Geotechnical Study of Highway 104 Available

A geotechnical study investigating the potential risk for sinkholes forming around the Oxford section of the Trans-Canada Highway is complete.

The study found the threat to Highway 104 is low, provided the province continues to regularly monitor for ground movement and take additional measures to control water run off from the highway and its ramps.

“Keeping the travelling public safe is our number one job,” said Lloyd Hines, Minister of Transportation. “We are moving immediately on the recommendations in the report by improving ditching and also by strengthening our monitoring program.”

The department will also develop a contingency plan to be followed if subsidence is observed near the highway and ramps.

The study, conducted by Harbourside Geotechnical Consultants, examined subsurface soil and rock conditions along and beneath the highway west of Exit 6. It found that while deposits that can dissolve in water (water soluble) such as gypsum are prevalent in the area, the deposits that can result in sink holes were deep underground. Water diversion efforts from the highway area with work underway will further reduce risk.

The study was prompted after a sinkhole formed beside the Oxford Lion’s Club in the Town of Oxford in 2018.

Quick facts:

• the study focused on a 500 metre section of Highway 104 just south of the Town of Oxford
• the investigation included or laser imagery, topographic and geological mapping, aerial photos, the drilling of six boreholes and lab analysis of the core samples
• the area investigated is more likely to experience gradual settling of the ground surface than a sudden collapse, according to the study. A monitoring system to detect ground deformations was recommended to manage risk at the site
• water soluble deposits ranged from just under 10 metres to almost 60 metres below the surface

Additional Resources:

The study is available at, https://novascotia.ca/tran/roadsafety/NSTIR-Oxford-Hwy-104-Sinkhole-Investigation.pdf