Numerical modelling of the application of capillary barrier systems for prevention of rainfall-induced slope instability

Abstract

There may be differences between this version and the published version. You are advised to consult the published version if you wish to cite from it. http://eprints.gla.ac.uk/305615/ Deposited on: 29 August 2023 Enlighten -Research publications by members of the University of Glasgow http://eprints.gla.ac.uk Numerical modelling of the application of Capillary Barrier Systems for prevention of rainfall-induced slope instability Author 1*

Development and numerical validation of a simplified method of analysis for the final steady state of sloping capillary barriers under constant intensity rain

“…shows that, provided 𝑡 𝑓 is greater than about 100mm, any sloping CB with the finer layer made of sandy silt has considerably greater water storage capacity than a corresponding CB with the finer layer made of fine to medium sand, as reported previously by Scarfone et al [16]. This is because, as noted above, a finer layer made of sandy silt can maintain high degree of saturation over considerably greater depth than a finer layer made of fine to medium sand.…”

“…In both cases, a fine gravel was assumed for the coarser layer. These were the same three materials as employed by Scarfone et al [16] in their numerical modelling of sloping CBs. The SWRCs of the fine to medium sand and the fine gravel were based on real materials tested by Yang et al [21], [22], although these authors rather misleadingly referred to the two materials as fine sand and gravelly sand respectively and this terminology was subsequently used by Scarfone et al [16].…”

“…These were the same three materials as employed by Scarfone et al [16] in their numerical modelling of sloping CBs. The SWRCs of the fine to medium sand and the fine gravel were based on real materials tested by Yang et al [21], [22], although these authors rather misleadingly referred to the two materials as fine sand and gravelly sand respectively and this terminology was subsequently used by Scarfone et al [16]. The sandy silt (referred to as silty sand by Scarfone et al [16]) was hypothetical, but typical of relevant materials from the literature.…”

“…The SWRCs of the fine to medium sand and the fine gravel were based on real materials tested by Yang et al [21], [22], although these authors rather misleadingly referred to the two materials as fine sand and gravelly sand respectively and this terminology was subsequently used by Scarfone et al [16]. The sandy silt (referred to as silty sand by Scarfone et al [16]) was hypothetical, but typical of relevant materials from the literature. In the FE modelling, all materials (both finer layer and coarser layer) were represented by the advanced hydraulic constitutive model (modVG-modM+LF) developed by Scarfone et al [10], which provides accurate modelling down to very low degree of saturation, including the role of film flow (important for the coarser layer of a CB).…”

“…It is generally assumed that to analyse the performance of sloping CBs subjected to realistic rainfall conditions, involving intermittent rainfall of varying intensity and evapotranspiration of varying intensity, complex multi-physics FE modelling will be required (e.g. [13], [14], [15], [16]). This is likely to be very time-consuming in a design setting, where it is desirable to consider multiple different CB designs (different material choices and different layer thicknesses) and multiple different rainfall scenarios to arrive at an optimum design.…”