Letteratura scientifica selezionata sul tema "Rock slope failure"
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Articoli di riviste sul tema "Rock slope failure"
1
Hussin, Hamzah, Tajul Anuar Jamaluddin e Muhammad Fadzli Deraman. "Mode of Slope Failure of Moderately to Completely Weathered Metasedimentary Rock at Bukit Panji, Chendering, Kuala Terengganu". Journal of Tropical Resources and Sustainable Science (JTRSS) 3, n. 2 (15 maggio 2015): 5–12. http://dx.doi.org/10.47253/jtrss.v3i2.522.
Testo completoAbstract (sommario):
Geology of Bukit Panji, Chendering, Kuala Teregganu consists of interbededmetasedimentary rocks (slate, phyllite and schists with minor quartzite) which haveexperience regional metamorphism. The age of this rock is Carboniferous. A development project which under construction in Bukit Panji, Kuala Terengganu hasenabled a landslide assessment to observe the modes of failure in moderately tocompletely weathered metasedimentary rock. Development on hillsides caused manyslope had to be cut to provide space for the infrastructure construction. From assessment analysis, a total of 21 cases of landslide failure occurred involving 17 cut slopes, and 4 cut-fill slopes. The most common type of failures is gully failures, with 9 cases represent 43% of all the observed slope failure. This was followed by 6 wedge failures, two planar and rock fall failures and one shallow sliding and toppling respectively. Cut slope failure involving moderate weathered rock mass (grade III) to the residual soil (grade VI). Relict structure was identified as the main factors controlling the failure, as well as water, natural slope-forming materials and the use of appropriate slope stabilization.
2
Zarraq, Ghazi. "Slope Stability Analysis of the Southwestern Limb of Kosret Anticline in Dokan, Northeastern Iraq". Iraqi Geological Journal 54, n. 2A (31 luglio 2021): 34–48. http://dx.doi.org/10.46717/igj.54.2a.3ms-2021-07-24.
Testo completoAbstract (sommario):
The stability of the rock slopes was studied on the southwestern limb of the Kosret Anticline in the Dokan Area in northeastern Iraq to analyze and indicate the danger of rock mass failures along the public street linking Dokan and Quesangaq, Erbil and the road which link between the city and the residential neighborhood of Dokan Lake, as well as the revealing and the analysis of the risk of landslides in the slopes and rocks detectors of exposed rocks of the formations in the study area. The stereographic projection was used in the analysis and classification of the rock slopes. This study has shown that the failures of rocks are fall and day lighting bedding plane. The factors that affect the stability of the slopes were assessed. This research mainly focuses on identifying the types of collapses along the rocky slopes and the factor that affects the instability of the studied slopes. It was found that it is the direction slopes and the interruption geometry. Different treatment methods have been proposed for the studied rock base on the rock slope analysis. The expected failure types that may occur along the road are plane sliding, rock fall, toppling, and probably the failure type in the future may be planner sliding due to the angle of the friction comes to zero degree. The rocky slopes along the road require constant monitoring due to their hazardous conditions. Where it was found that the attitude of the joints and their frequency with the relation between the attitude of the slopes and the rock beds played an important role in the failures, as well as the weak rocks of the Marl layers of the Shiranish, Kometan and Tanjero formations play a key role in responding to weathering and erosion factors that increase the failures of rock slopes.
3
Xian-Wen, Huang, Zhi-Shu Yao, Wang Bing-Hui, Zhou Ai-Zhao e Peng-Ming Jiang. "Soil-Rock Slope Stability Analysis under Top Loading considering the Nonuniformity of Rocks". Advances in Civil Engineering 2020 (16 dicembre 2020): 1–15. http://dx.doi.org/10.1155/2020/9575307.
Testo completoAbstract (sommario):
Soil-rock slopes are widely distributed in central or western China. With the development of transportation, many subgrades are being built on mountainsides and therefore, slope stability has to be estimated under high loadings. To obtain better estimation results, a new rock contour establishing algorithm was developed, capable of considering interlock effect between rocks. Then, computed tomography (CT) and unconfined triaxial tests with ring top loadings were conducted. Based on rock distribution characteristics (obtained by CT photos) and the appearance of shear failure surfaces in slopes under ring top loadings, four rock skeleton status and five shear failure surface developing models were introduced. Based on the developed rock contour establishing algorithm, ten groups (twelve models per group) were established and calculated by finite element method (FEM). After this, normalized ultimate loading increasing multiple N, which was the ultimate loading ratio of rock-containing slope to uniform soil slope, was introduced to evaluate the influence of rock distributions on slope stability. The value of N was increased with the increase of rock content due to rock skeleton status. The values of N in slopes with angular rocks were about three times higher than those with round rocks which was due to complex geometric shape and distribution characteristics of angular rocks. Then, considering different slope angles (50°–60°), rock contents (0%–60%), and rock shapes (round and angular), the ultimate loading increasing multiple N of soil-rock slopes under high loadings was calculated and suggested for engineering designs. Finally, based on the failure surfaces of numerical modes, three typical failure modes were developed, which could be reference for designers to deal with slopes.
4
Al-E’Bayat, Mariam, Dogukan Guner, Taghi Sherizadeh e Mostafa Asadizadeh. "Numerical Investigation for the Effect of Joint Persistence on Rock Slope Stability Using a Lattice Spring-Based Synthetic Rock Mass Model". Sustainability 16, n. 2 (20 gennaio 2024): 894. http://dx.doi.org/10.3390/su16020894.
Testo completoAbstract (sommario):
This study underscores the profound influence of rock joints, both persistent and non-persistent with rock bridges, on the stability and behavior of rock masses—a critical consideration for sustainable engineering and natural structures, especially in rock slope stability. Leveraging the lattice spring-based synthetic rock mass (LS-SRM) modeling approach, this research aims to understand the impact of persistent and non-persistent joint parameters on rock slope stability. The Slope Model, a Synthetic Rock Mass (SRM) approach-based code, is used to investigate the joint parameters such as dip angle, spacing, rock bridge length, and trace overlapping. The results show that the mobilizing zones in slopes with non-persistent joints were smaller and shallower compared to slopes with fully persistent joints. The joint dip angle was found to heavily influence the failure mode in rock slopes with non-coplanar rock bridges. Shallow joint dip angles led to tensile failures, whereas steeper joint dip angles resulted in shear-tensile failures. Slopes with wider joint spacings exhibited deeper failure zones and a higher factor of safety, while longer rock bridge lengths enhanced slope stability and led to lower failure zones. The overlapping of joint traces has no apparent impact on slope stability and failure mechanism. This comprehensive analysis contributes valuable insights into sustainable rock engineering practices and the design of resilient structures in natural environments.
5
Tamrakar, Naresh Kazi, e Jaya Laxmi Singh. "Slope mass rating of rock slopes of the Malekhu River, central Nepal Lesser Himalaya". Journal of Nepal Geological Society 47, n. 1 (30 giugno 2014): 36–46. http://dx.doi.org/10.3126/jngs.v47i1.23102.
Testo completoAbstract (sommario):
The Malekhu River is one of the major tributaries of the Trishuli Ganga River fl owing from the south in Malekhu region, central Nepal. Riverbank slope stability is a topic of concern as rock mass condition and slope stability of riverbank slopes are important parameters for riverbank erodibility. Fourteen sites in the Malekhu River were selected for rock mass rating (RMR) and then slope mass rating (SMR) by using a graphic method. The potentially vulnerable sites were identifi ed after conducting field study in different slopes. The results indicate that there occur modes of failures ranging from stable (good rock mass) to partially stable (normal rock mass) in all the study sites. The unstable (bad rock mass) and completely unstable (very bad rock mass) slopes are, however, distributed only in some slopes. The unstable slope of plane failure mode is Ka1, whereas the completely unstable slopes of plane failure mode are Rb2, Ml1 Slope 1 and Ml2. The unstable slope of toppling failure mode is Ml2. When wedge failure mode is considered, the slopes at Ti1 and Ka1 are unstable while the slopes at Kh1, Ka1, Ml1 Slope 1 are completely unstable. The rock slopes with unstable to completely unstable states are considered bad (SMR Class IV: 21–40) to very bad (SMR Class V: 0–20) rock mass with fair to poor rock mass rating, respectively. These bad to very bad rock mass slopes are vulnerable to slope movements and river erosion, and they require mitigative measures.
