simonetta cola - Profile on Academia.edu (original) (raw)
Papers by simonetta cola
Underground warehouses for food storage in the Dolomites (Eastern alps – Italy) and energy efficiency
Tunnelling and Underground Space Technology
European Journal of Environmental and Civil Engineering
This paper presents a numerical study carried out in the context of the development of a new appl... more This paper presents a numerical study carried out in the context of the development of a new application of plate anchors for landslide stabilization. The plates are positioned on the slope's ground surface and linked to a deeper stable layer with a steel grouted bar, thus acting as discontinuous elements constrasting the slope movement. This technique is less expensive compared to standard retaining structures, especially in medium and deep landslides. Moreover, plate anchors can bear large displacements of the unstable moving mass without losing efficiency. Evaluating the stabilizing force and its optimization in relation to the plate shape are of great interest. Numerous studies have investigated the bearing capacity of rectangular and circular thin plates at small strains, but the performance of alternative shapes, such as cones or truncated cones, has never been considered. The numerical study here presented applies the Material Point Method to investigate the behaviour of plate anchors with different 3D shapes at large displacements. The numerical model is validated with the results of some smallscale laboratory tests. The pull-out resistance, the soil stress and displacement fields around the plate, and the group effect have been investigated, thus obtaining preliminary indications for the design of these elements.
Hydraulic conductivity changes in compacted clayey barriers due to temperature variations in landfill top covers
Bulletin of Engineering Geology and the Environment
Collapse of granular–cohesive soil mixtures on a horizontal plane
Acta Geotechnica
Geosciences
Composite anchors are special passive sub-horizontal reinforcements recently developed for remedi... more Composite anchors are special passive sub-horizontal reinforcements recently developed for remediation of unstable slopes. They are composed of a hollow steel bar, installed by a self-drilling technique in the soil, coupled with tendons cemented in the inner hole to increase the global anchor tensile strength. The anchors are primarily intended to stabilise medium to deep landslides, both in soils or weathered rock masses. Among the valuable advantages of composite anchors are their low cost, ease of installation, and flexibility in execution, as testified by a rapid increase in their use in recent years. The bond strength at the soil-anchor interface is the main parameter for both the design of these reinforcements and the evaluation of their long-term effects for landslide stabilisation. After a brief description of the composite anchor technology, this paper presents a novel methodology for monitoring the strain and stress accumulated in the anchors over time when installed in an...
Scientific reports, Jan 31, 2017
A distributed optical fibre sensing system is used to measure landslide-induced strains on an opt... more A distributed optical fibre sensing system is used to measure landslide-induced strains on an optical fibre buried in a large scale physical model of a slope. The fibre sensing cable is deployed at the predefined failure surface and interrogated by means of optical frequency domain reflectometry. The strain evolution is measured with centimetre spatial resolution until the occurrence of the slope failure. Standard legacy sensors measuring soil moisture and pore water pressure are installed at different depths and positions along the slope for comparison and validation. The evolution of the strain field is related to landslide dynamics with unprecedented resolution and insight. In fact, the results of the experiment clearly identify several phases within the evolution of the landslide and show that optical fibres can detect precursory signs of failure well before the collapse, paving the way for the development of more effective early warning systems.
Procedia Engineering
The investigation of the collapse of a well-known soil volume is a simple experiment that permits... more The investigation of the collapse of a well-known soil volume is a simple experiment that permits to make several interesting considerations. This paper, at first, presents a brief overview of some physical experiments led to understand how the composition of a three-phase mixture influences the mass collapse. In particular, the run-out and the maximum height of the deposit are considered as two fundamental quantities for characterizing the behaviour of the mass in each test. In a second step, the experimental results obtained are used as case studies for the calibration of a mesh-less numerical model. Several simulations are carried out using the SPH-Geoflow code implementing a Bingham law to reproduce each bi-phases test. A comparison between the numerical results and the physical data permits to choose the most reliable value of the constitutive parameters for each tested case. The errors between the physical and the numerical run-out and maximum heights become the fundamental quantity to define the quality of the best simulation. Indeed, some final considerations about the relationship existing among the constitutive parameters and the kaolin content of the mixtures are reported.
