Study On Deformation Mechanism And Its Control In Mining Roadways With Extra Thick Compound Roof

In the process of coal mining,supporting of extra thick compound roof has been a difficult problem.If support is unreasonable,it will happen in large area roof caving.The disasters caused great loss to people’s life and property.With the increase of mining depth,the problem is becoming more and more serious.In order to solve the problem and ensure the mine safety,This paper studies the failure rule of extra thick compound roof Under the influence of different condition,different factors and different supporting method.Research content is as follows:Using theoretical calculation methods of Rock mass mechanics and Elastic mechanics,this article analyzed mechanism of abscission layer,dislocation,fracture damage mechanics of the extra thick compound roof.it is concluded that the roof of the weak position is the ends and the middle in the rock beam.At the same time,based on the arch beam supporting theory and stress equilibrium theory,this paper discusses that thick compound roof use anchor net supporting is feasible in theory.In rock beam of the extra thick compound roof,movement displacement and shear stress on both sides is greater than the middle.The greater the lateral pressure coefficient is,The easier the rock beam damage is,however,their damage rule is basically consistent.With the increase of Angle of roof,the stability of surrounding rock will be more weak.Reasonable bolt supporting angle is advantageous to extra thick compound roof’ control.Grouting on both sides of the roof compared with full face roof grouting,The former deformation displacement is only 5% larger than the latter.Under the condition of roadway driving along goaf,roadway pressure appear softer,On the whole,Supporting the difficulty and cost decreased,it is beneficial.Through three mine engineering examples,this article analyzed the applicable condition of several kinds of supporting schemes.