6
Lemaire, Emilie, Anne-Sophie Mreyen, Anja Dufresne e Hans-Balder Havenith. "Analysis of the Influence of Structural Geology on the Massive Seismic Slope Failure Potential Supported by Numerical Modelling". Geosciences 10, n. 8 (18 agosto 2020): 323. http://dx.doi.org/10.3390/geosciences10080323.
Testo completoAbstract (sommario):
The stability of rock slopes is often guided significantly by the structural geology of the rocks composing the slope. In this work, we analysed the influences of structural characteristics, and of their seismic responses, on large and deep-seated rock slope failure development. The study was focused on the Tamins and Fernpass rockslides in the European Alps and on the Balta and Eagle’s Lake rockslides in the southeastern Carpathians. These case studies were compared with catastrophic rock slope failures with ascertained or very likely seismic origin in the Tien Shan Mountains. The main goals was to identify indicators for seismically-induced rock slope failures based on the source zone rock structures and failure scar geometry. We present examples of failures in anti-dip slopes and along-strike rock structures that were potentially (or partially) caused by seismic triggering, and we also considered a series of mixed structural types, which are more difficult to interpret conclusively. Our morpho-structural study was supported by distinct element numerical modelling that showed that seismic shaking typically induces deep-seated deformation in initially “stable” rock slopes. In addition, for failures partially triggered by dynamic shaking, these studies can help identify the contribution of the seismic factor to slope instability. The identification of the partial seismic origin on the basis of the dynamic response of rock structures can be particularly interesting for case histories in less seismically active mountain regions (in comparison with the Andes, Tien Shan, Pamirs), such as in the European Alps and the Carpathian Mountains.
7
Zhang, Fei, Jing Cao e Hai Ming Liu. "Research on the Failure Mechanism of Bedding High Rock Slope at an Open-Pit Mine". Advanced Materials Research 671-674 (marzo 2013): 266–73. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.266.
Testo completoAbstract (sommario):
The bedding high rock slope is most likely to failure in the rock slopes. It is the sliding and bending deformation model (buckling failure) according to deformation characteristic of the north wing slope at the open-pit mine. Considering the influence of rocky self-weight, seismic force and groundwater, the failure mechanism of bedding high rock slope by energy method is researched on the basis of stability theory for elastic plane. And the critical length is obtained. Finally, the influences of model geometry on the critical length, such as the rock stratum dip angle, thickness and width length ratio, is analyzed.
8
Mohammad. R. Abood, Amera. I. Hussein e Marwan. A. Marhon. "Study of rock slope stability for formation outcrops in limb north eastern poor anticline North Iraq". Tikrit Journal of Pure Science 22, n. 3 (27 gennaio 2023): 119–29. http://dx.doi.org/10.25130/tjps.v22i3.721.
Testo completoAbstract (sommario):
This Study aims at rock Slopes Stability for formation in limb northـeastern poor anticline (Fatha, Injana and Mukdadyah). In (5) Stations, representing all types of failures (taken place and possible). General Survey for rock Slopes included Classification and engineering description according to [1][2]. The slopes in the area are Classified based on the direction of the Strike Slopes and Strike of beds into Parallel and Oblique Lateral Slopes according to [3] Classification and the Slope Types are Concordant Slope and discordant Slope.
The main modes of Failures involved rock Fall and Toppling. The Plane Sliding possible with existence conditions must occurrence of Failure. In addition to rolling and Slumping Which Some times Follows the above mentioned Modes of Failures. The main reasons for Failures occurring are differential Weathering Which Cause to over hanging Slopes by under Cutting in addition to the discontinuities in rocks Masses.
9
Guo, Qifeng, Jiliang Pan, Meifeng Cai e Ying Zhang. "Analysis of Progressive Failure Mechanism of Rock Slope with Locked Section Based on Energy Theory". Energies 13, n. 5 (3 marzo 2020): 1128. http://dx.doi.org/10.3390/en13051128.
Testo completoAbstract (sommario):
Progressive failure in rock bridges along pre-existing discontinuities is one of the predominant destruction modes of rock slopes. The monitoring and prediction of the impending progressive failure is of great significance to ensure the stability of the rock structures and the safety of the workers. The deformation and fracture of rocks are complex processes with energy evolution between rocks and the external environment. Regarding the whole slope as a system, an energy evolution equation of rock slope systems during progressive failure was established by an energy method of systemic stability. Then, considering the weakening effect of joints and the locking effect of rock bridges, a method for calculating the safety factor of rock slopes with a locked section was proposed. Finally, the energy evolution equation and the calculation method of safety factor are verified by a case study. The results show that when the energy dissipated in the progressive failure process of rock bridges is less than the energy accumulated by itself, the deformation energy stored in the slope system can make the locked section deform continuously until the damage occurs. The system energy equal to zero can be used as the critical criterion for the dynamic instability of the rock slope with locked section. The accumulated deformation energy in the slope system can promote the development of the cracks in the locked section, and the residual energy in the critical sliding state is finally released in the form of kinetic energy, which is the main reason for the progressive dynamic instability of rock slopes.
10
Whittall, John, Erik Eberhardt e Scott McDougall. "Runout analysis and mobility observations for large open pit slope failures". Canadian Geotechnical Journal 54, n. 3 (marzo 2017): 373–91. http://dx.doi.org/10.1139/cgj-2016-0255.
Testo completoAbstract (sommario):
Objectively forecasting the runout of a potential open pit slope failure, in addition to identifying the failure itself, is a critical component of a mine’s risk management plan. Recent losses arising from large open pit slope failures demonstrate shortcomings in current practice. A dataset of 105 pit slope failures was compiled to compare open pit runout trends against established empirical runout relationships for natural landslides. Fahrböschung angle versus volume and Fahrböschung angle versus slope angle relationships provide reasonable runout estimates. Open pit slopes have the advantage of removing the influence of morphological features, vegetation, and liquefiable substrates while controlling the travel path angle and roughness. In such a controlled environment, landslide mobility has a strong sensitivity to slope angle, material properties, and fall height, and is only modestly sensitive to volume. A grouping of highly mobile open pit slope cases involving weathered, saturated, collapsible rock mass materials exceed expected runout distances when compared with established runout trends. This suggests mobility for these weaker rock masses is controlled by pore pressures mediating basal friction. The result is that two different runout exceedance trends are observed based on whether the unstable rock mass involves fresh, strong rocks or weathered weak rocks.
Tesi sul tema "Rock slope failure"
1
De-Vilder, Saskia Joan. "Controls on the evolution of strength and failure style in shallow rock slope failures". Thesis, Durham University, 2018. http://etheses.dur.ac.uk/12819/.
Testo completoAbstract (sommario):
Rock fall failure comprises fracturing through zones of intact rock, known as rock bridges, and kinematic release along discontinuity surfaces. Understanding controls on magnitude – frequency relationships of rockfalls, and their associated failure characteristics aids susceptibility analysis and interpretation of pre-failure deformation. For failure to occur, these rock bridges must have been weakened, with this damage accumulation driven by a suite of weathering processes. This thesis aims to explore the spatial and temporal controls on weathering induced strength degradation and its subsequent influence on the mechanics of rockfall detachment. Within this, it examines the role of gravitational ambient stress, as dictated by slope topography and rock mass structure, which recent research suggests influences the efficiency of weathering processes. The project integrates field observations, analogue experiments and numerical modelling over varying spatial scales. Terrestrial laser scanning and gigapixel photography are combined to forensically map rock bridge attributes within rockfall detachment surfaces. The role of slope geometry and rock mass structure in concentrating stress is assessed via conceptual finite element models. Finally, samples are subjected to stress conditions induced by the slope structure and environmental conditions in a series of weathering analogue experiments. Together, these results indicate that weathering significantly reduces intact rock strength with areas of stress concentration purely a mechanical control on rockfall release rather than a temporal control on weakening. Weaker rock is characterised by substantial post-peak strength, which requires multiple stages of brittle fracture before ultimate failure occurs. This in turn influences the stages of failure required through rock bridges before final failure, with this number of rock bridges dependent on rockfall size. Mechanically, failure mode is dependent on rock bridge proportion, distribution and location for individual rockfalls. A conceptual model describes magnitude-frequency characteristics and the observable pattern of pre-failure deformation expected for different stages of weathering.
2
Fadlelmula, Fadlelseed Mohamed Mohieldin. "Probabilistic Modeling Of Failure In Rock Slopes". Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608549/index.pdf.
