地应力条件下黏弹性充填节理岩体中的应力波传播规律

STUDY FOR STRESS WAVE PROPAGATION IN VISCOELASTIC FILLED JOINTED ROCK MASS WITH IN-SITU STRESSES

  • 摘要: 考虑到地应力对充填节理岩体力学性能的影响以及岩体黏弹性所引起的应力波幅值衰减和时间延迟效应,该文基于时域递归分析法,引入应力波的品质因子,建立了考虑地应力条件下平面P波在黏弹性充填节理岩体中的传播方程。研究中充填节理采用改进的三单元模型,并假定节理接触界面法向满足非线性双曲变形模型,切向满足线性模型。研究结果表明:随着地应力的增大,应力波的透射系数增大,能量损耗减小;充填节理倾角变化将改变入射角和节理的应力分布,进而对波传播特性产生影响;节理充填厚度的增加会加大应力波能量的损耗,透射系数相应减小;应力波的能量损耗随着频率的增大而明显减小,体现了对高频波的阻碍和过滤;随着节理接触界面初始刚度的增大,应力波的透射系数逐渐增大而反射系数逐渐减小,但能量损耗无明显变化。

     

    Abstract: Considering the influence of in-situ stresses on the mechanical properties of filled jointed rock mass and the attenuation of stress wave amplitude and time delay caused by the viscoelasticity of rock mass, and using the time-domain recursive analysis method, the P-wave propagation equations in viscoelastic filled jointed rock mass under in-situ stresses are established by introducing the quality factors of stress wave. In the analysis, an improved three-element model is adopted for filled joints, and the deformation of the joint contact interfaces is assumed to satisfy the nonlinear hyperbolic deformation model in normal direction and the linear elastic model in tangential direction. The results show that with the increase of in-situ stress, the transmission coefficients of stress wave increase and the energy dissipation of stress wave decreases. The change of the filled joint angle will change the impinge angle and stress distribution of the joint, which has obvious effect on the wave propagation characteristics. The increase of joint filled thickness increases the energy dissipation and decreases the transmission coefficients. The energy dissipation of stress wave decreases obviously with the increases of wave frequency, which reflects the obstruction and filtering effect of high frequency waves. With the increases of initial stiffness of joint contact interface, the transmission coefficients of stress wave increase gradually and the reflection coefficients decrease gradually, while the energy dissipation does not change significantly.

     

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