Roof cutting pressure relieving for entry-forming in soft rock roadway of deep fully-mechanized caving mining
Aiming at the supporting difficulty for deep soft rock roadway of full-mechanized caving mining in Niaoshan mine field,the stress and strain characteristics of deep rock layers with non restricted movement were explained.In the fully mechanized caving face,the roof cutting pressure relieving entry-forming technology was adopted.At the same time,theoretical analysis,numerical simulation,and engineering experiments were carried out to study the feasibility of deep roadway retaining.The roadway retaining process was divided into three zones and targeted control measures were proposed for design.The technology was tested on site in the air return way of the 11031 fully mechanized caving face in Niaoshan Coal Mine,which showed that,from the beginning of excavation to the end of mining,the roof subsidence of the roadway at the slitting site was greatest,followed by than the roadway center and the solid coal rib.The maximum subsidence was 155,128 and 81 mm,respectively.When the roof separation was stable,it was about 119 mm.According to the numerical simulation,the maximum subsidence of the roof was 175 mm after the slitting.The deformation of the surrounding rock in the deep soft rock roadway was effectively controlled,and various monitoring indicators were favorable,verifying the correctness of the design for the deep roadway in the fully mechanized caving face.
deep coal seamsupporting designentry-forming with roof cutting pressure relievinggob-side entry retaining
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