Testo completoAbstract (sommario):
This study presents the results of probabilistic modeling of plane and wedge types of slope failures, based on the &rdquoAdvance First Order Second Moment (AFOSM)&rdquo
reliability method. In both of those failure types, two different failure criteria namely, Coulomb linear and Barton Bandis non-linear failure criteria are utilized in the development of the probabilistic models. Due to the iterative nature of the AFOSM method, analyzing spreadsheets have been developed in order to carry out the computations. The developed spreadsheets are called &ldquo
Plane Slope Analyzer (PSA)&rdquo
and &ldquo
Wedge Slope Analyzer (WSA)&rdquo
. The developed probabilistic models and their spreadsheets are verified by investigating the affect of rock and slope parameters such as, ground water level, slope height, cohesion, friction angle, and joint wall compressive strength (JCS) and their distribution types on the reliability index (&
#946
), and probability of slope failure (PF). In this study, different probability distributions are used and the inverse transformation formulas of their non-normal variates to their equivalent normal ones are developed as well. In addition, the wedge failure case is also modeled by using system reliability approach and then the results of conventional probability of failure and the system reliability approach are compared.
3
CAMONES, LUIS ARNALDO MEJIA. "MODELLING OF STEP-PATH TYPE FAILURE MECHANISMS IN FRACTURED ROCK SLOPE USING DISCRETE ELEMENTS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2010. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33108@1.
Testo completoAbstract (sommario):
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Diferentes mecanismos de ruptura são considerados no momento de avaliar a estabilidade de um maciço rochoso fraturado. Entre estes, os mecanismos de ruptura tipo planar, em cunha e tombamentos têm sido estudados intensivamente, existindo atualmente modelos matemáticos que permitem avaliá-los. Estes mecanismos de ruptura são restritos a taludes pequenos e com fraturas contínuas, nas quais o deslizamento ocorre ao longo destas descontinuidades. Em casos de taludes de grande altura ou quando a persistência das fraturas é pequena em relação à escala do talude, o fraturamento torna-se descontínuo. Neste caso, o mecanismo de ruptura mais provável é o tipo Step-Path, o qual, a superfície de ruptura é formada por fraturas que se propagam através da rocha intacta juntando-se entre elas. Este fenômeno de união de fraturas é chamado de coalescência. Análises de estabilidade, como os probabilísticos ou por equilíbrio limite, são usados atualmente para avaliar estes tipos de rupturas, não se tendo ainda o desenvolvimento de um modelo numérico que possa representá-lo e reforçar estas teorias. O presente trabalho avalia o uso do Método dos Elementos Discretos na modelagem do mecanismo de ruptura tipo step- path, realizando uma análise de estabilidade que permita comparar os seus resultados com o método de equilíbrio limite. Foi utilizado o programa PFC nas versões 2D e 3D, assim como o programa FracGen para a geração de fraturas tridimensionais. A análise tridimensional foi feita mediante um acoplamento PFC3D-FracGen. A pesquisa inclui a análise e modelagem dos fenômenos de coalescência em amostras, assim como a influência da anisotropia na resistência das rochas em ensaios triaxiais.
Different failure mechanisms are considered when a fracturated rock mass is valued. Some of them are being subject of accurate study, like planar failure mechanism, wedges and toppling, which are currently valued by mathematical models. These failure mechanisms are restricted to small slopes and with continue fractures, where the sliding occurs along these discontinuities. To height slopes or when the fracture persistence is smaller than the slope scale, the fracturing becomes discontinuous. In this case, the most probable failure mechanism to happen is the step-path type, in which the failure surface is composed by fractures that propagate through the intact rock and that are joined together. This phenomenon of fracture union is known as coalescence. Stability analysis, like probability analysis or limit equilibrium analysis are currently utilized to evaluate this kind of failures, but its important to develop a numerical model to represent and reinforce these theories. This work aims to evaluate the use of Discrete Element Method to model step-path failure mechanism on a stability analysis and to compare the results with limit equilibrium method. The program used to simulate the slope is PFC (2D and 3D) and the program FracGen was used to generate three-dimensional fractures. Three-dimensional analysis was done by a coupling between PFC3D and FracGen. The research includes the analysis and modeling of coalescence phenomenon on rock samples, as well as the analysis of the anisotropy influence on rock strength obtained from triaxial tests.
4
Chiaravalloti, Rosario. "Numerical modelling and back analysis of a rock slope failure occurred in 2005 at Scascoli (Bologna, Italy)". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
Cerca il testo completoAbstract (sommario):
The rock slope failure object of this study occurred on the 12th of March, 2005, within the Scascoli Gorges in the Savena Valley, 25 km south of Bologna, in the Northern Apennines, Italy. The failure involved a volume of rock of nearly 30000 m3 that detached from an 80 m high cliff and fell on the river bed and onto the adjacent road, denoted as “Strada Provinciale – Fondovalle Savena”, damming the first and destroying the latter. The conformation of the cliff, known as “Mammellone 1”, was rather convex, overhanging and undercut at the base where in contact with the river bed. The event is the last of a series of mass movements which occurred in a 15-year span in the area. With integration of past analyses and surveys, possible causes and mechanism of failure have been investigated by means of two and three-dimensional kinematic analysis (using the software DIPS and SWEDGE by Rocscience, 2016), photogrammetry and terrestrial laser scanning comparison (Cloud Compare, Daniel Girardeau-Montaut, 2016; Autocad, Autodesk, 2016) and two-dimensional finite element numerical modelling (RS2, Rocscience, 2016). The use of a finite element method to model a predominantly blocky structure has shown to be effective and to produce good results if data integration, boundary conditions and geometry of the site are well correlated between each other to best fit the resulting scenario. The design of the numerical model considered the relative position of crown and scarp to the discontinuity families and to the geometry of the cross section, to better costrain the failure surface. Furthermore, the process of formation of the valley was taken into account in order to consider also stress-strain conditions prior to the road construction and river erosion. This was carried out by multi-staging the modelling process considering the natural erosion and the advancement of the landslide on the hydrogeological left side of the Savena steam before the last rockfall event.
5
PIOVANO, GIOVANNA. "Combined finite-discrete element modelling of key instabilities which characterise deep-seated landslides from massive rock slope failure". Doctoral thesis, Politecnico di Torino, 2012. http://hdl.handle.net/11583/2502740.
Testo completoAbstract (sommario):
The expression “landslide from massive rock slope failure” (MRSF) is used to indicate large-scale landslides characterised by a variety of complex initial failure processes and unpredictable postfailure behaviour. In this context, deep-seated landslides are classified as “landslides from massive rock slope failure”. Typically, deep-seated landslides are slow mountain deformations which may involve movement along discrete shear surfaces and deep seated mass creep.
The long-term development of deep-seated slope deformations creates suitable conditions for the subsequent occurrence of other slope deformations. Deep-seated landslides in mountain areas can be spatially interconnected with other types of slope deformations such as debris flows, debris slides, rock avalanches, topple, translational, rotational and compound sliding and complex type of mass movements.
It is to be recognized that many aspects of large-scale landslides need be investigated in order to gain the necessary confidence in the understanding and prediction of their behaviour and in the associated risk assessment. The present thesis is to contribute to such understanding with specific reference to a number of mass movements which characterize large-scale landslides.
An advanced numerical technique (FDEM) which combines finite elements with discrete elements has been applied in this thesis for improving such understanding. The open source research code, called Y2D, developed at the Queen Mary, University of London by Prof. Munjiza has been used. Considering that this code has not yet been applied to slope stability problems, a series of numerical tests have been carried out to assess its suitability to properly and efficiently simulate geomechanical problems.
To this purpose standard rock failure mechanisms as well as laboratory tests have been modelled first and the results obtained have been compared with available analytical and numerical solutions. The advantages of the application of FDEM has been outlined by showing that both the simulation of failure initiation and progressive development to fragmentation of the rock mass is possible as this is deposited at the slope toe. The case study of interest for this thesis is the Beauregard massive landslide located in the Aosta Valley (Northwestern Italy). At this site the presence of an extensive deep-landslide insisting on the left abutment of an arch-gravity dam is well recognised.
Based on detailed studies, the investigated area has been subdivided into zones which are characterised by different geomorphologic and geostructural features. Different landslide mechanics as well as different landslide activities upstream of the dam site have been identified and studied in detail.
