10,388 research outputs found
The Future of Canadian Climate Policy — with Marc Lee
No full textMarc Lee is a Senior Economist at the Canadian Centre for Policy Alternatives\u27 BC Office. In addition to tracking federal and provincial budgets and economic trends, Marc has published on a range of topics from poverty and inequality to globalization and international trade to public services and regulation. Marc is the Co-Director of the Climate Justice Project, a research partnership with UBC\u27s School of Community and Regional Planning that examines the links between climate change policies and social justice.Resources:Climate Justice Project: www.policyalternatives.ca/projects/cli…tice-projectMarc Lee\u27s Posts on Policy Note: www.policynote.ca/author/marclee/Canadian Centre for Policy Alternatives: www.policyalternatives.ca/Marc\u27s Twitter: twitter.com/MarcLeeCCPA International Panel on Climate Change, 2021 report: www.ipcc.ch/report/ar6/wg1
The neglected role of karst features in rock mass characterization and stability assessment
No full textStability analyses in karst settings, whether to assess the equilibrium conditions of natural slopes or to design engineering interventions, coexist with a significant uncertainty related to difficulties in modelling karst features. As a matter of fact, most of the rock mass classification systems do not directly take into account the presence of karst structures such as voids, conduits or caves, which can strongly influence the mechanical behaviour and the water flow in rock masses.
In the last decades, the identification and characterization of discontinuity systems for rock mass characterization, aimed at stability analyses, have been intensively investigated by means of remote sensing techniques. However, semi-automatic or automatic methods for the extraction of discontinuities from point clouds are not easily applicable in karst because surface and subsurface features produce irregular surfaces, which are difficult to classify even using the most-advanced algorithms. This occurs even more heavily in the case of soft rocks, such as calcarenites.
In this study, a demonstration of the influence of karst features in rock mass characterization and slope stability assessment is presented. First, the results of the Discontinuity Set Extractor (DSE) software used on an appropriate case study show that the irregular surfaces produced by carbonate dissolution, further enhanced by weathering, caused an incorrect classification of the discontinuity sets. Second, a high-resolution Digital Outcrop Model (DOM) was used to generate a very fine mesh (average element size = 35 cm, to take into account the large-scale karst structures) and to carry out 3-D numerical stability analyses by means of Finite Element Method, using a continuum-based approach. Although in the current conditions the examined slope is stable, the results illustrate that the maximum shear strain is localized in correspondence of the karst features (e.g. caves and voids) and at the sea level. By applying the Shear Strength Reduction method, it was found out that weathering processes can cause the same structures to be under yield and lead to localized failures.
In addition, the key role that the discontinuities (extracted using an ad-hoc procedure) play on the rock mass mechanical behaviour was investigated using a 2-D FEM, based on a discontinuum approach. The results, which are in agreement with field observations, point out that karst processes, which features are characterized by the highest values in pervasiveness and aperture of the discontinuity systems and tend to reduce the rock bridges over time, need to be implemented in the rock mass classification systems and in numerical modelling techniques to avoid incorrect results
Geomechanical characterization of rock masses by means of remote sensing techniques
No full textImproving the methods for the characterization of rock masses by integrating traditional field surveys with remote sensing techniques is fundamental for practical and realistic discontinuous modelling, in order to identify the failures and kinematics, develop landslide susceptibility assessment and plan prevention and mitigation measures.
A 20 m-high cliff at Polignano a Mare (Southern Italy) was selected as case study for the presence of well-developed discontinuities (bedding and joints) and due to the local morphology, consisting of a valley with opposite slopes at a distance of 150 m, and a pocket beach at their toe. This configuration allowed to perform both traditional and remote sensing surveys. First, photogrammetry methods were carried out on the ground and with the help of a boat. Structure from Motion (SfM) technique was then used to process and combine the pictures, in order to elaborate a raw point cloud of the case study. Secondly, high resolution Terrestrial Laser Scanning (TLS) and Unmanned Aerial Vehicle (UAV) techniques were conducted after positioning Ground Control Points (GCPs) all over the rock mass, with the aim of obtaining a more detailed point cloud. Eventually, a unique and optimized georeferenced point cloud was obtained by combining the previous models, also removing the non-geological objects. Furthermore, Infrared Thermography (IT) was carried out in order to investigate the fracture pattern, the areas of concentrated stress, and the presence of humidity and voids.
The structural analysis of the rock mass was performed directly on the point cloud, by testing procedures and algorithms for the automatic identification of discontinuity sets and of their orientation, spacing, persistence and roughness.
