Abstract Acoustical waves propagating along the free surface of granular media under gravity are investigated in the framework of elasticity theory. The influence of stress on a surface wave is analyzed. The results have shown that two types of surface waves, namely sagittal and transverse modes exist depending on initial stress states, which may have some influence on the dispersion relations of surface waves, but the influence is not great. Considering that the present experimental accuracy is far from distinguishing this detail, the validity of elasticity theory on the surface waves propagating in granular media can still be maintained.
Fund: Project supported by the National Natural Science Foundation of China (Grant No. 11274390) and the Natural Science Foundation of the Guangxi Higher Education Institutions of China (Grant No. 2013YB158).
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