Abstract: Rapid,convenient,and reliable acquisition of shallow urban underground structures in densely populated areas with intense anthropogenic noise is significant for promoting the digital transparency and safe development of urban underground spaces.With the advancement of nodal seismometers,passive-source seismic imaging methods have been widely applied to image underground structures at various scales,successfully demonstrating the detection of shallow underground structures in urban underground spaces.Under the constraints imposed by urban roads and narrow spaces,linear dense arrays show high adaptability among various passive-source array deployment patterns.In a test area with known underground pipeline anomalies,this study designed three linear array arrangement patterns with spacings of 1 m,3 m,and 5 m for 1 h continuous observation of noise data.This study employed the extended spatial autocorrelation(ESPAC) method to extract surface-wave frequency dispersion data for shear-wave velocity inversion.Moreover,by comprehensively analyzing the raw data,frequency dispersion curves,and the shear-wave velocity profile obtained through inversion,this study provided a scientific understanding and basis for the parameter selection of the closely spaced linear dense array observation system for passive-source seismic detection of urban underground spaces.Finally,based on the experimental results,this study selected a scientifically reasonable observation system for detection in a real-world urban underground space construction and exploration project,revealing the complete stratigraphic structure and water-conducting structures like fracture zones at the construction area.Therefore,closely spaced linear dense arrays can yield higher resolution and accuracy in detecting urban underground spaces,showing higher adaptability in areas with severe anthropogenic interference.