An Instrumented Flume for Infiltration Process Modeling, Landslide Triggering and Propagation

Abstract

Rainfall is the most common cause of landslides, so it is important to know the processes underlying failure starting with the rainfall infiltration processes into the granular soils, the distribution of the water content and pore pressure in both saturated and unsaturated layers, to include their effects in terms of slope stability. Although the literature is full of simulation models, the complexity of phenomena would impose a more detailed analysis by a well-equipped flume. For that purpose, a meter-scale laboratory experiment at the University of Calabria was designed and built. It is very useful for carrying out complex tests to analyze the response of loose soils or debris in terms of stability. It is composed of two channels: the first one was adopted for analyzing the triggering mechanisms, the second one for the propagation phases. Both channels are equipped with suitable sensors for monitoring the main physical variables, i.e., spray nozzle systems to apply a specific rainfall intensity; minitensiometers and TDR (Time Domain Reflectometry) for measuring, respectively, suction values and water content; miniaturized pressure transducers for pore water pressures; and laser displacement sensors. This paper describes in detail the instrumented flume and explores its potential through the analysis of a homogeneous slope of pyroclastic soil. An experiment was carried out to reproduce landslide triggering in pyroclastic soils, evolving in mudflow, by considering a homogeneous deposit. The measurements carried out allowed testing the apparatus, describing the behavior of the soil after rainfall infiltration and better identifying factors particularly significant in the collapse mechanism and process evolution.

An Empirical Approach for Modeling Hysteresis Behavior of Pyroclastic Soils

“…The stratigraphy observed on site is shown in Figure 2, and the physical properties (specific gravity G, porosity n, saturated hydraulic conductivity k sat , effective cohesion c and friction angle φ ) are indicated in Table 1. For more details on physical, size distribution and other properties, it is possible to refer to [29,30].…”

Physical Modelling of Rainfall-Induced Sandy and Clay-Like Slope Failures

“…Tey concluded that the diference of generation mechanism of PWP values may be the deciding factor in the diference in the type of failure. An instrumented fume of a homogeneous slope of pyroclastic soil was analysed by Spolverino et al [25]. Te test showed that the role of suction and soil density was essential for this type of soil and that failure occurred when the suction was close to zero, reducing the efects of apparent cohesion, while density strongly conditioned the dynamics with which the instability manifested itself.…”

Hydrological monitoring of a slope covered by stratified pyroclastic deposits and analysis of infiltration processes

“…Hydraulic disciplines such as seepage analysis and soil water circulation processes play a decisive role in understanding the processes that cause rain‐induced subsidence. (Bogaard & Greco, 2016; Capparelli et al, 2020; de Luca & Capparelli, 2022; Spolverino et al, 2019; von Ruette et al, 2014; Wieczorek & Glade, 2005). The hydrogeological response of the groundwater regime to the triggering of deep‐seated landslides is strongly correlated to the history of prior rainfall (Lv et al, 2019; Padilla et al, 2014).…”