Supporting rockfall risk management along roadways in Yosemite National Park, California (USA) by field-constrained high-resolution 3D modeling
Federico AgliardiPaolo FrattiniGreg M. StockSimone DemontiFederico FranzosiCamilla LanfranconiBrian D. Collins
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Yosemite National Park is a major natural asset of the USA and attracts millions of visitors each year. Its geology and geomorphology make it particularly susceptible to rockfalls, with tens of kilometers of granite cliffs up to 1000 m in height. Between 2010 and 2020, 640 rockfalls were recorded; almost half of these caused damage to the road network somewhere within the park. Approximately 300 rockfalls affected the Merced River corridor, which contains the El Portal Road, the entranceway preferred by about 30% of the visitors. In addition to causing road damage and temporary road closures, rockfalls have also caused fatalities along roadways. Because National Park policies generally preclude mitigations on natural slopes, rockfall risks along roads are mitigated through traffic management practices based on the evaluation of local hazard conditions. Due to the widespread occurrence of rockfalls and the variability of geological conditions, implementing these practices remains challenging and requires a distributed yet accurate quantitative rockfall analysis approach. We performed high-resolution 3D rockfall simulations using the Hy-Stone rockfall runout model over an area about 18 km2 in size that contributes to rockfall hazards along two sections of roadway within the park, including the El Portal Road.We set up our models using existing datasets (1m LiDAR DEM, canopy height, geological and vegetation maps), a database of Yosemite rockfall events (1857-2020), and new field surveys of infrastructure, rockfall paths and deposits, and visible damage caused by previous rockfalls. We identified rockfall sources using a morphometric approach refined by mapping rockfall evidence and additional unstable areas. Sources were classified into “cliff” and “roadcut” (engineered) categories. We mapped Quaternary deposits at the scale of consideration, reclassified vegetation types in categories relevant to rockfall interactions, and produced a unique condition map for model parametrization.We calibrated Hy-Stone parameters (initial velocity, impact restitution, and rolling friction coefficients) by the back analysis of occurred rockfalls, for which field-based evidence was collected by NPS and USGS. We used post-event aerial pictures of the 2017 Parkline rockfall to map the location and size of 4700 blocks, producing a reference block size distribution for the simulations. Model parameters were calibrated by optimizing the fit between simulated and observed arrest locations and volumes.We performed forward simulations over the study area considering “cliff” rockfall sources and two different block volume scenarios: a) realistic, stochastically variable volumes; b) worst-case, constant volume (100 m3). An additional simulation considered roadcut sources with variable block volumes. Results were extracted as raster maps of block frequency, velocity, energy, and height and validated against the historical and field databases, making it possible to perform a quantitative evaluation of rockfall susceptibility using the Rockfall Hazard Vector (RHV) method.Our models combine robust 3D simulations with detailed field data, allowing the characterization of rockfall susceptibility over a large area with the spatial accuracy typical of site-specific studies. This provides robust inputs to quantitative risk analysis that will allow optimizing risk management and granting safer access to the park.Keywords:
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An overview of traditional and modern engineering systems used rockfall protection is given. The main parameters which are considered in the study of stone-fall processes and in the designing of structures against rockfall are analyzed. Features of the calculation and the global experience of using flexible rockfall barriers are described.
Keywords: rockfall, structures against rockfall, flexible rockfall protection barriers, trajectory of rockfall, impact energy of rock
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Collapse is the most devastating disaster in natural landscape scenic spot. There are 34 potential rockfalls distributed in different positions of Helankou. All potential rockfalls pose a serious threat to rock paintings and tourists. Firstly, we comprehensively investigated the genesis, distribution, lithology and geometric characteristics of the 34 potential rockfalls. Secondly, we used the rockfall to analyze the movement process and energy change of the rockfalls. And then we found that there was a high probability that the falling points of the rockfalls can be the rock painting area and the tourist boardwalk. So we decided to use manual cleaning methods to clean up the potential rockfall, because mechanical and blast cleaning could cause irreparable damage to rock paintings. For the large-volume rock, it was better to crush by static crushing agent first. Finally, we did the rock crushing experiment to select the optimal arrangement of static crushing agent. We had the following conclusions. (1)The reasons for the formation of the potential rockfall are the concave of thin-layer, the rock layer level, and the two sets of joints to cut the thick-layer metasandstone. (2)The rockfalls can be divided into three different types: bedrock exposed, solitary belt, and debris flow gully. (3)It is very likely that the falling rocks can fall in the rock paintings area and destroy the rock paintings. (2)The best solution for the control of rockfall is static crushing combined with manual handling. And there is an optimal arrangement of static crushing agent. In short, our study can provide a new way and reference for the prevention of the rockfall disaster in Helankou Rock Painting.
