Le frane superficiali di tipo flusso indotte da pioggia coinvolgono diverse tipologie di terreno ... more Le frane superficiali di tipo flusso indotte da pioggia coinvolgono diverse tipologie di terreno e spesso causano perdita di vite umane e ingenti disastri socio-economici. Tale circostanza è connessa alla limitata presenza di segnali premonitori nella fase di pre-rottura (soprattutto in assenza di efficienti sistemi di monitoraggio), alle alte velocità raggiunte dalla colata nella fase di propagazione ed all’aumento del volume di detrito coinvolto, a causa dell’erosione del terreno lungo il percorso. Per via delle loro caratteristiche e delle conseguenze che possono causare, la valutazione della suscettibilità di questi fenomeni franosi diventa un aspetto da indagare in dettaglio soprattutto nell’ottica di una corretta pianificazione territoriale e di una virtuosa gestione del territorio. Il presente contributo intende fornire una valutazione preliminare della suscettibilità all’innesco di frane superficiali di tipo flusso detritico attraverso l’implementazione di un modello fisicamente basato (TRIGRS). Il modello è stato testato e validato in un’area studio del Sud Italia da tempo interessata da questa tipologia di fenomeni franosi. I risultati ottenuti sono soddisfacenti, se confrontati con l’evento franoso che ha interessato l’area di studio nel 2001, sia in termini di localizzazione delle aree di innesco sia in termini di individuazione delle aree potenzialmente instabili.
Abstract The hydraulic properties of geotextiles are fundamental parameters in the design and cho... more Abstract The hydraulic properties of geotextiles are fundamental parameters in the design and choice of a geotextile for filtration and drainage applications. In these applications, hydraulic requirements must be met. These requirements are typically the retention, clogging, and hydraulic conductivity performance of filters and the transmissivity of drains, in addition to other specific requirements of the project. This chapter deals with the relevant hydraulic properties of geotextiles and subsequent test methods used to obtain them. In some cases, additional inquiry and research are recommended. The main groups of referred standard are the American Society for Testing and Materials and the International Organization for Standardization together with the European Committee for Standardization.
Permeable reactive barriers (PRBs) based on the use of zero valent iron (ZVI) represent an effici... more Permeable reactive barriers (PRBs) based on the use of zero valent iron (ZVI) represent an efficient technology for the remediation of contaminated groundwater, but the literature evidences “failures”, often linked to the difficulty of fully understanding the long-term performance of ZVI-based PRBs in terms of their hydraulic behavior. The aim of this paper is to provide an overview of the long-term hydraulic behavior of PRBs composed of ZVI mixed with other reactive or inert materials. The literature on the hydraulic performance of ZVI-based PRBs in full-scale applications, on long-term laboratory testing and on related mathematical modeling was thoroughly analyzed. The outcomes of this review include an in-depth analysis of factors influencing the long-term behavior of ZVI-based PRBs (i.e., reactive medium, contamination and the geotechnical, geochemical and hydrogeological characteristics of the aquifer) and a critical revision of the laboratory procedures aimed at investigating ...
Nel presente studio si riportano i risultati di prove d’interazione in colonna condotte al fine d... more Nel presente studio si riportano i risultati di prove d’interazione in colonna condotte al fine di valutare l’efficienza di barriere permeabili reattive (BPR) costituite da Fe 0 e da miscele granulari Fe 0 /pomice e Fe 0 /lapillo per la bonifica di acque di falda contaminate da metalli pesanti, in particolare nichel e zinco, ad una concentrazione iniziale di 50 mg/l. La necessita di miscelare il Fe 0 con la pomice o il lapillo, nasce dall’intento di migliorare il comportamento idraulico di una barriera costituita da solo Fe 0 . Infatti, la conducibilita idraulica di una BPR di solo Fe 0 puo diminuire nel tempo, a causa di differenti fattori, con conseguente inefficacia del processo di bonifica. Le prove in colonna hanno evidenziato le migliori prestazioni delle miscele, rispetto al solo Fe 0 , in termini di rimozione dei contaminanti (con particolare riferimento a soluzioni contaminate da nichel), e di mantenimento nel tempo della conducibilita idraulica (con particolare riferimento...
