The impacts of hysteresis on variably saturated hydrologic response and slope failure

Abstract

This investigation employs 3D, variably saturated subsurface flow simulation to examine hysteretic effects upon the hydrologic response used to drive unsaturated slope stability assessments at the Coos Bay 1 (CB1) experimental catchment in the Oregon Coast Range, USA. Slope stability is evaluated using the relatively simple infinite slope model for unsaturated soils driven by simulated pore-water pressures for an intense storm that triggered a slope failure at CB1 on 18 November 1996. Simulations employing both hysteretic and non-hysteretic soil-water retention curves indicate that using either the drying soil-water retention curve or an intermediate soilwater retention curve that attempts to average the wetting and drying retention curves underestimates the near-surface hydrologic response and subsequently the potential for slope failure. If hysteresis cannot be considered in the hydrologic simulation, the wetting soil-water retention curve, which is seldom measured, should be used for more physically based slope stability assessment. Without considering hysteresis or using the wetting soil-water retention curve, the potential for landsliding in unsaturated materials may be underestimated and a slope failure could occur when simulations predict stability.

Impact of earthquake-induced-landslides on hydrologic response of a steep mountainous catchment: a case study of the Wenchuan earthquake zone

“…The model can simulate the surface and subsurface hydrologic responses, a great deal of the distributed response data (e.g., surface saturation, discharge) can be outputted, and there is no a priori assumption of a specific runoff-generation mechanism (e.g., Horton or Dunne overland flow). InHM had been successfully applied in hydrologic-response simulations of a catchment/watershed scale ( VanderKwaak and Loague, 2001;Loague and VanderKwaak, 2002;Loague et al, 2005;Ebel et al, 2008;Mirus et al, 2009;2011;Mirus and Loague, 2013), sediment transport (Heppner and Loague, 2008;Ran et al, 2012;, and slope failure (BeVille et al, 2010;Ebel et al, 2010). The two governing equations of the surface and subsurface flow components of InHM are presented in the following paragraphs, and the complete description of InHM is referred to (VanderKwaak, 1999;Heppner et al, 2006).…”

Assessing the detail needed to capture rainfall‐runoff dynamics with physics‐based hydrologic response simulation

“… f Hysteretic water retention curve is replaced with the nonhysteretic wetting curve, as recommended by Ebel et al [2010]. …”

Multi-hazard Approaches to Civil Infrastructure Engineering

“…Table 20.2 summarizes the material parameters for fluid flow and water retention characteristics. Even though hysteresis in the water retention behavior is expected to influence the hydromechanical response of a slope subjected to cyclic wetting and drying (Ebel et al 2010), only the wetting curve was considered in the present simulations. The parameters shown in Table 20.2 are similar to those reported for the soil deposit in CB1.…”