含充填节理岩体中应力波传播规律的三维模拟

3D simulation of stress wave propagation in jointed rock mass with filling joint

为研究应力波在含充填节理岩体空间中的传播特性,采用离散元软件探讨不同产状节理对P波透、反射规律的影响。首先,建立三维节理岩杆的计算模型,合理选用透射边界和Rayleigh阻尼;然后,将所得计算结果与等效波阻抗理论解相比较,以验证模型的合理性;最后,分别考虑不同节理角度、厚度、间距、数目及入射波频率下的P波透、反射系数变化特征。结果表明:在节理倾向方位角β为0°~60°时,透射系数随β的增大而减小,而在β为60°~90°时随β的增大而增大;透射系数随入射波频率的增大而减小,反射系数反之。若定义节理间距与厚度的正比关系,则透射系数随节理间距的增加而增加,反射系数反之;此外,根据不同节理厚度下的节理数目与透(反)射系数关系曲线特征,定义图线中的包络线为临界透(反)射曲线,则在给定节理数目时,其透(反)射系数总大(小)于临界透(反)曲线上对应的透(反)射系数数值。

In order to study the propagation characteristics of stress wave in rock mass with filling joints,the Three-Dimension Distinct Element Code was used to explore the influence of different occurrence joints on the penetration and reflection rules of P wave.First,a computational model of three-dimensional jointed rock rods was established,and the transmission boundary and Rayleigh damping were reasonably selected.Then,the calculated results were compared with the theoretical solutions of equivalent wave impedance to verify the rationality of the model.Finally,the variation characteristics of P wave transmission and reflection coefficient at different joint angles,thicknesses,spacing,numbers and incident wave frequencies were considered.Results show that when the azimuth angle of joint inclination is 0°~60°,the transmission coefficient decreases with the increase of beta,but increases with the increase of beta when the azimuth angle is 60°~90°.The transmission coefficient decreases with the increase of the incident wave frequency,while the reflection coefficient decreases.If the proportional relation between joint spacing and thickness is defined,the transmission coefficient increases with the increase of joint spacing,while the reflection coefficient decreases.In addition,according to the number of joints under different thicknesses of the joint and transmission(reflection)shot coefficient curve characteristics,its envelope for critical transmission(reflection)curve is defined.Then,when the number of joints is given,the transmission(reflection)coefficient is larger(smaller)than the corresponding value on the critical transmission(reflection)curve.