Mechanism of non-uniform failure surrounding rock along the strike in gob-side entry retaining of Daliuta 52606 working face
In Daliuta Coal Mine,the stress deformation of concrete wall and coal pillar in gob-side entry retaining face is obviously related to the buried depth of coal seam.In order to obtain the mechanism of the buried depth affecting the non-uniform failure of surrounding rock on the gob-retaining side,similar material simulation and theoretical analysis are used to study the rock collapse structure and stress distribution law based on the mining of the 52606 gob-side entry retaining working face.The results show that,the corresponding periodic weighting step increases gradually from 10 m to about 20 m as the burial depth increases.The range of abutment stress increase enlarges,the stress concentration coefficient increases,and the distance between the peak stress position and the working face decreases.The increase of crack density in the roof of the working face is not conducive to the formation of support structure in the area of large buried depth,and is not conducive to the stability of entry retaining.The caving angle at the stop-mining line side with larger buried depth is 34°,and the caving angle of the open-off cut side with a smaller buried depth is 43°.The decrease in collapse angle and the increase in length of the cantilever structure,as well as the weakening of the supporting force of the broken surrounding rock,are the main reasons for the large deformation of the roadway in the deeply buried area.
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