Such an area is thought to be at an intermediate stage of development of the deep seated landslide compared with the sector which insists on the dam. The observed failure mechanism has been ascribed to a large sliding on a compound surface. Some other failure mechanisms have been recognized, such as large flexural toppling and local block toppling instability.
The final part of the thesis has been devoted to the FDEM numerical modelling of a large scale failure mechanism based on brittle behaviour of the rock mass. The aim is to apply the “total slope failure” approach through the application of FDEM. Such a technique has demonstrated the significant potential in predicting the development of possible slope instability phenomena.
6
Büch, Florian. "Seismic response of Little Red Hill - towards an understanding of topographic effects on ground motion and rock slope failure". Thesis, University of Canterbury. Geological Sciences, 2008. http://hdl.handle.net/10092/1251.
Testo completoAbstract (sommario):
A field experiment was conducted at near Lake Coleridge in the Southern Alps of New Zealand, focusing on the kinematic response of bedrock-dominated mountain edifices to seismic shaking. The role of topographic amplification of seismic waves causing degradation and possible failure of rock masses was examined. To study site effects of topography on seismic ground motion in a field situation, a small, elongated, and bedrock-dominated mountain ridge (Little Red Hill) was chosen and equipped with a seismic array. In total seven EARSS instruments (Mark L-4-3D seismometers) were installed on the crest, the flank and the base of the 210 m high, 500 m wide, and 800 m long mountain edifice from February to July 2006. Seismic records of local and regional earthquakes, as well as seismic signals generated by an explosive source nearby, were recorded and are used to provide information on the modes of vibration as well as amplification and deamplification effects on different parts of the edifice. The ground motion records were analyzed using three different methods:comparisons of peak ground accelerations (PGA), power spectral density analysis (PSD), and standard spectral ratio analysis (SSR). Time and frequency domain analyses show that site amplification is concentrated along the elongated crest of the edifice where amplifications of up to 1100 % were measured relative to the motion at the flat base. Theoretical calculations and frequency analyses of field data indicate a maximum response along the ridge crest of Little Red Hill for frequencies of about 5 Hz, which correlate to wavelengths approximately equal to the half-width or height of the edifice (~240 m). The consequence of amplification effects on the stability and degradation of rock masses can be seen: areas showing high amplification effects overlap with the spatial distribution of seismogenic block fields at Little Red Hill. Additionally, a laboratory-scale (1:1,000) physical model was constructed to investigate the effect of topographic amplification of ground motion across a mountain edifice by simulating the situation of the Little Red Hill field experiment in a smallscale laboratory environment. The laboratory results show the maximum response of the model correlates to the fundamental mode of vibration of Little Red Hill at approximately 2.2 Hz. It is concluded that topography, geometry and distance to the seismic source, play a key role causing amplification effects of seismic ground motion and degradation of rock mass across bedrock-dominated mountain edifices.
7
Bonilla, Sierra Viviana. "De la photogrammétrie à la modélisation 3D : évaluation quantitative du risque d'éboulement rocheux". Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI072/document.
Testo completoAbstract (sommario):
Les analyses structurale et mécanique des pentes rocheuses constituent des éléments clés pour l'évaluation de leur stabilité. L'utilisation complémentaire de la photogrammétrie et des modèles numériques qui couplent les réseaux discrets de discontinuités (DFN selon son sigle en anglais) avec la méthode des éléments discrets (DEM selon son sigle en anglais), présente une méthodologie qui peut être utilisée pour évaluer le comportement mécanique des configurations tridimensionnelles de terrain pour lesquelles l'existence de discontinuités non persistantes peut être supposée. La stabilité des masses rocheuses est généralement supposée être contrôlée par la résistance au cisaillement le long des plans de discontinuité. Si les discontinuités sont non persistantes, avec leur continuité interrompue par la présence de ponts rocheux (portions de roche intacte reliant la masse rocheuse au massif), leur résistance apparente augmente considérablement. Dans ce cas, la contribution des ponts rocheux localisés entre ces discontinuités doit être prise en compte dans l'analyse de stabilité. La déstabilisation progressive des massifs rocheux dans lesquels des discontinuités non persistantes sont présentes, peut être étudiée par des simulations numériques réalisées à l'aide de l'approche DEM. La roche intacte est représentée comme un assemblage de particules (ou éléments discrets) liées entre elles par des contacts dont les lois de comportement spécifiques peuvent être calibrées pour représenter correctement le comportement de la roche. L'intérêt de la méthode est qu'elle permet de simuler l'initiation de la rupture et sa propagation à l'intérieur de la matrice rocheuse du fait de la rupture des contacts cohésifs entre les particules. De plus, les discontinuités préexistantes peuvent être prises en compte explicitement dans le modèle en utilisant une loi de contact ad hoc qui assure un comportement mécanique représentatif des plans de discontinuité. Des analyses de stabilité ont été effectuées et ont mis en évidence le rôle des ponts rocheux dans la génération de nouvelles surfaces de rupture qui peuvent se développer à travers des mécanismes de rupture mixte en traction et en cisaillement. On peut considérer la formulation de Jennings comme l'une des premières méthodes d'analyse de la stabilité des pentes rocheuses qui évaluent la résistance au glissement comme une combinaison pondérée des résistances mécaniques des ponts rocheux et des plans de discontinuité. Sa validité a été discutée et systématiquement comparée aux résultats obtenus à partir de simulations numériques. Il a pu être montré que la formulation de Jennings perd sa validité dès que la rupture des ponts rocheux intervient majoritairement par des mécanismes de traction. Une formulation complémentaire a alors été proposée. En ce qui concerne l'étude de la stabilité des massifs rocheux sur site, il a été montré que l'association entre les données issues de la photogrammétrie en haute résolution et l'approche DFN-DEM peut être utilisée pour identifier des scénarios de rupture. L'analyse en retour de cas réels a montré que les surfaces de rupture peuvent être simulées comme le résultat de mécanismes combinant la fracturation des ponts rocheux et le glissement le long des discontinuités préexistantes. La rupture d'un dièdre qui a eu lieu dans une mine de charbon australienne, a été utilisée pour valider cette méthodologie. Des simulations numériques ont été réalisées pour déterminer les scénarios pour lesquels les surfaces de rupture simulées et celles repérées sur le terrain, peuvent être utilisés pour calibrer les paramètres de résistance du modèle numérique. Le travail présenté ici répond à un besoin plus général visant à améliorer la gestion des risques naturels et miniers liés aux masses rocheuses instables. La méthodologie proposée constitue une alternative robuste dédiée à renforcer la fiabilité des analyses de stabilité pour les pentes rocheuses fracturées à structure complexeStructural and mechanical analyses of rock mass are key components for rock slope stability assessment. The complementary use of photogrammetric techniques and numerical models coupling discrete fracture networks (DFN) with the discrete element method (DEM) provides a methodology that can be applied to assess the mechanical behaviour of realistic three-dimensional (3D) configurations for which fracture persistence cannot be assumed. The stability of the rock mass is generally assumed to be controlled by the shear strength along discontinuity planes present within the slope. If the discontinuities are non–persistent with their continuity being interrupted by the presence of intact rock bridges, their apparent strength increases considerably. In this case, the contribution of the rock bridges located in-between these discontinuities have to be accounted for in the stability analysis. The progressive failure of rock slope involving non–persistent discontinuities can be numerically investigated based upon simulations performed using a DEM approach. The intact material is represented as an assembly of bonded particles interacting through dedicated contact laws that can be calibrated to properly represent the behaviour of the rock material. The advantage of the method is that it enables to simulate fracture initiation and propagation inside the rock matrix as a result of inter-particle bond breakage. In addition, pre–existing discontinuities can be explicitly included in the model by using a modified contact logic that ensures an explicit and constitutive mechanical behaviour of the discontinuity planes. Stability analyses were carried out with emphasis on the contribution of rock bridges failure through a mixed shear-tensile failure process, leading to the generation of new failure surfaces. Jennings' formulation being considered to be one of the first rock slope stability analysis that evaluates the resistance to sliding as a weighted combination of both, intact rock bridges and discontinuity planes strengths, its validity was discussed and systematically compared to results obtained from numerical simulations. We demonstrate that the validity of Jennings' formulation is limited as soon as tensile failure becomes predominant and an alternative formulation is proposed to assess the resulting equivalent strength. Regarding field slope stability, we show that the combination of high resolution photogrammetric data and DFN-DEM modelling can be used to identify valid model scenarios of unstable wedges and blocks daylighting at the surface of both natural and engineered rock slopes. Back analysis of a real case study confirmed that failure surfaces can be simulated as a result of both fracture propagation across rock bridges and sliding along pre-existing discontinuities. An identified wedge failure that occurred in an Australian coal mine was used to validate the methodology. Numerical simulations were undertaken to determine in what scenarios the measured and predicted failure surfaces can be used to calibrate strength parameters in the model. The work presented here is part of a more global need to improve natural and mining hazards management related to unstable rock masses. We believe that the proposed methodology can strengthen the basis for a more comprehensive stability analysis of complex fractured rock slopes
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Jarvis, Jeremy James. "Large scale toppling failure in metamorphic rock slopes". Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/11287.
