Mechanics of a tectonized soil slope: influence of boundary conditions and rainfall

The Vadoncello landslide was mobilized in December 1993 and is still active. It involves highly tectonized soils and is the reactivation of a landslide dragged by a larger landslide at the toe of the slope soon after the 1980 Irpinia (Southern Italy) earthquake. Investigations and monitoring of the Vadoncello landslide were carried out, between 1994 and 1996, within an EC funded research project. The slope has been found to be formed of chaotic successions of soil and rock strata which have been grouped into soil complexes. The soil mechanical properties are shown to be very poor, the deep soils being prone to large plastic straining even due to relatively small loading changes. The soil displacements show that a shallow fast rotational sliding has occurred at the top of the slope and a shallow earthflow has developed downslope, both lying above deeper soils involved in a mechanism of slow and long-lasting irrecoverable movements. These slow deep movements are considered to be consequent to the plastic flow of the clayey soils. They can be activated by the effects of seasonal rainfall, of low-medium intensity seismic events and by the effects of the morphological changes resulting from the slow movements themselves. The landslide reactivation in 1993 is seen to have been the combination effect of a low return-period rainfall event and the slow movements active at depth in the slope

Analysis of the micro to macro response of clays to compression

An investigation of clay microstructure and its evolution under 1D and isotropic compression is presented for different clays. Data from the literature are compared to original results on two Italian clays, obtained using SEM, image processing, MIP and on-purpose swelling tests. The effects of composition and loading history on clay microstructure, as well as its changes along the compression path (pre- and post-gross-yielding) are analysed and a conceptual model of microstructure evolution is proposed for the clays under study. NC clays at early virgin compression, either natural or reconstituted, are found to possess an open fabric of random-low orientation, complying with a prevailing inter-aggregate and a smaller intra-aggregate porosity, whose size and distribution depend on composition. Under 1D compression, either in the field or in the laboratory, the inter-aggregate porosity is lost, at a rate dependent on composition and loading history, and the dominant intra-aggregate micro-pore is progressively reduced. Accordingly, perfectly oriented stacks of domains are recognised which, though, embed preserved random particle arrangements even at large pressures, resulting in an increase of average orientation up to the reach of a steady orientation degree. Isotropic compression causes faster microstructure evolution, although large pressures are required to change 1D-induced fabric orientation.Peer ReviewedPostprint (author's final draft

Characterisation of the multi-scale fabric features of high plasticity clays

An investigation of the microstructural features of a high-plasticity clay, in both its natural conditions and reconstituted in the laboratory, is described. Scanning electron microscopy is used here to characterise the fabric at different magnifications, while image processing of the micrographs delivers a quantitative assessment of the fabric orientation. The results of energy-dispersive X-ray spectroscopy and swelling tests, as reported in a previous study by the authors, are used to characterise the bonding nature and strength, as well as mercury intrusion porosimetry to investigate clay porosimetry. Despite their identical composition, the natural and the reconstituted clay have experienced different deposition and loading history, generating different microstructural features that are shown to underlie their differences in state. For both clays, one-dimensional (1D) compression to medium–high pressures is seen to determine a well-oriented medium magnification fabric. However, larger-scale observations and the corresponding image processing results reveal non-uniform local fabric features, hence making fabric characterisation dependent on the scale of analysis and bringing about the issue of identifying the clay micro-scale representative element volume relating to the clay macro-behaviour. The micro-REV is identified for the clays under study and its connection with the macro-behaviour characterised. The microstructural evolution induced by 1D compression to very high pressures is shown to concern mainly the clay porosity and porosimetry, the fabric orientation being steady, thus explaining the isotropic hardening observed in laboratory tests.Peer ReviewedPostprint (author's final draft

Post-symposium written discussion: Ground movements in highly tectonized soil slopes - The Vadoncello-Serra dell'Acquara landslides

The town of Senerchia (Sele river valley - southern Apennines) lies in a tectonically active area close to the epicentre of the 1980 earthquake (M=6.8). The slope south-cast of the town includes three major landslides, principally in structurally complex formations. The Serra dell' Acquara mudslide involves clays and marls of the Sicilide Unit and is 33 m deep at maximum. The 1980 earthquake remobilized it. Its left flank is bordered upslope by a detrital slab crossed by the crown of the Cimitero landslide, deep seated in the clayey units, which was not remobilized by the earthquake. In 1980 ground movements took place on this side of the slope shortly south of the slab. where more clayey soils outcrop, giving rise to the subsidiary Vadoncello landslide. Since 1980 this slope had not undergone significant deformations until 1993, except for some retrogression of the crown. On 29 December 1993 major movements started. giving rise to a significant extension of the Vadoncello landslide, which is currently still active (Figure 2). The development of this landslide has been under monitoring during I 995 and 1996 (Figure I) as part of a research project founded by the European Community (EEC 1996). Although shallow mudsliding downslope and crown retrogression at the top are the fastest processes on the slope, these are not che leading instability processes. They are related to deeper, although slower, soil deformations, which interact with the other landslide bodies, as briefly discussed in the following

Applicazioni di tecniche di telerilevamento con sistema termovisivo all'infrarosso per l'individuazione di efflussi costieri e di aree di drenaggio di corpi franosi

