应力波在充填节理岩体中传播规律的数值研究

Numerical study on stress wave propagation across filled joints

通过离散元数值模拟对应力波在含一组平行充填节理岩体中的传播规律开展研究,并应用等效介质模型对应力波在含多条小间距充填节理岩体的传播规律进行分析。首先,通过数值模拟结果与理论结果的对比,验证UDEC模拟应力波在单个充填节理处的传播规律的可行性。然后将UDEC模型进行扩展研究应力波在含一组平行充填节理的岩体中的传播规律,并对充填厚度、节理间距、节理数量展开参数分析。研究发现,随着充填厚度的增加,对于不同的节理间距和数量,透射系数均减小,而节理数量对透射系数的影响与节理间距有关。存在2个临界值将节理间距对透射系数的影响规律划分为3个不同区间,当节理间距足够大时,透射系数趋于稳定,且稳定值与节理数量呈指数函数关系。最后,当节理间距较小时,采用一维等效介质多条充填节理进行分析,并对入射波频率、充填材料特性、充填厚度以及节理数量展开了参数分析对比,结果表明一维等效介质可用于简化应力波在多个小间距的充填节理中的传播计算。

The discrete element simulations were conducted to investigate the wave transmission across a set of parallel filled joints. In addition,the equivalent medium model was used to analyze the wave transmission across multiple filled joints with small space. Firstly,the feasibility of UDEC was verified through the comparative analysis of results of numerical simulation and two theoretical methods. Subsequently,the numerical simulation was extended to investigate the wave transmission across a set of parallel filled joints. Moreover,the parametric analysis for the effects of filled thickness,joint space and number on transmission coefficients was carried out. The results revealed that the transmission coefficient decreases with increasing the filled thickness,which is not affected by joint space and number. However,the influence of joint number on transmission coefficient is related to joint space. Note that the influence of joint space on transmission coefficient can be divided into three different ranges by two critical values. Transmission coefficient tends to be stable when the joint space is large enough. And the stable value in exponential function with joint number. Finally,the equivalent medium model was used to analyze the wave transmission across multiple filled joints with small space. Then,the effect of relevant parameters such as incident wave frequency,filled material properties,filled thickness and joint number on wave transmission was carried out. The results show that the equivalent medium model can be used to describe wave transmission across multiple filled joints with small space.