Geotechnical Monitoring of Deep Shoring Adjacent to Train Infrastructure-Paper

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The project used automated geotechnical monitoring during deep excavation beside Burnaby’s elevated Gilmore train station and guideway. A secant pile wall extending up to 37 m deep was supported by soil anchors, while a bracing system protected three guideway piers within the excavation.<br /><br />The monitoring system combined a robotic total station, inclinometers, tiltmeters, extensometers, strain gauges, and anchor load cells. Data was collected remotely and used to track structural movements and loads, with text and email alerts for threshold exceedances. A year of baseline data showed that guideway movements were strongly correlated with temperature, so monitoring thresholds were adjusted to account for seasonal and daily variation.<br /><br />During construction, guideway movements remained within the initial Level 1 threshold through completion of Phase 1 excavation. Thermal effects were also evident in the bracing, with daily load variations of up to 400 kN and anchor-load changes of about 10 kN. Challenges included blocked total-station sightlines, equipment damage, and occasional power or communication interruptions.<br /><br />As braces were removed and the building structure took over their support, movements at Pier 29 increased. The monitoring system was reconfigured to provide more frequent readings during jacking. The pier was raised approximately 5 mm, and remote movement and strain measurements agreed with manual surveys and jack gauges. The experience demonstrated that automated monitoring could provide reliable, real-time information for managing excavation and protecting nearby infrastructure, while accounting for temperature effects and adapting to changing construction needs.

Keywords

geotechnical monitoring

deep excavation

Burnaby

Gilmore station

secant pile wall

soil anchors

guideway piers

robotic total station

inclinometers

temperature effects