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Studies on Centrifuge Modelling of Rainfall-Induced Landslides
Journal
Lecture Notes in Civil Engineering
ISSN
23662557
Date Issued
2022-01-01
Author(s)
Bhattacherjee, Dipankana
Viswanadham, B. V.S.
Abstract
Recently, the frequency of rainfall-induced landslides has increased globally. In this study, an attempt has been made to investigate the response of slopes constructed with locally available soil subjected to rainfall through a series of centrifuge model tests. A custom-designed simulator was used for inducing rainfall at high gravities using the 4.5 m radius large-beam centrifuge facility at IIT Bombay, INDIA, at 30 gravities. Three typical rainfall intensities were simulated on silty sand slopes of 7.2 height with 7.5 m crest width and 2 V:1H inclination, having an initial water table up to slope base. The first model was subjected to a prolonged and light rainfall intensity of 10 mm/h, whereas, the second and third models were subjected to short-span moderate and heavy rainfall intensities of 20 mm/h and 50 mm/h, respectively. The deformed slope profiles, crest settlements, slope face movements, and phreatic surfaces developed during rainfall were investigated based on instrumentation data and digital image analysis. The intensity of rainfall was observed to play a crucial role in governing the failure mechanism of landslides. A light rainfall intensity of 10 mm/h caused a deep-seated face failure on account of deeper rainwater infiltration inside the slope body, where each stage of sliding corresponded to a level of increase in pore pressure. A moderate rainfall of 20 mm/h corresponded to an abrupt rotational slip originating at the toe, whereas an intense cloudburst of 50 mm/h triggered extensive erosion accompanied by sliding block failure.
Volume
186
Subjects