山区公路微动探测方法应用试验研究

Research for the application of microtremor survey method to high-way construction in mountainous areas

复杂山区的公路建设运营对地球物理探测提出了巨大挑战.非侵入式微动探测方法无需主动震源,作为地震类方法的一种,其独特的优势已经体现在地热资源探测、城市地下空间精细探测等领域.针对目前山区公路建设运营中对地球物理探测的重大需求,本文研究微动探测方法的应用效果.首先,根据研究区地形设计了十字形与直线型进行野外微动数据的采集,进而利用空间自相关法从微动信号中提取瑞雷波频散曲线,最后获得视S波速度剖面.通过与高密度电法探测结果对比发现微动探测方法在山区可以有效的识别隐伏构造和不同的岩性层、刻画高速异常地质体等.在灵活改变观测系统的情况下,针对山区公路建设对地质信息的要求,该方法可以提供关键的精细地质结构信息.通过本研究,初步证实了微动探测方法在山区探测的有效性,为后续复杂条件下的地球物理探测提供了新的有效探测手段.

Highway construction and operation in complex mountainous areas launch one challenges to geophysical exploration. As one kind of seismic method, non-invasive microtremor survey method does not need artificial sources. It has applied various filed such as geothermal exploration and the fine detection of urban underground space. In view of the great demand of geophysical detection in mountain highway construction and operation, the application effect of microtremor survey method is studied in this paper. Firstly, it deployed cross and line observation system based on the observation condition to collected the microtremor signal. Then, the Rayleigh wave dispersion curve was extracted using SPAC method. At last, the apparent S-wave velocity section was achieved. Comparison between the result of microtremor survey method and high density electrical method, it shows that microtremor survey method can effectively identify the buried fault and different rock layers, describe the high wave velocity anomalies. Under the condition of flexible change of observation system, this method can provide key geological structure information for the requirement of geological information in mountain highway construction. Through this study, the effectiveness of microtremor survey method in mountain area is preliminatively confirmed, which provides a new effective detection method for subsequent geophysical exploration under complex conditions.