地震映像高精度时频分析方法在铁路隧底隐伏岩溶识别中的应用研究

Application of seismic image high-precision time-frequency analysis method in identification of hidden karst at the bottom of railway tunnel

铁路岩溶隧道隧底隐伏岩溶危及列车行车安全,为了彻底消除安全隐患,保证运营安全,在新建铁路工程静态验收前须完成隧底隐伏岩溶探测、整治设计、整治施工等工作。岩溶探测手段以物探为主钻探为辅,地震映像法作为成熟的物探方法得到了大量应用。地震映像剖面包括时域和频域信息,由于目前用于地震映像时频分析方法计算过程较繁琐、精度不高,实际生产中并未得到广泛应用,资料分析仍以时域的波形特征识别为主,而波形特征具有复杂性、多解性,资料解释准确度不高。这里引入Wigner-Ville改进方法对地震映像剖面进行时频分析,得到高精度的瞬时频率属性剖面,综合利用地震映像剖面的时域和频域信息进行解释,减少了多解性,提高了判释的准确度。本新方法在铁路隧底隐伏岩溶探测中得到了成功验证,对类似岩溶勘探具有重要的借鉴作用。

he hidden karst at the bottom of the railway karst tunnel endangers the safety of trains.In order to completely eliminate the potential safety hazards and ensure the safety of operation,the detection of the hidden karst at the bottom of the tunnel,the renovation design,and the renovation construction must be completed before the static acceptance of the new railway project.The karst detection method is supplemented by geophysical exploration,and the seismic image method has been widely used as a mature geophysical method.The seismic image profile includes time domain and frequency domain information.Due to the complicated calculation process and low precision of the current seismic image time-frequency analysis method,it has not been widely used in actual production.The data analysis is still based on the waveform characteristics of the time domain.However,the waveform features are complex and multi-solved,and the data interpretation accuracy is not high.This paper introduces the improved Wigner-Ville method to analyze the seismic image profile in time and frequency,and a high-precision instantaneous frequency attribute profile is obtained.The extensive use of the time domain and frequency domain information of the seismic image profile is used for interpretation,which reduces the multi-solution and improves the interpretation accuracy.The new method has been successfully verified in exploring hidden karst at the bottom of railway tunnels and has an essential reference for similar karst exploration.