Study On The Behaviors And Failure Characteristics Of Cable Bolt Under Various Shearing Loading Experimental Environment

Cable strands transfer mechanism,as an important part of anchorage support in underground engineer,has consistently been one of the research interests and difficulties in the rock mechanics field.Cable bolt,due to predominant property,is widely concerned with almost every respect of underground mining activities to reinforce underground open area and promote strength in weak strata.So far,the research has been done mainly focuses on the mechanical properties of tensile strength of cable strand,with little attention been paid to the lateral force to fail support system.In this thesis,with the purpose of providing positive reference for underground design and construction,we investigated the support abilities,mechanical properties and failure forms of cable bolted concrete joint under shear force.Using experimental methods,this thesis systematically studied different cable strands in bolted discontinues concrete joint under shearing,measuring the axial and lateral load and displacement to research the mechanical proper ties and failure modes of fully grout pre-tension cable strands.The influence factors were also analyzed to discuss the impact on shear resistance of bolted joint.The uni-axial compressive experiment on concrete samples demonstrates whether the strength of concrete satisfied the requirement of design.The uni-axial tensile tests of wire from cable strand were carried out to research their failure and relative mechanism properties.Megabolt single shear test and UOW double shear test was carried out to mea sure the shear resistance and corresponding shear displacement of different cable strand and load-displacement curves depicted the variation in different loading stages: There were four distinct stages of the shear profile,which are elastic stage,non-linear stage,plastic stage and rapid drop stage.Based on recorded shear-induced forces and displacements,tests are analyzed about the joint shear strength,the pretension and surface profile effect,de-bonding and the failure modes of cable wires.Finally,the diversities between double shear test and single shear test were compared and the traits of apparatus were analyzed.Based on the results of two tests,the factors influence on the variation was listed and explained.