Abstract: In order to investigate the monitoring accuracy of Beidou deformation monitoring system under construction interference conditions, the BDS deformation monitoring system is applied to an underground garage deep foundation settlement monitoring project in Xi'an, and the settlement monitoring data during the construction period and after the construction period are obtained. According to the wavelet noise reduction principle, the monitoring data are smoothed and noise reduced, and the BDS monitoring data are compared with the level monitoring data for analysis. Finally, the final settlement of the site was predicted. The results show that the construction interference will cause the BDS monitoring data to contain a large amount of noise in a certain wavelength range. However, after the 5-layer decomposition of the original data by Daubechies wavelets, smooth settlement monitoring data can be obtained, and the average relative error of the processed data and the level monitoring data is less than 10.31%. The final settlement at the site was obtained in the range of 100~110 mm based on the noise reduction data using the modified Gompertz function prediction method. The related results can provide a reference for the application of BeiDou positioning system in the ground deformation observation project.

Key words: BeiDou deformation monitoring system, deep foundation pit, settlement monitoring, wavelet noise reduction, subsidence prediction