Tesis sobre el tema "Rockfal hazard"
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PARANUNZIO, ROBERTA. "Statistical inference of the relations among air temperature, land-use change, and rockfall hazard". Doctoral thesis, Politecnico di Torino, 2017. http://hdl.handle.net/11583/2675019.
Texto completoCain, Samuel Franklin. "Rating Rockfall Hazard in Tennessee". Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/9972.
Texto completoMaster of Science
Peng, Baishan. "Rockfall Trajectory Analysis : Parameter Determination and Application". Thesis, University of Canterbury. Geological Science, 2000. http://hdl.handle.net/10092/5802.
Texto completoRose, Brett Tyler. "Tennessee Rockfall Management System". Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/29263.
Texto completoPh. D.
Jacklitch, Carl Jonathan. "A Geotechnical Investigation of the 2013 Fatal Rockfall in Rockville, Utah". Kent State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=kent1464978379.
Texto completoKanari, Mor. "Evaluation of rockfall hazard to Qiryat Shemona - possible correlation to earthquakes". Jerusalem : Ministry of National Infrastructure. Geological Survey of Israel, 2008. http://www.gsi.gov.il/Eng/_Uploads/231GSI-24-2008.pdf.
Texto completoThis work was submitted as M.Sc. Thesis to the Department of Geophysics and Planetary Sciences, Tel Aviv University / T.P. "September 2008" At head of title: Tel-Aviv University. Raymond and Beverly Sackler faculty of exact sciences. Includes bibliographical references.
Vick, Louise Mary. "Evaluation of field data and 3D modelling for rockfall hazard analysis". Thesis, University of Canterbury. Geological Sciences, 2015. http://hdl.handle.net/10092/10845.
Texto completoDomènech, i. Surinyach Guillem. "Assessment of the magnitude-frequency relationship of landslides and rockfalls : application to hazard mapping". Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/347218.
Texto completoDegut al creixement exponencial de la població durant les últimes dècades, l’avaluació de la perillositat de colades de terra i despreniments i la seva zonificació han esdevingut eines fonamentals pel que fa a la planificació del territori, sobretot en zones muntanyoses. La perillositat degut a fenòmens de vessant va ser definida com la probabilitat d’ocurrència d’un fenomen potencialment danyí en una determinada àrea i per un determinat període de temps. D’aquesta manera, és necessari conèixer la probabilitat d’ocurrència (o freqüència) per cada tipus d’esllavissada i magnitud. L’objectiu d’aquesta tesis és el desenvolupament d’una metodologia objectiva, quantitativa i reproduïble que permeti l’obtenció de les relacions magnitud-freqüència per colades de terra, de mida mitja i gran i per despreniments. Aquest procediment s’ha aplicat a la Vall de Barcedana i la Serra del Montsec per grans colades de terra i despreniments, respectivament. Les dues àrees d’estudi estan situades dins de la Conca de Tremp (Pirineu Oriental). Pel que fa a les colades de terra, s’ha distingit entre 1) reactivacions i 2) vessants intactes. La freqüència de les reactivacions s’ha obtingut a partir de l’anàlisi d’11 grups d’ortofotos que cobreixen des del 1956 al 2013. La magnitud s’ha calculat com l’àrea de les trencades mitjançant la cartografia d’esllavissades i les ortofotos. La relació magnitud-freqüència resultant de les reactivacions ha servit per obtenir la probabilitat de reactivació per un determinat volum. Aquesta ha estat comparada amb la probabilitat de reactivació determinada a partir dels llindars de pluja que han donat lloc a la reactivació de 4 grans esllavissades, també situades dins la Conca de Tremp. Les dates de reactivació han estat aproximades mitjançant la dendrogeomorfologia i els llindars s’han determinat mitjançant l’anàlisi ROC. La susceptibilitat de les primeres trenades s’ha obtingut mitjançant un model determinista anomenat SINMAP. La freqüència per cada classe de susceptibilitat s’ha calculat mitjançant un inventari de primeres trencades identificades al camp i a través d’ortofotos. S’ha desenvolupat un algoritme per tal d’obtenir l’àrea de les colades de terra més grans que la mida del píxel a través de l’agregació automàtic de píxels situats en un mateix vessant i que presenten una mateix classe de susceptibilitat. Finalment, s’ha definit la matriu magnitudfreqüència per la zonificació de la perillositat dels vessants intactes. Pel que fa als despreniments, s’ha definit una metodologia per obtenir la distribució de volums de cicatrius de despreniments d’un penya-segat. S’ha assumit que els volums de cicatrius de despreniments poden ser una primera aproximació dels volum de despreniments. En aquest cas, la distribució de les cicatrius de despreniments s’ha calculat utilitzant un núvol de punts d’alta resolució de la paret obtingut amb un LIDAR terrestre. S’han calculat vàries distribucions de volums per tal de tenir en compte els diferents mecanismes de despreniment i el conseqüent rang de volums despresos. Finalment, s’ha proposat una metodologia per tal de convertir la freqüència estadística (% de volums de cicatrius), calculada en el pas anterior, a freqüència temporal (número anual de volums de cicatrius). Per això, el volum total de material desprès s’ha calculat mitjançant el núvol de punts, mencionat anteriorment. El període de temps durant el qual s’ha desprès tot el volum de material s’ha estimat mitjançant la datació de la superfície inicial a partir de la qual va començar l’actual activitat de despreniments. Aquesta datació s’ha fet mitjançant l’isòtop cosmogenic, 36Cl.