Studying the shear strength of a naturally weathered clay is important to understand rain-induced... more Studying the shear strength of a naturally weathered clay is important to understand rain-induced slope failures in weathered soils. However, experimental studies on naturally weathered soils are limited. The paper focuses on the laboratory experimental investigation carried out to analyse the shear strength of a naturally weathered stiff clay that can be found in unsaturated conditions in situ. This has an important practical relevance in the evaluation of the stability conditions of natural slopes at clay outcrops. Different experimental techniques of suction measurement were used to obtain the soil-water retention curve of the clay over a wide range of suctions. Scanning electronic microscope (SEM) observations and results of mercury intrusion porosimetry (MIP) tests are also presented to highlight the considerable fabric arrangement modifications at the microstructural level induced by wetting–drying processes. Moreover, isotropic consolidated drained triaxial compression tests ...
Residual deformations due to sustained and cyclic loading, acting on full-scale reinforced soil-r... more Residual deformations due to sustained and cyclic loading, acting on full-scale reinforced soil-retaining walls, could lead to an unacceptable serviceability limit state. In the present study, the writers carried out an extensive experimental programme comprising several monotonic and multistage tensile tests on a high-density polyethylene (HDPE) uniaxial extruded geogrid. Based on analysis of the test results, a combined empirical model has been developed that can predict the tensile behaviour of a specific HDPE geogrid subject to cyclic tensile loading. The paper presents the results and analyses of the effect of cyclic tensile loading histories (varying pre-stress tensile load, frequency, amplitude and number of cycles) on those parameters that are characteristic of hysteresis loops (i.e. the maximum and residual strains cumulated during each cyclic loading, tensile stiffness and area of the hysteresis loops). The results show that the average strain rate and the loading time affect the material's tensile response, as well as the combination of pre-stress tensile load and loading amplitude. The writers also investigated the difference between the load-strain relations for the monotonic test and those for the multistage tests, and concluded that the effects of cyclic loading histories are not due to material degradation.
A crucial role in the conception of landslide risk mitigation strategies is played by the design ... more A crucial role in the conception of landslide risk mitigation strategies is played by the design of mitigation measures aimed at reducing risk to acceptable levels. In the case of extremely rapid landslides, such as debris flows, artificial obstacles are very common mitigation measures, designed either to stop or to deviate the flowing mass. In the design of these types of sheltering structures, crucial is the evaluation of the impact forces exerted by the flowing mass on the structure, commonly accepted, this latter, to be a function of many variables, such as structure location, structure geometry, local topographic profile, flowing mass height, velocity and so on. Protection structures dissipate the flowing mass energy either partially or totally and, for this purpose, they are set along the potential flowing path where the debris is transported and, more prevalently, deposited. This paper focuses on a procedure for simply evaluating the impact forces transmitted with time to quasi-rigid protection structures. The approach is based on the hypotheses of (i) employing a numerical code capable of describing the propagation of the rapid landslide in its downhill path and (ii) adding, in the evaluation of the impact force, the hydrodynamic and the quasi-static terms. Despite its simplicity, the proposed procedure takes into account most of the engineering factors governing the problem, synthetized by the authors by using geometrical non-dimensional ratios. To clarify the proposed procedure, the results of numerical analyses are discussed and the influence of the above mentioned factors critically analysed
(*) Mediterranea University of Reggio Calabria Dep. DICEAM via Graziella Loc. Feo di Vito 89060 R... more (*) Mediterranea University of Reggio Calabria Dep. DICEAM via Graziella Loc. Feo di Vito 89060 Reggio Calabria, Italy. nicola.moraci@unirc.it (**)ETS de Ingenieros de Caminos Universidad Politécnica de Madrid Ciudad Universitaria, s/n 28040 Madrid, Spain (***)University of Padua Dep. ICEA via Ognissanti, 39 35129 Padova, Italy ANALYSES AND DESIGN PROCEDURE OF A NEW PHYSICAL MODEL FOR DEBRIS FLOWS: RESULTS OF NUMERICAL SIMULATIONS BY MEANS OF LABORATORY TESTS
