The Application Of Rayleigh Wave Investigation In BenXi DongShan's Mined-out Areas

According to the development of domestic arid abroad geophysical exploration. Rayleigh wave exploration method in the mined-out areas is the development trend. Rayleigh wave exploration is a new seismic exploration method for low layer in recent years. It has been widely used in the domains of engineering geological exploration and engineering quality testing, since it is easy and quick to operate with less limit of the operating site and directly get surface wave velocity parameters regarding the depth of the strata.After the coal mining, the exploitation of coal seam makes more mined-out areas, the collapse of which will make the ground sink and split, devastate the infield and buildings, and destroy the ecological environments. In this paper, Benxi Dongshan Elementary school former site worked-out section as object of study.The using of Se2404ep seismic and using of Rayleigh wave exploration methods (transient state way) survey conducted in the area. And I carried out the detailed reorganization analysis and the research to the material. At the base of the theories analysis at the Rayleigh wave and the work with people of the past, to deduct the Rayleigh wave of multi-media dispersion equation. According to the actual geological conditions, the two-media model for the medium forward modeling. We analyze the frequency dispersion of Rayleigh wave. We analysis the seismic waves in the mined-out areas, and aggregate method of seismic data picked up. We adopt Fourier transform, digital filter and wavelet and relevance analysis to process data. According to the geophysical feature of the mined-out areas, How the mined-out areas affect the Rayleigh wave dispersion curves were analyzed, and how the feature of the dispersion curves vary with the mined-out areas were also discussed. Then I carried on the geologic interpretation and identify the suspected location of the mined-out area. At last, suspected mined-out area is the proof. It proved the existence of mined-out area. The validity and practicability of this method used for the shallow core mined-out areas was presented. So the method has the better apply effect and development foreground.The results of the research provide a powerful technological support for prospecting the mined-out areas and reducing the hidden safety hazards.