Debido al crecimiento exponencial de la población durante las últimas décadas, la evaluación de la peligrosidad de coladas de tierra y desprendimientos i su zonificación se ha convertido en herramientas indispensables para la planificación del territorio, sobretodo en zonas montañosas. La peligrosidad debido a fenómenos de vertiente fue definida como la probabilidad de ocurrencia de un fenómeno potencialmente dañino en una determinada área y en un determinado período de tiempo. Así, es necesario conocer la probabilidad de ocurrencia (o frecuencia) para cada tipo de deslizamiento y magnitud. El objetivo de esta tesis es el desarrollo de una metodología objetiva, cuantitativa y reproducible que permita la obtención de las relaciones magnitud-frecuencia para coladas de tierra, de tamaño medio y grande y para desprendimientos. Este procedimiento se ha aplicado en Valle de Barcedana y en la Sierra del Montsec para grandes coladas de tierra y desprendimientos, respectivamente. Las dos áreas de estudio están situadas dentro de la Cuenca de Tremp (Pirineo Oriental). En cuanto a las coladas de tierra, se ha distinguido entre 1) reactivaciones y 2) vertientes intactos. La frecuencia de las reactivaciones se ha obtenido a partir del análisis de 11 grupos de ortofotos que engloban des del 1956 hasta el 2013. La magnitud se ha calculado como el área de las roturas mediante la cartografía de deslizamientos y ortofotos. La relación magnitud-frecuencia de las reactivaciones ha permitido obtener la probabilidad de reactivación per un determinado volumen. Esta ha sido comparada con la probabilidad de reactivación determinada a partir de los umbrales de lluvia que han dado lugar a la reactivación de 4 grandes deslizamientos, también situados dentro de la Cuenca de Tremp. Las fechas de reactivación han sido aproximadas mediante la dendrogeomorfología y los umbrales se han determinado mediante el análisis ROC. La susceptibilidad de las primeras roturas se ha obtenido mediante un modelo determinista llamado SINMAP. La frecuencia para cada clase de susceptibilidad se ha calculado mediante un inventario de primeras roturas identificadas en el campo y a través de ortofotos. Se ha desarrollado un algoritmo para obtener el área de las coladas de tierra más grandes que el tamaño del píxel a través de la agregación automática de píxeles situados en una misma vertiente y que presentan una misma clase de susceptibilidad. Finalmente, se ha definido la matriz magnitud-frecuencia para la zonificación de la peligrosidad de las vertientes intactas. En lo que concierne a los desprendimientos, se ha definido una metodología para obtener la distribución de volúmenes de cicatrices de desprendimientos de un acantilado. Se ha asumido que los volúmenes de cicatrices de desprendimientos pueden ser una primera aproximación de los volúmenes de desprendimientos. En este caso, la distribución de las cicatrices de desprendimientos se ha calculado utilizando una nube de puntos de alta resolución de la pared obtenida con un LIDAR terrestre. Se han calculado varias distribuciones de volúmenes para tener en cuenta los diferentes mecanismos de desprendimiento y el consecuente rango de volúmenes desprendidos. Finalmente, se ha propuesto una metodología para transformar la frecuencia estadística (% de volúmenes de cicatrices), calculada en el paso anterior, en frecuencia temporal (número anual de volúmenes de cicatrices). Para esto, el volumen de material desprendido se ha calculado mediante la susodicha nube de puntos. El período de tiempo durante el cual se ha desprendido la totalidad del volumen de material se ha estimado mediante la datación de la superficie inicial a partir de la cual empezó la actual actividad de desprendimientos. Esta datación se ha hecho mediante el isótopo cosmogénico 36Cl.
Brilli, Nicolò. "Valutazione del rischio da caduta massi con Rockfall Hazard Rating System lungo la strada comunale della Montagna (Sansepolcro,AR)". Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
Buscar texto completoMisconel, Michele. "Analisi del rischio da caduta massi con Rockfall Hazard Rating System lungo la strada statale 612 (Molina di Fiemme, TN)". Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/12224/.
Texto completoAndreini, Lorenzo. "Analisi del rischio da caduta massi con Rockfall Hazard Rating System lungo la SP29 di Sovramonte (BL) e la SP19 di Lamon (BL)". Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Buscar texto completoVALAGUSSA, ANDREA. "Relationships between landslides size distribution and earthquake source area in a perspective of seismic hazard zoning". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2015. http://hdl.handle.net/10281/68458.
