Field investigation of deformation characteristics and stress mobilisation of a soil slope

Anthony Kwan Leung, Charles Wang Wai Ng

    Research output: Contribution to journalArticle

    12 Citations (Scopus)
    219 Downloads (Pure)

    Abstract

    Stress mobilisation and deformation of a slope are important for engineers to carry out reliable design of retaining systems. However, most case histories reported mainly on the response of pore-water pressure (PWP), whereas knowledge about the stress-deformation characteristics of slope is limited. In this study, a saprolitic soil slope was instrumented to monitor not only the responses of PWP but also horizontal stress and horizontal displacement. To assist in the interpretation of field data, a series of laboratory tests was conducted to characterise the volume change behaviour of soil taken from the site, under the effects of both net stress and suction. During a rainstorm event when positive PWP built up, a remarkably large displacement of 20 mm was recorded between 5.5 and 6 m depths, and the top 5 m of the slope exhibited translational down-slope movement. This caused an increase in effective horizontal stress by 350%, which reached a peak value close to 40% of an effective passive stress. During the subsequent dry season when suction was recovered, an up-slope rebound of 10 mm was recorded. Comparison of field and laboratory data reveals that the rebound was attributed to suction-induced soil shrinkage. This rebound led to a decrease in the effective horizontal stress previously built up during the storm event.
    Original languageEnglish
    Number of pages12
    JournalLandslides
    Early online date20 Feb 2015
    DOIs
    Publication statusPublished - 2015

    Keywords

    • Deformation
    • Slope ratcheting
    • Stress mobilisation
    • Suction
    • Saprolitic soil
    • Field monitoring

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