True-triaxial experimental study on the rockburst characteristics of rock mass with a structural plane
Engineering practices have demonstrated that rock masses containing structural planes exhibit wider ranges,higher frequencies and greater risks in terms of engineering safety in relation to rockbursts.Consequently,investigating the mechanism and failure characteristics of such rockbursts is of paramount importance,in order to prevent,control and treat deep-buried rockburst disasters.Based on the typical failure mode of rockbursts in tunnels for rock masses containing structural planes,laboratory true-triaxial tests were conducted on granite,limestone and sandstone specimens with structural planes.The load-displacement relationship,acoustic emission,ejection acceleration,and high-speed photography techniques were utilized to investigate the characteristics and failure mechanism of the rock masses under different joint dip angles and lithologies.The experimental results demonstrate that the failure mode of rock masses containing structural planes is significantly influenced by the dip angle(i.e.,the angle between the maximum principal stress plane and the structural plane)and the parameters(such as internal friction angle and cohesion)of the structural planes.In particular,when the dip angle of the structural plane is small,the surrounding rocks can undergo strain-type splitting failure.With increasing dip angle,the rock mass exhibits a characteristic shear-slip failure along the structural surface.When the rock mass containing structural planes undergoes strain-type splitting failure,tension cracks or fractures approximately parallel to the free surface occur on both sides of the structural plane,leading to the occurrence of violent rockbursts.The boundary of the rockburst pit is enclosed by the structural plane and the split fracture,and the maximum acceleration of the rockburst ejection can reach 13.56 g.In contrast,when the rock mass with structural planes is subjected to shear-slip failure,the failure energy of the rock mass is greatly weakened,and almost no dynamic failure phenomenon occurs.These research results present significant implications for disaster prevention,control,and mitigation strategies in deep buried underground engineering.
rock mechanicsrockburststructural planedip angletrue-triaxial testacoustic emission
万方数据
维普