The next step of this research will concern the evaluation of the instability mechanisms with the help of kinematic analyses, by means of stereographic projections. Finally, the reliability of the procedure for a complete rock mass characterization, which is expected to be obtained as the final result, will be tested by means of numerical stability solutions, after calibrating the geomechanical model and importing the fracture system in an appropriate software
Climate Justice & Inequality: The Future of Canadian Climate Policy — with Marc Lee
No full textMarc Lee is a Senior Economist at the Canadian Centre for Policy Alternatives\u27 BC Office. In addition to tracking federal and provincial budgets and economic trends, Marc has published on a range of topics from poverty and inequality to globalization and international trade to public services and regulation. Marc is the Co-Director of the Climate Justice Project, a research partnership with UBC\u27s School of Community and Regional Planning that examines the links between climate change policies and social justice.Resources: Climate Justice Project: https://www.policyalternatives.ca/projects/climate-justice-projectMarc Lee\u27s Posts on Policy Note: https://www.policynote.ca/author/marclee/Canadian Centre for Policy Alternatives: https://www.policyalternatives.ca/Marc\u27s Twitter: https://twitter.com/MarcLeeCCPA International Panel on Climate Change, 2021 report: https://www.ipcc.ch/report/ar6/wg1
Characterization of landslide dams in the San Juan province (Argentina)
No full textRiver blockages caused by landslide deposition are common phenomena in active mountain chains, influencing erosion-sedimentation patterns and acting as primary and secondary hazards. Regional scale analyses regarding their spatial distribution and morphometry allow establishing boundary conditions for their occurrence and stability, and determine differences among regions with different landscape and climatic conditions. Owing to the combination of endogenous and exogenous factors, landslide dams are frequent phenomena in the Andes. In the Argentinean NW and the Patagonian Andes, previous studies showed that stability of landslide dams determined by morphometric parameters generally matched satisfactorily with dam behavior, with some exceptions in which climatic component played an important role in dam longevity. Aiming to expand the knowledge of landslide dams in the Argentinean Andes, in this work we analyzed the stability of rock avalanche dams in the Pampeam flat slab subduction zone. In the study area, mountain dynamics creates suitable conditions for the occurrence of 34 rock avalanches with volumes up to 0.3 km3. They developed in deeply carved valleys (Cordillera) and Inter-thrust valleys (Precordillera). 22 impoundments of rivers resulted from channelized rock avalanches with long runouts (4-10 km) that blocked tributaries rivers, but most of them by rock avalanches that filled the valley bottom, with run up in the opposite slope and limited movement parallel to the valley axis. Most of the dams breached in unknown times, except for the last event that occurred on November 12th 2005. The quantification of morphometric parameters and contributing areas indicates the existence of dams with dimensionless blockage index above 2.75 (stable domain) and below 3.08 (instable domain). The Los Erizos dam in our study area and the Barrancas dam in the Patagonian Andes show that besides morphometric parameters, climatic conditions are decisive. Stable landslide dams lasting for millennia can collapse suddenly due to anomalous weather conditions, and unstable dams can have a higher longevity depending on the season controlling the inflow into the lake.Fil: Penna, Ivanna Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Longchamp, Celine. Universite de Lausanne; SuizaFil: Derron, Marc Henri. Universite de Lausanne; SuizaFil: Jaboyedoff, Michel. Universite de Lausanne; SuizaEGU General Assembly 2013AustriaEuropean Geosciences Unio
Vulnerability Assessment of Buildings Exposed to Deep-seated Landslide Activity in the Joshimath town of Chamoli, Uttarakhand, India
No full textUrban risks and resilience in the rwandan context
No full textThe rapid urbanization in Rwanda, a country with a disrupted habitat culture has led to a congestion of the capital, which concentrates all services. This has, among other things, a particular form of nature and impacts of natural hazards.
Within the context of the natural hazards of Rwanda, we address the problems of the natural hazards due to rains in a watershed of Kigali (natural hazards analysis database and GIS data problematics) and Ruhengeri. Debris flows / landslides modelling are performed including source areas identification and potential propagation zones, with regard to the built-up areas and available maps. This is integrated in a conceptual multi-hazards and complex natural systems for the two cities. It demonstrates the highly complex situation at risk and how people were resilient before "modernity". This leads us to develop a plan dedicated to the communication of sustainable solutions, to make solutions possible
Henri Temianka Correspondence; (bernheimer)
No full textThis collection contains material pertaining to the life, career, and activities of Henri Temianka, violin virtuoso, conductor, music teacher, and author. Materials include correspondence, concert programs and flyers, music scores, photographs, and books.https://digitalcommons.chapman.edu/temianka_correspondence/1167/thumbnail.jp
Henri Temianka Correspondence; (bonvalot)
No full textThis collection contains material pertaining to the life, career, and activities of Henri Temianka, violin virtuoso, conductor, music teacher, and author. Materials include correspondence, concert programs and flyers, music scores, photographs, and books.https://digitalcommons.chapman.edu/temianka_correspondence/1215/thumbnail.jp
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