Homeowners can mitigate some of the problems of building near cliff edges, even where soil is unstable, says a geotechnical engineer.
Richard Brimmell of Brimmell Engineering Ltd. in Victoria said many of Victoria’s unstable soil sites have already been built upon. Declaring them off-limits is not reasonable.
“People like to build all over the place and that is where engineers come in,” said Brimmell.
Although each property is different, general measures can be taken to strengthen a cliff edge, he said, including:
• Installing retaining walls to hold soil in place.
• Improving drainage; pipes that carry water away or drilling of wells to collect water in a column can help prevent an unstable water buildup in the soil.
• Planting foliage. Trees have deep roots to add structural strength to a cliff edge. Low-lying plants can improve water run-off.
Since every building site is different, subject to a variety of forces, conditions and stresses, only a specific examination and analysis can determine what measure or measures will work best in a location, Brimmell said.
He added that slumps and slides like the recent one on the Gorge Waterway are relatively common.
“Shoreline situations, on the ocean like this, they fail.”