Proceedings of the Institution of Civil Engineers - Geotechnical Engineering, 2016
This paper reports on an experimental investigation on the behaviour of small-diameter piles, com... more This paper reports on an experimental investigation on the behaviour of small-diameter piles, commonly referred to as micropiles. This particular type of deep foundation is frequently used in many barely accessible Italian mountainous areas, often characterised by complex ground profiles composed of mixtures of coarse soils with some fine matrix elements including cobbles and large-diameter boulders. In such ground conditions, the lack of reliable site and laboratory geotechnical investigations providing an accurate soil mechanical description and conservative approaches for micropile design often lead to significant underestimation of the vertical ultimate load. In order to improve micropile design in such geological contexts, a new field trial investigation involving tension and compression load tests on micropiles up to failure was set up in a selected test site located in the Italian alpine region. From interpretation of the load tests carried out so far, the reliability of commonly used calculation methods for estimating bearing capacity is discussed. As a result, a new approach for a more suitable calculation of the mobilised shaft and base resistance of micropiles bored in highly coarse soils is tentatively proposed.
Combined geophysical surveys for the characterization of a reconstructed river embankment
Engineering Geology, 2016
Egu General Assembly Conference Abstracts, Apr 1, 2013
Canadian Geotechnical Journal, 2002
The main feature of the shallowest quaternary basin of the well-renowned historic city of Venice,... more The main feature of the shallowest quaternary basin of the well-renowned historic city of Venice, Italy and its surrounding lagoon, is the presence, apparently without any regular trend in depth and site, of a predominant silt fraction. This is always combined with clay and (or) sand, forming a chaotic and erratic interbedding of different sediments whose mineralogy is however variable in a relatively narrow range due to a unique geological origin and a common depositional environment. After a brief description of the basic soil indexes of the Venice lagoon soil, the present study, based on a comprehensive geotechnical laboratory investigation, describes the range of variation of the most relevant time-independent geotechnical properties. Moreover, a new grain size index, combining the geometrical characteristics of the particle distribution, is introduced. It is shown that the soil response at large and very small strains can be related to this grain size index, which appears to be able to include the influence of the soil grading on the description of the overall mechanical behavior.
Water Resources Research, 2010
A fully coupled thermohydromechanical (THM) finite element approach is used here to model the gro... more A fully coupled thermohydromechanical (THM) finite element approach is used here to model the groundwater and saturation response of a typical salt marsh of the Venice lagoon (Italy) subjected to both tide fluctuation and flooding. The soil forming the marsh, whose relevant material parameters have been measured experimentally in the laboratory, is assumed to be an homogeneous multiphase porous medium, in a thermodynamic equilibrium state both in fully saturated and partially saturated conditions. More particularly, the study is aimed at analyzing separately the various couplings of several factors such as soil stiffness, water conductivity, capillary suction, and humidity exchange with atmosphere including also the occurrence of marsh flooding on the overall mechanical response of the marsh subjected to tidal oscillations of very narrow amplitude. From the analysis carried out so far, the numerical approach adopted here seems capable of describing most of the relevant features of marsh behavior, thus showing the importance of THM couplings to explain the groundwater pressure evolution induced by lagoon tide cycles. In addition, the model seems to provide some interesting explanations concerning the evolving instability of marsh scarps, which is one of the main causes of the rapid overall deterioration of the typical Venice lagoon landscape.
