Deformation Failure Mechanism And Support Technology Of Composite Roof In Coal Roadway

As the increasing of coal mining depth, the problem of layer fragmentation in coal roadwayroof become increasingly prominent, roof maintenance become more and more difficulty.There are so many accidents of roof maintenance in coal roadway. Such as roof layerdamaged hardly, the supporting damaged hardly, and very bad convergence of roadwaysection. These problem affected the normal operation of coal mine company. How to controlthese bad influence or even reduce the problem, and make a very stable environment of coalroadway to issuer the production running well. This is a very important and become the keyof product coal safety and efficiently in our country. This paper summarizes the findings ofexisting studies, builds a mechanics model of composite roof in coal roadway, analyze thismodel with mechanics theory and simulation software. Based on this study we analyze aengineering example and redesigning the supporting system.The chief content of this paper is:(1) Summarizes the findings of existing studies. Obtain the forces between each rock layerin composite roof in coal roadway, and get the general rule of reform of composite roof incoal roadway. Then, bring up the research direction of this paper.(2) Analyze the deformation failure mechanism in theoretic way. See the composite roof asthe rock beam, study the forces of single rock beam with elastic mechanics and mechanics ofmaterials. Then get the deformation of rock beam with load. We get the expression of directstress of rock beam by the calculation. Calculate the wreck point on rock beam with the limitequilibrium. And then we could get the height of wreck in composite roof. And could use theexpression to judge rock beam. With these analysis we get out affections which could lead todamage the roof. (3) Depend on the calculation of deformation failure mechanism of composite roof. We canstudy the supporting system of composite roof. Bringing up the design concept of“multi-angle rigid beam hanging roofbolt supporting”. We design the length of roofboltdepends on the environment of roadway, and change the angle of anchor by calculating thefailure surface. Using roofbolt to make the rock layer joint tightly as a beam, and hang thisbeam on the stable rock in deep roof with anchor cable. Using prestressing force of bolt toreduce the initial deformation.(4) As the sophisticated environment of geological conditions of roadway, we think thedynamic informative design for roadway is matched well. This design approach can make theinformation of geological conditions accurate.(5) Made the cheng and wang village slope mining area coal mine5106face eturn airtransportation tunnel as an exemple, to calculate the roof stress condition, according to thecalculation results and the proposed bolting support design to optimization the support design.then, the numerical simulation software was used to verify the supporting roadway stabilitybefore and after optimization.