Estimation of soil properties of shallow landslide source areas by dynamic penetration tests: first outcomes from Northern Tuscany (Italy)

Abstract

In Northern Tuscany (Italy) rapid, shallow landslides often cause casualties and severe damage. Aimed at contributing to the characterisation of the source areas of rapid, shallow landslides, this paper deals with the geotechnical parameterisation of the mainly involved soil by means of dynamic penetration tests. The source areas are usually located in difficult access sites, where boring and undisturbed sampling are very hard and onerous. Therefore, the results of 177 dynamic penetration tests were analysed, including dynamic probing (DP) tests and standard penetration tests (SPT). The results of these tests were related to relative density D r and friction angle Φ′ of the soil by means of empirical equations. The distribution and variability of these parameters were analysed and related to soil type, test type and probing depth. The D r and Φ′ values coming from the DP and SPT tests were found to be comparable. The Φ′ values coming from DP tests and direct shear tests showed an acceptable correlation, confirming the utility of the DP tests. The DP test can thus be an effective tool in the estimation of the properties of potentially unstable soil slope covers

Hydrological factors affecting rainfall-induced shallow landslides: From the field monitoring to a simplified slope stability analysis

“…Rainfall-induced shallow landslides affecting superficial deposits of small thickness (generally lower than 2 m) are common phenomena all over the world. In the last years, important events were recorded in many regions of Italy (Cascini et al, 2008;Montrasio and Valentino, 2008;Damiano et al, 2012;Cevasco et al, 2013;D'Amato Avanzi et al, 2013;Sorbino and Nicotera, 2013;Zizioli et al, 2013Zizioli et al, , 2014Grelle et al, 2014), in Switzerland (Von Ruette et al, 2011;Lehmann and Or, 2012;Springman et al, 2013), in Hong Kong (Fuchu et al, 1999), in South Korea (Park et al, 2013), in USA (Schmidt et al, 2001;Godt et al, 2008a, b;Godt et al, 2009;Baum et al, 2010), in many areas of Central America (Capra et al, 2003;Harp et al, 2009;Eichenberg et al, 2013).…”

Long-term hydrological monitoring of soils in the terraced environment of Cinque Terre (north-western Italy)

“…This primarily depends on the difficulties in collecting undisturbed soil samples for laboratory testing (Vannucci et al, 2019). Furthermore, in terraced landscapes, the execution of in-situ tests can be sometimes constrained by the rugged morphological conditions (D'Amato Avanzi et al, 2013;Cevasco et al, 2013;Cevasco et al, 2014).…”

“…Two DP tests were executed close to the upstream and downstream ends of the alignment, while one was carried out close to the installed hydro-geotechnical monitoring instruments (Figure 2). A medium dynamic penetrometer (DPM) (Stefanoff et al, 1988) was used, because of easily transportable on steep terraced slopes (D'Amato Avanzi et al, 2013); this equipment works with a 30 kg hammer mass dropping from a 20 cm height to drive steel roads and a conical tip (diameter 35.7 mm, tip angle 90 °, cross section 10 cm 2 ) through the ground. The number of blows required to advance the steel Frontiers in Earth Science frontiersin.org conical tip through the soil for each rod length of 10 cm (N 10 ) was registered.…”

“…The test ended when N 10 ≥50, assuming this condition as indicative of bedrock occurrence. In order to evaluate the state of soils, N 10 was normalized to the number of blows referred to the Standard Penetration Test (N SPT ) by means of a correlation factor taking into account the ratio between the specific energies per blow for the two test types (i.e., N SPT = δ*N 10 with δ = 0.73) (Odebrecht et al, 2005;D'Amato Avanzi et al, 2013). The empirical correlation between N SPT and the relative density (D R ) proposed by Gibbs and Holtz (1957) was then used.…”

An Update on Rainfall Thresholds for Rainfall-Induced Landslides in the Southern Apuan Alps (Tuscany, Italy) Using Different Statistical Methods

“…In this case, the chosen area is in the southern Apuan Alps (northwestern Tuscany, Italy). The Apuan Alps are well known not only for their beautiful environment, presence of well-known marble quarries, and proximity to popular tourist beaches (e.g., Versilia beach), but also because they are highly prone to shallow landslides and floods [14,[43][44][45]. From this point of view, it is strategic for local authorities to be able to use warning tools based on weather forecasting and rainfall observation.…”