Some Approaches to the Prediction of Permeability Parameters in a Finite Element Program for Early Warning

Abstract

Recently, landslides often occurred in natural soil slopes in the tropical region, which correlate with the rainy season. Rainfall infiltration leads to groundwater level fluctuations. The increased positive pore-water pressures due to rainfall influence have affected the properties and behavior of the unsaturated soil slope. In this research, the Finite Element Method of SEEP/W and SLOPE/W analyzes the factor safety of the slope affected by pore water pressure change due to rainfall. The Soil Water Characteristic Curve (SWCC) and Hydraulic Conductivity function were obtained from sieve analysis and Atterberg's limit. In addition, unsaturated soil properties from the UNSODA code are estimated based on grain-size distribution using the SWRC program. The study area is in Khanom District, southern Thailand. The results show that the soil slope at the site became unstable on November 18, 2021, with F.S. = 1.0, which agrees well with the date of the disaster. In conclusion, the slope stability analysis without the parameters from the unsaturated soil hydraulic database (UNSODA) leads to the F.S. value being higher than the actual value, and the alarm estimation would be inaccurate. Doi: 10.28991/CEJ-2022-08-12-014 Full Text: PDF

Using geophysics to guide the selection of suitable sites for establishing sustainable earthen fishponds in the Niger-Delta region of Nigeria

“…Although the side of the pond is sometimes lined with polyethylene materials to minimize water loss, its base and sides are sometimes left unlined, which could be areas of water loss via vertical or horizontal seepages [ 21 , 27 ]. The vertical or horizontal flow of water within the subsurface depends on the soil type and its hydraulic properties, such as the infiltration coefficient in the unsaturated zone or hydraulic conductivity in the saturated zone [ 26 , 28 ]. When vertical and/or horizontal flow occurs, water loss results in the fishponds becoming unsustainable.…”