Texto completoEarthquakes have been recognized as a major cause of landsliding (Keefer, 1984), and landslides triggered by earthquakes have been documented since the IV century (Seed, 1968). The spatial distribution of earthquake-induced landslides around the seismogenetic source has been analysed to better understand the triggering of landslides in seismic areas and to forecast the maximum distance at which an earthquake, with a certain magnitude, can trigger landslides. However, when applying such approaches to old earthquakes one should be concerned about the undersampling of smaller landslides, which can be cancelled, by erosion and landscape evolution. For this reason, it is important to characterize carefully the size distribution of landslides as a function of distance from the earthquake source. I analysed six earthquakes in the world that triggered significant amount of landslides (Finisterre 1993, Northridge 1994, Niigata 2004, Wenchuan 2008, Iwate 2008 and Tohoku 2011) to better understand the relation between the spatial distribution of the landslides, the peak ground acceleration (PGA), the distance from the sources, the relief and the lithologies of the area. I observed a strong relationship between landslides size and PGA, while the relationship between the distance from the source and the landslide size distribution is not clear, due to the interaction of different factors such as relief and lithology. I also developed magnitude frequency curves (MFC) for different distances from the source area by using different methods, such as: the maximum likelihood estimator of cumulative power-law distribution (Clauset et al, 2009); the maximum likelihood estimator of non-cumulative power-law function; the least square regression of non-cumulative log power-law function and the maximum likelihood estimator of Double Pareto distribution. I observed a decrease of the spatial density of landslides with distance, with a small effect of the size of these landslides. I also identify the Double Pareto function as the best tool for the fitting of the data (Valagussa et al., 2014a). In order to define the hazard due to earthquake-induced landslides, I developed a methodology for quantitative probabilistic hazard zonation for rockfalls (Valagussa et al., 2014b). I applied and demonstrated the method in the area of Friuli (Eastern Italian Alps) that was affected by the 1976 Mw 6.5 earthquake. Four rockfall datasets have been prepared from both historical data and field surveys. The methodology relies on a three-dimensional hazard vector (RHVmod), whose components include the rockfall kinetic energy, the fly height, and the annual frequency. The values of the first two components are calculated for each location along the slope using the 3D rockfall runout simulator Hy-STONE. The rockfall annual frequency is assessed by multiplying the annual onset frequency by the simulated transit frequency. The annual onset frequency is calculated 2 through a procedure that combines the extent of unstable areas, calculated for 10 different seismichazard scenarios with different annual frequencies of occurrence, and the magnitude relativefrequency relationship of blocks as derived from the collected field data. For each annual frequency of occurrence, the unstable area is calculated as a function of morphometric and earthquake characteristics. A series of discriminant-analysis models, using the rockfall datasets and DEMs of different resolution (1 and 10 m), identified the controlling variables and verified the model robustness. In contrast with previously published research, I show that the slope curvature plays a relevant role in the computation of the unstable area. To ensure the validity of the peak ground acceleration used as seismic parameter in the discriminant function, I also try to define a map of PGA based on the precarious balanced rocks surveyed on the field.
Da, Silva Garcia Bruna. "Analyse des mécanismes d'interaction entre un bloc rocheux et un versant de propagation : application à l'ingénierie". Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAI062/document.
Texto completoNumerous uncertainties related to the machanical interaction between rock boulders and the natural slope during block falls persist; and the forecast of such events is therefore still uncertain. Nevertheless, digital tools and computing power are constantly evolving. Previously, trajectory calculations were restricted to simplified geometries and two-dimensional ballistic movements, but it is now possible to incorporate refinements such as the complex shape of the blocks, three-dimensional numerical models of terrain of large sizes, as well as a better accounting of the dissipative mechanisms at the point of impact between the block and the run-out slope.The main objective of this work is to analyze, with a discrete elements code in three dimensions, the influence of the shape and interaction parameters on the nature of the rebound in an engineering context. We first present a methodology for identifying and studying the sensitivity of contact parameters, developed and validated from laboratory experiments. This methodology was subsequently applied to two block fall experiments conducted on medium and large real-scale scenarios.The study conducted on a medium scale allowed the numerical model to be compared with data obtained during an experimental rockfall tests campaign commissioned by the SNCF and conducted in collaboration with IRSTEA in a railway. The analyzes that were carried out mainly focused on the impact velocities of the blocks with ballast and propagation distances.The large-scale study is based on a series of block releases performed at the experimental site (Authume quarry, France) as part of a Benchmark proposed inside the National Project C2ROP. The mainly goal of this Benchmark is to access and compare trajectory softwares, numerical computation codes and engineering practices to define their relevance and validity domains. As part of the thesis, this work was conducted in several phases (blind phase and then conducted taking in account partial data measured during the experimental tests) and we present the evolution of these analyzes at the end of each one of these phases. The study focused on the velocities, heights and energies of the blocks at certain points of the propagation profile, as well as on the stopping positions of the blocks. The influence of block shapes on run-out distances is also presented.Lastly, an internal Benchmark performed within the IMSRN company shows the importance, on the analyzes, of the expertise of the operator, and the consequences derived from the application of different trajectography tools (in 2D and in 3D). This work highlights the current issues that are often faced by engineering offices and engineers in charge of risk quantification
Bottelin, Pierre. "Caractérisation des phases pré-et post-rupture d'éboulements rocheux de taille intermédiaire : apport des enregistrements sismiques". Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENU015/document.
