American Society of Civil Engineers


Effect of Antecedent Rainfall Patterns on Rainfall-Induced Slope Failure


by Arezoo Rahimi, (Project Officer, School of Civil and Environmental Engineering, Nanyang Technological Univ., Block N1, B4b-07, Nanyang Avenue, Singapore 639798.), Harianto Rahardjo, (corresponding author), (Professor, School of Civil and Environmental Engineering, Nanyang Technological Univ., Block N1, 01b-36, Nanyang Avenue, Singapore 639798 E-mail: chrahardjo@ntu.edu.sg), and Eng-Choon Leong, M.ASCE, (Associate Professor, School of Civil and Environmental Engineering, Nanyang Technological Univ., Block N1, 01c-80, Nanyang Avenue, Singapore 639798.)

Journal of Geotechnical and Geoenvironmental Engineering, Vol. 137, No. 5, May 2011, pp. 483-491, (doi:  http://dx.doi.org/10.1061/(ASCE)GT.1943-5606.0000451)

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Document type: Journal Paper
Abstract: Rainfall-induced slope failure occurs in many parts of the world, especially in the tropics. Many rainfall-induced slope failures have been attributed to antecedent rainfalls. Although it has been identified as a cause of rainfall-induced slope failure, the pattern or distribution of the antecedent rainfall has not received adequate attention. In this study, parametric studies were performed by using three typical rainfall patterns, identified by analysis of available rainfall data for Singapore and two different soil types to represent high- and low-conductivity residual soils of Singapore. Antecedent rainfall patterns were applied on soil slopes and a transient seepage analysis was conducted. The computed pore-water pressures were used in stability analyses to calculate the safety factor of the slope. Results indicated that antecedent rainfall affected the stability of both high-conductivity (HC) and low-conductivity (LC) soil slopes. However, the stability of the LC soil slope was more significantly affected than the HC soil slope. Patterns of antecedent rainfall controlled the rate of decrease in factor of safety, the time corresponding to F s( min) and the value of F s( min). Delayed rainfall pattern resulted in the lowest minimum factor of safety, F s( min), for the HC soil slope, and advanced rainfall pattern resulted in the lowest F s( min) for the LC soil slope.


ASCE Subject Headings:
Rainfall
Slopes
Failures
Slope stability
Tropical regions

Author Keywords:
Rainfall pattern
Antecedent rainfall
Rainfall-induced slope failure
Slope stability
Factor of safety