Mining stress evolution law of surrounding rock in short wall fully-mechanized caving stope of steeply inclined coal seam
The horizontal sublevel short wall fully-mechanized caving mining of 3-3c steeply inclined coal in Xinjiang,named as Longquan Coal Mine,is taken as the engineering background.By means of the combination of physical similarity simulation experiment and numerical calculation,the deformation and failure law of surrounding rock in multi-sublevel stope is investigated in detail and the evolution characteristics of the first principal stress size and direction is analyzed through quantitative characteriza-tion method.And the transmission and evolution mechanism of mining stress is revealed while the rea-sonable stage height of short wall fully-mechanized caving mining of steeply inclined seam is also deter-mined.The result can be concluded as follows:the stress transfer path of surrounding rock in steeply in-clined short wall fully-mechanized caving face is characterized as asymmetric deflection with the forma-tion of asymmetric stress envelope arch along the roof above the goaf.And the stress of rock mass in the middle and upper part of the goaf is released while the stress of rock mass near the roof at the bottom of the subsection is concentrated.During the period of mining from the first section to the third section,the height of the roof caving and variation of fracture increase slightly while the value of stress arch height is close to the ratio of mining height.And the first principal stress concentration peak is small while the stress deflection degree is low.It turns out that the stability of surrounding rock structure of multi-section stope is better.As the mining stage moves to the fourth section,a large area of roof caving collapse.Due to the impact of caving gangue,it leads to the occurrence of slip failure,a large-scale chain disaster of surrounding rock,the rapid increase of stress arch height as well as the rise of arch height and the ratio of mining height.And it's convincing that the reasonable stage height can be divided into three sections with the value about 30 m,which is of great benefit to the prevention of the chain disaster induced by the instability of sudden change of surrounding rock as well as the elimination of the occurrence of stope dynamic disaster from the start.
steeply inclined coal seamshort wall fully-mechanized cavingfirst principal stressstress transfer pathstress deflection directionstage height
万方数据
维普
