Design And Research Of The Reverse Four-link Transition Support For Low-position Top Coal Caving

The transition support for top coal caving is one of the most important supporting equipment in comprehensive mechanized mining of top coal caving.Its performance and quality directly determine the output and efficiency of fully mechanized top coal caving face,and is the key to safe and reliable production of mine.In recent years,the problems of no caving,poor stability of support,small back caving space,low support efficiency and poor mechanical characteristics of four-link transition support have appeared in the practical application of the transition support for top coal caving,which have caused a huge impact on the recovery rate of mine resources and seriously affected the safe and efficient production of coal mine working face.Therefore,the thesis combines the conditions of thick coal seams in fully mechanized caving face to design and study the reverse four-link transition support for low position top coal caving,which provides support for solving engineering practice problems,and has broad application prospects and popularization and application value.Firstly,based on the occurrence condition of thick coal seam in Tingnan Coal Mine,this thesis firstly analyzes the caving behavior and the law of mining pressure appearance of the fully mechanized caving working face,analyzes the influence of caving on the stability of the transition support by UDEC simulation,and studies the relationship between the caving transition support and the surrounding rock stiffness and strength coupling characteristics of the working face.Secondly,by comparing with the scheme of four-link transition support for top coal caving,the reverse four-link transition support is determined and the main technical parameters of the transition support are determined.The optimum value of the reverse four-link transition support for top coal caving is calculated by analytic method,and the structure design of the reverse four-link mechanism is completed.The parameters of the key components of the transition support,such as the top beam,the coal mining mechanism and the column,are calculated and structured,and the use of Solidworks software to establish a virtual prototype model of transition support for top coal caving.Thirdly,according to the load-bearing characteristics of the support,the whole frame is calculated mechanically,and the mechanical characteristics of the reverse four-link transition support are analyzed.The reliability of the transition support under different working conditions is analyzed by AN SYS Workbench,and the weak links of the transition support in the simulation are optimized,and the modal analysis and fatigue life of the top beam and the base of the main structure are carried out.Finally,according to the action function of the top coal transition support,the overall design of the hydraulic control system of the top coal transition support is carried out.The hydraulic simulation software AMESim is used to simulate and analyze the column control loop,the tail beam-insert control loop and the push-forward control loop of the transition support,and the support control loop to verify the dynamic stability of the hydraulic control system.In this thesis,modern design methods such as computer aided design are used to analyze the structural design and mechanical characteristics of top-coal caving transition support,so as to improve the reliability of top-coal caving reverse four-link transition support design.The electro-hydraulic control system is used to design the transition support of top coal caving,and the rationality of the hydraulic system is analyzed by AMESim simulation,which ensures the stability of the hydraulic system of the support.The research of the thesis has certain practical guiding significance for solving the technical problems of low strength,poor mechanical properties and unstable control system of the transitional support for the top coal caving.