Foundation problems in Champlain clays during droughts. I: Rainfall deficits in Montréal (1930–1988)

Abstract

During the exceptionally dry summer of 1983, extensive settlement problems developed in lightweight buildings founded in the clay deposits of the Montréal area. In this paper a modified budget method that keeps a running balance of precipitation (P) and potential evapotranspiration (PET) is applied to the region of study to obtain the soil moisture depletion or rainfall deficit (RD) throughout the period 1930–1988. It is shown that extensive foundation problems have developed whenever the rainfall deficit has exceeded 170 mm of water. Key words: settlement problems, clay deposits, evapotranspiration methods, precipitation, rainfall deficit, dry weather.