深部巷道围岩非对称破坏规律研究

Research on Asymmetric Failure Law of Surrounding Rock in Deep Tunnels

深埋煤层巷道围岩的塑性区形态及范围对煤矿生产安全具有重要意义。本文以山西某矿150505工作面顺槽为研究背景,通过理论分析的手段,研究了侧压系数和应力偏转角度对圆形巷道围岩塑性区形态的影响规律。研究结果表明:在非等压应力场下,巷道围岩会呈现圆形、椭圆形、蝶形三种形态,当巷道围岩形成蝶形塑性区时,围岩的塑性区较大;巷道围岩的塑性区偏转程度与围岩主应力偏转程度存在一一对应关系,塑性区的偏转角度与主应力偏转角度基本一致;当蝶形塑性区最大尺寸蝶叶旋转至巷道上方时,巷道容易产生冒顶,这也是巷道围岩产生非对称破坏的原因所在。目前的现有支护能力无法减小巷道围岩塑性区,但可以较好地控制顶板围岩形成冒顶。

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.