Jordan Journal of Civil Engineering

Reliability Analysis of Hillslopes under Different Rainfall Patterns


Adarsh Chatr; Ramanandan S; Sundaravel V; Vidya Bhushan Maji;


Rainfall-induced slope failures and landslides stand out as prominent natural disasters, frequently wreaking havoc across the globe. Within the undulating landscapes of The Nilgiris, Tamil Nadu, India, landslides persistently inflict substantial damage on lives and infrastructure. This study focuses on the stability analysis of a typical hillslope in the Kurumbadi area of The Nilgiris, considering four distinctive antecedent and recorded rainfall patterns at the rain gauge station. The investigation reveals that both recorded and advanced rainfall patterns exert notable influences on the rate of change of the factor of safety, prompting their exclusive consideration in reliability analysis. To conduct the reliability analysis, the study employs a combination of Response Surface Methodology (RSM), Fast Lagrangian Analysis of Continua (FLAC), and First-Order Reliability Method (FORM). Significantly, the research sheds light on the impact of rainfall on hillslope stability, taking into account soils with varying degrees of compaction, specifically medium dense and loose soils. The findings underscore that the probability of failure is notably higher for advanced rainfall patterns in both medium dense and loose soils. Furthermore, the probability of failure is consistently greater for loose soil compared to medium dense soil, indicating heightened vulnerability of hillslopes with loose soil to advanced rainfall patterns. This insight into the probability of failure serves as a valuable tool for assessing slope instability under diverse rainfall intensities and durations. The outcomes of the study can be instrumental in implementing early warning measures based on predetermined target values, offering a proactive approach to mitigating the impact of rainfall-induced slope failures in the region.


Rainfall patterns, slope failures, Nilgiris, probability of failure, reliability