Investigating the seasonal variability of electromagnetic soil properties using field monitoring data from Time-DomainudReflectometry probesud

摘要

Shallow geophysical techniques such as Ground Penetrating Radar (GPR) have been widely used to detect buried utilities. However, these techniques are influenced by ground properties such as the electromagnetic (EM) and geotechnical soil properties. This research focused on the long-term monitoring of these soil properties in the field in order to establish the amount, and the causes, of variation and their impact on GPR results. A Time-Domain Reflectometry monitoring station was developed and was installed in an anthropogenic sandy soil at the University of Birmingham campus (U K). The monitoring lasted approximately 22 months, during which GPR surveys were con ducted over specifically buried targets. The results indicated a significant seasonal variation of the EM soil properties. The variation was found to be strongly dependent on the amount of rainfall and only marginally related to the variation of soil temperature. This variation was shown to affect the GPR results. During wet periods and soon after rainfall events the quality of the GPR images reduced considerably, making it difficult to distinguish some of the buried targets. The seasonal variation of the EM soil properties should be taken in to account when planning GPR surveys in order to maximize the detection of buried utilities.