STONE: a computer program for the three-dimensional simulation of rock-falls (original) (raw)
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GIS-Based Rockfall Hazard Assessment in Support of Decision Making
When designing infrastructure, settlements or facilities in mountainous areas, rockfall hazard assessment is considered essential, as it is a major hazard worldwide. Rockfall hazard estimation can help greatly in the design of countermeasures, such as barriers and net fences, in order to protect the built environment, as well as for landuse planning. Rockfall modelling is considered an effective way of estimating rockfall hazard despite the complicated processes involved. In this paper, a new three-dimensional rockfall simulation model, developed in the GIS environment, is proposed as a tool for assessing rockfall hazard for a local-or regional-scale area. The model, adopting a kinematic approach, can simulate rockfall trajectories based on the topography, the frictional characteristics of the ground, the magnitude and direction of the initial velocity and the restitution coefficients on the block velocity. The model is implemented in an application, called ROCKFALL ANALYSIS, running in the ArcGIS environment allowing stochastic analysis and, even more, threedimensional visualization and animation of rockfalls. By means of case studies we evaluate both the simulation model and the application as a tool assisting spatial analysis and planning, which can be used in decision-making and design concerning transportation infrastructure or large technical works, such as dams.
Computer simulation of stone falls and rockfalls
Acta geographica Slovenica, 2005
The paper gives an overview of the literature on available computer (simulation) models of stone falls and rockfalls, divided into 2D and 3D models. 2D models consider single blocks in the rockfall mass as lumped mass or a rigid body, and are used to assess the single rockfall runout distance. Opposed to the 2D models, 3D models are composed not only of a dispositional model (depicting rockfall source areas) and friction model (determination of deposition areas and maximum runout distances), but also from a trajectory model (determination of travel areas).
Digital Elevation Models of Rockfalls and Landslides: A Review and Meta-Analysis
Geosciences, 2021
The scope of this paper is to summarize previous research pertaining to the use of digital elevation models (DEMs) and digital terrain models (DTMs) in the study of rockfalls and landslides. Research from 1983 to 2020 was surveyed in order to understand how the spatial resolution of DEMs and DTMs affects landslide detection, validation, and mapping. Another major question examined was the relationship between the DEM resolution and the extent of the rockfall or landslide event. It emerged from the study that, for landslides, the majority of researchers used DEMs with a spatial resolution of between 10 m and 30 m, while for rockfalls, they used DEMs with a spatial resolution of between 5 m and 20 m. We concluded that DEMs with a very high resolution (less than 5 m) are suitable for local-scale occurrences, while medium-resolution (from 20 m to 30 m) DEMs are suitable for regional-scale events. High resolution is associated with high accuracy and detailed structural characteristics, w...
Rockfall hazard and risk assessment in the Yosemite Valley, California, USA
Natural Hazards and Earth System Sciences, 2003
Rock slides and rock falls are the most frequent types of slope movements in Yosemite National Park, California. In historical time 392 rock falls and rock slides have been documented in the valley, and some of them have been mapped in detail. We present the results of an attempt to assess rock fall hazards in the Yosemite Valley. Spatial and temporal aspects of rock falls hazard are considered. A detailed inventory of slope movements covering the 145-year period from 1857 to 2002 is used to determine the frequency-volume statistics of rock falls and to estimate the annual frequency of rock falls, providing the temporal component of rock fall hazard. The extent of the areas potentially subject to rock fall hazards in the Yosemite Valley were obtained using STONE, a physically-based rock fall simulation computer program. The software computes 3-dimensional rock fall trajectories starting from a digital elevation model (DEM), the location of rock fall release points, and maps of the dynamic rolling friction coefficient and of the coefficients of normal and tangential energy restitution. For each DEM cell the software calculates the number of rock falls passing through the cell, the maximum rock fall velocity and the maximum flying height. For the Yosemite Valley, a DEM with a ground resolution of 10×10 m was prepared using topographic contour lines from the U.S. Geological Survey 1:24 000-scale maps. Rock fall release points were identified as DEM cells having a slope steeper than 60 • , an assumption based on the location of historical rock falls. Maps of the normal and tangential energy restitution coefficients and of the rolling friction coefficient were produced from a surficial geologic map. The availability of historical rock falls mapped in detail allowed us to check the computer program performance and to calibrate the model parameters. Visual and statistical comparison of the model results with the mapped rock falls confirmed the accuracy of the model. The model results are compared with a previous map of rockfall talus and with a geomorphic assessment of rock fall hazard based on potential energy referred to as a shadow angle approach, Correspondence to: F. Guzzetti (F.Guzzetti@irpi.cnr.it) recently completed for the Yosemite Valley. The model results are then used to identify the roads and trails more subject to rock fall hazard. Of the 166.5 km of roads and trails in the Yosemite Valley 31.2% were found to be potentially subject to rock fall hazard, of which 14% are subject to very high hazard.