Modified compressibility of cohesive sediments induced by thermal anomalies due to a borehole heat exchanger
Engineering Geology, 2016
Induced thermal compaction in cohesive sediments around a borehole heat exchanger: laboratory tests on the effect of pore water salinity
Environmental Earth Sciences, 2016
Soil nailing is an economic and efficient method to reinforce soils, involving the insertion of t... more Soil nailing is an economic and efficient method to reinforce soils, involving the insertion of threaded bars into natural unstable slope for increasing the overall stability or into cut slopes during the top-down process of excavation. The retained soil, the resisting reinforcements and the external facing are the main components of a soil-nailed structure. Their composite interactions determine the performance of soil-nail construction in terms of deformations and stability. Even if the international codes deal about the possibility of use rigid or flexible external facing, the role of facing stiffness is not sufficiently studied and evaluated. To this aim, some tests with various facing types, differing in stiffness and continuity, were carried out so far in 1g small scale physical model. The experimental results show the importance of both flexional and axial stiffness of facing in controlling the deformation of the wall during excavation and the maximum surcharge applicable at the rear of wall. RÉSUMÉ: Le clouage du sol est une méthode économique et efficace pour renforcer le sol en place: il consiste en l'insertion de barres d'acier filetées ou d'autres barres dans les pentes naturelles instables ou dans des talus au cours du processus de l'excavation pour augmenter la stabilité globale. Le sol soutenu, les barres résistantes et le parement extérieur sont les principales composantes d'une structure du sol cloué. Leurs interactions mutuelles déterminent la performance du soil nailing en termes de déformations et de stabilité. Même si les codes internationaux considèrent la possibilité d'utiliser des parements extérieurs rigides ou flexibles, le rôle de la raideur du parement n'a pas été suffisamment étudié et évalué. Avec ce but ont été réalisées des épreuves dans un modèle physique avec des parements différents en rigidité et continuité. Les résultats expérimentaux soulignent l'importance de la raideur en flexion et en traction-compression du parement extérieur dans le contrôle de la déformation de la paroi pendant l'excavation, et la valeur maximale de la charge applicable à l'arrière du mur.
Application of a high resolution Distributed Temperature Sensor in a physical model reproducing subsurface water flow
Measurement, 2015
Reinforcement works for the slope stabilization: standard and new approaches for the use of micropiles and anchors
Frana di Brusole' situazione geologica e geotecnica
Underground warehouses for food storage in the Dolomites (Eastern alps – Italy) and energy efficiency
Tunnelling and Underground Space Technology
European Journal of Environmental and Civil Engineering
This paper presents a numerical study carried out in the context of the development of a new appl... more This paper presents a numerical study carried out in the context of the development of a new application of plate anchors for landslide stabilization. The plates are positioned on the slope's ground surface and linked to a deeper stable layer with a steel grouted bar, thus acting as discontinuous elements constrasting the slope movement. This technique is less expensive compared to standard retaining structures, especially in medium and deep landslides. Moreover, plate anchors can bear large displacements of the unstable moving mass without losing efficiency. Evaluating the stabilizing force and its optimization in relation to the plate shape are of great interest. Numerous studies have investigated the bearing capacity of rectangular and circular thin plates at small strains, but the performance of alternative shapes, such as cones or truncated cones, has never been considered. The numerical study here presented applies the Material Point Method to investigate the behaviour of plate anchors with different 3D shapes at large displacements. The numerical model is validated with the results of some smallscale laboratory tests. The pull-out resistance, the soil stress and displacement fields around the plate, and the group effect have been investigated, thus obtaining preliminary indications for the design of these elements.
Hydraulic conductivity changes in compacted clayey barriers due to temperature variations in landfill top covers
Bulletin of Engineering Geology and the Environment
Collapse of granular–cohesive soil mixtures on a horizontal plane
Acta Geotechnica
Geosciences
Composite anchors are special passive sub-horizontal reinforcements recently developed for remedi... more Composite anchors are special passive sub-horizontal reinforcements recently developed for remediation of unstable slopes. They are composed of a hollow steel bar, installed by a self-drilling technique in the soil, coupled with tendons cemented in the inner hole to increase the global anchor tensile strength. The anchors are primarily intended to stabilise medium to deep landslides, both in soils or weathered rock masses. Among the valuable advantages of composite anchors are their low cost, ease of installation, and flexibility in execution, as testified by a rapid increase in their use in recent years. The bond strength at the soil-anchor interface is the main parameter for both the design of these reinforcements and the evaluation of their long-term effects for landslide stabilisation. After a brief description of the composite anchor technology, this paper presents a novel methodology for monitoring the strain and stress accumulated in the anchors over time when installed in an...