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Lithology
Bedrock
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Abstract The road network in Central Nepal suffered blockades and damage from numerous landslides and rockfalls due to the earthquake sequence in Gorkha, Nepal, in 2015. Additionally, frequent rainstorms in the area contributed to the recurrence of rockfalls and other types of landslides, hindering road infrastructure development and environmental management. Despite the several existing regional and local studies on landslide susceptibility in the area, rockfall-specific analysis is still lacking. In this paper, we assessed rockfall susceptibility in the sections of the Pasang Lhamu highway and the Galchhi-Rasuwagadhi highway in the Rasuwa district using a physically based model. We generated three-dimensional rockfall trajectories along the roads and used them to infer the rockfall susceptibility of the area. We selected potential locations for the initiation of rockfalls based on the optimization of the gridded slope angle, relief, and terrain ruggedness, validated the source map using statistical parameters, and compared them with a field-mapped rockfall source inventory. As a result, we identified which road sections in Ramche, Dandagaun, and Syaprubesi are highly susceptible to rockfalls. We published the field-based inventory of rockfall sources and segment-wise rockfall susceptibility of highways, where a rockfall susceptibility index of 5 indicated very high susceptibility and 1 very low susceptibility. Such findings and maps are helpful for researchers, land planners, developers, government bodies working on disaster risk reduction, and policymakers to design a preliminary framework for rockfall mitigation and sustainable roads.
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Abstract. Rockfall presents an ongoing challenge to the safe operation of transportation infrastructure, creating hazardous conditions which can result in damage to roads and railways, as well as loss of life. Rockfall risk assessment frameworks often involve the determination of rockfall runout in an attempt to understand the likelihood that rockfall debris will reach an element at risk. Rockfall modelling programs which simulate the trajectory of rockfall material are one method commonly used to assess potential runout. This study aims to demonstrate the effectiveness of a rockfall simulation prototype which uses the Unity 3D game engine. The technique is capable of simulating rockfall events comprised of many mobile fragments, a limitation of many industry standard rockfall modelling programs. Five fragmental rockfalls were simulated using the technique, with slope and rockfall geometries constructed from high-resolution terrestrial laser scans. Simulated change detection was produced for each of the events and compared to the actual change detection results for each rockfall as a basis for testing model performance. In each case the simulated change detection results aligned well with the actual observed change in terms of location and magnitude. An example of how the technique could be used to support the design of rockfall catchment ditches is shown. Suggestions are made for future development of the simulation technique with a focus on better informing simulated rockfall fragment size and the timing of fragmentation.
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Бұл зерттеужұмысындaКaно моделітурaлы жәнеоғaн қaтыстытолықмәліметберілгенжәнеуниверситетстуденттерінебaғыттaлғaн қолдaнбaлы (кейстік)зерттеужүргізілген.АхметЯссaуи университетініңстуденттеріүшін Кaно моделіқолдaнылғaн, олaрдың жоғaры білімберусaпaсынa қоятынмaңыздытaлaптaры, яғнисaпaлық қaжеттіліктері,олaрдың мaңыздылығытурaлы жәнесaпaлық қaжеттіліктерінеқaтыстыөз университетінқaлaй бaғaлaйтындығытурaлы сұрaқтaр қойылғaн. Осы зерттеудіңмaқсaты АхметЯсaуи университетіндетуризмменеджментіжәнеқaржы бaкaлaвриaт бaғдaрлaмaлaрыныңсaпaсынa қaтыстыстуденттердіңқaжеттіліктерінaнықтaу, студенттердіңқaнaғaттaну, қaнaғaттaнбaу дәрежелерінбелгілеу,білімберусaпaсын aнықтaу мен жетілдіружолдaрын тaлдaу болыптaбылaды. Осы мaқсaтқaжетуүшін, ең aлдыменКaно сaуaлнaмaсы түзіліп,116 студенткеқолдaнылдыжәнебілімберугежәнеоның сaпaсынa қaтыстыстуденттердіңтaлaптaры мен қaжеттіліктерітоптықжұмыстaрaрқылыaнықтaлды. Екіншіден,бұл aнықтaлғaн тaлaптaр мен қaжеттіліктерКaно бaғaлaу кестесіменжіктелді.Осылaйшa, сaпa тaлaптaры төрт сaнaтқa бөлінді:болуытиіс, бір өлшемді,тaртымдыжәнебейтaрaп.Соңындa,қaнaғaттaну мен қaнaғaттaнбaудың мәндеріесептелдіжәнестуденттердіңқaнaғaттaну мен қaнaғaттaнбaу деңгейлерінжоғaрылaту мен төмендетудеосытaлaптaр мен қaжеттіліктердіңрөліaйқын aнықтaлды.Түйінсөздер:сaпa, сaпaлық қaжеттіліктер,білімберусaпaсы, Кaно моделі.
