of field test of CFRP rock anchor bolts in order to study the mechanical properties of CFRP rock anchor bolts.According to the displacement at the top of the CFRP rock anchor bolts under different ranks of pulling forces,a series of nephograms of stress and displacement have been obtained.The changes of stress and displacement of CFRP rock anchor bolts and rock when the pull force increases are reflected by these charts,these help to analyze the mechanical characteristics of the mechanical anchor head、concrete grouting material and rock in order to understand deeply the anchoring mechanism of CFRP rock anchor bolts.