Browsing by Author "Lee, Min Lee"

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    Influence of rainfall pattern on suction distribution and slope stability
    (Universiti Teknologi Malaysia, 2008) Lee, Min Lee
    Rainfall-induced slope failure is one of the most severe disasters in tropical regions causing major loss of life and property. This study was carried out to investigate the effect of various rainfall patterns on the suction distribution, hence on slope stability. A series of numerical analyses were conducted via Seep/W on an infinite slope model to simulate the responses of the slope consisting of typical soil types to the extreme rainfalls of five selected locations in the Malaysian Peninsular. One-dimensional infiltration tests were also performed by using a soil column model, instrumented with tensiometers and gypsum blocks, to provide laboratory evidences for the findings of numerical study. The study shows that the combination of antecedent rainfall and major rainfall is the critical rainfall pattern for shallow failure, while the prolonged antecedent rainfall contributes to the deep-seated failure for most types of soil. The critical combined duration of antecedent rainfall and major rainfall varies from 11 hours to 13 days. The duration can be estimated from an equation proposed in this study. The critical duration of antecedent rainfall varies from 1 day to 30 days, depending on the soil type, slip plane depth and geographical location. Soil permeability could significantly affect the pattern and the duration of critical rainfall. A computer software (PERISI) was developed to perform the preliminary evaluation of rainfall-induced slope instability. The critical suction distribution and factor of safety computed by PERISI software show good agreement with the results of numerical simulation and field monitoring