Mechanical Damage Characteristics And Application Of Deep Water-Bearing Coal Samples In Zhujixi Coal Mine

The bearing capacity of coal in protective coal pillar of deep roadway is significantly weakened under the action of high ground stress load and complex water environment,which is closely related to the sensitivity of the corresponding physical and mechanical characteristics of coal measures sedimentary rock under the action of water.In this thesis,the deep coal samples buried at a depth of 1000 meters in Zhujixi Coal Mine in Huainan Mining Area were selected as the research object.Through data collection,laboratory experiments,data analysis and other research methods,the water absorption characteristics test,wave velocity information detection,mechanical experiment analysis,mass fractal statistics and acoustic emission monitoring of the deep coal sample specimens were carried out.It is concluded that the deep coal sample specimens in Zhujixi Coal Mine have the characteristics of ’ easy saturation,relatively enhanced overall structural integrity after saturation,and the overall destruction of the coal sample specimens caused by the tensile failure of the main penetrating fissures ’.Based on the above physical and mechanical properties,combined with the control factors such as water content of coal sample specimens,main fracture parameters and system structure size,through theoretical analysis,formula derivation and other research methods,the load beam main control fracture model of deep coal sample failure and instability in Zhujixi Coal Mine is established.The mechanism of the above instability and failure characteristics of deep water-bearing coal samples in Zhujixi Coal Mine is qualitatively expounded,and the calculation formula of peak strength of deep coal samples in Zhujixi Coal Mine is quantitatively deduced.The sensitivity analysis and strength verification are carried out.The calculation results are more in line with the experimental data,and have further numerical simulation and industrial test value.Through the numerical simulation inversion of the instability process of the preset fractured coal pillar in the deep part of Zhujixi Mine,combined with the grouting equipment of the mine,the suitable grouting pressure for the reinforcement of the preset fractured coal pillar is simulated.Through the on-site industrial test,it is shown that the initial grouting scheme under the condition of grouting pressure can effectively reduce the swelling and floor heave of the roadway.At the same time,it also avoids the problem of coal instability,overall lifting and waste of slurry caused by excessive grouting pressure,and achieves a good reinforcement effect,which can provide some references for the design and engineering of similar projects.This thesis has 59 figures,10 tables and 84 references.