Study On The Strata Behavior Regularity Of Drilling Fully-mechanized Working Face With Large Mining Height In Zhaozhuang NO.2 Mine

The large mining height drilling fully-mechanized has the characteristics of energy efficient and technology simply, which suits to conventional working face length more than ten meters, but also used for the recovery of small section resources and coal pillar. It can adapt to the changes in geological and mining conditions easily compared with general large scale mechanized mining, which is an effective way to realize safety and high efficiency mining for small and medium sized mine. Through strata behavior regularity of large mining height drilling fully-mechanized face is studied, structural form of overburden rock and law of stress distribution can be learned, which has a great significance for application of the technology of large mining height drilling fully-mechanized.In this paper, the strata behavior regularity of large mining height drilling fully-mechanized in shorter mining face is studied by the means of field measurement, theoretical analysis, similar simulation and numerical simulation. The overburden movement is studied and calculated theoretically by "key strata theory". With the field monitoring, ground pressure behavior is analyzed, the suitable support working resistance is investigated. The law of overburden movement and collapse features is analyzed by similar simulation. Distribution law of rock stress is analyzed with FLAC3D numerical simulation method, and the relationship between mining speed and rock stress is studied.The study shows that, the strata behavior regularity of shorter working face is remarkable, main roof pressure is gradeâ…¡, and the support load and coefficient of dynamic load are smaller during the first weighting than during the periodic ground pressure. Comparing to general length working face, periodic weighting increases, coefficient of dynamic load decreases, abutment pressure peak and effect range increases too. Roof pressure is more concentrated, support load is 76% of the general length working face, support load is static load, and the suitable working resistance range is 4.3 times mining height of pillar weight. Height of caving zone is 2.5 to 3 times mining height; "voussoir beam" structure is formed in the higher level, which can generate an additional force to immediate roof through movement, and its periodic instability causes periodic ground pressure. Working face decreases, pressure arch height decreases, overburden deformation and caving region decreases too. So, strata behavior of shorter working face weaker than the general length working faces. Mining height increases, the effect range of abutment pressure gradually and the position of peak point are nonlinearly increases, and the center coefficient of stress reduces.