Coupling Mechanism Of Bolt-cable Support And Its Application In The Gateroad Of No.3 Coal Seam At Dongfeng Coal Mine

The technique of mining roadway supporting is a key procedure in coal production.Therefore,how to reduce the cost and improve the efficiency is a significant subject.Currently,the rate of bolt supporting in coal mining is early 100%and the technique has become the main form of roadway supporting.Nevertheless,the research on joint bolt-anchor rope supporting is far behind engineering practice and there still exist various unreasonable phenomena.This paper deals with the mining roadway of No.3 coal seam of Dong Feng Coal Mine.Aiming at the reasonableness of the combined support of the mining roadway,the bolt-anchor cable joint support technology is carried out.Through the rock mechanics experiment,it is pointed out that the surrounding rock integrity of the mining roadway is better,and the fine sandstone strength is higher at about 6.5m from the roof of the roadway.It is beneficial to the maintenance of the roadway.Through theoretical analysis,the existing suspension theory and composite beam theory are calculated,and its practicability in engineering design is evaluated.By analyzing the reinforcement mechanism of the bolt(cable)to the surrounding rock,it is pointed out that the mechanism of the anchor bolt and the anchor cable is closely related to the surrounding rock conditions.When the bolt is used in the rectangular coal roof,and the thickness of the top coal is more than the anchor length,the main function of the bolt is the effect of extrusion and reinforcement,and the next is the suspension.The main mechanism of anchor bolt in No.3 coal mining roadway in Dongfeng Coal Mine is the multi arch structure with a certain bearing capacity on the roof of the roadway,and the arch structure is suspended by the anchor cable.At last,with the help of computer aided engineering program(Midas GTX NX)and three dimensional finite difference program(FLAC3D),the numerical calculation model is established.The vertical stress field distribution and the vertical displacement of roadway roof are systematically studied under different spacing of anchor bolts.Under the combination of different anchor bolts and anchor cables,the wall rock of roadway roof is vertical.Based on the distribution characteristics of vertical stress field and the rule of vertical displacement,a reasonable parameter suitable for combined support of bolt and anchor rope in mining gateway of Dongfeng Coal Mine is put forward.And the application of research results in the Dongfeng Coal mine site,through the monitoring results show that good control effect of rock.