Hydraulic support with large mining height structural optimal design and adaptability analysis

Aiming at the problems of dynamic mining pressure and rib spalling instability,the “ cantilever beam and bond-beam” structural model of roof strata and simplified dynamic model between hydraulic support with large mining height and surround rock were established based on the 7. 0 m mining practice in Hongliulin mine. The reasonable working resistance of 7. 0 m mining height hydraulic support was determined. The mechanical property and adaptability for working face surrounding rock were contrastively analyzed from the aspect of hydraulic support frame and working face guard device. Hydraulic support structures were optimally designed. The results show that the rock strata above the “voussoir beam” structure could be seen the boundary conditions for the dynamic model,and the anti-impact proper- ties requirement of hydraulic cylinder was the theoretic criterion,which could obtain the reasonable working resistance of hydraulic support through a dynamic simulation analysis. Two-prop shied large mining height hydraulic support was better than four-pillars from supporting intensity,four bar mechanism stress state and weight,etc. The joint system of face guard and extensible canopy had a higher face guard force,a better place of application of force and dependability than the fission system of face guard and extensible canopy. The anti-impact double-telescopic prop and high pressure column system were adopted to raise the adaptability of hydraulic support to surrounding rock.