Texto completoMid-size rockfalls (103-105 m3) represent a substantial hazard in mountainous areas, because of relative high rate of occurrence and destructive power. Consequently, few protection means can be applied, emphasizing the need for monitoring techniques and early warning prior to the collapse. After the rupture, quantitative information on the rockfall propagation phase is scarce, owing to their suddenness and location in steep and rugged slopes. In this thesis work, an experimental approach is proposed to derive valuable information from seismic records during rockfall pre-rupture and post-rupture phases. The first part of this work aims at testing the applicability of the ambient vibration technique to monitor unstable rock compartments dynamic response in the pre-rupture phase. This technique (commonly employed in civil engineering for structural health monitoring) reveals the resonant frequencies of a structure, a decrease in frequency revealing potential damage. A previous case study of an unstable limestone compartment brought to light a #30% decrease in fundamental resonant frequency (f1) two weeks before the collapse. Following this innovative work, we selected and instrumented four prone-to-fall medium-size rock compartments located in the Occidental Alps, showing various geological contexts (limestones, argillite and shale-sandstone series), deformation patterns and failure mechnisms. Ambient vibrations recorded on-site revealed caracteristic seismic noise features. Spectral peaks were observed and attributed to resonant frequencies of the rock compartments, the fundamental resonant frequency (f1) showing clear polarization parallel to the line of maximum slope gradient, and perpendicular to the main bounding fracture observed at most of the sites. Similar findings were made for an unstable rock compartment located in a volcanic caldera, characterized by rapid morphological changes and intense rockfall activity. The dynamic response of the rear fracture network was explored, showing that spectral content of seismic noise is controlled by the caldera structure in the 0.5-5 Hz range. The direction of vibration is polarized perpendicularly to the fractures, while vibration amplitudes are linked to compartment uncoupling from the rock massif. In this case, the physical origin of seismic noise amplification may be due to complex 2D or 3D resonance effects. For the four alpine sites, the fundamental frequency f1 was monitored over more than one year, showing fluctuations clearly correlated with temperature oscillations. The thermal control over f1 is highly complex, showing both positive and negative correlations, depending on site morphology and destructuration, as well as on the studied oscillations periods (daily or seasonal). No change in fundamental frequency resulting from damage was observed over this time span. One site, characterized by intense rock fracturing and a deep-open rear fracture, showed high f1 sensitivity to temperature changes. Thermo-mechanical numerical simulations revealed that both material contraction-dilation and thermal dependancy of the elastic modulus control f1 fluctuations. In addition, high amplitude seasonal f1 oscillations were explained by ice formation in the rear fracture. A criterion was developped to separate thermal-induced f1 fluctuations from damage effects, under the hypothesis that thermal sensitivity of a rock compartment increases towards failure. The second part of this work relates to the post-rupture phase of rockfalls. The seismic records generated by two mid-size rockfalls {one natural, one provoked{ that occured in the same place were analyzed, showing complex enveloppe and spectrogram features. Both events showed close magnitude, duration and spectral content. The seismic signals of the provoked event were calibrated using video shots, allowing estimation of fallen material velocity during the successive propagation phases
Farvacque, Manon. "Evaluation quantitative du risque rocheux : de la formalisation à l'application sur les linéaires et les zones urbanisées ). How argest wildfire events in France? A Bayesian assessment based on extreme value theory ). Hows rockfall risk impacted by land-use and land-cover changes? Insights from the French Alps. Quantitative risk assessment in a rockfall-prone area: the case study of the Crolles municipality (Massif de la Chartreuse, French Alps)". Thesis, Université Grenoble Alpes, 2020. https://tel.archives-ouvertes.fr/tel-02860296.
Texto completoRockfalls are a common type of fast moving landslide, corresponding to the detachment of individual rocks and boulders of different sizes from a vertical or sub-vertical cliff, and to their travel down the slope by free falling, bouncing and/or rolling. Every year, in the Alpine environment, rockfalls reach urbanized areas causing damage to structures and injuring people. Precise rockfall risk analysis has therefore become an essential tool for authorities and stakeholders in land-use planning.To this aim, quantitative risk assessment (QRA) procedures originally developed for landslides have been adapted to rockfall processes. In QRAs, rockfall risk for exposed elements is estimated by coupling the hazard, exposure and vulnerability components. However in practice, the estimation of the different components of risk is challenging, and methods for quantifying risk in rockfall-prone regions remain scarce. Similarly, the few studies which so far performed QRAs for rockfall assume stationary, precluding reliable anticipation of the risk in a context where environmental and societal conditions are evolving rapidly and substantially. Moreover, rockfall risk remains - as for most of natural hazards - always defined as the loss expectation. This metric offers a unique risk value, usually inconsistent with short/long term constraints or trade-offs faced by decision-makers.On this basis, this PhD thesis therefore aims at (i) reinforcing the basis of QRA, (ii) assessing the effect of environmental changes on rockfall risk, and (iii) proposing method for quantifying rockfall risk from measures of risk alternative to the standard loss expectation. In that respect, we propose a QRA procedure where the rockfall risk is quantified by combining a rockfall simulation model with the physical vulnerability of potentially affected structures and a wide spectrum of rockfall volumes as well as release areas. The practicability and interest of this procedure is illustrated on two real case studies, i.e. the municipality of Crolles, in the French Alps, and the Uspallata valley, in the central Andes mountains. Similarly, the effect of environmental changes on rockfall risk is considered by comparing rockfall risk values in different land-use and land-cover contexts. Last, we implement in our procedure on an individual basis two quantile-based measures, namely the value-at-risk and the expected-shortfall, so as to assess rockfall risk for different risk-management horizon periods. All in all, this PhD thesis clearly demonstrates the added value of QRA procedure in the field of rockfall, and reinforces its basis by implementing analytical, statistical or numerical models. The resulting panel of risk maps, also proposed under non-stationary contexts, are of major interest for stakeholders in charge of risk management, and constitute appropriate basis for land-use planning and prioritizing of mitigation strategies
Delonca, Adeline. "Les incertitudes lors de l'évaluation de l'aléa de départ des éboulements rocheux". Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0184/document.
