Impact of climate change on shallow ground hydro-thermal properties

Changes in hydro-thermal properties in the unsaturated zone of the shallow ground impacts the stability and serviceability of structures placed within that zone. Ground response to climate change is an important consideration that has a bearing on the soil dynamics and the depth of the reactive zone. In this study, a numerical model was developed in VADOSE/w to simulate suction, moisture content and temperature variation in soil under changing climatic conditions. Weather patterns in three 10-year periods, 1990–2000, 2030–2040 and 2070–2080, were considered. Six sites from Australia with varying climatic conditions were chosen to predict the soil behaviour. Four different criteria were developed to determine the equilibrium suction and reactive zone depth. Predictions indicated that there will be an increase in suction and ground temperature, while soil moisture content decreases in the future. A criterion based on moisture content variation deems more appropriate to demarcate the reactive zone depth. Both equilibrium suction and reactive zone depth tend to increase under the predicted climatic conditions. The influence of depth to water table on equilibrium suction was highlighted. It is recommended that soil characteristics and depth to water table should be considered along with climate indices when estimating ground suction.