| Based on the 8.0m ultra high-seam working face mining practice in Jinjitan coal mine,the paper analyzed the characteristics of mining pressure,and came up with the strength,stiffness and stability coupling relationship between hydraulic support and surrounding rock,and studied the strength coupling relationship emphatically,and came up with the surrounding rock stability control technology for working face with 8.0m mining height,and carried out mining pressure monitoring and adaptability evaluation of hydraulic support,which adopted the combined method of theoretical analysis,numerical simulation and field measurement.The following research findings are obtained.(1)The mining pressure behaviors has obviously dynamic pressure and period of the magnitude,and the culture hydraulic support working resistance computing method didn’t adopt to working face with super mining height.The loading from roof strata to hydraulic support are divided into static and dynamic load.The hydraulic support should not only have reasonable support resistance,but also have certain compressibility.The coupling relationship between hydraulic support and surrounding rock are divided into strength coupling,stiffness coupling and stability coupling.(2)Based on the stress path effect analysis results of difference roof layer,the “cantilever beam + voussoir beam” mechanical model for super high mining working face was established.The energy accumulation-relation-transition-response process of surrounding rock damage and hydraulic support response was analyzed.The inferior key strata 2 was considered as the boundary conditions of the model,the dynamical model of hydraulic support and surrounding rock strength coupling was established,which was applied to analyze the whole process of the roof strata fracturing and hydraulic support response,which obtained the criterion and computing method of hydraulic support to adapt the roof strata fracturing.(3)Based on the stress path effect analysis results of coal wall spalling,the mainly damage form of hard coal wall was analyzed.The process of coal wall spalling can divided into coal wall damage and the damaged coal wall instability.The “tensile fracturing-slippage” mechanical model for coal wall spalling was established to obtain the relation of coal wall damage depth,width,mining height and mine strength.The critical support force for controlling coal wall spalling was obtained.Through carrying out the single target multifactor sensitivity analysis of coal wall spalling,the main influencing factors sensitive ordering of coal wall damage and damaged coal instability were obtained,and the coal wall spalling controlling method was raised.(4)Based on the strength coupling relationship research result of hydraulic support and roof strata,coal wall,the “double-factors” control method for hydraulic support reasonable working resistance calculate was raised,and the hydraulic support types and coal wall guarding mechanism types were analyzed comparatively.The hydraulic support strength failure mechanical mechanism for super height working face was studied.(5)For the coal seam occurrence conditions with super height mining in Jinjitan coal mine,the large bore impact double expansion column,three-grade coordinating coal wall guarding mechanism were adopted.The mine ground pressure of super height mining working face was monitored in field.The hydraulic support adaptability evaluation method for super mining height working face was raised based on the coupling relationship between hydraulic support and surrounding rock.Through field monitoring,the ZY21000/38/82 D was able to satisfy the supporting demand. |
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