Experimental study on the shear performance of quasi-NPR steel bolted rock joints  

作　　者：Manchao He Shulin Ren Haotian Xu Senlin Luo Zhigang Tao Chun Zhu 

机构地区：[1]State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Beijing,100083,China [2]School of Mechanics and Civil Engineering,China University of Mining and Technology,Beijing,100083,China [3]School of Earth Sciences and Engineering,Hohai University,Nanjing,210098,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2023年第2期350-362,共13页岩石力学与岩土工程学报（英文版）

基　　金：This study has been funded by the National Natural Science Foundation of China(Grant No.41941018)and the Second Tibetan Plateau Scientific Expedition and Research Grant(Grant No.2019QZKK0708).

摘　　要：Quasi-NPR(negative Poisson’s ratio)steel is a new type of super bolt material with high strength,high ductility,and a micro-negative Poisson’s effect.This material overcomes the contrasting characteristics of the high strength and high ductility of steel and it has significant energy-absorbing characteristics,which is of high value in deep rock and soil support engineering.However,research on the shear resistance of quasi-NPR steel has not been carried out.To study the shear performance of quasi-NPR steel bolted rock joints,indoor shear tests of bolted rock joints under different normal stress conditions were carried out.Q235 steel and#45 steel,two representative ordinary bolt steels,were set up as a control group for comparative tests to compare and analyze the shear strength,deformation and instability mode,shear energy absorption characteristics,and bolting contribution of different types of bolts.The results show that the jointed rock masses without bolt reinforcement undergo brittle failure under shear load,while the bolted jointed rock masses show obvious ductile failure characteristics.The shear deformation ca-pacity of quasi-NPR steel is more than 3.5 times that of Q235 steel and#45 steel.No fracture occurs in the quasi-NPR steel during large shear deformation and it can provide stable shear resistance.However,the other two types of control bolts become fractured under the same conditions.Quasi-NPR steel has significant energy-absorbing characteristics under shear load and has obvious advantages in terms of absorbing the energy released by shear deformation of jointed rock masses as compared with ordinary steel.In particular,the shear force plays a major role in resisting the shear deformation of Q235 steel and#45 steel,therefore,fracture failure occurs under small bolt deformation.However,the axial force of quasi-NPR steel can be fully exerted when resisting joint shear deformation;the steel itself does not break when large shear deformation occurs,and the supporting effect of the jointed rock mass i

关 键 词：Energy absorption bolt Quasi-NPR(Negative Poisson’s ratio)steel Bolted rock joints Shear test Shear performance 

分 类 号：TU45[建筑科学—岩土工程]