Landslide susceptibility analysis allows drawing the susceptibility maps of anarea, where the pre... more Landslide susceptibility analysis allows drawing the susceptibility maps of anarea, where the predicted areas involved by rapid landslides are drafted. The paper shows the susceptibility zoning of debris flows performed in an area in the Province of Reggio Calabria (Italy), regularly and historically involved by rapid flow-like landslide events.In particular, the source areas of landslides have been predicted using an empirical/heuristic method based on observed phenomena and on geological/geomorphological setting of the area (detailed and validated in field thematic maps). Then, propagation phase of debris flows has been analysed by advanced methods (numerical model) to assess the path, the travel distance and velocity of flowing mass. The obtained results represent a preliminary level of zoning of the area, developed on the base of nowadays available data, on which more sophisticated studies can be developed
Le frane superficiali di tipo flusso indotte da pioggia coinvolgono diverse tipologie di terreno ... more Le frane superficiali di tipo flusso indotte da pioggia coinvolgono diverse tipologie di terreno e spesso causano perdita di vite umane e ingenti disastri socio-economici. Tale circostanza è connessa alla limitata presenza di segnali premonitori nella fase di pre-rottura (soprattutto in assenza di efficienti sistemi di monitoraggio), alle alte velocità raggiunte dalla colata nella fase di propagazione ed all’aumento del volume di detrito coinvolto, a causa dell’erosione del terreno lungo il percorso. Per via delle loro caratteristiche e delle conseguenze che possono causare, la valutazione della suscettibilità di questi fenomeni franosi diventa un aspetto da indagare in dettaglio soprattutto nell’ottica di una corretta pianificazione territoriale e di una virtuosa gestione del territorio. Il presente contributo intende fornire una valutazione preliminare della suscettibilità all’innesco di frane superficiali di tipo flusso detritico attraverso l’implementazione di un modello fisicamente basato (TRIGRS). Il modello è stato testato e validato in un’area studio del Sud Italia da tempo interessata da questa tipologia di fenomeni franosi. I risultati ottenuti sono soddisfacenti, se confrontati con l’evento franoso che ha interessato l’area di studio nel 2001, sia in termini di localizzazione delle aree di innesco sia in termini di individuazione delle aree potenzialmente instabili.
Abstract The hydraulic properties of geotextiles are fundamental parameters in the design and cho... more Abstract The hydraulic properties of geotextiles are fundamental parameters in the design and choice of a geotextile for filtration and drainage applications. In these applications, hydraulic requirements must be met. These requirements are typically the retention, clogging, and hydraulic conductivity performance of filters and the transmissivity of drains, in addition to other specific requirements of the project. This chapter deals with the relevant hydraulic properties of geotextiles and subsequent test methods used to obtain them. In some cases, additional inquiry and research are recommended. The main groups of referred standard are the American Society for Testing and Materials and the International Organization for Standardization together with the European Committee for Standardization.
Permeable reactive barriers (PRBs) based on the use of zero valent iron (ZVI) represent an effici... more Permeable reactive barriers (PRBs) based on the use of zero valent iron (ZVI) represent an efficient technology for the remediation of contaminated groundwater, but the literature evidences “failures”, often linked to the difficulty of fully understanding the long-term performance of ZVI-based PRBs in terms of their hydraulic behavior. The aim of this paper is to provide an overview of the long-term hydraulic behavior of PRBs composed of ZVI mixed with other reactive or inert materials. The literature on the hydraulic performance of ZVI-based PRBs in full-scale applications, on long-term laboratory testing and on related mathematical modeling was thoroughly analyzed. The outcomes of this review include an in-depth analysis of factors influencing the long-term behavior of ZVI-based PRBs (i.e., reactive medium, contamination and the geotechnical, geochemical and hydrogeological characteristics of the aquifer) and a critical revision of the laboratory procedures aimed at investigating ...
Nel presente studio si riportano i risultati di prove d’interazione in colonna condotte al fine d... more Nel presente studio si riportano i risultati di prove d’interazione in colonna condotte al fine di valutare l’efficienza di barriere permeabili reattive (BPR) costituite da Fe 0 e da miscele granulari Fe 0 /pomice e Fe 0 /lapillo per la bonifica di acque di falda contaminate da metalli pesanti, in particolare nichel e zinco, ad una concentrazione iniziale di 50 mg/l. La necessita di miscelare il Fe 0 con la pomice o il lapillo, nasce dall’intento di migliorare il comportamento idraulico di una barriera costituita da solo Fe 0 . Infatti, la conducibilita idraulica di una BPR di solo Fe 0 puo diminuire nel tempo, a causa di differenti fattori, con conseguente inefficacia del processo di bonifica. Le prove in colonna hanno evidenziato le migliori prestazioni delle miscele, rispetto al solo Fe 0 , in termini di rimozione dei contaminanti (con particolare riferimento a soluzioni contaminate da nichel), e di mantenimento nel tempo della conducibilita idraulica (con particolare riferimento...
