Distribution characteristics and mechanical analysis of main stress direction of roof in steeply dipping coal seam
In order to analyze the influence of the rotation of the maximum principal stress direction of the roof on the deformation and damage of the roof,taking the 25221 working face of the 2130 Mine of Xinjiang Coking Coal Group as the background,physical similarity simulation and FLAC3D numerical simulation were carried to analyze the roof failure and rock structure evolution characteristics,the distribution of the maximum principal stress direction contour and its influence on the roof failure during the mining of steeply dipping coal seam.On this basis,the roof mechanical model was established to discuss the distribution characteristics of the roof deflection.The results show that:With the advancement of coal mining,the range of bearing arch above the roof failure envelope increases,and the arch extends to the middle and upper part of the rock stratum;The contour distribution pattern of the maximum principal stress direction of the roof gradually evolves from"m"to"n"type(the maximum principal stress direction of the roof in the middle and upper part of the goaf deflects greatly);Under the synergetic effect of the principal stress direction deflection and the optimal expansion crack angle,the middle and upper parts of the roof are damaged and migrate to the high level rock stratum,gradually.With the roof data fed into the roof mechanical model through Python programming,it shows that,the deflection peak value appears at 4/5 of the roof along the dip.
steeply dipping seamroof bearing structuredirection of maximum principal stressroof failure characteristics
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