Study on tipping mechanism of hydraulic powered support applied in fully mechanized top coal caving mining face with high inclined soft seam

Based on the engineering practice difiulty of the powered support tipping frequently occurred in the mining process of the fuly mechanized topcoal caving mining face in the high inclined sof seama ite mornitoring and measuring and theoreical analysis combined metod was appiedto the study on the powered support tiping features and infuence factors. With the establishnent of thec rti l tpping mechanics mode of the powered supr. an analysis was conducted on the crtital tipping status of the powered suppor. The resuts showed that at the inclned direction ofthe coal mining face,No.50 powered suport at th tog section ofth coalmining face had a unloading rate up to48.26%,a lcading attenuation rate up to 0% in the circulaton a tiping nunber up to 21 times and average tipig angle up to19'.Those indexes were obviously igher than the powered supporsat the midle and low sections of the coal mining face. Along the inclined diection and during thetop cal aving period from the low to top,the average tpping angle of the powered suppot wa11.3 and during the cal caing perod from the top tolowthe average ipping angle of the powered suport was 5.7".The st ailiy of the powered supports was at the low section,midle section and top section of the ceal mining face in sequence. The sof top coal broken andfalling and th tliding roling in the inclined direcion were the main causesof the powered suppot tppin . More the load transmission coefficient of the top coal was and higher possibility of the powered support tipping would be.