Testo completo
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Ковров, Олександр Станіславович, Александр Станиславович Ковров e O. S. Kovrov. "Геомеханічне обґрунтування параметрів стійких укосів кар’єрів в складноструктурному масиві м’яких порід". Thesis, Видавництво НГУ, 2011. http://ir.nmu.org.ua/handle/123456789/152.
Testo completoAbstract (sommario):
Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.15.09 – «Геотехнічна і гірнича механіка». – ДВНЗ «Національний гірничий університет», Дніпропетровськ, 2011.Диссертация на соискание ученой степени кандидата технических наук по специальности 05.15.09 – «Геотехническая и горная механика». – ГВУЗ «Национальный горный университет», Днепропетровск, 2011.
Thesis for obtaining scientific degree of Candidate of Technical Sciences in specialty 05.15.09 - Geotechnical and rock mechanics. – State Higher Educational Institution “National Mining University”, Dnipropetrovs’k, 2011.
Дисертація присвячена вирішенню актуальної науково-технічної задачі вдосконалення геомеханічної оцінки стійкості укосів уступів на кар’єрах, що складаються з м’яких розкривних порід, з урахуванням складної геологічної структури, гідрогеологічних характеристик родовища й навантажень від гірничо-транспортного устаткування. У роботі виконаний аналіз впливу фізико-географічних, природно-геологічних, гідрогеологічних, інженерно-геологічних і гірничо-технічних факторів на геомеханічну стійкість укосів і бортів кар’єрів. Результати моделювання на еквівалентних матеріалах та чисельного моделювання методом кінцевих елементів дозволило проаналізувати геомеханічні процеси у породних уступах і встановити закономірності порушення їх стійкості. Отримані експериментальним шляхом фізико-механічні характеристики розкривних порід (суглинки, глини) для гірничо-геологічних умов кар’єрів №7 "Північ" й №7 "Південь" Вільногірського ГМК використані для геомеханічної оцінки стійкості укосів уступів залежно від фізико-механічних характеристик, вологості порід і навантажень від гірничо-транспортного устаткування. Закономірності, отримані в результаті експериментальних досліджень зразків гірських порід і чисельного моделювання використані для розробки рекомендацій із забезпечення геомеханічної стійкості укосів розкривних уступів для гірничо-геологічних та гірничотехнічних умов Мотронівсько-Анновської ділянки Малишевського комплексного циркон-рутил-ільменітового родовища, що планується до введення в експлуатацію на ВГМК.
Диссертация посвящена усовершенствованию геомеханической оценки устойчивости откосов уступов на карьерах, сложенных мягкими вскрышными породами, с учетом сложной геологической структуры, гидрогеологических характеристик месторождения и нагрузок от горно-транспортного оборудования. В работе выполнен анализ влияния физико-географических, природно-геологических, гидрогеологических, инженерно-геологических и горно-технических факторов на геомеханическую устойчивость откосов и бортов карьеров; рассмотрены основные подходы к расчету потенциальных поверхностей скольжения в прибортовом массиве пород, а также аналитические и эмпирические критерии прочности, которые наиболее часто используются в практике геомеханических исследований. Для моделирования устойчивости откосов и бортов карьеров, сложенных мягкими вскрышными породами, принят критерий прочности Кулона-Мора. В качестве инструмента численного моделирования использована программа конечно-элементного анализа Phase2 компании Rocscience Inc. широко используемая в практике инженерного анализа как в Украине, так и за рубежом. Использование метода моделирования на эквивалентных материалах позволило проанализировать геомеханические процессы, происходящие при сдвижении массива пород, слагающих породный уступ, и установить закономерности нарушения его устойчивости. Выполнены серийные испытания образцов на одноплоскостном срезном приборе П10-С и определены физико-механические характеристики вскрышных пород (суглинки, глины) для горно-геологических условий карьеров №7 «Север» и №7 «Юг» Вольногорского ГМК. Полученные экспериментальным путем значения сцепления и угла внутреннего трения использованы для геомеханической оценки устойчивости откосов уступов действующих и проектируемых карьеров ВГМК. Разработана гидрогеомеханическая модель, описывающая распределение деформаций и напряжений в откосах уступов карьера с учетом физико-механических характеристик верхнего слоя вскрыши и влагонасыщения пород за счет инфильтрации атмосферных осадков. По результатам моделирования определены коэффициенты запаса устойчивости борта карьера в зависимости от физико-механических характеристик, влажности вмещающих пород и внешних нагрузок горно-транспортного оборудования. Закономерности, полученные в результате экспериментальных исследований образцов горных пород и численного моделирования использованы для разработки рекомендаций по обеспечению геомеханической устойчивости откосов вскрышных уступов для горно-геологических и горнотехнических условий Мотроновско-Анновского участка Малышевского комплексного циркон-рутил-ильменитового месторождения, которое планируется к введению в эксплуатацию на ВГМК. Разработан алгоритм оценки долговременной геомеханической устойчивости откосов и бортов карьеров, учитывающий геометрические параметры уступов, сложную геологическую структуру породного массива, гидрогеологические характеристики месторождения и нагрузки от горно-транспортного оборудования. Рассчитаны зависимости угла откоса уступа от влажности верхнего вскрышного горизонта суглинков. Установлено, что для существующих гидро-геологических условий с учетом физико-механических свойств пород рекомендуемые значения КЗУ=1,1…1,3 будут обеспечены при угле наклона откоса α=37…47°. В результате комплексной оценки геомеханической устойчивости откосов разработана номограмма для расчета КЗУ и рациональных геометрических параметров вскрышных уступов, сложенных суглинками. Установлено, что при средней высоте вскрышного уступа 20 м и изменении угла наклона откоса с проектных 37º до рекомендуемых 47º для условий Вольногорского горно-металлургического комбината сокращение объемов вскрышных работ на 1 км длины фронта работ составит ∆V=78,91тыс.м3. В результате корректировки угла наклона откоса и формировании более крутого геометрического профиля уступа, при его высоте Н=20 м, на 10° (α1-α2=47°-37°) рассчитан экономический эффект Сэ=0,72…0,90 млн. грн на 1 км длины фронта горных работ при средней себестоимости вскрыши Св=10,85…13,40 грн/м3.
The dissertation is devoted to solving an actual scientific and technical task of improving geomechanical evaluation of slope stability in open-pit benches composed of soft rocks with consideration of complex geological structure, deposit hydro-geological characteristics and loads of mining-transportation equipment. Analysis of influence of physiographic, geological, hydro-geological, geotechnical and mining-technical factors on geomechanical stability of slopes and pitedges is carried out. Results of simulation of equivalent materials and FEM numerical modeling allowed analyze geomechanical processes in rock benches and ascertain laws of their instability. Experimentally derived physical and mechanical characteristics of overburden rocks (loams, clays) for geological conditions of open-pits №7 "Sever" and №7 "Yug" of Vil’noghirs’k Mining and Metallurgical Plant (VGMK) are used for geomechanical evaluation of slope stability depending on physical and mechanical characteristics, rock moisture, and external loads from mining and transport equipment. Regularities obtained in experimental research of rock samples and numerical modeling are used to develop recommendations for ensuring geomechanical slope stability of overburden benches for geological and mining conditions of Motronivs’ko-Annovs’kyi section of Malyshevs’ke complex zircon-rutile-ilmenite placer deposit which is planned to put into exploitation on VGMK.
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Anyintuo, Thomas Becket. "Seepage-Coupled Finite Element Analysis of Stress Driven Rock Slope Failures for BothNatural and Induced Failures". Scholar Commons, 2019. https://scholarcommons.usf.edu/etd/7731.
