Influence of changes in extreme daily rainfall distribution on the stability of residual soil slopes

ABSTRACT

Many landslides triggered by intense rainfall have occurred in mountainous areas in Thailand, causing major economic losses and infrastructure damage. Extreme daily rainfall is a significant trigger for hillslope instability. Increases in extreme daily rainfall intensity due to climate change may be one of the key factors responsible for the increased landslides. Thus, in this context, changes in the intensity of extreme daily rainfall in Chiang Mai Province in North Thailand and their effects on hillslope stability are analyzed. Extreme rainfall is modeled using a generalized extreme value distribution and estimated for various return periods. A numerical analysis of seepage and an infinite slope stability model are combined to understand the hillslope response under extreme rainfall conditions. The analysis period is divided into two periods of 34 years: 1952 to 1985 and 1986 to 2019. According to the analysis results, the distribution of extreme daily rainfall changes in terms of location. The average annual daily maximum rainfall increased by approximately 11.13%. The maximum decrease in the safety factor is approximately 4.5%; therefore, these changes in extreme daily rainfall should be considered in future landslide prevention policies.

KEYWORDS:

• Extreme rainfall
• generalized extreme value distribution
• slope stability
• landslide
• pore water pressure
• climate change
• residual soil

Acknowledgments

This research was supported by the Department of Geography, Faculty of Social Sciences, Kasetsart University. The authors gratefully acknowledge the rainfall data of the Thai Meteorological Department (TMD) and soil data of Geotechnical Engineering Research and Development Center, Department of Civil Engineering, Faculty of Engineering, Kasetsart University.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from the corresponding author, Thapthai Chaithong, upon reasonable request. https://drive.google.com/drive/folders/1HXMBMuQyUiK-Lm9DV6ArTFULymqee69h?usp=sharing

Additional information

Funding

This research was supported by the Department of Geography, Faculty of Social Sciences, Kasetsart University.

Notes on contributors

Thapthai Chaithong

Thapthai Chaithong is a lecturer in Department of Geography, Faculty of Social Sciences, Kasetsart University. He obtained his Ph.D. in Environmental Studies from Graduate School of Environmental Studies, Tohoku University, Japan. He obtained his M.Eng. in Civil Engineering from Kasetsart University, Thailand. He obtained his B.Eng. in Civil Engineering from King Monguk’s University of technology North Bangkok. His research interests include the development of analytical models for predicting landslide and debris flows, unsaturated soil behaviour, soil hydrology, and climate change. Now, his research focuses on the relation between changes in extreme climate (rainfall, temperature, and wind speed) and natural disasters.