Application of microtremor survey method in the study of stratum structure:A case study of Binhai New Town, Fuzhou City

The microtremor detection technology has been widely used in the exploration of shallow geological structure because of its swiftness, economy and being less limited by site conditions. The authors adopted the efficient and high-density data acquisition and processing technology based on the linear array,and deployed 14 survey lines in the core area of Binhai New Town, Fuzhou City to divide the bedrock depth. The Rayleigh wave phase velocity dispersion curve was extracted from the vertical component of the preprocessed microtremor signal by spatial autocorrelation method, and the shear wave velocity structure was inversed by nonlinear genetic algorithm. The application results showed that the microtremor technology could effectively detect the bedrock buried depth and stratum structure, the buried depth of the intensely weathered granite was 34~53 m and the that of the moderately weathered granite was 40~60 m in the study area, which is consistent with the borehole data collected in the area. The research results provided an important data basis for the safety utilization evaluation of underground space in the core area of Binhai New Town, Fuzhou City.