Testo completoAbstract (sommario):
Rock slope failures leading to rock falls and rock slides are caused by a multitude of factors, including seismic activity, weathering, frost wedging, groundwater and thermal stressing. Although these causes are generally attributed as separate causes, some of them will often act together to cause rock slope failures. In this work, two of the above factors, seepage of water through cracks and crack propagation due to the after effects of blasting are considered. Their combined impact on the development of rock falls and rock slides is modeled on ANSYS workbench using the Bingham Canyon mine slope failure of 2013 as a case study. Crack path modeling and slope stability analysis are used to show how a combination of crack propagation and seepage of water can lead to weakening of rock slopes and ultimate failure. Based on the work presented here, a simple approach for modeling the development of rock falls and rock slides due to crack propagation and seepage forces is proposed. It is shown how the information from remote sensing images can be used to develop crack propagation paths. The complete scope of this method involves demonstrating the combination of basic remote sensing techniques combined with numerical modeling on ANSYS workbench.
Libri sul tema "Rock slope failure"
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Evans, Stephen G., Gabriele Scarascia Mugnozza, Alexander Strom e Reginald L. Hermanns, a cura di. Landslides from Massive Rock Slope Failure. Dordrecht: Springer Netherlands, 2006. http://dx.doi.org/10.1007/978-1-4020-4037-5.
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Zhang, Ke. Failure Mechanism and Stability Analysis of Rock Slope. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-5743-9.
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H, Dowding C., American Society of Civil Engineers. Geotechnical Engineering Division. e ASCE National Convention (1985 : Denver, Colo.), a cura di. Rock masses: Modeling of underground openings, probability of slope failure, fracture of intact rock : proceedings of the symposium. New York, N.Y: ASCE, 1985.
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Strom, Alexander, Stephen G. Evans, Reginald L. Hermanns e Gabriele Scarascia Mugnozza. Landslides from Massive Rock Slope Failure. Springer, 2006.
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Zhang, Ke. Failure Mechanism and Stability Analysis of Rock Slope: New Insight and Methods. Springer, 2020.
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Zhang, Ke. Failure Mechanism and Stability Analysis of Rock Slope: New Insight and Methods. Springer Singapore Pte. Limited, 2021.
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(Editor), Stephen G. Evans, Gabriele Scarascia Mugnozza (Editor), Alexander Strom (Editor) e Reginald L. Hermanns (Editor), a cura di. Landslides from Massive Rock Slope Failure (Nato Science Series: IV: Earth and Environmental Sciences). Springer, 2006.
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(Editor), Stephen G. Evans, Gabriele Scarascia Mugnozza (Editor), Alexander Strom (Editor) e Reginald L. Hermanns (Editor), a cura di. Landslides from Massive Rock Slope Failure (Nato Science Series: IV: Earth and Environmental Sciences). Springer, 2006.
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Dowding, Charles H. Rock Masses: Modeling of Underground Openings/Probability of Slope Failure/Fracture of Intact Rock : Proceedings of the Symposium Sponsored by the Geotechnical eng. Amer Society of Civil Engineers, 1985.
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Glastonbury, James Peter. The pre-and post-failure deformation behaviour of rock slopes. 2002.
Cerca il testo completoCapitoli di libri sul tema "Rock slope failure"
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Wyllie, Duncan C. "Toppling failure". In Rock Slope Engineering, 269–90. Fifth edition. | Boca Raton : Taylor & Francis, CRC Press, 2017.: CRC Press, 2017. http://dx.doi.org/10.4324/9781315154039-10.
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Wyllie, Duncan C. "Plane failure". In Rock Slope Engineering, 189–216. Fifth edition. | Boca Raton : Taylor & Francis, CRC Press, 2017.: CRC Press, 2017. http://dx.doi.org/10.4324/9781315154039-7.
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Wyllie, Duncan C. "Wedge failure". In Rock Slope Engineering, 217–38. Fifth edition. | Boca Raton : Taylor & Francis, CRC Press, 2017.: CRC Press, 2017. http://dx.doi.org/10.4324/9781315154039-8.
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Wyllie, Duncan C. "Circular failure". In Rock Slope Engineering, 239–68. Fifth edition. | Boca Raton : Taylor & Francis, CRC Press, 2017.: CRC Press, 2017. http://dx.doi.org/10.4324/9781315154039-9.
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Wyllie, Duncan C. "Circular failure". In Rock Slope Engineering, 239–68. Taylor & Francis Group, 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742: CRC Press, 2017. http://dx.doi.org/10.1201/9781315154039-10.
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Wyllie, Duncan C. "Toppling failure". In Rock Slope Engineering, 269–90. Taylor & Francis Group, 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742: CRC Press, 2017. http://dx.doi.org/10.1201/9781315154039-11.
Testo completo
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Wyllie, Duncan C. "Plane failure". In Rock Slope Engineering, 189–216. Taylor & Francis Group, 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742: CRC Press, 2017. http://dx.doi.org/10.1201/9781315154039-8.
Testo completo
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Wyllie, Duncan C. "Wedge failure". In Rock Slope Engineering, 217–38. Taylor & Francis Group, 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742: CRC Press, 2017. http://dx.doi.org/10.1201/9781315154039-9.
Testo completo
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Loew, Simon, e Jan Klimeš. "Introduction: Rock-Slope Instability and Failure". In Landslide Science for a Safer Geoenvironment, 69. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-04996-0_12.
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Pan, Bing, Shuhong Hu, Weiwei Wu, Yongjin Cheng e Zhen Jiang. "Stability Analysis of Tailrace Outlet Slope at Right Bank of Kala Hydropower Station". In Lecture Notes in Civil Engineering, 473–82. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-4355-1_44.
Testo completoAbstract (sommario):
AbstractThe tailrace outlet slope located on the right bank of the Kala hydropower station represents a typical bedding slope characterized by a moderate to large dip angle. The excavation at the toe of the slope create favourable conditions for rock mass deformation and failure. In order to evaluate the slope’s stability, a thorough investigation and analysis of the engineering geological conditions are conducted. Additionally, the stress-strain characteristics resulting from the slope excavation are simulated utilizing the discrete element software 3DEC. Finally, the strength reduction method is used to evaluate the safety factor of the slope. The research results show that the stability of the slope is notably influenced by the presence of medium and large dip structural planes, the cutting excavation at slope toe can lead to deformation and localized block instability. The implementation of the system pre-stressed cables effectively increases the safety factor of the slope and ensures the stability of the tailrace outlet slope. These findings will provide valuable references for the design of similar rock slopes.
Atti di convegni sul tema "Rock slope failure"
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Ashraf, M., M. Z. Emad, M. Waqas e H. Moazzam. "Numerical Simulation of Toppling Failure in Sedimentary Rock Slope Cuts with Alternating Soft and Hard Bands". In 58th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2024. http://dx.doi.org/10.56952/arma-2024-0864.
Testo completoAbstract (sommario):
ABSTRACT: Rock slope stability is a major concern in mega engineering projects, and it has been a major focus of engineering geology for over three centuries. The toppling failure mode is considered as one of the most complex and challenging to stabilize. The complexity of slope failures increases with a combination of mechanisms and the presence of different geological units and structures. Numerical modeling is a powerful tool for analyzing and simulating rock slope stability. This paper aims to assess and propose stabilization methods for toppling failure and complex toppling failure, using numerical modeling software FLAC 2D. The paper introduces a technique for assessing toppling failure in alternating soft-hard rock bands during adverse conditions and proposes innovative stabilization methods based on simulation effects. The results suggest that numerical modeling software can effectively assess toppling failure, design support, and reinforcement methods, and help predict and reduce the risk of slope collapse in toppling zones through appropriate stabilization techniques. 1. INTRODUCTION The stability of rock slopes, as explained by Hoek (1981), is a critical aspect of numerous geotechnical engineering endeavors, owing to their susceptibility to failure triggered by diverse factors such as geological conditions (Wyllie and Mah, 2004), environmental forces, and material properties. Rock slope failures can result in severe consequences, encompassing loss of life, infrastructure damage, and economic disruption (Evans, 2006). For over three centuries, engineering geology has been truly involved in investigating slope stability, which delineates capacity of a slope to withstand internal and external forces without collapsing (Azarafza, 2021). This aspect remains a captivating and expansive domain, encompassing various manifestations of rock and soil failures, as expounded by Li (2022). Ensuring the safety of individuals and structures necessitates the deployment of dependable and precise methods for assessing rock slope stability. Understanding the prevailing failure mechanisms and delineating stable and unstable zones within a slope are pivotal prerequisites for accurate assessment (Mat, 2023). Hoek (1981) categorizes simplified failure modes into four types: plane, wedge, circular, and toppling.
