Analysis of data quality after modification of the component borehole strain at Jijitai, Xinjiang

The borehole strain observation system at Jijitai was damaged and unable to resume normal operation owing to a power supply failure, leading to its reinstallation and modification. To evaluate the reliability of the modified system, this study assessed the data quality of the multi-component borehole strain observations after the modification by examining the accuracy of tidal factors, the self-consistency test of plane strain, relative in situ calibration, and analysis of major interference factors. The results indicate that during the initial phase of instrument installation, the observation system was unstable, and maintenance was not performed in a timely manner, resulting in overall poor data quality. After the observation system was stabilized and properly zero-point adjusted, the data quality improved significantly. The tidal factor accuracy met the standards for ClassⅠdeformation stations; the plane-strain self-consistency test performed well; and the relative in-situ calibration coefficients for each component were close to the ideal value of 1. This suggests that the coupling between the strain probe, expansive cement, and bedrock was satisfactory and that the quality of the modified observation data was higher. Groundwater-level changes remained the primary source of interference, with sharp fluctuations readily causing data inconsistencies. After removing groundwater interference through linear regression, the quality of the observational data further improved. Enhancing the operational maintenance of observation systems is essential to ensure stable data quality.