Search

This study aims to assess the liquefaction potential of soil deposits where soil boiling and liquefaction have been first observed since the Pohang earthquake in 2017. We use multi-physics techniques for site characterizations and laboratory analysis for in situ soil samples. Depth-dependent engineering soil properties are analyzed using effective stress–depth models, where extensive datasets compiled from previous studies enhance data reliability. A physics-inspired and data-driven framework successfully establishes a lower bound for low plastic clay and upper bound for loose silt for porosity, electrical resistivity, and shear wave velocity data and divides the sediment into four different soil layers. In particular, there may exist a transitional zone from loose silt to low plastic clay (i.e., depth z = 4–10 m), where the silt tends to be contractive when subjected to cyclic events and plays a critical role in the determination of time to pore pressure dissipation, so that this layer may be sensitive to liquefaction. The factor of safety is calculated based on the field test results to verify the liquefaction potential of fine-dominant sediments where clays prevail. The data interpretation approach and physical model framework proposed in this study can be applied to the evaluation of liquefaction susceptibility for fine-dominant soil deposits. [ABSTRACT FROM AUTHOR]

Human noroviruses (NoVs) are the leading cause of food- and waterborne outbreaks of acute nonbacterial gastroenteritis worldwide. As a result of the lack of a mammalian cell culture model for these viruses, studies on persistence, inactivation, and transmission have been limited to cultivable viruses, including feline calicivirus (FCV). Recently, reports of the successful cell culture of murine norovirus 1 (MNV-1) have provided investigators with an alternative surrogate for human NoVs. In this study, we compared the inactivation profiles of MNV-1 to FCV in an effort to establish the relevance of MNV-1 as a surrogate virus. Specifically, we evaluated (i) stability upon exposure to pH extremes; (ii) stability upon exposure to organic solvents; (iii) thermal inactivation; and (iv) surface persistence under wet and dry conditions. MNV-1 was stable across the entire pH range tested (pH 2 to 10) with less than 1 log reduction in infectivity at pH 2, whereas FCV was inactivated rapidly at pH values <3 and >9. FCV was more stable than MNV-1 at 56°C, but both viruses exhibited similar inactivation at 63 and 72°C. Long-term persistence of both viruses suspended in a fecal matrix and inoculated onto stainless steel coupons were similar at 4°C, but at room temperature in solution, MNV-1 was more stable than FCV. The genetic relatedness of MNV-1 to human NoVs combined with its ability to survive under gastric pH levels makes this virus a promising and relevant surrogate for studying environmental survival of human NoVs. [ABSTRACT FROM AUTHOR]