Texto completoThe present dissertation proposes to study uncertainties in rockfall hazard assessment process, on the basis of the Baecher & Christian typology (2005), which identifies (1) decision uncertainties, (2) knowledge uncertainties, and (3) natural variability. Decision uncertainties are due to the subjectivity of experts’ assessment. An experiment has been realized in order to evaluate the influence of the expertise level, and the chosen method (qualitative or quantitative) on the rockfall hazard. The rockfall hazard levels obtained by the qualitative method are quite uniform while the quantitative method produces more disparate results. We have shown that, classically, the expertise level has no influence on the assessment if the method is precisely detailed. In the case of spectacular sites, experts do not overestimate the hazard. The natural variability is associated to the temporal variability of the rockfalls. We have studied the statistical correlation between meteorological and rockfall databases. We have developed a method that takes into account the probability of occurrence of the studied triggering factor (rainfalls and temperatures). This new approach is easy to use, and also helps to determine the conditional probability of rockfall according to a given meteorological factor. This approach will help to optimize risk management in studied areas based on their meteorological conditions. A work on these databases also has allowed the unpredictability of the rockfalls to be highlighted. Indeed, the delay between two rockfalls follows a Poisson distribution. Knowledge uncertainties may concern the preparatory factors. We have studied them with numerical models of a rock block sliding along a planar joint, depending on the proportion and position of rock bridges (distinct elements - UDEC). Two stages of the failure process have been highlighted; they have been controlled by the stress redistribution induced by the failure, and the propagation of the rock bridges. However, these two phases are not identified when studying block displacements. We also have shown the influence of the position of rock bridges on the propagation of failure. This research provides an operational tool, and guidelines on assessment process that may help engineers in charge of a rockfall risk analysis to justify and refine the obtained risk estimations
Oussalah, Tarik. "Comportement des sables sous sollicitation d’impact à faible vitesse : application au dimensionnement de couches de sol protégeant les structures des impacts rocheux". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSET004/document.
Texto completoAn extensive experimental parametric study has been carried out to characterize how impact loads of low velocity (lower than 100 km/h) are transmitted to a structure through a protective sand layer. Different rock fall conditions have been considered, corresponding to actual conditions in current practice. The experimental program consisted of 43 full scale impact tests on a sand layer protecting a concrete foundation mat, combining three sand layer thicknesses (1, 1.5 and 2 m), impacting blocs of equivalent diameters in the range of 0.42 to 1.79 m and five free falling heights, up to 33 m. Based on the analysis of pressure cells measurements for the different rock fall conditions, the pressure induced at the interface between the protective sol layer and the structure by an impact was expressed in terms of impact conditions, defined by layer thickness (D), size of the impacting bloc (B) and height of free fall (H). Procedures to derive the model parameters from the tests are explained in detail. A numerical model was developed to simulate an impact on a structure protected by a soil layer based on a deformation analysis approach. The Finite Element code ABAQUS was used. The bloc, the soil and the structure were considered as different bodies, having contact conditions between them. The stress‐strain relationship in the soil was assumed to be elastoplastic. Friction angle and dilation angles were derived from laboratory tests on the sand. The elastic modulus was assumed constant, equal to usual values for compacted sands. An approach is proposed for the design of soil layers to protect structures from impacting loads due to rock falls
Le, Roy Gaëlle. "Détection et caractérisation multi-méthodes des éboulements rocheux". Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALU012.
Texto completoAmongst mass wasting events, rockfalls remain the most unpredictable and the most frequent hazard in the alpine region. In a context of growing urbanization in mountainous regions, rockfalls represent an increasing risk for local communities and infrastructures. This thesis aims to develop an association of relevant methods for rockfall monitoring. One objective of this thesis is to associate topography measurement and seismological monitoring in order to improve significantly in understanding rockfalls dynamics. This work was mainly carried out in the Chartreuse massif (Isère, French Alps), and in particular two cliffs, Mount Saint-Eynard and Mount Granier. Using photogrammetry, we acquired diachronic Digital Elevation Models (DEMs) of the cliffs. Such monitoring enables us to carry out rockfall inventories and occurrence frequency analysis. It also provides us information on rockfall locations and their structural configurations. Combining DEMs and rockfall seismic monitoring allowed us to study relations between rockfall properties (location, volume, geometry, propagation, etc.) and the induced seismic signal. Characteristics of the seismic signal (duration and energy, frequency content, envelope shape) vary depending on the event propagation mode (mass-flow, free-fall, sliding, bouncing …). Selecting events with the same propagation type provides a more accurate characterization of rockfalls properties than when mixing different types of events. For free-falling rockfalls, we analyze the seismic signal of the detachment phases and first impacts. We found relations between seismic signals parameters and rockfalls potential energy, free-fall heights, and volumes. For mass-flow type events, we found a scaling law between rockfalls seismic energy and their volumes. By coupling DEMs and seismic records, we can reconstruct rockfall sequence with accurate timing and correct volume estimations. Controlled block releases were realized in laboratory and on-site to widen our observations on rockfall events
Furet, Agathe. "Modélisations expérimentale et numérique d'ouvrages pare-blocs modulaires : Application à la technologie Bloc Armé®". Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALI038.
