节理分布形式对交叉节理岩体动态力学特性与破坏模式影响研究

Study on the influence of joint distribution on dynamic mechanical characteristics and failure mode of cross-jointed rock mass

为揭示交叉节理对岩体动态强度及破坏模式的影响机制,对不同节理分布形式下含交叉节理岩体动态力学行为进行研究,考虑交叉节理夹角、贯通度、主节理贯通度及应变率等参数的影响,开展分离式霍普金森压杆(SHPB)冲击试验,同时设置高速摄像实时记录试样破坏过程,分析交叉节理岩体动态力学特性、能量耗散、起裂‐破坏规律。研究结果表明:(1)随节理夹角、(主)节理贯通度增大,交叉节理岩体动态抗压强度与弹性模量呈下降趋势,且具有明显率相关性。(2)试样的主裂纹总沿主节理面产生,随贯通度增大由翼裂纹转变为翼裂纹和共面裂纹,不同节理分布形式起裂情况与连通方式有所差异,主要为3种破坏模式:沿加载方向的劈裂拉伸破坏、沿预制节理面的拉伸破坏、沿预制节理面的拉剪复合破坏。(3)随着主节理贯通度和夹角的增加,入射波波阵面节理面长度增加,可通过节理面的透射能降低,试样破损程度加剧导致耗散能骤增。

s:In order to reveal the influence mechanism of intersecting joints on the dynamic strength and failure mode of rock mass,the dynamic mechanical behavior of rock mass with intersecting joints under different joint distribution forms was studied,considering the angle,penetration degree of intersecting joints,penetration degree of main joints and strain rate,etc.Influenced by the parameters,the split Hopkinson pressure bar(SHPB)impact test was carried out,and a high-speed camera was set to record the failure process of the sample in real time.The dynamic mechanical properties,energy dissipation and crack initiation-failure laws of the cross-jointed rock mass were analyzed.The research results show that:(1)with the increase of joint angle and(main)joint penetration,the dynamic compressive strength and elastic modulus of cross-jointed rock mass show a downward trend,and there is an obvious rate correlation.(2)The main cracks of the sample always occur along the main joint surface,and change from wing cracks to wing cracks and coplanar cracks with the increase of penetration.The crack initiation and connection modes are different in different joint distribution forms.The main three failure modes are splitting tensile failure along the loading direction,tensile failure along the prefabricated joint surface and tensile-shear composite failure along the prefabricated joint surface.(3)With the increase of the penetration and included angle of the main joints,the length of the joint surface of the incident wave front increases,the transmission energy through the joint surface decreases,and the damage degree of the sample increases,resulting in a sudden increase of the dissipated energy.