Scientific reports, Jan 31, 2017
A distributed optical fibre sensing system is used to measure landslide-induced strains on an opt... more A distributed optical fibre sensing system is used to measure landslide-induced strains on an optical fibre buried in a large scale physical model of a slope. The fibre sensing cable is deployed at the predefined failure surface and interrogated by means of optical frequency domain reflectometry. The strain evolution is measured with centimetre spatial resolution until the occurrence of the slope failure. Standard legacy sensors measuring soil moisture and pore water pressure are installed at different depths and positions along the slope for comparison and validation. The evolution of the strain field is related to landslide dynamics with unprecedented resolution and insight. In fact, the results of the experiment clearly identify several phases within the evolution of the landslide and show that optical fibres can detect precursory signs of failure well before the collapse, paving the way for the development of more effective early warning systems.
Procedia Engineering
The investigation of the collapse of a well-known soil volume is a simple experiment that permits... more The investigation of the collapse of a well-known soil volume is a simple experiment that permits to make several interesting considerations. This paper, at first, presents a brief overview of some physical experiments led to understand how the composition of a three-phase mixture influences the mass collapse. In particular, the run-out and the maximum height of the deposit are considered as two fundamental quantities for characterizing the behaviour of the mass in each test. In a second step, the experimental results obtained are used as case studies for the calibration of a mesh-less numerical model. Several simulations are carried out using the SPH-Geoflow code implementing a Bingham law to reproduce each bi-phases test. A comparison between the numerical results and the physical data permits to choose the most reliable value of the constitutive parameters for each tested case. The errors between the physical and the numerical run-out and maximum heights become the fundamental quantity to define the quality of the best simulation. Indeed, some final considerations about the relationship existing among the constitutive parameters and the kaolin content of the mixtures are reported.
Proceedings of the Institution of Civil Engineers - Geotechnical Engineering, 2016
This paper reports on an experimental investigation on the behaviour of small-diameter piles, com... more This paper reports on an experimental investigation on the behaviour of small-diameter piles, commonly referred to as micropiles. This particular type of deep foundation is frequently used in many barely accessible Italian mountainous areas, often characterised by complex ground profiles composed of mixtures of coarse soils with some fine matrix elements including cobbles and large-diameter boulders. In such ground conditions, the lack of reliable site and laboratory geotechnical investigations providing an accurate soil mechanical description and conservative approaches for micropile design often lead to significant underestimation of the vertical ultimate load. In order to improve micropile design in such geological contexts, a new field trial investigation involving tension and compression load tests on micropiles up to failure was set up in a selected test site located in the Italian alpine region. From interpretation of the load tests carried out so far, the reliability of commonly used calculation methods for estimating bearing capacity is discussed. As a result, a new approach for a more suitable calculation of the mobilised shaft and base resistance of micropiles bored in highly coarse soils is tentatively proposed.
Combined geophysical surveys for the characterization of a reconstructed river embankment
Engineering Geology, 2016
Egu General Assembly Conference Abstracts, Apr 1, 2013
Canadian Geotechnical Journal, 2002
The main feature of the shallowest quaternary basin of the well-renowned historic city of Venice,... more The main feature of the shallowest quaternary basin of the well-renowned historic city of Venice, Italy and its surrounding lagoon, is the presence, apparently without any regular trend in depth and site, of a predominant silt fraction. This is always combined with clay and (or) sand, forming a chaotic and erratic interbedding of different sediments whose mineralogy is however variable in a relatively narrow range due to a unique geological origin and a common depositional environment. After a brief description of the basic soil indexes of the Venice lagoon soil, the present study, based on a comprehensive geotechnical laboratory investigation, describes the range of variation of the most relevant time-independent geotechnical properties. Moreover, a new grain size index, combining the geometrical characteristics of the particle distribution, is introduced. It is shown that the soil response at large and very small strains can be related to this grain size index, which appears to be able to include the influence of the soil grading on the description of the overall mechanical behavior.