Texto completoThis Cifre thesis investigates the impact response of protective structures based on the Bloc Armé® technology, developed by Géolithe Innov and Géolithe. This structure is made of concrete blocks linked by vertical and horizontal metal reinforcements. The main innovation lies in the reinforcement system which ensures the bonding of the blocks and gives the structure an ability to distribute the forces and dissipate energy.Two types of real-scale experiments permit to characterize the dynamic response of the structure. Firstly, the structure laid horizontally on a support layer is subjected to high- energy impacts (2000 kJ) by freely dropping of a projectile. Secondly, lower energy impact tests (125 kJ) are carried out by horizontal impact on a vertical wall of limited dimensions. Reduced models of the structure, at ¼ scale, are also tested under impact in the laboratory. This campaign permits to test many walls of different configurations under various impact conditions. These experimental campaigns illustrate the deformation mechanisms under localized dynamic solicitation for this kind of articulated structure. The different displacement modes of vertical walls and several phenomena dissipating impact energy are highlighted and quantified. The numerous measurements made during the tests constitute an important experimental database, supporting the development of the numerical model.A numerical model, developed with the finite differences method, is proposed for this structure. A realistic approach is followed for the modeling: each element of the structure is modeled explicitly. A simple model is deliberately considered for the concrete constituting the blocks. The model is calibrated based on values from the literature and measurements made specifically. The comparison of impact simulations results with experimental ones attests of the ability of the model in reproducing the global dynamic behavior of the structure and in estimating its residual displacement, in particular. The model quantifies the energy dissipation resulting from plasticization of the concrete blocks and from friction in the structure.The model is then used to simulate the response of walls of various geometries and under high energy impact. The outlooks of this work are to propose a robust model able to simulate the structure response to impacts with energies up to 5,000 kJ, considering structures with complex geometries
Dupire, Sylvain. "Evaluation des effets des incendies sur la capacité de protection des forêts contre les chutes de blocs dans les Alpes françaises". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI020/document.
Texto completoRockfalls are a major natural hazard in the French Alps due to their high probability of spatial and temporal occurrence. Forests constitute an efficient nature-based solution to mitigate this hazard while protecting human lives and assets. However, this ecosystem service may be disrupted by others natural hazards such as wildfires likely to be more frequent and intense in the current and future context of climate changes.This PhD thesis proposes to assess the effects of fires on the protection capability of forests against rockfalls in the French Alps.A methodology to evaluate the protection capability of a forest against rockfalls is first developed. It consists in modeling rockfalls propagations on 3886 forest plots taken in the French Alps to calculate three quantitative indicators that assess the reduction of the frequency (BARI), the intensity (MIRI) and the overall reduction (ORPI) of rockfalls due to the presence of a forest. These indicators are used to identify the predominant forest variables for assessing the protective effect: the length of forest along the slope, the basal area and the mean diameter. Forest stands with a heterogeneous distribution of diameters and made up of several tree species generally offer a better protection than monospecific and regular stands, thus underlining the influence of forest diversity. This work shows that coppices have the highest protection capabilities, followed by hight stands dominated by deciduous species and mixed stands; coniferous stands coming last.Spatio-temporal trends in fire weather in the French Alps are investigated over the period 1959-2015 and reveal a major contrast between Southern Alps which experienced a strong increase (in intensity, frequency, duration and seasonality) especially at high elevation, and Northern Alps, where a slight increase at low elevation and no significant trends at high elevation are observed. These results are then used to define three types of fires (winter, summer, and dry summer) for which post-fire tree mortality is studied at the tree and forest stands levels. These analyses show that only summer fires are likely to significantly affect the forest ecosystems, particularly at low elevations where deciduous stands (especially coppice) dominate.The effect of fires on the protection capabilities of forests is assessed by comparing rockfalls propagation simulations without fire to simulations after each type of fire in which the trees with a high post-fire mortality are not taken into account. The ORPI values for each forest plot and fire type are thus calculated and compared to the reference scenario without fire thus making it possible to quantitatively assess the reduction of the protection capabilities. Low elevation stands, subject to warmer and drier climatic conditions, show reductions of the protective effect in the range 60-100%. It mainly concerns coppices and deciduous stands. At high elevation, the reduction is in the range 30- 65%.In conclusion, this PhD thesis proposes an original method to quantify the protection capabilities of a forest against rockfalls before and after a fire and improve the knowledge of these two natural hazards and their associated risks. The multi-hazard analysis conducted at the end of the thesis makes it possible to understand the potential cascading effects in the main forest types and for four bioclimatically homogeneous territories of the French Alps
Bellamy, Derrick LaDon. "Electronic data collection for rockfall hazard evaluation". 2002. http://etd.utk.edu/2002/BellamyDerrick.pdf.
Texto completoTitle from title page screen (viewed Feb. 28, 2003). Thesis advisor: Eric Drumm. Document formatted into pages (v, 148 p. : ill. (some col.)). Vita. Includes bibliographical references (p. 27-29).
Jiung, Yan-Dian y 江晏佃. "The Evaluation and Prediction for Rockfall Hazard and Risk". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/77733669564395110571.
Texto completo國立交通大學
土木工程系
87
Rockfall often occurs along mountainside road slopes, especially during or after a heavy rainfall. Occasionally, the occurrence of a rockfall results in traffic interruption, property damage, and personal injury or death. The consequence of a rockfall incidence may be very serious and unacceptable for a community. The hazard potential of a rockfall depends on various factors including geology, topography, and weather, among many environmental factors. In the conventional approach, the hazard potential of rockfall is usually evaluated in a deterministic manner. Compared to other aspects of geotechnical engineering, the rockfall problem has a higher degree of uncertainty. It seems reasonable to take the probabilistic nature of rockfall problem into account. This thesis makes use of reliability analysis to investigate the probability of rockfall hazard. It also examines the influence of rainfall on hazard potential. By collecting relevant information concerning the factors that affect the rockfall hazard, this thesis attempts to establish a probabilistic model for evaluating rockfall hazard associated with the condition of rainfall. It establishes an empirical correlation between the minimum rockfall hazard rating and rainfall characteristics (including the cumulative rainfall and the daily rainfall at the time of rockfall). The probability of rockfall is calculated from the safety margin (the difference between the threshold index and the rockfall potential index). The threshold index is assumed normally distributed; it is calibrated from real rockfall records using an optimization procedure. The proposed approach is applied in evaluating the rockfall hazard along the central cross-ridge route. The comparison of the predicted results and the actual case records shows very good agreement. In addition, this thesis adopts the concept of risk analysis and suggests an approach to evaluate the potential for traffic interruption, human life loss and property damage due to a rockfall occurrence.