Studying the shear strength of a naturally weathered clay is important to understand rain-induced... more Studying the shear strength of a naturally weathered clay is important to understand rain-induced slope failures in weathered soils. However, experimental studies on naturally weathered soils are limited. The paper focuses on the laboratory experimental investigation carried out to analyse the shear strength of a naturally weathered stiff clay that can be found in unsaturated conditions in situ. This has an important practical relevance in the evaluation of the stability conditions of natural slopes at clay outcrops. Different experimental techniques of suction measurement were used to obtain the soil-water retention curve of the clay over a wide range of suctions. Scanning electronic microscope (SEM) observations and results of mercury intrusion porosimetry (MIP) tests are also presented to highlight the considerable fabric arrangement modifications at the microstructural level induced by wetting–drying processes. Moreover, isotropic consolidated drained triaxial compression tests ...
Residual deformations due to sustained and cyclic loading, acting on full-scale reinforced soil-r... more Residual deformations due to sustained and cyclic loading, acting on full-scale reinforced soil-retaining walls, could lead to an unacceptable serviceability limit state. In the present study, the writers carried out an extensive experimental programme comprising several monotonic and multistage tensile tests on a high-density polyethylene (HDPE) uniaxial extruded geogrid. Based on analysis of the test results, a combined empirical model has been developed that can predict the tensile behaviour of a specific HDPE geogrid subject to cyclic tensile loading. The paper presents the results and analyses of the effect of cyclic tensile loading histories (varying pre-stress tensile load, frequency, amplitude and number of cycles) on those parameters that are characteristic of hysteresis loops (i.e. the maximum and residual strains cumulated during each cyclic loading, tensile stiffness and area of the hysteresis loops). The results show that the average strain rate and the loading time affect the material's tensile response, as well as the combination of pre-stress tensile load and loading amplitude. The writers also investigated the difference between the load-strain relations for the monotonic test and those for the multistage tests, and concluded that the effects of cyclic loading histories are not due to material degradation.
A crucial role in the conception of landslide risk mitigation strategies is played by the design ... more A crucial role in the conception of landslide risk mitigation strategies is played by the design of mitigation measures aimed at reducing risk to acceptable levels. In the case of extremely rapid landslides, such as debris flows, artificial obstacles are very common mitigation measures, designed either to stop or to deviate the flowing mass. In the design of these types of sheltering structures, crucial is the evaluation of the impact forces exerted by the flowing mass on the structure, commonly accepted, this latter, to be a function of many variables, such as structure location, structure geometry, local topographic profile, flowing mass height, velocity and so on. Protection structures dissipate the flowing mass energy either partially or totally and, for this purpose, they are set along the potential flowing path where the debris is transported and, more prevalently, deposited. This paper focuses on a procedure for simply evaluating the impact forces transmitted with time to quasi-rigid protection structures. The approach is based on the hypotheses of (i) employing a numerical code capable of describing the propagation of the rapid landslide in its downhill path and (ii) adding, in the evaluation of the impact force, the hydrodynamic and the quasi-static terms. Despite its simplicity, the proposed procedure takes into account most of the engineering factors governing the problem, synthetized by the authors by using geometrical non-dimensional ratios. To clarify the proposed procedure, the results of numerical analyses are discussed and the influence of the above mentioned factors critically analysed
(*) Mediterranea University of Reggio Calabria Dep. DICEAM via Graziella Loc. Feo di Vito 89060 R... more (*) Mediterranea University of Reggio Calabria Dep. DICEAM via Graziella Loc. Feo di Vito 89060 Reggio Calabria, Italy. nicola.moraci@unirc.it (**)ETS de Ingenieros de Caminos Universidad Politécnica de Madrid Ciudad Universitaria, s/n 28040 Madrid, Spain (***)University of Padua Dep. ICEA via Ognissanti, 39 35129 Padova, Italy ANALYSES AND DESIGN PROCEDURE OF A NEW PHYSICAL MODEL FOR DEBRIS FLOWS: RESULTS OF NUMERICAL SIMULATIONS BY MEANS OF LABORATORY TESTS
Landslide susceptibility analysis allows drawing the susceptibility maps of anarea, where the pre... more Landslide susceptibility analysis allows drawing the susceptibility maps of anarea, where the predicted areas involved by rapid landslides are drafted. The paper shows the susceptibility zoning of debris flows performed in an area in the Province of Reggio Calabria (Italy), regularly and historically involved by rapid flow-like landslide events.In particular, the source areas of landslides have been predicted using an empirical/heuristic method based on observed phenomena and on geological/geomorphological setting of the area (detailed and validated in field thematic maps). Then, propagation phase of debris flows has been analysed by advanced methods (numerical model) to assess the path, the travel distance and velocity of flowing mass. The obtained results represent a preliminary level of zoning of the area, developed on the base of nowadays available data, on which more sophisticated studies can be developed
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