The Research On Mechanism Of Broken Anchor Wire In Roadway And Protective Measures Of The Ejection

Due to changes in the coal mine geological conditions, the same will producedifferent lithological changes of surrounding rock of roadway, the supportingtheory, the same kind of supporting design cannot solve the protean geologicalconditions of the roadway support. Down hole different surrounding rock ofroadway is different to the requirement of supporting technology, anchor cable stillexist some of the larger technology lack of restriction. In terms of the mininggateway, due to the effect of mining, large deformation of surrounding rock ofroadway characteristics, lead to pressure under the action of bolt anchor cablebolting in large deformation is easy to make the bolt anchor cable force than theultimate strength and rupture, the cave of roadway roof subsidence caused, two forthe extrusion of destruction, the bottom of the bass drum etc. Phenomenon, causeof roadway support difficulty, maintenance, repair rate is high, seriously affect thenormal production of mine.On the anchor rope breakage phenomenon at the sametime breaking part has not been fully clamping of coal or rock, the ejection injuryaccidents extremely easily, serious threat to personnel of production safety. The coal mine in our country has anchor cable tensile ejection hurt accidents occurfrequently, causing serious social impact, so it is necessary to fully analysis andresearch to this defect, find out the root cause of it, to seek scientific and feasibilityof the solution.From the point of view of the mechanics analysis of roadway anchor wirebreakage has two situations: one, shear failure; Second, the axial damage. Specificfor anchor shear failure is due to the anchor rope around the anchor solid along theanchor cable of the tangential deformation caused the shear force, when thetangential deformation of the anchor cable can bear the limit of the shear strength,the anchor shear breakage. Anchor axial fracture was caused by axial force inanchor is greater than the tensile strength, axial force of the anchor cableinstallation time can be considered as on the pre-tightening force of anchor cable,as the working face mining effect, the stope wall rock loose often severedeformation and breakage, general deformation is quite large, especially horizontaldeformation, this will lead to the axial force of anchor cable is subjected to therapid increase in a short time, when reaching the critical tensile strength, the axialtensile breakage happens.Its damage mechanism can consider from three factors:first, the tunnel geological structure; Second, the prestressing force of anchor cable;Third, the structure of the anchor itself. Anchor cable in the event of a breakage, ifhas not been fully clamping of coal or rock, the ejection will happen, ejectionspeed is quite large, anchor cable if at such a speed effect on man, is like a bulletinto the human body, to the person’s harm if for gas mine at the same time, theanchor rope eject the hard to avoid collision with other objects which sparks, easyto cause the gas explosion, the consequences will be very serious. So the study ofcontrol cable breakage is very necessary, should cause the attention.In Changzhi SanYuan Nanyao Xiaochang coal,the engineering background of 30211working face, the face3#coal roadway anchor cable breakage ejectionproblem analysis and proposed the feasible preventive measure. Roadwaydeformation through investigating and observing the anchor cable breakagesituation in the field, through the theoretical analysis of anchor cable breakagemechanism and the deformation occurring during roadway extraction usingFLAC3D numerical simulation to study the cause of the30211working facegateway anchor cable breakage, to combine the technology of some effective paths,anchor wire breakage ejection of protective measures, formed a set of relativelycomplete effective anchor wire breakage ejection protective system.The research results of this paper will provide other similar working faceunder the condition of anchor cable breakage repair to provide certain theoreticalbasis and the reference value.