不同围压与节理特征下盘形滚刀破岩数值研究

Numerical study on breaking rock by disc cutter at different confining pressure and joint characteristics case

为了研究围压、节理特征对盘形滚刀破岩的影响,采用颗粒离散元法建立了不同围压、节理特征下的盘形滚刀破岩模型并进行数值仿真,研究不同围压与节理特征下对应的破碎模式、破岩比能耗和裂纹数目。研究表明：盘形滚刀破岩时,随着围压与节理特征的变化,会呈现4种破碎模式;其中当围压为50 MPa,节理间距小于60 mm以及节理倾角在30°附近时呈围压促进破碎模式,该破碎模式类似于岩爆,破岩比能耗极低;当围压和节理间距一定时,比能耗随着节理倾角的增大先减小后增大,且在30°时取得最小值;当围压和节理倾角一定时,比能耗随着节理间距的增大而增大;当节理间距一定时,节理倾角在0°,90°附近时,比能耗随着围压的增大而增大。而当节理倾角在15°~75°时,比能耗随围压由1 MPa增加到25 MPa时而增大,由25 MPa增加到50 MPa时而减小;另外,破碎模式、比能耗和裂纹数目三者关系密切,其中比能耗和裂纹数目之间的变化趋势相反。

In order to study the effects of confining pressure and joint characteristics on breaking rock by disc cutter, the rock-breaking model at different confining pressure ,joint characteristics case was established by using the particle discrete element method and was performed simultaneously. Crushing mode, specific energy and number of cracks was analyzed at different confining pressure, joint characteristics case. The results show that when the disc cutter breaks rock,there exist four crushing modes as the confining pressure,joint spacing and joint angle changes. Among these crushing mode, the crushing mode of confining-pressure-promoting occurs when the confining pressure is 50 MPa,joint spacing is less than 60 mm and joint angle is near 30°. At the same time, this mode is similar to rock burst and has low specific energy in breaking rock ;When the confining pressure and joint spacing is constant, the specific energy decrea- ses and then increases with the increase of joint angle. It reaches a minimum when the joint angle is 30° ; When theconfining pressure and joint angle is constant, the specific energy increases with the increase of joint spacing; When the joint spacing is constant and the joint angle is near 0° or 90° ,the specific energy increases with the increase of confi- ning pressure. However, when the joint angle ranges in 15°-75°, the specific energy increases with the increase of con- fining pressure from 1 MPa to 25 MPa and decrease with the increase of confining pressure from 25 MPa to 50 MPa; In addition, crushing mode, specific energy and number of cracks has close relationship. The trend of changing is oppo- site between the specific energy and the number of cracks when confining pressure and joint characteristics change.