Magnitude and frequency of rock falls and rock slides along the main transportation corridors of southwestern British Columbia

1999 ◽  
Vol 36 (2) ◽  
pp. 224-238 ◽  
Author(s):  
O Hungr ◽  
S G Evans ◽  
J Hazzard
Keyword(s):  
British Columbia ◽  
Rock Slope ◽  
Sampling Procedure ◽  
Rock Fall ◽  
Rock Falls ◽  
Geological Conditions ◽  
Transportation Corridors ◽  
Risk Magnitude ◽  
Frequency Relationship ◽  
Rock Slides

The two main transportation corridors of southwestern British Columbia are subject to a range of rock slope movements (rock falls, rock slides, and rock avalanches) that pose significant risks to road and rail traffic travelling through the region. Volumes of these landslides range from less than 1 m3 to over 4.0 × 107 m3. A database of rock falls and slides was compiled for rail and highway routes in each transportation corridor using maintenance records spanning four decades. The records number approximately 3500, of which about one half includes information on volume. Magnitude - cumulative frequency (MCF) relationships were derived for each corridor. A scaled sampling procedure was used in part to reduce the effects of censoring. Both corridors yield MCF curves with significant linear segments on log-log plots at magnitudes greater than 1 m3. The form of both railway and road plots for each corridor shows similarity over several orders of magnitude. The slope of the linear segments of the curves depends on geological conditions in the corridors. Temporal histograms of the data show a trend towards reduction of rock fall frequency as a result of rock slope stabilization measures, implemented during the 1980s and 1990s. A risk analysis methodology using the slope of the magnitude-frequency relationship is outlined. The major part of the risk to life in the case examined results from rock falls in the intermediate-magnitude range (1-10 m3).Key words: rock fall, rock slide, landslide hazard, risk, magnitude-frequency, British Columbia.

scholarly journals Rockfall hazard and risk assessment in the Yosemite Valley, California, USA

2003 ◽  
Vol 3 (6) ◽  
pp. 491-503 ◽  
Author(s):  
F. Guzzetti ◽  
P. Reichenbach ◽  
G. F. Wieczorek
Keyword(s):  
Friction Coefficient ◽  
Computer Program ◽  
Rolling Friction ◽  
Rock Fall ◽  
Flying Height ◽  
Rock Falls ◽  
Slope Movements ◽  
Yosemite Valley ◽  
Rolling Friction Coefficient ◽  
Rock Slides

Abstract. Rock slides and rock falls are the most frequent types of slope movements in Yosemite National Park, California. In historical time (1857–2002) 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, 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.

scholarly journals Short Communication: Monitoring rock falls with the Raspberry Shakes

2018 ◽  
Author(s):  
Andrea Manconi ◽  
Velio Coviello ◽  
Maud Galletti ◽  
Reto Seifert
Keyword(s):  
Seismic Data ◽  
Slope Failure ◽  
Rock Slope ◽  
Low Cost ◽  
Late Summer ◽  
Swiss Alps ◽  
Rock Fall ◽  
Rock Falls ◽  
Monitoring Period ◽  
Seismic Sensors

Abstract. We evaluate the performance of the low-cost seismic sensors Raspberry Shake (RS) to identify and monitor rock fall activity in alpine environments. The test area is a slope adjacent to the Great Aletsch glacier in the Swiss Alps, i.e. the Moosfluh deep-seated instability, which is undergoing an acceleration phase since the late summer 2016. A local seismic network composed of three RS seismometers was deployed starting from May 2017, in order to record rock fall activity and its relation with the progressive rock slope degradation potentially leading to a large rock slope failure. Here we present a first assessment of the seismic data acquired from RS sensors after a monitoring period of 1-year. A webcam was installed on the opposite side of the active slope, acquiring images every 10 minutes to validate the occurrence and identify rock falls as well as their location and approximate size. Despite seismic data were collected mainly to identify rock fall phenomena, other event types were recorded during the monitoring period. Thus, this work provides also general insights on the potential use of low cost sensors in environmental seismology investigations.

Earthquake triggered rock falls and their role in the development of a rock slope: The case of Skolis Mountain, Greece

2015 ◽  
Vol 191 ◽  
pp. 71-85 ◽  
Author(s):  
I. Koukouvelas ◽  
A. Litoseliti ◽  
K. Nikolakopoulos ◽  
V. Zygouri
Keyword(s):  
Rock Slope ◽  
Rock Falls

STUDY ON MECHANISM OF ROCK FALL AT TUNNEL CUTTING FACE AFTER BLASTING

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Fumi Sato ◽  
Naotaka Kikkawa ◽  
Nobutaka Hiraoka ◽  
Kazuya Itoh ◽  
Naoaki Suemasa
Keyword(s):  
Crack Opening ◽  
Experimental Tests ◽  
Rock Fall ◽  
Tunnel Construction ◽  
Rock Falls ◽  
Dem Simulation ◽  
Tensile Stresses ◽  
Simulation Based ◽  
Small Cracks ◽  
Gas Expansion