Hsieh, Feng Lung y 謝豐隆. "Rockfall Hazard Rating and Predicting System Using Artificial Neural Network". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/18919464907140443403.
Texto completo國立交通大學
土木工程系
88
Based on the experience, the professional engineer provides the rating weights of the influenced parameters in the rockfall hazard rating systems. Therefore, the given rating weights will strongly depend on anybody’s subjective sense. One can obtain more conviction in the results of learning by using Artificial Neural Network (ANN). The network framework will be perfect by increasing of the learned cases. ANN is not alike traditional hazard rating system that will affect the function in using. The objects of this study are the areas along the Central Cross-Range Highway and the New Central Cross-Range Highway. The former area had been destroyed seriously and was temporarily closed due to 921 Chi-Chi Earthquake in 1999. The later area had been destroyed nearby 121.2k、136.8k、146.2k、147.7k. It presented the outstanding results of learning and rating for two areas through ANN. Furthermore, the another ANN model includes the geologic factors and two rainfall parameters will predict the hazard of raining for all slopes. Based on the ANN model, the rockfall hazard ranks can be determined following the weather forecast from the Central Weather Bureau. Also, the road manager should temporarily stop the road users to get into the area if it had been destroyed seriously.
Spadari, Michele. "Experimental and numerical investigations on barriers for rockfall hazard mitigation". Thesis, 2013. http://hdl.handle.net/1959.13/1038004.
Texto completoManaging the rockfall hazard is a complex task, which involves several phases from land planning to the design of protective structures. Despite the increasing interest in rockfall-related research over the last few decades, some issues remain only partially addressed to date. In particular, existing predictive tools for the simulation of block trajectories could be improved and the criteria for the design of flexible metallic barriers are potentially flawed by block size effects. In the Australian context, the lack of research into rockfall phenomena has prevented the development of a comprehensive hazard characterisation so far; moreover, some types of barriers currently in use present cost-effectiveness issues. In this thesis, formed by six peer-reviewed publications, the aforementioned issues are investigated, with the aim of improving the knowledge regarding rockfall, especially for the Australian environment. The first paper presents the results of extensive in situ tests performed in different geological environments in NSW. Rockfall motion parameters are obtained for the first time in the Australian context and uncommonly high values of the normal coefficient of restitution are highlighted. An investigation of these results is undertaken in the second paper through extensive laboratory testing: low impacting angles, rotational energy and block shape are correlated to the high values of kn obtained in the experiments. In the third paper, the results from in situ tests are applied to real profiles taken from a database of Australian slopes: a basic hazard characterisation is performed using a 2D lumped mass model and low impact energy values are found for most of the cases. The fourth paper shows a comparison between four different flexible barriers, carried out by full-scale laboratory testing. The results provide an insight on the estimation of the barriers’ performance: in particular, stiffness and load transmission are evaluated, and modifications to improve the performance of one of the systems are suggested. Experimental and numerical evidence of the bullet effect are presented in the fifth and sixth papers. A Finite Element model of a mesh panel, calibrated by means of laboratory testing, is used to validate an innovative dimensional approach.
Jesus, Oktoviano Viegas Tilman de. "Slope Stability and Rockfall Hazard Analysis along Karimbala Road, Liquiça Municipality, Timor-Leste". Master's thesis, 2018. http://hdl.handle.net/10316/86456.
