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1.
Within the engineering profession and natural sciences, vulnerability is widely accepted to be defined as the degree of loss
(or damage) to a given element or set of elements within the area affected by a threat. The value of vulnerability is expressed
nondimensionally between 0 and 1. It is a fundamental component in the evaluation of landslide risk, and its accurate estimation
is essential in making a reasonable prediction of the landslide consequences. Obviously, vulnerability to landslides depends
not only on the characteristics of the element(s) at risk but also on the landslide intensity. This paper summarizes previous
research on vulnerability to landslides and proposes a new quantitative model for vulnerability of structures and persons
based on landslide intensity and resistance of exposed elements. In addition, an approximate function is suggested for estimating
the vulnerability of persons in structures. Different methods for estimating the vulnerability of various elements to slow
or rapid landslides are discussed. Finally, the application of the new model is illustrated through an example. 相似文献
2.
Zhongqiang Liu Farrokh Nadim Alexander Garcia-Aristizabal Arnaud Mignan Kevin Fleming Byron Quan Luna 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2015,9(2):59-74
The effective management of the risks posed by natural and man-made hazards requires all relevant threats and their interactions to be considered. This paper proposes a three-level framework for multi-risk assessment that accounts for possible hazard and risk interactions. The first level is a flow chart that guides the user in deciding whether a multi-hazard and risk approach is required. The second level is a semi-quantitative approach to explore if a more detailed, quantitative assessment is needed. The third level is a detailed quantitative multi-risk analysis based on Bayesian networks. Examples that demonstrate the application of the method are presented. 相似文献
3.
Finn Løvholt Sylfest Glimsdal Carl B. Harbitz Natalia Zamora Farrokh Nadim Pascal Peduzzi Hy Dao Helge Smebye 《Earth》2012,110(1-4):58-73
In the aftermath of the 2004 Indian Ocean tsunami, a large increase in the activity of tsunami hazard and risk mapping is observed. Most of these are site-specific studies with detailed modelling of the run-up locally. However, fewer studies exist on the regional and global scale. Therefore, tsunamis have been omitted in previous global studies comparing different natural hazards. Here, we present a first global tsunami hazard and population exposure study. A key topic is the development of a simple and robust method for obtaining reasonable estimates of the maximum water level during tsunami inundation. This method is mainly based on plane wave linear hydrostatic transect simulations, and validation against results from a standard run-up model is given. The global hazard study is scenario based, focusing on tsunamis caused by megathrust earthquakes only, as the largest events will often contribute more to the risk than the smaller events. Tsunamis caused by non-seismic sources are omitted. Hazard maps are implemented by conducting a number of tsunami scenario simulations supplemented with findings from literature. The maps are further used to quantify the number of people exposed to tsunamis using the Landscan population data set. Because of the large geographical extents, quantifying the tsunami hazard assessment is focusing on overall trends. 相似文献
4.
Ebrahim Farrokh Jamal Rostami Chris Laughton 《Rock Mechanics and Rock Engineering》2011,44(4):431-445
Estimation of advance rate and utilization of tunnel boring machines (TBM) are some of the important steps in planning a TBM
tunneling project. Estimation of the utilization factor depends on realistic analysis of downtime components. Among the different
parameters influencing TBM downtime, tunnel support is the most influential factor, which can take up to 50% of the total
excavation time in some cases. Although, there are some rock mass classification systems specifically developed to link ground
conditions with the type and amount of support installed in TBM tunneling, the related downtime for support installation has
not been studied in detail. Unit supporting time (UST) is the time required for the installation of ground support per unit
length of tunnel. Support installation time (SIT) is the time required for installation of a single ground support element.
In this paper, approximate ranges of UST and SIT are discussed and analyzed on the basis of recorded ground SIT from a number
of TBM tunneling projects. The primary goal of this paper is to link UST with rock mass classifications that have been specifically
developed to assess ground support requirements for different tunnel sections using open-type TBM. An accurate estimate of
UST and SIT allows for realistic determination of the related downtime and TBM utilization rate. 相似文献
5.