There are around 10 casualties due to rock-fall at cutting face annually in conventional tunnel construction in Japan. As from the analysis conducted on the cases involving such casualties, workers were either killed or seriously injured when they works in front of or near the cutting face. For the purpose of evaluating the mechanism of rock fall at tunnel cutting face, this paper performed experimental tests which involved blasting to excavate a model ground of tunnel cutting face, and then analyzed the stress state which is in the cutting face by using Discrete Element Method (DEM) simulation. Based on the results, the tensile stresses remained even when the action of gas expansion due to blasting has completed. Therefore, it is suggested that rock falls might be induced because of the residual tensile stresses. The tensile stresses would gradually open small cracks between rocks and then rocks may suddenly fall after sufficient crack opening due to gravity.

scholarly journals CLIFF COLLAPSE HAZARD FROM REPEATED MULTICOPTER UAV ACQUISITIONS: RETURN ON EXPERIENCE

2016 ◽  
Vol XLI-B5 ◽  
pp. 805-811 ◽  
Author(s):  
T.J. B. Dewez ◽  
J. Leroux ◽  
S. Morelli
Keyword(s):  
Control Point ◽  
Point Clouds ◽  
Point Of View ◽  
Rock Fall ◽  
Mitigation Measures ◽  
Density Parameter ◽  
Computational Point ◽  
Black And White ◽  
Dense Point ◽  
Frequency Relationship

Cliff collapse poses a serious hazard to infrastructure and passers-by. Obtaining information such as magnitude-frequency relationship for a specific site is of great help to adapt appropriate mitigation measures. While it is possible to monitor hundreds-of-meter-long cliff sites with ground based techniques (e.g. lidar or photogrammetry), it is both time consuming and scientifically limiting to focus on short cliff sections. In the project SUAVE, we sought to investigate whether an octocopter UAV photogrammetric survey would perform sufficiently well in order to repeatedly survey cliff face geometry and derive rock fall inventories amenable to probabilistic rock fall hazard computation. An experiment was therefore run on a well-studied site of the chalk coast of Normandy, in Mesnil Val, along the English Channel (Northern France). Two campaigns were organized in January and June 2015 which surveyed about 60 ha of coastline, including the 80-m-high cliff face, the chalk platform at its foot, and the hinterland in a matter of 4 hours from start to finish. To conform with UAV regulations, the flight was flown in 3 legs for a total of about 30 minutes in the air. A total of 868 and 1106 photos were respectively shot with a Sony NEX 7 with fixed focal 16mm. Three lines of sight were combined: horizontal shots for cliff face imaging, 45°-oblique views to tie plateau/platform photos with cliff face images, and regular vertical shots. Photogrammetrically derived dense point clouds were produced with Agisoft Photoscan at ultra-high density (median density is 1 point every 1.7cm). Point cloud density proved a critical parameter to reproduce faithfully the chalk face’s geometry. Tuning down the density parameter to “high” or “medium”, though efficient from a computational point of view, generated artefacts along chalk bed edges (i.e. smoothing the sharp gradient) and ultimately creating ghost volumes when computing cloud to cloud differences. Yet, from a hazard point of view, this is where small rock fall will most likely occur. Absolute orientation of both point clouds proved unsufficient despite the 30 black and white quadrants ground control point DGPS surveyed. Additional ICP was necessary to reach centimeter-level accuracy and segment rock fall scars corresponding to the expected average daily rock fall volume (ca. 0.013 m3).

scholarly journals Stability analysis of rock slope and calculation of rock lateral pressure in foundation pit with structural plane and cave development

2021 ◽  
Author(s):  
Jin Xu ◽  
Yansen Wang
Keyword(s):  
Safety Factor ◽  
Rock Slope ◽  
Lateral Pressure ◽  
Rock Foundation ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Failure Characteristics ◽  
Karst Caves ◽  
Geological Conditions ◽  
The Stability

Abstract In this study, numerical simulations were carried out to analyze the influence of caves in different positions and shapes, in combination with structural planes, on the stability of the slope and the failure characteristics of a rock slope in a deep foundation pit with high inclination structural planes and cave development. The schemes for substituting a single karst cave for karst caves were constructed. Based on the penetration failure characteristics of karst caves between parallel structural planes, methods for calculating the safety factor of the rock foundation pit and the upper bound of the lateral pressure of the supporting structure under the combined influence of the caves and structural planes were developed, which can be used to assess the safety factor of a rock mass and to calculate the lateral pressure under complex geological conditions.

