饱水花岗岩巷道岩爆声发射时序特性实验研究

Experimental Research on AE Temporal Sequences Property of Rock-burst in Roadway with Saturated Granite

为了探讨水对岩石岩爆性能的影响,采用双轴微机控制伺服压力系统及PCI-2声发射监测系统对干燥及饱水花岗岩进行了室内岩爆模拟声发射试验。研究结果表明:水对花岗岩的强度、变形特征有较大影响。饱水使花岗岩峰值强度下降了12.69%,变形模量下降了8.24%;水在一定程度上抑制了花岗岩内部原生裂纹的孕育进度,降低了岩爆过程中声发射的活跃程度。水平卸荷后,干燥花岗岩累积振铃计数近似直线增长,饱水花岗岩则呈"台阶"状上升;干燥花岗岩岩爆过程中b值历经孕育区、发展区、下降区;饱水花岗岩b值第三阶段则为群聚区,意味着水可以软化岩样,降低岩爆烈度;水改变了花岗岩岩爆过程中内部裂纹的破坏机制,饱水花岗岩水平卸荷后的Ra值呈束状分布,内部裂纹以拉—剪—拉共存的形式破坏,而干燥花岗岩则呈张拉破裂为主,剪切为辅的破坏形式。

In order to discuss influence of water to rock burst,biaxial servo microcomputer control system and PCI-2 AE temporal system were applied to sound reflection simulation of rock burst in door,results showed that water was an important influence element for granite strength and deformation. Saturated water reduced the peak strength of granite by 12. 69%,deformation modulus decreased by8. 24%,initial fissures of granite development were restrained by water somewhat,AE activity was decreased during rock burst process,accumulative ring down count of dry granite climbed approximately straight after horizontal unloading,but as saturated granite it climbed as 'step',value b of rock burst process in dry granite,which included inoculation zone,development zone,decline zone,and the third zone of saturated granite was cluster zone,its means that water could soften rock sample and decreased rock burst intensity,the broken mechanism of inner fissures of granite rock burst was changed by water,value Ra liked a bunch distribution after saturated granite horizontal unloading,the broken style of inner fissures was tensile- shear- tensile,but to dry granite tensile failure was the primary broken style,and shear failure was auxiliary.