Changes in Thornthwaite Moisture Index and Reactive Soil Movements under Current and Future Climate Scenarios—A Case Study

Abstract

Expansive soils go through significant volume changes due to seasonal moisture variations resulting in ground movements. The ground movement related problems are likely to worsen in the future due to climate change. It is important to understand and incorporate likely future changes in design to ensure the resilience of structures built on such soils. However, there has been a limited amount of work quantifying the effect of climate change on expansive soils movement and related behaviour of structures. The Thornthwaite Moisture Index (TMI) is one of the commonly used climate classifiers in quantifying the effect of atmospheric boundary on soil behaviour. Using the long-term weather data and predicted future changes under different emission scenarios, a series of TMI maps are developed for South Australia. Potential changes in ground movement are then estimated for a selected area using a simplified methodology where the effect of future climate is captured through changes in TMI. Results indicate that South Australia is likely to face a significant reduction in TMI under all emission scenarios considered in this study. The changes in TMI will lead to a considerable increase in potential ground movement which will influence the behaviour of structures built on them and in some areas may lead to premature failure if not considered in the design.

Effect of soil anisotropy and variability on the stability of undrained soil slope

“…Soil slopes, i.e., cuttings or embankments, are an integral part of our transport network. Since the variability of material quality is common in soils, especially for silty or clayey soils (Karim et al, 2011;Devkota et al, 2022;Karim et al, 2022), the uncertainty on the stability of these slopes is an inherent challenge (Griffiths, 1982;Huang et al, 2006;Gould et al, 2011;Kasama and Whittle, 2011;Karim et al, 2021). Further, the mechanics for slope stability analysis that involves the conventional limit state approach uses simplifications and approximations, which adds to the uncertainty of their design.…”

Influence of Weather, Soil Variability, and Vegetation on Seasonal Ground Movement: A Field Study

“…Mitchell [28] showed that it is possible to account for expansive soil movement in design using empirical methods without heavily relying on experience. Later works [1,[30][31][32][33][34] highlighted the importance of better understanding the influence of atmospheric boundary interaction and changes in climate on the behaviour of shallow-depth structures on/in expansive soils. Several previous works have related climate with depth of suction change, e.g., Hu et al [35], Davenport [36], Walsh et al [37] and Fityus et al [38] generated depth of suction change (H s ) databases for different areas of Australia.…”

Accounting for Expansive Soil Movement in Geotechnical Design—A State-of-the-Art Review

“…The climate in Australia and around the world will continue to change in the coming decades, leading to significant socio-economic impacts [11]. Accounting for all climate variables can be a complex exercise, and changes in rainfall and temperature have been considered as the primary variables in most studies that investigated the soil-atmospheric boundary interaction, especially the ones looking at the effect of climate change [12][13][14][15][16][17]. Changes in temperature and rainfall may affect the behaviour of geotechnical infrastructure.…”

“…Depending on the geolocation, local climate, expected future changes in the climate, and structure type, these effects can vary. Although soil-atmospheric boundary interactions have been an active area of research over the last two decades, limited attention has been paid to reactive soil movement and its interaction with structures [16]. This problem is likely to worsen because of climate change.…”