Water Resources Research, 2010
A fully coupled thermohydromechanical (THM) finite element approach is used here to model the gro... more A fully coupled thermohydromechanical (THM) finite element approach is used here to model the groundwater and saturation response of a typical salt marsh of the Venice lagoon (Italy) subjected to both tide fluctuation and flooding. The soil forming the marsh, whose relevant material parameters have been measured experimentally in the laboratory, is assumed to be an homogeneous multiphase porous medium, in a thermodynamic equilibrium state both in fully saturated and partially saturated conditions. More particularly, the study is aimed at analyzing separately the various couplings of several factors such as soil stiffness, water conductivity, capillary suction, and humidity exchange with atmosphere including also the occurrence of marsh flooding on the overall mechanical response of the marsh subjected to tidal oscillations of very narrow amplitude. From the analysis carried out so far, the numerical approach adopted here seems capable of describing most of the relevant features of marsh behavior, thus showing the importance of THM couplings to explain the groundwater pressure evolution induced by lagoon tide cycles. In addition, the model seems to provide some interesting explanations concerning the evolving instability of marsh scarps, which is one of the main causes of the rapid overall deterioration of the typical Venice lagoon landscape.
Modified compressibility of cohesive sediments induced by thermal anomalies due to a borehole heat exchanger
Engineering Geology, 2016
Induced thermal compaction in cohesive sediments around a borehole heat exchanger: laboratory tests on the effect of pore water salinity
Environmental Earth Sciences, 2016
Soil nailing is an economic and efficient method to reinforce soils, involving the insertion of t... more Soil nailing is an economic and efficient method to reinforce soils, involving the insertion of threaded bars into natural unstable slope for increasing the overall stability or into cut slopes during the top-down process of excavation. The retained soil, the resisting reinforcements and the external facing are the main components of a soil-nailed structure. Their composite interactions determine the performance of soil-nail construction in terms of deformations and stability. Even if the international codes deal about the possibility of use rigid or flexible external facing, the role of facing stiffness is not sufficiently studied and evaluated. To this aim, some tests with various facing types, differing in stiffness and continuity, were carried out so far in 1g small scale physical model. The experimental results show the importance of both flexional and axial stiffness of facing in controlling the deformation of the wall during excavation and the maximum surcharge applicable at the rear of wall. RÉSUMÉ: Le clouage du sol est une méthode économique et efficace pour renforcer le sol en place: il consiste en l'insertion de barres d'acier filetées ou d'autres barres dans les pentes naturelles instables ou dans des talus au cours du processus de l'excavation pour augmenter la stabilité globale. Le sol soutenu, les barres résistantes et le parement extérieur sont les principales composantes d'une structure du sol cloué. Leurs interactions mutuelles déterminent la performance du soil nailing en termes de déformations et de stabilité. Même si les codes internationaux considèrent la possibilité d'utiliser des parements extérieurs rigides ou flexibles, le rôle de la raideur du parement n'a pas été suffisamment étudié et évalué. Avec ce but ont été réalisées des épreuves dans un modèle physique avec des parements différents en rigidité et continuité. Les résultats expérimentaux soulignent l'importance de la raideur en flexion et en traction-compression du parement extérieur dans le contrôle de la déformation de la paroi pendant l'excavation, et la valeur maximale de la charge applicable à l'arrière du mur.
Application of a high resolution Distributed Temperature Sensor in a physical model reproducing subsurface water flow
Measurement, 2015
Reinforcement works for the slope stabilization: standard and new approaches for the use of micropiles and anchors
Frana di Brusole' situazione geologica e geotecnica