Geotechnical Evaluation of Subdivision Setback from River Valley Slopes

Abstract

This paper addresses a geotechnical study to determine the desirable setback of housing lots from the crest of a valley slope for a 160-acre subdivision bordered on its east by a 30 m deep river valley and a Canadian National Rail (CNR) track, and on its south by a 20 m deep ravine. This study was prompted by observations from aerial photos of past slope instability along the east valley slope above and below the rail track, and along the ravine slopes. Historic geotechnical reports from the CNR indicated significant instability with the east slope and railway track twenty-eight (28) years before and proved invaluable to the overall study.