Key technologies for stability research and monitoring of composite roof in shallow fully mechanized mining face
The strength analysis and effective monitoring of mining pressure in longwall fully mechanized mining face are of great significance to ensure the stability and safety of the mining face.Based on the roof conditions of Chahasu No.31319 working face,the specific indicators of mine pressure of working face are determined,and the basic roof load of the working face and the initial and periodic weighting interval of the working face are calculated;the basic roof mechanical bearing model is established,the roof stability analysis is carried out,and the roof of No.31319 working face is analyzed in combination with roof separation conditions;the mining filed partition bearing model is established by using the elastic foundation beam theory.The mining filed is simplified into original rock Ⅰ zone,support Ⅱ zone,basic roof indirect-gangue Ⅲ zone and goaf collapse Ⅳ zone.The variation characteristics of mechanical parameters such as mechanical deflection,rotation angle,bending moment,shear force and other mechanical parameters of the basic roof at working face in different mining stages are obtained:the deflection curve image of the basic roof under different loads shows a downward parabolic change,and the overall change of the rotation angle is an"S"shape,the bending moment has an upward parabolic change,and the shear force changes linearly.Combining with the theoretical analysis results,the monitoring outcome of mine pressure in No.31319 fully mechanized mining face and the layout method of measuring points are proposed.The research results build a key foundation for prevention and control of roof disasters at working face and coal mine safe and efficient mining.
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