Amir Hossein Vakili Mohamad Razip bin Selamat Parsa Mohajeri Hossein Moayedi 《Geotechnical and Geological Engineering》2018,36(4):1933-1951
Dispersive soils have become common materials for the construction industry. Highly susceptible to internal erosion and piping, dispersive soils must only be used with specific engineering measure in order to avoid failures that were often catastrophic. In an earth dam, clayey soils are used for the core and sandy materials are used for the filter to retain the eroded core soils and prevent their migration. In the absence of first-rate core material, dispersive soils have been used instead. This paper provides a review of the current knowledge and experiences regarding filtration of core soils, particularly the dispersive ones. The engineering problems associated with the use of dispersive soils are discussed and significant findings from previous studies on protective filters are summarized. It is worthy to note that the current review considers both, the conventional, rather empirical filter design criteria based on particle sizes and the current, quite theoretical state-of-the-art filter design criteria based on constriction sizes, with discussion given on the advantages and disadvantages of both. The information provided by this review should be handy for the study, design, construction, and operation of related geotechnical and geo-environmental projects. 相似文献
6.
Estimating the impact forces exerted by a submarine debris flow on a pipeline is a challenge, and there is room for considerably more work to advance the state of the art. To this end, an experimental program was performed to investigate the impact on two pipeline installation scenarios: 1) suspended pipeline and 2) laid-on-seafloor pipeline. The results and observations from the experimental investigation are discussed. The definition of Reynolds number was modified for non-Newtonian fluids and an ad hoc method was developed to estimate the drag force exerted by an impact perpendicular to the pipe axis. The method may be used in prototype situations to estimate the drag force from submarine debris flow impact on pipelines. The experimental program was complemented by Computational Fluid Dynamics (CFD) analyses, the details of which are discussed in the accompanying paper. 相似文献
7.
G��raldine Guerri Jean-Baptiste Daban Sylvie Robbe-Dubois Richard Douet Lyu Abe Jacques Baudrand Marcel Carbillet Anthony Boccaletti Philippe Bendjoya Carole Gouvret Farrokh Vakili 《Experimental Astronomy》2011,30(1):59-81
SPHERE (which stands for Spectro-Polarimetric High-contrast Exoplanet REsearch) is a second-generation Very Large Telescope (VLT) instrument dedicated to high-contrast direct imaging of exoplanets whose first-light is scheduled for 2011. Within this complex instrument one of the central components is the apodized Lyot coronagraph (ALC). The principal aim of this paper is to report the first laboratory experiment of the ALC designed for the SPHERE instrument. The performance and sensitivity of the optical configuration was first numerically studied with an end-to-end approach (see the results in paper I subtitled ??Detailed numerical study??). Made confident by the results, we then tested a prototype on an infrared coronagraphic bench. We measured the transmission profiles of the apodizer prototype and the coronagraphic performance of the apodized Lyot coronagraph in Y, J, and H bands. The coronagraph sensitivity to lateral and longitudinal misalignments of its three main components (apodizer, coronagraphic mask and Lyot stop) was finally studied in H band. We can conclude that the prototype meets the SPHERE technical requirements for coronagraphy. 相似文献
8.
This discussion examines the conclusion reached in the paper that in a single‐story asymmetric‐plan building the maximum displacement demand in the different resisting elements is reached for the same deformation configuration of the system and that the resultant of the seismic forces producing such demand is located at the center of resistance. It is shown that this conclusion is valid only for the particular model studied and cannot be generalized. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
9.
Summary Data on the performance of operating mines in rock salt and potash from United States and British sources is reviewed. A design validation scheme for nuclear waste repositories is proposed, based on back analysis of the response of operating evaporite mines. 相似文献
10.
Global landslide and avalanche hotspots 总被引：6，自引：7，他引：6
Farrokh Nadim Oddvar Kjekstad Pascal Peduzzi Christian Herold Christian Jaedicke 《Landslides》2006,3(2):159-173
Allocating resources for natural hazard risk management has high priority in development banks and international agencies working in developing countries. Global hazard and risk maps for landslides and avalanches were developed to identify the most exposed countries. Based on the global datasets of climate, lithology, earthquake activity, and topography, areas with the highest hazard, or “hotspots”, were identified. The applied model was based on classed values of all input data. The model output is a landslide and avalanche hazard index, which is globally scaled into nine levels. The model results were calibrated and validated in selected areas where good data on slide events exist. The results from the landslide and avalanche hazard model together with global population data were then used as input for the risk assessment. Regions with the highest risk can be found in Colombia, Tajikistan, India, and Nepal where the estimated number of people killed per year per 100 km2 was found to be greater than one. The model made a reasonable prediction of the landslide hazard in 240 of 249 countries. More and better input data could improve the model further. Future work will focus on selected areas to study the applicability of the model on national and regional scales. 相似文献