The use of camera operating in the 8-12 µm range of electromagnetic wave spectrum, prove to be satisfactory in various sectors of the engineering geology. The results of some surveyings carried out by means of fixed stations on the land have been presented. The interpretation of the thermography which have been obtained is related to the meaning which is likely to be ascribed to the temperature distribution on the surface of the investigated bodies. In fact, the system shows in the form of shades of gray or of false colour the thermal energy radiated and reflected by the observed bodies. Starting from the most traditional applications concerning the census of submarine springs, but still prerogative of the most sophisticated systems based on the use of airborne multi-spectral scanners, the easiest thermovision system, which is also likely to be used on platforms installed on small aircraft, may stretch the applications range of remote sensing techniques to various field of the engineering geology. Besides the low cost and readiness of the survey, the thermovision system, used from fixed stations, allows to obtain images in the scale of the desired detail.Examples which have been presented refer to the location of submarine springs flowing along a part of the coast near Polignano (Bari, Apulia region) and near Maratea (Potenza, Basilicata Region), the observation of a landslide near Brindisi di Montagna (Potenza, Basilicata region). In the discussion of data resulting from thermographies taken on the above said objectives one can even realize factors which may negatively affect the image interpretation such as, for instance, the disturbance caused by vegetation to the temperature distribution on the land surface

Mechanisms of earthquake induced chemical and fluid transport to carbonate groundwater springs after earthquakes

Mechanisms by which hydrochemical changes occur after earthquakes are not well documented. We use the 2016-2017 central Italy seismic sequence, which caused notable hydrochemical transient variations in groundwater springs to address this topic, with special reference to effects on fractured carbonate aquifers. Hydrochemistry measured before and after the earthquakes at four springs at varying distances from the epicenters all showed immediate post-mainshock peaks in trace element concentrations, but little change in major elements. Most parameters returned to pre-earthquake values before the last events of the seismic sequence. The source of solutes, particularly trace elements, is longer residence time pore water stored in slow moving fractures or abandoned karstic flowpaths. These fluids were expelled into the main flow paths after an increase in pore pressure, hydraulic conductivity, and shaking from co-seismic aquifer stress. The weak response to the later earthquakes is explained by progressive depletion of high solute fluids as earlier shocks flushed out the stored fluids in the fractures. Spring \u3b413CDIC values closest to a deep magma source to the west became enriched relative to pre-earthquake values following the August 24th event. This enrichment indicates input from deeply-sourced dissolved CO2 gas after dilation of specific fault conduits. Differences in carbon isotopic responses between springs are attributed to proximity to the deep CO2 source. Most of the transient chemical changes seen in the three fractured carbonate aquifers are attributed to local shaking and emptying of isolated pores and fractures, and are not from rapid upward movement of deep fluids

The α1-adrenergic receptors: diversity of signaling networks and regulation

The α1-adrenergic receptor (AR) subtypes (α1a, α1b, and α1d) mediate several physiological effects of epinephrineand norepinephrine. Despite several studies in recombinant systems and insightfrom genetically modified mice, our understanding of the physiological relevance and specificity of the α1-AR subtypes is still limited. Constitutive activity and receptor oligomerization have emerged as potential features regulating receptor function. Another recent paradigm is that βarrestins and G protein-coupled receptors themselves can act as scaffolds binding a variety of proteins and this can result in growing complexity of the receptor-mediated cellular effects. The aim of this review is to summarize our current knowledge on some recently identified functional paradigms and signaling networks that might help to elucidate the functional diversity of the α1-AR subtypes in various organs

Global Assessment Report on Disaster Risk Reduction 2019

The Global Assessment Report on Disaster Risk Reduction (GAR) is the flagship report of the United Nations on worldwide efforts to reduce disaster risk

A geo-chemo-mechanical study of a highly polluted marine system (Taranto, Italy) for the enhancement of the conceptual site model

The paper presents the results of the analysis of the geo-chemo-mechanical data gathered through an innovative multidisciplinary investigation campaign in the Mar Piccolo basin, a heavily polluted marine bay aside the town of Taranto (Southern Italy). The basin is part of an area declared at high environmental risk by the Italian government. The cutting-edge approach to the environmental characterization of the site was promoted by the Special Commissioner for urgent measures of reclamation, environmental improvements and redevelopment of Taranto and involved experts from several research fields, who cooperated to gather a new insight into the origin, distribution, mobility and fate of the contaminants within the basin. The investigation campaign was designed to implement advanced research methodologies and testing strategies. Differently from traditional investigation campaigns, aimed solely at the assessment of the contamination state within sediments lying in the top layers, the new campaign provided an interpretation of the geo-chemo-mechanical properties and state of the sediments forming the deposit at the seafloor. The integrated, multidisciplinary and holistic approach, that considered geotechnical engineering, electrical and electronical engineering, geological, sedimentological, mineralogical, hydraulic engineering, hydrological, chemical, geochemical, biological fields, supported a comprehensive understanding of the influence of the contamination on the hydro-mechanical properties of the sediments, which need to be accounted for in the selection and design of the risk mitigation measures. The findings of the research represent the input ingredients of the conceptual model of the site, premise to model the evolutionary contamination scenarios within the basin, of guidance for the environmental risk management. The study testifies the importance of the cooperative approach among researchers of different fields to fulfil the interpretation of complex polluted eco-systems