TITLE:
Multistage Triaxial Behavior of Shallow Landslide Hazard Site Soil of Rangamati Sadar Area, Bangladesh
AUTHORS:
Mahmuda Khatun, Abu Taher Mohammad Shakhawat Hossain, Hossain Md. Sayem
KEYWORDS:
Multistage Triaxial, Shear Strength, Critical State, Stress Path, Landslide
JOURNAL NAME:
Engineering,
Vol.15 No.10,
October
20,
2023
ABSTRACT: The soil samples were collected from a shallow landslide hazard site of the Rangamati Sadar in Bangladesh to determine the shear strength properties of the soil. Multistage triaxial consolidation undrained test has become worldwide more accepted to determine the shear strength parameters. Multistage triaxial undrained tests were performed on five samples taken from five different depths of boreholes. Samples were evaluated under two natural conditionsand three remolded situations. Samples were consolidated before shearing atconfining pressures from 50 kPa to 1200 kPa. All the test resultsare discussed in terms of deviator stress versus axial strain, mean effective stress versus deviator curves, stress ratio versus axial strain, and excess p. w. p.versus axial strain curves. The samples consolidated at low effective stress first displayed peak positive values of excess p. w. p., followed by increased strains due to sample bulging failure, and only a few samples formed a shear surface failure. The strength parameters were estimated using the maximum deviator stress as the failure criterion i.e. the overall value of the cohesion is 20 kPaand the friction angle is 34°. Hence, the critical state line has been constructed and the critical state parameters have been calculated. The critical state stress ratio M was calculated to be 0.036. The shear strength of soil is one of the significant mechanical properties that are thoroughly used to assess the landslide and liquefaction potentiality of the soil.