微动探测技术在地层结构研究中的应用——以福州滨海新城核心区为例

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

微动探测技术以其快速、经济、受场地条件限制小等特点,广泛应用于浅部地质结构探测。该文采用基于线形台阵的高效、高密度数据采集与处理技术,在福州滨海新城核心区部署14条测线用于基岩埋深划分,通过空间自相关法从预处理后的微动信号垂直分量中提取瑞雷波相速度频散曲线,利用非线性遗传算法反演横波速度结构。结果表明,微动探测技术有效探测出研究区基岩埋深和地层结构,探明强风化花岗岩埋深为34~53 m,中风化花岗岩埋深为40~60 m,与区内搜集到的钻孔资料吻合,为福州滨海新城核心区地下空间安全利用评价提供了重要的科学依据。

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.