节理岩体单轴瞬态卸荷动态响应机理

Dynamic Response Mechanism of Uniaxial Transient Unloading in Jointed Rock Mass

为了研究深部节理岩体开挖瞬态卸荷力学响应及变形损伤规律,通过理论分析、室内试验、数值分析等技术手段,深入研究了深部节理岩体开挖中的瞬态卸荷力学机理及动力响应,探讨了瞬态卸荷和节理的相互作用机制,建立了可描述现场原位试验的数值模型。结果表明:在单轴瞬态卸荷的第1阶段中,岩体内不会产生拉应力,而在第2阶段中,反射拉伸应力波将动能完全转化为弹性势能,导致岩体内产生拉应力;当有节理存在时,卸载波会在节理处产生透反射现象,导致节理张开量与节理刚度呈负相关;在节理岩体的单轴瞬态卸荷第2阶段中,反射拉伸应力波传递至节理时,会导致节理大幅度张开,诱发岩体的位移突变现象。研究结果对于深入了解单轴瞬态卸荷作用下岩体的力学响应机制具有重要意义,为开展深部岩体瞬态卸荷研究提供了重要的参考依据。

This study aims to examine the mechanical responses and deformation damage mechanisms of deep jointed rock masses during transient unloading.We investigated the mechanical behavior and dynamic responses of these rock masses during transient unloading through theoretical analyses,laboratory experiments,numerical simulations,and other methods.Our research identifies several key factors influencing the dynamic response to transient unloading in jointed rock formations.We develop a numerical model that describes in-situ field conditions closely.Initial findings reveal that in the first stage of uniaxial transient unloading,the rock mass experiences no tensile stress.However,in the subsequent second stage,the reflection of tensile stress waves transforms all kinetic energy into elastic potential,creating tensile stresses within the rock mass.Additionally,the unloading process generates transreflectance at rock joints,leading to an inverse relationship between joint opening and stiffness in the presence of joints.In the second stage of uniaxial transient unloading,significant joint opening occurs,causing a sudden displacement in the rock mass as the reflected tensile stress wave reaches the joint.This research enhances our understanding of the mechanical behavior of rock masses under uniaxial transient unloading,providing valuable insights for addressing transient unloading challenges in deep rock mass excavations.