Abstract: The noise signal source deviates from the survey line direction during data collection and processing of underground engineering survey using the linear microtremor method. Hence, the polarization analysis method is adopted, and a microtremor survey technology in urban strong noise environment is proposed based on theoretical research and onsite practice, allowing for effective data collection and accurate processing. The proposed method is applied to the water conveyance tunnel project from Luotian reservoir to Tiegang reservoir in Shenzhen, China. The outcomes indicate the following: (1) The polarization analysis method can calculate the azimuth angle of linear microtremor data in strong urban noise environments, obtaining the azimuth of noise signals from different sources. (2) When the deviation angle of the noise source is large, frequency division polarization analysis can be performed on the data to obtain azimuth information for micro motion data processing, resulting in a more accurate apparent shear wave velocity profile in the measurement area. This technology improves the quality of survey results by accurately correcting the orientation of survey data.

Key words: water conveyance tunnel, microtremor survey technology, data correction, polarization analysis