Abstract
To build a comprehensive understanding of long-term hydro-mechanical processes that lead to shallow landslide hazards, this study explicitly monitored the volumetric water content (VWC) and rainfall amount for a weathered granite soil slope over a four year period. From the 12 operational landslide monitoring stations installed across South Korea, the Songnisan station was selected as the study site. VWC sensors were placed in the subsurface with a grid-like arrangement at depths of 0.5 and 1.0 m. Shallow landslide hazards were evaluated by applying an infinite slope stability model that adopted a previously proposed unified effective stress concept. By analyzing the variations in the monitored VWC values, the derived matric suctions and suction stresses, and the calculated factor of safety values, we were able to obtain numerous valuable insights. In particular, the seasonal effects of drainage and evapotranspiration on the slope moisture conditions and slope stability were addressed. Preliminary test results indicated that continuous rainfall successfully represented the derived matric suction conditions at a depth of 1.0 m in the lower slope, although this was not the case for the upper and middle slopes. The significance of a future study on cumulative field monitoring data from various sites in different geological conditions is highlighted.
Highlights
As the wetting process test condition better represents the phenomena of soil slope saturations induced by rainfall infiltration that directly led to the reduction of slope stability in reality, the curve-fit parameters derived from the wetting process soil–water characteristic curve (SWCC) were (a)
As the the wetting wetting process process test test condition condition better better represents represents the the phenomena phenomena of of soil soil slope saturations induced by rainfall infiltration that directly led to the reduction of slope stasaturations induced by rainfall infiltration that directly led to the reduction of slope stability bility in reality, the curve-fit parameters derived from the wetting process were in reality, the curve-fit parameters derived from the wetting process SWCC were applied to applied to theinanalyses in this study
As a result of rainfall infiltration, the degree of saturation increases, while matric suction decreases in soils according to a unique relationship represented by the SWCC
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. It is possible to predict the landslide occurrence time and size in response to the velocity of mass movements using a large-scale laboratory flume [13] This approach can be applied to reactivated slopes, such as clay-rich creep mass movement along pre-existing slip surfaces [14,15]. Matric suction and volumetric water content monitoring in unsaturated soils subjected to rainfall infiltration are essential for slope stability analyses [16,17,18,19,20,21]. A combination of rain gauges and volumetric water content sensors is an efficient and effective means of examining the slope stability of a weathered soil slope. Water 2021, 13, 2330 continuous rainfall amounts at the study site were utilized to validate the continuous rainfall to represent slope moisture conditions that may lead to the initiation of shallow landslide hazards
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