Trial of the PRIME System for Geoelectrical Condition Monitoring on Critical Railway Earthwork Infrastructure

A geoelectrical monitoring system has been installed on a section of railway earthwork embankment as part of a trial to prove the capability of the technology to produce results of value to rail infrastructure asset owners when used in operational environments. This study reports the preliminary results of a two-year period of monitoring on a site containing an active but slow-moving and closely monitored rotational slip failure in the embankment of an operational railway. During the trial, geoelectrical imaging data were collected on a daily basis from a grid array of electrodes covering approximately 500 m2. The data quality was excellent, even during the hot, dry summer of 2022, and the resulting resistivity models show clear, strong anticorrelations with measured soil moisture and matric suction, as would be expected, at five different locations across the site. These results show that geophysical monitoring complements traditional point sensors and will help to understand the dynamics of soil moisture changes in highly heterogeneous earthworks with varying vegetation cover.