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Tohm, Calvin, Bret Lingwall e Linus Uy. "Monitoring Slope Movement Using Unmanned Aerial Vehicles". In 58th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2024. http://dx.doi.org/10.56952/arma-2024-0430.
Testo completoAbstract (sommario):
ABSTRACT: Slope movement post precipitation events are a well-documented and understood phenomenon. The increase in moisture, if able to infiltrate the hill slope, can lead to the buildup of excess pore water pressure resulting in a decrease in shear strength of the soil. This phenomenon results in surficial failures that can slowly degrade the stability of a hill slope and eventually lead to failure. Monitoring this using traditional surveying techniques can prove to be time consuming and difficult due to the sheer number of points required to accurately capture the slope movement. To overcome this, this study sought to use unmanned aerial vehicle (UAV) techniques and equipment to monitor existing slope movement and failures. A study area in Rapid City, South Dakota around the South Dakota School of Mines and Technology (SDSMT) campus, which included multiple existing slope failures, was used. To monitor slope movement, photogrammetric imagery was taken of the study area both prior to and after precipitation event. Drone imagery was used to construct structure from motion (SFM) models to monitor slope movement by comparing previous flights to one another. All areas of interest or failures documented from the flights were individually ground truthed to ensure accuracy of the imagery. From this study it was found that seepage areas were a high indicator of slope failure of exposed ground surfaces and SFM models were able to accurately capture and document slope failures that had occurred after precipitation events. 1. INTRODUCTION Seasonal weather cycles result in the development of anisotropic stresses within the surface layer of earthen structures, resulting in altered engineering properties and the development of an active layer of soil1. These weathering cycles include iterative shrink-swell with wetting and drying and freeze-thaw as well as times of acidic water, organic acids, and other chemical weathering processes. As the degree and severity of weathering cycles increases, this active layer propagates downward and results in near surface (upper 5-m) failures, weakening the overall integrity of geotechnical earth structures, resulting in increased erosion rates2-5, slope failure5, and compromised hydraulic conductivity in dams and levees2,7-9. These alterations in the engineering properties of earthen structures results in unforeseen or premature failure for slopes sensitive to changes in properties and conditions in the active zone (3 to 5-m), especially materials in the upper 1-m sensitive to seasonal freeze-thaw. Therefore, it is understood that seasonal weathering cycles are a key contributor to obscelense of earthworks.
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Fleischer, N. A., e R. D. Thomas. "A Discussion of Traditional Rock Slope Stability Analysis Methods with a Technical Evaluation of a Former Quarry Site in Jessup, Pennsylvania". In 58th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2024. http://dx.doi.org/10.56952/arma-2024-0265.
Testo completoAbstract (sommario):
ABSTRACT: Rock slope stability is generally controlled by the orientations of the discontinuities present in a rock mass. Depending upon the orientations of these features and the orientation of the slope in question, slope failures may be possible. In this analysis, common analytical methods are discussed and presented for a site in Pennsylvania. An analysis first begins with discontinuity mapping. In this study, quarry walls were mapped, and observations of active slope failures were made. The data collected were plotted on stereonets for cluster and kinematic analyses, which identified several potential failures. Field and laboratory data were used to calculate the Factor of Safety for each predicted failure mode for each slope. Several slopes had elevated failure risks and mitigation recommendations were provided to the client. Rock slope stability analysis is a crucial step when considering development in proximity to rock slopes. It is necessary to understand the continuity of the rock mass and failure risks, and to mitigate those risks which can have devastating impacts on human lives and infrastructure. This technical paper aims to present a basic example of a complete analysis in the hope of providing a guide for fundamental rock slope stability analysis methods. 1. INTRODUCTION Rock slope stability at a site is generally controlled by the orientations and conditions of the discontinuities (bedding planes, fractures, faults, and joints) that are present in the rock mass. These roughly planar features often form the edges of the individual blocks of rock that constitute the overall rock mass. Depending upon the orientations of these features and the orientation and dip of the slope in question, planar, wedge, and/or toppling failures may be indicated. Other factors such as the presence of groundwater, vegetation, ice, surcharge loads, seismicity, along with the geomechanical properties of the rock can also greatly affect the stability of rock slopes. 2. BASIC FIELD METHODS To understand the fabric of the rock mass and determine the orientations of the discontinuities present throughout, a geologist or geotechnical engineer should visit the site of the proposed or existing rock slope to complete a thorough reconnaissance of the slope(s) in question. The reconnaissance should involve a systematic evaluation of rock slope conditions including detailed rock discontinuity mapping, observation, examinations of the presence of groundwater and photo-documentation of key rock slope features.
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Shandilaya, Shivesh, e Shahrzad Roshankhah. "Failure Mechanisms in Jointed Rock Slopes Concerning the Dip Angle of Continuous Joints". In 58th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2024. http://dx.doi.org/10.56952/arma-2024-0827.
Testo completoAbstract (sommario):
ABSTRACT: Jointed rock slopes surround critical infrastructure and communities, such as dams, roads, tunnels, bridges, mines, and buildings. The mechanical behavior of jointed rock masses depends on the complex interactions between joints, rock matrix, boundary conditions, and loading states. When a jointed rock mass undergoes environmental stressors, the generated tensile and shear cracks through intact rock blocks and pre-existing discontinuities determine the mechanisms and implications of the consequent slope failure. However, predicting fracture evolution, corresponding stress transfer mechanisms, and consequent failure states are challenging due to the complex interactions between the slopes' structural components. This study aims to understand the effects of such interactions on the overall response of slopes concerning the dip angle of continuous natural fractures when a local failure is triggered in fractures close to the slope face. This study employs the combined finite discrete element method (FDEM) to examine the slopes' mechanical response, including the progressive failure mechanisms. The results of this quantitative analysis are processed and visualized through graphical representations depicting the distinct failure modes observed in jointed rock slopes with various dip angles. 1 INTRODUCTION Failure of rock slopes ranks among the most dangerous geological hazards, causing yearly fatalities, significant disruptions to infrastructure, environmental challenges, and adverse socioeconomic impacts. Thus, it is crucial to detect the early signs of failure by understanding the mechanisms that drive new fractures, activate pre-existing fractures, and finally cause a global failure. Failure of rock slopes occurs for various reasons that contribute to either an increase in shear stresses applied on the slope or a decrease in the shear strength of the rock mass. The latter may happen due to weathering, water infiltration, and anthropogenic activities. Studies show that the impact of shear strength reduction on the failure mechanism of jointed rock slopes depends on factors like joint or discrete fracture network (DFN) density (Wang et al., 2003), roughness (Ban et al., 2020, Rullière et al., 2020) and orientation of the joints (Bahaaddini et al.,2013), the properties of the infill material within the joints (Jiang et al., 2015), the degree of saturation of the infill (Indraratna et al., 2014), and the average normal stress acting on the joints (Mišcˇević et al., 2014). The arrangement of fractures within a rock mass can also determine the potential for block detachment, toppling, and sliding. Highly connected fracture networks can delineate potential sliding or toppling blocks, significantly influencing slope stability (Romer & Ferentinou, 2019).
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Keissar, Y., I. R. Brown, M. H. Gardner e N. Sitar. "DEM Modeling of 3D Kinematics in Rock Slope Failure". In 58th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2024. http://dx.doi.org/10.56952/arma-2024-0511.