scholarly journals CLIFF COLLAPSE HAZARD FROM REPEATED MULTICOPTER UAV ACQUISITIONS: RETURN ON EXPERIENCE

2016 ◽  
Vol XLI-B5 ◽  
pp. 805-811 ◽  
Author(s):  
T.J. B. Dewez ◽  
J. Leroux ◽  
S. Morelli
Keyword(s):  
Control Point ◽  
Point Clouds ◽  
Point Of View ◽  
Rock Fall ◽  
Mitigation Measures ◽  
Density Parameter ◽  
Computational Point ◽  
Black And White ◽  
Dense Point ◽  
Frequency Relationship

Cliff collapse poses a serious hazard to infrastructure and passers-by. Obtaining information such as magnitude-frequency relationship for a specific site is of great help to adapt appropriate mitigation measures. While it is possible to monitor hundreds-of-meter-long cliff sites with ground based techniques (e.g. lidar or photogrammetry), it is both time consuming and scientifically limiting to focus on short cliff sections. In the project SUAVE, we sought to investigate whether an octocopter UAV photogrammetric survey would perform sufficiently well in order to repeatedly survey cliff face geometry and derive rock fall inventories amenable to probabilistic rock fall hazard computation. An experiment was therefore run on a well-studied site of the chalk coast of Normandy, in Mesnil Val, along the English Channel (Northern France). Two campaigns were organized in January and June 2015 which surveyed about 60 ha of coastline, including the 80-m-high cliff face, the chalk platform at its foot, and the hinterland in a matter of 4 hours from start to finish. To conform with UAV regulations, the flight was flown in 3 legs for a total of about 30 minutes in the air. A total of 868 and 1106 photos were respectively shot with a Sony NEX 7 with fixed focal 16mm. Three lines of sight were combined: horizontal shots for cliff face imaging, 45°-oblique views to tie plateau/platform photos with cliff face images, and regular vertical shots. Photogrammetrically derived dense point clouds were produced with Agisoft Photoscan at ultra-high density (median density is 1 point every 1.7cm). Point cloud density proved a critical parameter to reproduce faithfully the chalk face’s geometry. Tuning down the density parameter to “high” or “medium”, though efficient from a computational point of view, generated artefacts along chalk bed edges (i.e. smoothing the sharp gradient) and ultimately creating ghost volumes when computing cloud to cloud differences. Yet, from a hazard point of view, this is where small rock fall will most likely occur. Absolute orientation of both point clouds proved unsufficient despite the 30 black and white quadrants ground control point DGPS surveyed. Additional ICP was necessary to reach centimeter-level accuracy and segment rock fall scars corresponding to the expected average daily rock fall volume (ca. 0.013 m3).

scholarly journals TECHNIQUES OF ROCKFALL INVENTORY IN EARTHQUAKE PRONE ROCK SLOPES

2017 ◽  
Vol 50 (3) ◽  
pp. 1756 ◽  
Author(s):  
V. Zygouri ◽  
I. Koukouvelas
Keyword(s):  
Rock Slope ◽  
Human Life ◽  
Rock Slopes ◽  
Severe Damage ◽  
Rock Falls ◽  
Protection Measures ◽  
Mountainous Regions ◽  
Assessment Techniques ◽  
Fast Movement ◽  
Integrated Study

A relevant hazard in mountainous regions is the steep rock slopes concentrating rock falls. Although rock falls are characterized by smaller rock volumes compared to other landslide types, can also provoke severe damage to buildings, infrastructures and human life due to their sudden and highly fast movement. The key to understand the processes that result in rock fall onset is an integrated study of the major causing parameters that affect slope stability. A rock slope may be subjected to many forms of triggering factors including tectonic, geomorphic, seismic, climatic or even human induced damages. This contribution provides an overview of the previous and current research related to rock falls and uses case studies of North Peloponnese in order to prove the usefulness of these methods in the Greek territory. Collecting data and production of thematic maps by means of field and remote sensing investigations can yield far more updated results incorporated in hazard assessment techniques and protection measures. 

scholarly journals Landslide susceptibility maps of Santiago city Andean foothills, Chile

2018 ◽  
Vol 45 (3) ◽  
pp. 433
Author(s):  
Marisol Lara ◽  
Sergio A. Sepúlveda ◽  
Constanza Celis ◽  
Sofía Rebolledo ◽  
Pablo Ceballos
Keyword(s):  
Landslide Susceptibility ◽  
Urban Areas ◽  
Debris Flows ◽  
Urban Expansion ◽  
Rock Falls ◽  
Susceptibility Maps ◽  
Geological Conditions ◽  
Landslide Processes ◽  
The City ◽  
Landslide Susceptibility Maps

The urban expansion of Santiago city includes areas with geomorphological and geological conditions with potential to be affected by landslide processes. This work presents compiled landslide susceptibility maps for the Andean foothills of Santiago city, between Maipo and Mapocho rivers. The maps identify the areas prone to the generation of slides, falls and flows. The results show that the oriental foothills of Santiago city have moderate to high susceptibility of rock falls, rock and soil slides and debris flows. The most important of these landslide types are debris flows, due to the runout of this processes that may reach urban areas posing a risk for the city, for which detailed hazard studies are required.

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