Research on Asymmetric Failure Law of Surrounding Rock in Deep Tunnels
The shape and range of plastic zone in the surrounding rock of deep buried coal seam tunnels are of great significance to coal mine production safety.This article takes the 150505 working face of a certain mine in Shanxi as the research background,and through theoretical analysis,studies the influence of lateral pressure coefficient and stress deflection angle on the shape of the plastic zone of the surrounding rock of the circular roadway.The research results indicate that under non isobaric stress fields,the surrounding rock of the tunnel will exhibit three shapes:circular,elliptical,and butterfly.When the surrounding rock of the tunnel forms a butterfly shaped plastic zone,the plastic zone of the surrounding rock is larger.There is a one-to-one correspondence between the degree of plastic zone deflection of the surrounding rock and the degree of principal stress deflection of the surrounding rock.The deflection angle of the plastic zone is basically the same as that of the principal stress deflection angle.When the maximum size of the butterfly shaped plastic zone rotates above the roadway,the roadway is prone to roof collapse,which is also the reason for asymmetric damage to the surrounding rock of the roadway.The current support capacity cannot reduce the plastic zone of the surrounding rock of the roadway,but it can effectively control the formation of roof collapse in the surrounding rock of the roof.
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