Identification of Hidden Karst at Tunnel Bottom Based on HHT Time Frequency Analysis Method
In the karst district,in order to reduce the safety hazard of railway tunnel engineering,it is necessary to carry out karst detection at the bottom of the tunnel,find out the karst development situation and provide timely control.Seismic imaging method is a fast,nondestructive and efficient detection method.Based on the difference between the attenuation and absorption of seismic wave and the frequency spectrum of seismic wave caused by karst and broken rock mass,the temporal and spatial distribution of instantaneous frequency recorded by seismic image is obtained by Hilbert-Huang Transform method.The frequency spectrum distribution of each mode after empirical mode decomposition is discussed.The measured data of a railway tunnel were processed and analyzed by HHT method after bad track removal,energy equalization and filtering pretreatment.The instantaneous frequency distribution characteristics of karst and broken rock mass area were discussed in detail.The data interpretation accuracy and karst identification accuracy of the underground seismic imaging method are improved by using the characteristics of time domain and frequency domain to identify the karst development and spatial distribution.
seismic imagingtime-frequency analysisHilbert-Huang Transform(HHT)identification of karst
万方数据
维普
