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对于某些非规则水平层状地质剖面,采用传递矩阵法获得的瑞利波频散曲线可能会出现截止或截断现象,但采用附加层的方法可避免这些现象的发生。通过采用附加层法前后相速度与激发强度大小的对比,来论证附加层法的正确性。对3个典型的非规则剖面进行模拟计算,利用传递矩阵法算得添加附加层前后瑞利波频散曲线,以及某些特征点处位移分量随深度的变化情况。通过对计算结果的对比分析可知,附加层法不仅可计算出地质剖面的实数导波,还可算出其泄漏模式波;在固定的频率点上,附加层的埋深越大,则添加附加层后算得的激发强度大小与原模型的误差越小;当附加层的埋深固定时,添加附加层后计算出的位移曲线与原位移曲线之间的误差随着对比点频率的增大而减小。可见,今后根据实际工作的精度要求,可用附加层法计算某些非规则剖面的瑞利波频散曲线。
For some irregular horizontal layered geological sections, the Rayleigh dispersion curve obtained by the transfer matrix method may be cut off or cut off. However, additional layers can be used to avoid these phenomena. The correctness of the additional layer method is demonstrated by comparing the phase velocity with the excitation intensity before and after the additional layer method. Three typical irregular sections were simulated and the Rayleigh wave dispersion curves before and after the addition of additional layers were calculated by using the transfer matrix method and the variation of the displacement components with depth at some feature points was also calculated. Through the comparative analysis of the calculated results, it can be seen that the additional layer method can not only calculate the real guided wave of the geological section but also calculate the leakage mode wave. At the fixed frequency point, the greater the additional layer depth, the additional layer The difference between the calculated excitation intensity and the original model is smaller. When the depth of the additional layer is fixed, the error between the calculated displacement curve and the original displacement curve decreases as the frequency of the contrast point increases small. Can be seen in the future, according to the actual requirements of the accuracy of work, additional layer method can be used to calculate the Rayleigh wave dispersion curve of some irregular sections.