Predictive GIS-Based Model of Rockfall Activity in Mountain Cliffs
Natural Hazards, 2003
Rockfall susceptibility has been analysed in mountain cliffs of the Cantabrian Range, North Spain. The main aim of this analysis has been to build a predictive model of rockfall activity from a low number of environmental and geological variables. The rockfall activity has been quantified in a GIS. The cartographic information used shows the spatial distribution of all the recent talus screes as well as their associated source areas in the rock-slopes. The area relation At/Ar (recent talus scree polygon/source basins) in the rock slopes has been used as the rockfall activity indicator. This relation has been validated in 50 pilot rock-slopes and compared with the relation number of recent rock fragments/source basin, obtained from field work. The environmental factors causing rockfall depend on the rock slope situation, and these are: altitude and sun radiation on the rock cliff. The geological factors considered are: lithology, relative position of the main discontinuities with respect to the topographic surface and two morphologic parameters: the roughness and slope gradient. A logistic regression analysis has been applied to a population of 442 limestone and quartzite rock cliffs. The dependent variable is the rockfall activity indicator, which allows the definition of two classes of rock cliff units: low and high activity. The independent variables are altitude, sun radiation (equinox radiation, summer solstice radiation, winter solstice radiation), slope roughness, slope gradient, anisotropy and lithology. Results suggest that it is possible to build a valid cartographic predictive model for rockfall activity in mountain rock cliffs from a limited number of easily obtainable variables. The method is especially applicable in massive rock slopes or in regions with uniform rock mass characteristics.
A review of rockfall mechanics and modelling approaches
Models can be useful tools to assess the risk posed by rockfall throughout relatively large mountainous areas (>500 km 2), in order to improve protection of endangered residential areas and infrastructure. Therefore the purpose of this study was to summarize existing rockfall models and to propose modifications to make them suitable for predicting rockfall at a regional scale. First, the basic mechanics of rockfall are summarized, including knowledge of the main modes of motion: falling, bouncing and rolling. Secondly, existing models are divided in three groups: (1) empirical models, (2) process-based models and (3) Geophysical Information System (GIS)-based models. For each model type its basic principles and ability to predict rockfall runout zones are summarized. The final part is a discussion of how a model for predicting rockfall runout zones at a regional scale should be developed. A GIS-based distribution model is suggested that combines a detailed process-based model and a GIS. Potential rockfall source areas and falltracks are calculated by the GIS component of the model and the rockfall runout zones are calculated by the process-based component. In addition to this model, methods for the estimation of model parameters values at a regional scale have to be developed.
Application of a rockfall simulation program in an alpine valley in Slovenia
Two rockfalls in the Trenta valley in NW Slovenia (Upper Soča River) were analyzed using a commercially available computer program for rockfall simulation (Rockfall version 6.1, forest module RockTree). The program was calibrated in the Osojnik rockfall in two longitudinal profiles. The starting values of relevant model parameters were taken from the literature and different combinations were tried out. The computer runs were performed using different number of blocks (0.2-6.0 m). The model was successfully calibrated using silent witnesses (more than 20 rockfall blocks with 1-340 m 3 , having shadow angles 28 • -32 • ). Rockfall run-out was mostly determined by terrain configuration (roughness) and vegetation (surface) properties. Large blocks had high total kinetic energy and large bounce height but not larger run-out than small blocks. The forest could effectively stop blocks smaller than 0.2 m, and had no effect on 6-m blocks. The calibrated model was then applied on the Berebica rockfall in two longitudinal profiles: with and without the rockfall gallery made of reinforced concrete in 2001. The program performance was tested using silent witnesses (over 10 rockfall blocks with 1-220 m 3 , having shadow angle of 28 • -30.5 • ). The simulation results (total kinetic energy, bounce height) confirmed the correctness of the decision to build a 276-m long rockfall gallery that was questioned by some experts. The study confirmed that the calibrated 2-D simulation models of rockfalls may be useful engineering tools when used carefully.
2013
A large DSGDS (Deep-Seated Gravitational Slope Deformation) which extends on an area of 3.75 km2 affects the southwest flank of Mount Ganderberg some 40 km north of Bolzano. The gravitational sagging of the slope is generating a wide field of tension cracks in the crown area where a rock slab of about 800.000 m3 shows clear precursory signs of possible detachment. In 1401 a rock avalanche detaching from the same area dammed the Passer River thus creating a 35 m deep lake which through sequential breaching caused many casualties in the villages downstream. Using geomorphological survey and historical analysis it was possible to estimate the volume of the landslide deposit in 2 × 106 m3. In this study the historical event is back-analyzed using the 2D code DAN-W in order to select the proper soil parameters to use in the modelling of the present potential rock avalanche. Then a 3D modelling is carried out using DAN3D software to evaluate the run-out scenario and the shape of the natural dam. Owing to the relevant discharge of the Passer River, a 2 × 106 m3 lake might be quickly filled. This can cause the breaching and subsequent collapse of the landslide dam with great risk and potentially heavy damages for the downstream population.