地质雷达电磁干扰分析及在隧洞岩溶探测中的应用

摘要

将地质雷达用于千岛湖配水工程某隧洞岩溶探测,分析了倾斜状电磁干扰异常与溶洞雷达异常差异,通过雷达剖面及疑似异常区单道时间-频率谱的分析,推断了隧底岩溶的性质及空间分布特征,含水溶洞在雷达剖面反映为同相轴错断,强振幅及能量高衰减的特性,高频干扰波振幅幅值较异常区小且能量不满足随时间推移逐渐衰减的规律,雷达成果为隧洞安全施工提供了准确的参考.%The Ground Penetrating Radar (GPR)was applied to detect karst caves in a tunnel in Thousand Island Lake water-supply pipeline project.The difference of radar anomalies between inclined electromagnet-ic interference and karst cave was analyzed.Then the properties and spatial distribution characteristics of the tunnel bottom of the karst cave were deduced by analyzing radar profiles and single-channel time-frequency spectrum of the suspected abnormal area.The water-filled karst caves were characterized by the phase axis fault,strong amplitude and high energy attenuation in the radar reflected profiles.The amplitude of high-fre-quency interference is smaller than abnormal area and the energy does not appear in accordance with the law that it should decay over time.The results of radar provide an accurate reference for the safety of tunnel con-struction.