间歇性动态剪切作用下泥质夹层剪切流变特性

动力反复扰动作用是驱动岩体渐进失稳的重要影响因素,为研究爆破振动对岩体软弱结构面的影响,进行了动态剪切力间歇性循环作用下泥质软弱夹层的扰动流变试验,对比分析了试样的单纯剪切流变、单纯循环动态剪切和间歇性动态剪切作用下流变变形特征。研究表明,软弱夹层试样在流变过程中,受动态剪切力间歇性循环扰动时,若初始剪应力水平和动态循环剪切应力峰值均较低,动力扰动对试样流变过程可能无明显的影响。而若初始剪应力水平较接近其剪切强度时,微弱且长期作用的动力扰动也可以加速其流变变形过程。循环动态剪切间歇性扰动作用下试样最终发生流变破坏时,存在一应力状态门槛值,该值由静态剪应力和动态剪应力峰值之和确定。对于受泥质夹层等流变性软弱结构面控制且受爆破振动长期影响的岩质边坡,应进行瞬态动力稳定性和长期动力稳定性的综合评价。

Rheological characteristic of argillaceous weak intercalation under intermittent dynamic shear loads

The cyclic dynamic load is one of the key factors making rock mass be damaged gradually.In order to investigate the influence of blasting vibration on the weak intercalation of rock mass,laboratory experiments were conducted to study the rheological characteristic of argillaceous intercalation under cyclic dynamic load.The static rheological characteristic,cyclic dynamic shearing characteristic and rheological characteristic with dynamic disturbance of specimens were comparatively analyzed.The analysis results show that when the specimens were disturbed by intermittent dynamic shearing stress in its rheological process,the dynamic disturbance might have no remarkable influence on the rheological deformation process of the specimens if the initial shearing stress and dynamic shearing stress were comparatively low.However,low-intensity dynamic disturbance might accelerate the rheological deformation process of the specimens remarkably if the initial shearing stress was close to its shearing strength.There was a stress threshold when the specimen was failure under the static shearing stress and intermittent dynamic shearing stress,which is determined by the sum of static shear stress and dynamic shear stress.For rock slopes controlled by rheological weak structural planes and influenced by long-term blasting vibration,the transient dynamic stability and long-term dynamic stability should be analyzed.