Subsidence of a Surficial Geological Stratum Due to Fluid Extraction: Mathematical Modelling of a Geomechanical Interaction Problem

Wednesday, 17 December 2014
Antony P Selvadurai, McGill University, Montreal, QC, Canada
The problem of ground subsidence due to fluid withdrawal becomes a topic of major importance when arid conditions resulting from extreme climate change events necessitates accessing the ground water regime to provide water for human consumption, agricultural and other industrial activities. A collateral effect of groundwater extraction is ground subsidence. The subsidence can be induced by alterations in the pore fluid pressures in an aquifer without the need for alterations to ground water levels. This paper examines the ground subsidence created by the uniform extraction of fluids from a flat disc-shaped extraction region located within fluid-saturated poroelastic domain, which results in the reduction in the pore water pressure within the flat disc-shaped region. In particular, attention is focused on the influence of the fluid extraction on a surficial layer that is elastic and can be modelled as a thick plate-type stratum. The influence of the fluid extraction over a flat circular region is modelled as a distribution of centers of dilatation. It is shown that the elastostatic model can be used to provide convenient estimates for the influences of the fluid extraction process on subsidence.