基于线形台阵的高精度微动技术在城区岩性地层精细划分中的应用

High precision microtremor technology based on linear array andits application to the fine division of lithostratigraphy

微动探测技术被广泛应用于构造、孤石、溶洞等勘查,但是,以常规圆形、嵌套三角形台阵等为代表的测量方式在城区施工会受到现场条件限制,难以实现长剖面数据的高效、高密度采集。针对这一问题,提出一种基于线形台阵多次覆盖的高效数据采集技术,该技术借鉴地震勘探多次覆盖观测系统的思想,布设一次线形台阵可以同时得到多个测点数据,可大大提高单台站数据的利用率。为了研究该采集技术的可行性和有效性,开展了单点频散曲线对比实验和横波速度剖面对比实验,并将其应用于福州城区岩性地层探测实验。实验结果表明:该技术极大地提升了微动数据采集的效率和测量密度,有效改善了探测精度和探测深度,为城市复杂地面环境下开展岩性地层精细划分提供了一种新的台阵布设方案。

The microtremor survey method is a new environmental protection geophysical exploration technology with strong anti-interference ability,large detection depth and wide application range.It has been widely used in structure,boulder,karst cave and some other fields.However,the single point data acquisition method represented by circular array is limited by the field conditions.It is difficult for this method to achieve high-efficiency and high-density data acquisition of long profile.This paper presents an efficient data acquisition technology based on linear array with multiple coverage in order to solve this problem.Based on the idea of multiple coverage observation system in seismic exploration,the dispersion curves of multiple measurement points can be obtained by setting up a linear array at one time,which greatly improves the utilization rate of single station data acquisition.The feasibility and effectiveness of the technology were studied by applying the technology to the detection of boulders along subway of Fuzhou airport.The experimental results show that the high-efficiency data acquisition technology based on linear array multiple coverage greatly improves the efficiency and density of microtremor data acquisition,effectively improves the detection accuracy and detection depth,and provides a new array layout scheme for urban complex ground environment.