Texto completoTimor-Leste tem uma topografia aproximada e uma geologia complexa que contribuem para a ocorrência de um grande número de problemas de estabilidade de taludes, que são agravados pelas recentes atividades de construção de estradas visando melhorar as estradas antigas. O grande número de cortes, às vezes com uma alta considerável, é uma causa frequente de várias instabilizações que exigem um estudo detalhado. A área onde foi realizada a pesquisa de Análise de Estabilidade de Taludes (SSA) está localizada em Maubara, no município de Liquiça, ao longo da estrada de Karimbala, que liga os municípios de Liquiça e Bobonaro. Verificou-se a ocorrência de instabilizações de taludes sistematicamente ao longo dos anos, sendo as mais recentes ocorridas em Janeiro de 2018. Os objetivos gerais desta pesquisa foram estudar os problemas de estabilidade de encostas e calcular o Fator de Segurança (FoS). Para a caracterização do material da encosta e sua classificação geomecânica, foi mapeada a inclinação para definir os materiais aflorantes, as descontinuidades foram caracterizadas e a resistência da rocha avaliada pelo martelo de Schmidt. Com base nos dados coletados no campo, as classificações geomecânicas RMR e SMR foram aplicadas aos taludes. A avaliação das condições de estabilidade também foi feita usando o software Rocscience (RocTopple, Slide, RocFall) adequado para cada caso de instabilizações. As diretrizes de classificação do sistema Rockfall Hazard Rating System (RHRS) para avaliar cada ocorrência também foram utilizadas. Os tipos de roturas identificadas foram queda de rochas, basculamento, queda de detritos, rotura planar e rotura em cunha. Quedas de pedras e queda de detritos são freqüentes em todos os taludes de TzPt1 a TzPt6, em contraste com a rotura em cunha, que ocorre apenas em TzPt2 e TzPt6. As duas principais causas de instabilidade dos taludes são as descontinuidades geológicas com orientação desfavorável e as chuvas intensas que adicionam peso e induzem altas pressões de água nos terrenos das encostas, aumentando o potencial de ocorrência de instabilizações de taludes, em períodos de chuvas moderadas a fortes. Os valores de FoS que foram calculados abaixo de 1,5, foram considerados insuficientes para uma estabilidade de longo prazo. Os resultados de RHRS calculados são maiores que 300. Portanto, pode-se concluir que os taludes TzPt1 a TzPt6 são vulneráveis a roturas. A mitigação deve ser implementada com urgência para reduzir os danos na estrada e nos condutores. É altamente recomendável desenvolver um projeto técnico adequado das encostas considerando um FoS adequado para a estabilidade a longo prazo, usando técnicas de melhoria ajustadas às condições locais tais como: redução da altura do talude (redução das tensões), redução do ângulo de inclinação (redução das tensões de sobrecarga), melhoria da drenagem (redução da pressão da água dos poros), reforço do talude (aumento da resistência ao cisalhamento da superfície potential de deslizamento). Nalguns taludes que apresentavam condições de instabilidade foram simulados alguns procedimentos de estabilização de modo a avaliar as melhores soluções a serem utilizadas.
Timor-Leste has a rough topography and a complex geology contributing to the occurrence of a large number of slope stability problems, which are aggravated by recent road construction activities aiming to improve the old roads. A large number of cuts, sometimes with a considerable high are a frequent cause of several failures that require a detailed study. The study area where the research on Slope Stability Analysis (SSA) was done, is located in Maubara, in the Municipality of Liquiça, along the Karimbala road, which links the Liquiça and the Bobonaro Municipalities. It was verified that slope failures have occurred systematically throughout the years, the most recent ones occurred in January 2018. The general objectives of this research were to study the slope stability problems and to compute the Factor of Safety (FoS). For the characterization of the slope material and its geomechanical classification, the slope was mapped to define the outcropping materials, the discontinuities were characterized and the strength of the rock was evaluated using the Schmidt hammer. Based on the data collected in the field, the RMR and the SMR geomechanical classifications were applied to the slope. The evaluation of the stability conditions was also done using the Rocscience software (RocTopple, Slide, RocFall) suitable for each individual slope failure. The Rockfall Hazard Rating System (RHRS) classification guidelines to rate each occurrence was also used. The types of failures identified were rockfall, toppling, debris fall, plane failure and wedge failure. Rockfalls and debris fall are frequent on all slopes from TzPt1 to TzPt6, in contrast to the wedge failure, which only occurs in TzPt2 and TzPt6. The main causes of slope instability are the geological discontinuities with unfavorable orientation, the surface weathering and the intense rainfall which add weight and induce high water pressure in the slopes. The FoS values computed lower than 1.5, are considered as insufficient for a long-term stability. The RHRS results computed are greater than 300. Therefore, it can be concluded that slopes TzPt1 to TzPt6 are vulnerable to additional slope failures. Mitigation must be urgently implemented to reduce damages in the road and drivers. It is highly recommended to develop proper technical design of the slopes considering a FoS suitable for long-term stability, using improvement techniques adjusted to the local conditions such as: reduction of slope height (reduction of overburden stress), reduction of slope angle (reduction of overburden stress), drainage improvement (reduction of pore water pressure), reinforcement of slope (increase of shearing resistance of slip surface). In a few slopes presenting unstable conditions a few improvement stability procedures were simulated, in order to evaluate the best procedure to be used.
Yuan-Chin, Lee y 李圓欽. "A Study of Traffic Characteristics Impact on Rockfall Hazard –Taiwan No.2 Seafront Highway". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/41077077300084262095.
Texto completo東南技術學院
防災科技研究所
96
The rock slope along Taiwan No.2 Seafront Highway-- located in northern Taiwan is prone to be fragmentized due to earthquake, wind weathering, orogeny, and sea erosion, etc. Moreover, most part of the roadway is excavated on one-side slope which will incur rockfall under the above circumstances. Therefore, several sections of this highway are classified as high risk areas of rockfall. As a matter of fact, rockfall causes frequent casualties on these sections of roadway according to the past record. The thesis attempts to explore the hazard risk of a vehicle driving through one of the most hazardous sections of this highway through analyzing the characteristics of the traffic flow. First, the field data is collected according to an experiment design. The χ2 goodness-fit tests are then deployed to check platoon size and vehicle gap size against exponential distribution and Weibull distribution, respectively. Combined with the basic principle of car-following theory, the probability of head-tail collision due to inadequate gap among vehicles is analyzed. Finally, the current hazard mitigation measures for improving rockfall hazard are examined for reference.
Marini, Federico y Giovanni Gigli. "Modellazione 3D di pareti rocciose finalizzata alla valutazione della pericolosità da caduta massi 3D rock slope modelling for rock fall risk assessment". Doctoral thesis, 2019. http://hdl.handle.net/2158/1154795.
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