Study On The Temporal And Spatial Evolution Law Of Surrounding Rock Deformation And Dynamic Reinforcement Technology Of Close Across Mining Roadway

Close across the mining pressure to solve the difficult problems such as large deformation and supporting of roadway surrounding rock,this paper takes Nayaotou return air up the hill from the upper 10 m ore six mining area in the 4th mining working face of mining influence and the engineering background of severe deformation,the integrated use of the site investigation,indoor test and theoretical analysis,numerical simulation and industrial test and other research methods,to close during the cross mining deformation of surrounding rock of roadway space-time evolution were studied,it is concluded that the surrounding rock stress and damage characteristics of the different stages,and puts forward the stress increase phase plate slot pressure relief,stress reduction phase drilling grouting reinforcement,In the stage of gradual compaction of the upper goaf,the dynamic reinforcement measures of the combined support of"U-shaped steel+reverse bottom arch+floor anchor cable"were carried out,and the key parameters of each reinforcement technology were determined.The research results were well achieved in the field,and the main results obtained during the period are as follows:(1)the face slab stress evolution mechanics model was established,the 4th mining is obtained during the mining face the stress concentration factor of any point in the floor strata,using Matlab and mathematical software Math CAD floor stress evolution rule:in the process of working face advancing,floor within a certain range decreases successively appear stress concentration and stress phenomenon;In the floor strata at the same position,the vertical stress concentration factor is much larger than the horizontal stress concentration factor and the shear stress concentration factor.(2)Using FLAC^3Dnumerical simulation software,the model of near-distance coal seam crossing uphill mining is established,and the temporal and spatial evolution law of roadway surrounding rock deformation is obtained:when the upper working face is more than 50m from the roadway,it is the stage that is not affected by cross-mining;When the upper working face is 50m to-5m away from the roadway,it is the stage of increasing mining stress.When the upper working face is-5m to-50m from the roadway,it is the stage of mining-induced stress reduction.When the upper working face is-50m to-80m away from the roadway,it is the stage of gradual compaction of the upper working face.When the upper working face is more than-80m away from the roadway,it is the stage of cross-mining influence on stability.(3)According to the bottom plate grooving pressure relief mechanism,the bottom plate grooving time was determined,and the key parameters such as grooving position,grooving width and grooving depth were determined by using numerical simulation and comparative study of different schemes.(4)Determine the grouting material and its water-cement ratio,grouting time and grouting depth of borehole through theoretical calculation and field measurement,and use COMSOL numerical simulation software to determine the key parameters such as grouting pressure,grouting time and grouting borehole layout.(5)Based on the dynamic reinforcement measures proposed in the above research,industrial tests are carried out.The field mine pressure observation shows that the dynamic reinforcement technology has achieved good results,which can effectively control the deformation of surrounding rock and significantly improve the load-bearing performance of surrounding rock.There are 66 pictures,5 tables and 94 references in this paper.