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The nationally-recognized Susquehanna
Chorale will delight audiences of all
ages with a diverse mix of classic and
contemporary pieces. The ChoraleAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂA¢AÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂs
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music making, successful in their
aim to make the audience feel,
to be moved, to be part of the
performance - and all this while
working at an extremely high
musical level.AÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂA¢AÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂAÂA Experience choral
singing that will take you to new
heights!
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During the last decade, large rockfalls occurred on the steep limestone slopes along the Adriatic Coast of Croatia, causing injury to people and serious damage to buildings and traffic facilities. The rockfalls along the limestone slopes were caused by unfavorable characteristics of the rock mass, weathering in combination with heavy rainfall and artificial influences during highway construction. Rockfall protection projects were conducted to protect human lives and facilities from future rockfalls. The rockfall protection program started with rockfall hazard analyses to identify the potential of rockfalls to occur and the potential consequences. At the locations of hazards where related risks were determined, detailed field investigations were conducted. Based on the indentified characteristics of potentially unstable rock masses, analyses of movement and resulting pathways were conducted. The trajectories, impact energy and the height of bouncing are dependent on slope geometry, slope surface roughness and rockfall block characteristics. Two protection measure approaches were adopted: prevention of rockfalls by removing potentially unstable rock mass or installation of rock mass support systems and suspending running rockfall masses with rockfall protection barriers. In this paper, rockfall hazard determination, rockfall analyses and rockfall protection designs for rockfall protection systems at selected locations on the limestone slopes along the Adriatic coast of Croatia are presented.
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Rockfalls and rock avalanches are active processes, including hazards for infrastructures and outdoor activities.Present rockfalls are well surveyed and documented in the Mont Blanc massif thanks to a network of observersset up in 2007, and composed of hut keepers, mountain guides, alpinists and infrastructure workers. Frequencyover the past 150 years of massif rockfall, studied by comparison of historical photographs, has strongly increasedduring the last 30 years, especially during very hot summer (2003 and 2015), likely due to permafrost degradationdriven by the climate change.In order to understand at a longer timescale the relationship between rockfall frequency and climate dynamicsin the Mont Blanc massif, we use Terrestrial Cosmogenic Nuclide (TCN) dating to obtain the exposure ages ofLateglacial and Holocene rockfall scars and old rockwall surfaces, and glacial and climate proxies to verify thehypothesis that rockfalls were more frequent in warm periods.55 samples have been collected at 9 sites of the Glacier du Geant basin, at elevation in the range 3300-3800 m a.s.l.These new exposure ages were completed by the 25 others TCN ages sampled during two previous campaigns andrecalculated using the newest input parameters. A total of 72 ages were obtained, between 0.04 ± 0.02 and 100.50± 8.50 ka.We found four age clusters. Two clusters are related to the Holocene Warm Period (∼ 6.1-7.4 ka) and RomanWarm Period (∼ 1.6-2.3 ka); a cluster of LIA-post-LIA ages is mainly composed by smaller rockfalls, consideredas the ‘normal’ erosion. A forth cluster have been recognized at ∼ 4.2-5.0 ka.Data suggest a relationship between the reflectance spectral data of the scar surfaces and exposure ages, mainlyin the E-SE-S aspects. Fresh rock surfaces of recent rockfall scars are light grey, whereas long-time exposedweathered rock surfaces range from light orange to dark red. This confirms the initial hypothesis: the redder a rocksurface, the older its age. Reflectance spectroscopy is used to quantify the granite surface colour and allow theestablishment of a robust relationship between scar exposure ages and colour of the rockwalls in the Mont Blancmassif.
Massif
Rockfall
Last Glacial Maximum
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