瑞利面波二维物理模型的数值模拟研究

Numerical simulation of the Rayleigh surface wave two-dimensional physical models

在瞬态多道瑞利面波的理论和模拟研究中,常将三维地质模型简化为二维模型来处理,以此降低分析问题的难度和节约建模成本,然而常规的实验室二维物理模型难以实现.本文基于有限元数值模拟技术对不同模型厚度的数值模型激发的声波波场进行了数值模拟,研究和分析了具有不同菲涅尔带半径R厚度的三维均匀半空间和横向非均匀模型的瑞利面波波场和频散特征,并与对应的二维数值模拟结果进行对比分析.研究表明,在模型厚度小于最小第一菲涅尔带半径R条件下,三维物理模型实验结果与二维数值模拟模型实验结果基本一致.因此,在实际物理模拟实验中,可用厚度小于最小第一菲涅尔带半径R的三维物理模型近似二维模型.本文最后以数值模拟确定的合理模型厚度制作物理模型进行实验,验证了本文提出的问题和解决方案的可行性.

In the experiments of multi-channel Rayleigh waves,often simplified two-dimensional model of three-dimensional geological model to deal with,in order to reduce the difficulty of analyzing problems and modeling of cost savings, but the conventional two-dimensional physics model difficult to achieve.Based on the acoustic wave field finite element numerical simulation model for the numerical models of different thickness of excitation to simulate,study and analyze the three-dimensional homogeneous half space and lateral heterogeneity model with different thickness of Fresnel zone radius R Rayleigh surface wave field and dispersion characteristics,and the corresponding numerical simulation of 2D results were analyzed. Studies have shown that the model is less than the minimum thickness of the first Fresnel zone radius R condition, three-dimensional physical model test results are consistent with the experimental results of two-dimensional numerical simulation model. Therefore, in the actual physical simulation,available in a thickness less than the minimum threedimensional physical model of the first Fresnel zone radius R approximate two-dimensional model. Finally, the numerical simulation of reasonable thickness of the model to determine the production of physical model experiments verify the feasibility of the proposed problems and solutions.