Testo completoAbstract (sommario):
ABSTRACT: We compare solutions obtained using 3D Limit-Equilibrium (LE) and the 3D Discrete Element Method (DEM) analyses of rock slope stability and runout to illustrate the importance of kinematics in modeling of rock slides. While 3D LE methods provide a measure of the factor of safety against failure, the failure surface is assumed, and the rock mass is typically represented by vertical columns in the analysis. Thus, the kinematic response of the rock mass is artificially constrained, and the quality of the analysis heavily depends on an accurate capture of the potential failure surface and the failure mechanism. In contrast, a specific mode of failure is not assumed in DEM, since natural discontinuities, joints, shears, and fractures, as observed in the field can be used to create a more realistic representation of the rock mass such that failure can occur along any of the discontinuities. We use a case of rock slope failure in an existing mine to illustrate the difference between 3D LE and 3D DEM analysis results. We also show that with an increasing number of rock blocks in the model (tighter spacing of the joints), the rock mass is less stable. This has implications for rock slope stability evaluations, as rock that is more fractured will be less kinematically constrained and require more mechanical strength to remain stable. Additionally, during rock slide initiation, the rock within the sliding mass may fracture and disintegrate, such that it becomes less constrained as it deforms. The outcome is a progressive rock slope failure and accelerating displacements as the rock blocks within the sliding mass become more fractured. 1 INTRODUCTION In fractured rock masses, slope failure occurs along pre-existing discontinuities, such as joints and fractures. The interaction between the discontinuities and the geometry of the slope plays an important role in the displacement of the blocky rock mass, both for failure initiation and runout. While 3D DEM methods have been available for some time, their utility for routine analyses has been limited due to their high computational demands and lengthy execution times in serial code implementations. However, the implementation of DEM in a modern HPC (High-Performance Computing) environment opens opportunities for efficient and affordable, full-scale analyses of failure initiation and runout.
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Ureel, S. D. "Case Study: Investigation, Analysis and Mitigation of Rock Instability for a Potential Slope Failure in Highly Weathered Granite at Pinto Valley Mine in Arizona". In 58th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2024. http://dx.doi.org/10.56952/arma-2024-0558.
Testo completoAbstract (sommario):
ABSTRACT: In the mining and civil engineering industries, slope stability issues have become essential problems to avoid ensuring site safety, maximum ore extraction and limited interruptions in production. Slope failures in mining operations are a cause for concern when dealing with potential safety hazards, accidents and injuries for mining personnel and damage to equipment. Predicting, monitoring and investigating slope failures are pertinent for safe working conditions and should be inspected continuously. A high wall composed of a small top layer of alluvium underlined by highly weathered granite at the Pinto Valley Mine in Arizona expressed warning signs such as rockfall, talus/debris retained on lower benches, tension cracks and displacements on the slope stability radar (SSR) during production adjacent to the slope. Detailed inspections, monitoring and mitigation were immediately initiated following these signs of instability. If the area of interest is not critical to production, the easiest plan of action would be to leave the material in place and let the slope fail naturally as long it will not cause any safety hazards; however, this is not the case for failure researched in this paper. Mine blasting and production need to continue below the failure due to high grade ore in the vicinity. This can only happen if the failure mechanism is well understood and the rate of displacement is low. This study was performed to understand the mechanisms that triggered the failure, the rock conditions before and after the failure and to show how to proceed with controlled mining procedures in organized manner. This study will show observations before, during and after the slope instability as well as successful mitigation efforts and analyses. The results acquired illustrated that slope instability can be predicted from SSR, the SRR exhibited real time monitoring and provided initiation for mining safety protocols and procedures. 1. INTRODUCTION Slope stability plays an important role in rock engineering. During the design, construction and post design phases of rock slope stability, engineers and geologists need to pay close attention to the rock conditions within the rock slope to prevent slope failures, protect employees and maintain economic profit. Slope geometry, material properties, and insitu stress conditions need to be investigated in order to understand the potential for rock slides, wedge failures, and other instabilities.
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Eberhardt, Erik. "Towards Mine Closure: Assessing the Long-Term Stability of Open Pit Mine Slopes". In 58th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2024. http://dx.doi.org/10.56952/arma-2024-1208.
Testo completoAbstract (sommario):
ABSTRACT: The long-term stability of engineered slopes is becoming a critical focus point as the number of open pit mines anticipated to close in the coming years is increasing, and governments, regulators, and society are collectively placing more emphasis on sustainable management of mineral resources and land use (IISD, 2021). However, there are currently few guidelines on assessing long-term slope stability. Of central importance is the recognition that rock mass properties are not constants, and therefore, open pit slopes that are presently stable may not remain so in the future. Conventional engineering analyses generally assume the strength of a rock mass to be constant and, in doing so, fail to explain the temporal nature of rock slope behavior seen in monitoring data. Data shows that pit slope movements are intermittent, correlating with benching and seasonal precipitation patterns. These initiate episodic damaging events that, in the closure context, control strength degradation and impact long-term slope performance through progressive failure (Eberhardt et al. 2004). This talk will summarize the author's research over the last 20 years into progressive failure, its advancement of our mechanistic understanding of deep-seated rock slope failure, and recent results and guidance in applying it to open pit slope stability assessments and mitigation efforts to aid mine closure designs. Empirical data will be presented to show the evidence for progressive failure, with a focus placed on transient pore pressures driven by seasonal precipitation. Upon closure, changes to the slope geometry (i.e., benching) cease, but seasonal precipitation continues. Progressive failure posits that transient pore pressures in response to infiltration or groundwater recharge act to locally decrease effective stresses, promoting slip along non-persistent discontinuities, which in turn may cause the slip of adjacent fractures and/or the failure of intact rock bridges. Such repeated fluctuations in pore pressures and effective stresses thus are a key driver of progressive failure and can be equated to fatigue, where the rock slope experiences a slow weakening through repeated load cycles. Results from mine closure analyses will be presented, demonstrating how slope displacement monitoring and modeled groundwater fluctuations can be used to calibrate numerical models and establish the degree of criticality present in a slope. The modeling of seasonal variations further enables reference to be made to time in calculations that are otherwise limited to stress-strain behavior. This provides a means to assess displacement rate thresholds at which behavior change may occur for a given failure mode, which can be used to establish and constrain early warning alarm thresholds and trigger action response plans (TARPs). Examples will also be provided incorporating allowances for the development of a pit lake post-closure and for long-term stability improvement through engineered buttress designs.
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Oppong, F., P. Khadka e O. Kolawole. "Investigation of the Failure Mechanisms for Inducing Rock Slope Hazard in New Jersey, United States". In 58th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2024. http://dx.doi.org/10.56952/arma-2024-0156.
Testo completoAbstract (sommario):
ABSTRACT: Rock slope stability analysis is of great interest to researchers and engineers due to its potential geo-hazards. This is primarily governed by the shear strength and the acting shear stress which is often expressed in terms of Factor of Safety (FoS) over a potential slip surface. This study investigated the susceptibility of road-cut slopes to rockfall hazard and its associated risks in Northeastern New Jersey, United States, as well as predicted the failure transition to rapid sliding. Four (4) vulnerable rock slopes were identified and demarcated for detailed slope stability analysis. The field data were subjected to three kinematic analyses (planar, toppling, and wedge analyses) using the Dips program in Rocscience software which showed a high potential for both planar and toppling failure and a low potential for wedge failure. The highest risk of failure will be due to toppling failure, with a 26% likelihood of critical failure, which exceeds the acceptable threshold. This indicates that the rock-cut slopes are in unstable conditions and need to be reinforced in the identified locations. It is further recommended that coupled expansive grouted anchor bolts and steel-mesh reinforcement support mechanisms be implemented to strengthen the stability of the cut slopes to prevent rockfalls. This study provides valuable insights for mitigating potential geohazard and the findings here are relevant to other locations across the world.. 1. INTRODUCTION Rockfalls are a major concern in mountainous areas as they can impact both the evolution of steep rocky landscapes and pose significant hazards (Stock and Uhrhammer, 2010; Barlow et al., 2012; Matasci et al., 2017). However, rockfall hazard is not limited to mountainous areas alone. Urban areas are also susceptible to rockfall hazards, particularly where excavations can destabilize slopes and create risks for people and infrastructure (Hungr et al., 2014; Corominas et al., 2017; Gili et al., 2022). Therefore, accurately predicting the areas where rockfalls are likely to occur is crucial for reliable hazard assessment. This requires an understanding of which areas are most likely to be affected by rockfall events (Guzzetti et al., 2003; Corominas et al., 2017; Gili et al., 2022).
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Gui, Zhong, Jian-Kang Chen, Zhen-Yu Wu, Han Zhang e Yan-Lin Shi. "Reliability Analysis of Rock Slope Involving Multiple Failure Mechanisms". In GeoCongress 2008. Reston, VA: American Society of Civil Engineers, 2008. http://dx.doi.org/10.1061/40971(310)22.
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Huber, Marius. "HOW DOES ANISOTROPY CONTROL ROCK SLOPE DEFORMATION? A DISCRETE ELEMENT MODELLING INVESTIGATION". In PRF2022—Progressive Failure of Brittle Rocks. Geological Society of America, 2022. http://dx.doi.org/10.1130/abs/2022pr-376035.
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