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Full-Text Articles in Physical Sciences and Mathematics
Study On Development Height Of Permeable Fractured Zone Based On Overburden Failure Transfer, Zhao Gaobo, Guo Wenbing, Lou Gaozhong, Ma Zhibao
Study On Development Height Of Permeable Fractured Zone Based On Overburden Failure Transfer, Zhao Gaobo, Guo Wenbing, Lou Gaozhong, Ma Zhibao
Coal Geology & Exploration
It is extremely significant for coal mining under water bodies and water conservation mining to research overburden failure and the height of permeable fractured zone. The processes of overburden failure transfer were analyzed, which could be divided into transmission development stage and transmission termination stage. Through theoretical analysis, mechanical model of strata suspended integrity and overhanging stability were established. The limited suspension distance and overhang distance of each stratum were proposed to judge the damage of each layer. A new theoretical method to predict the development height of permeable fractured zone was put forward. The project example was compared with …
Mechanical Characteristics And Test Of Rotary Drilling Of Pdc Anchor Bit, Zhang Youzhen, Zhang Ning, Zhang Xianzhen
Mechanical Characteristics And Test Of Rotary Drilling Of Pdc Anchor Bit, Zhang Youzhen, Zhang Ning, Zhang Xianzhen
Coal Geology & Exploration
For the construction requirements of the fast and accurate drilling of anchor hole in a coal roadway, the main mechanical factors are analyzed in theory through the establishment of PDC anchor bit rotary drilling mechanics model. The results show that the axial force of the PDC cutting tooth increases with the increase of the penetration depth, and shows the trend of first decreasing and then increasing with the increase of the cutting angle. When the friction coefficient of the coal-bearing strata is 0.20 to 0.43, the optimum cutting angle is from 15.0° to 18.3°, and the axial force and the …