A Numerical Simulation Research To The Reyleigh Surface Wave Of The Tunnel Engineering

Rayleigh surface wave are used in various areas of underground surveys because its collection is convenient, it has a large share of the energy ratio of the seismic wave field, and surface wave has a kinematic characteristics of velocity dispersion, etc. Transient Rayleigh wave method with artificial excitation has been widely used in the civil project including the stratification of site,the distribution of karst cave exploration, etc.Traditionally,the research and application of Rayleigh surface wave is focus on Rayleigh surface wave velocity dispersion characteristics (kinematic characteristics) of the active source,using of frequency-wave number (F-K) transform to extract velocity dispersion curves.Then it requires a observation permutation that contains a certain number of arranged detectors, and the depth of exploration is proportional to the scale arrangement. However, the tunnel project, due to the limited size of the limitations of the working face, and the difficulty of detector placement, surface wave exploration methods have not been able to get used.The Phase rule can effectively break this bottleneck with a little number of wave field recording.Through the correlation analysis of the phase we can obtain the surface wave dispersion curves.This paper researches two methods of dispersion for the working face to make a comparative analysis about the curve extraction, by means of finite element numerical simulation.The purpose is to use a fewer detectors or a collection of short arrangement to collect effective Rayleigh wave.In addition, when the Rayleigh surface wave is propagating, the synthesis phase of the campaign consists of two mutually perpendicular vibration when the particle motion, vibration particle trajectories in the opposite direction along the propagation direction of the elliptical orbits.The spectral ratio of surface wave horizontal component and a vertical component (H/V) also carries a stratigraphic information, you can respond effectively to deal with the surface waves problem which is brought by the limited size of the working face.In this paper, the results of research aimed at solving problems of the traditional method of Rayleigh surface wave exploration where we may encounter on the tunnel face, for the expansion of the scope of application of the Rayleigh surface wave in the project to provide some theoretical guidance.