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Experimental evidence for shallow, slow‐moving landslides activated by a decrease in ground temperature
Author(s) -
Shibasaki Tatsuya,
Matsuura Sumio,
Okamoto Takashi
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl069604
Subject(s) - landslide , slip (aerodynamics) , geology , shear (geology) , geotechnical engineering , creep , soil water , instability , direct shear test , shear stress , residual strength , rheology , shear zone , shear strength (soil) , materials science , petrology , soil science , composite material , tectonics , seismology , mechanics , physics , thermodynamics
In order to understand the trigger mechanism of slow‐moving landslides occurring in the early cold season from late autumn to winter, we investigated the effect of temperature on the shear strength of slip surface soils. Displacement‐controlled and shear stress‐controlled box shear experiments were performed on undisturbed slip zone soils under residual strength conditions. Test results conducted at temperatures from 9 to 25°C showed remarkable shear strength reductions with decreasing temperature. Creep‐like slow shear displacements were induced by a decrease in temperature. These temperature‐dependent shear behaviors are attributed to the rheological properties of hydrous smectite that dominantly compose the soil material along the failure surface. Our experimental results imply that ground temperature conditions influence slope instability, especially for shallow landslides occurring in smectite‐bearing rock areas.