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Penetration tests in shallow layered unsaturated pyroclastic soil deposits of Southern Italy
No full textThe paper deals with a recent extensive in-situ and laboratory investigation carried out in a site characterized by thin layered unsaturated air-fall volcanic (pyroclastic) soil deposits, which are very steep and prone to slope failures turning into catastrophic flows (Cervinara, Southern Italy). The field campaign was based on iron-rod drillings, penetration tests and hand-excavated shafts, beside to the collection of undisturbed soil specimens used for laboratory tests. The real sequence of the soil layers was identified in more than two hundreds verticals. In addition, while a series of available literature formulas are detected as unreliable for these soils, the paper propose new reliable empirical correlations between the soil friction angle (of three lithotypes) and both the number of blows of the penetration test and the vertical stress
Suction Controlled Laboratory Tests on Undisturbed Pyroclastic Soil: Stiffnesses and Volumetric Deformations
No full textSimple Shear Tests on Unsaturated Soils
No full textRainfall induces landslides in several geo-environmental contexts through a variety of triggering mechanisms. In shallow covers of unsaturated silts or loose sands, static liquefaction may occur upon shearing or wetting. The paper proposes simple shear and wetting tests performed on remoulded specimens of air-fall volcanic pyroclastic silty sands from Sarno site (Italy), where huge flowslides occurred. Simple shear wetting tests reproduce the initial stress conditions in the field as well as the stress path of the most common triggering mechanisms which take place during critical rainfalls. The tests are carried out through the Unsaturated Simple Shear apparatus designed at the University of Salerno. First, simple shear tests are performed in dry and saturated conditions and the results compared in terms of shear strength and volumetric response. Then, wetting tests - under constant vertical stress or constant shear stress - are performed. The experimental results are presented and the future research is outlined
Sulla doppia porosità di alcuni terreni piroclastici della Regione Campania
No full textIncontro annuale dei Ricercatori in Ingegneria Geotecnica (IARG
Laboratory investigations on static liquefaction potential of pyroclastic soils involved in rainfall-induced landslides of the flow-type
No full textWetting simple shear tests on pyroclastic soils involved in shallow landslides
No full textShallow landslides are frequently triggered by rainfall in several geo-environmental contexts,
and typical examples are those occurring in pyroclastic soil deposits of Southern Italy, where unsaturated
soils are characterized by a metastable structure and may experience static liquefaction phenomena upon shearing. This paper describes some simple shear and wetting tests on remoulded specimens of an unsaturated pyroclastic soil performed through a Simple Shear apparatus equipped for unsaturated soil testing. The initial stresses of the specimens are those typical of a steep slope, and the stress paths reproduce
a typical triggering mechanism for rainfall-induced shallow landslides. In the first stage of the tests, the net vertical stress was constant and the shear stress was increased at a fixed time rate. In the second stage, both the net vertical stress and the shear stress were kept constant and the suction reduced through the injection of water into the specimen from the bottom. In the tests, the soil exhibited mostly the same stress-strain behaviour during the shear stage, but different strain behaviour during the wetting stage
An experimental plot for hydrological processes modeling
Full text linkIn this paper we describe the data and some preliminary analysis as the investigations of infiltration process, soil water content profiles dynamic and water movement systems, referring to an experimental plot. The broad aim of the work is to test the usefulness for hydrological modelling of a soil moisture monitoring methodology which is based on capacitance devices and has the benefit to be an easy and low cost system. Collected data are expected to be useful to improve the general understanding at the field scale
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