Study On Rayleigh-wave Filed Forward Of Two-dimensional Rolling Ground Model

The energy of Rayleigh wave is strong and it has high signal to noise ratio, while the method is simple, efficient field, Hence it has been widely used to dispose the engineering geological problems and engineering detection problems, we used zigzag frequency dispersion curve to solve several geological problems in fact work. However, it must be acknowledged that many theoretical problems in Rayleigh wave exploration have not been well settled. For example, the zigzag frequency dispersion curve of the formation mechanism, what characteristics the wave field propagation of Rayleigh wave has. The inversion is base on the forward, so the forward is necessary.At the moment, Rayleigh wave forward is still the level of surface. In fact, the surface is rough and Rayleigh wave is propagated along the surface. Wherefore, it's necessary to study and probe into the propagation mechanism and physical mechanism of Rayleigh wave. The scheme described in this paper uses the high-order staggered grid, based on a decoupled system of first-order differential equations. The method is fast and accurate when using dense spatial sampling. In the irregular free surface condition, an accurate and simple condition is proposed, In the proposed free surface condition, stresses are calculated so that the normal stresses perpendicular to the boundary and shear stresses on the free surface are zero. The calculation of particle velocities at the free surface does not involve any specific calculations, and the particle velocities are set to zero above the free surface. To examine the validity of the proposed method, we have discussed Rayleigh-wave propagation in some complicated mediums(two-layer model in the rolling ground, the pattern of underground cavity, weak intercalation). In short, the scheme study the rolling ground of the Rayleigh-wave's finite-difference.