scholarly journals Stability of the Foundation of Buried Energy Pipeline in Permafrost Region

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Yan Li ◽  
Huijun Jin ◽  
Zhi Wen ◽  
Xinze Li ◽  
Qi Zhang
Keyword(s):  
Mitigation Strategies ◽  
Slope Instability ◽  
Frost Heave ◽  
Mitigation Measures ◽  
Formation Mechanisms ◽  
Permafrost Region ◽  
Buried Pipelines ◽  
Foundation Soil ◽  
Thaw Settlement ◽  
Permafrost Regions

During operation, a buried pipeline is threatened by a variety of geological hazards, particularly in permafrost regions, where freezing-thawing disasters have a significant influence on the integrity and safety of the buried pipelines. The topographical environmental conditions along the pipeline, as well as the influence of frost heave and thaw settlement on the pipeline’s foundation soil, must be considered in the design and construction stage. Theoretical analysis, numerical modeling, field testing, and mitigation measures on vital energy pipelines in permafrost have been widely documented, but no attempt has been made to review the freezing-thawing disasters, current research methodologies, and mitigation strategies. This article reviews the formation mechanisms and mitigation measures for frost hazards (e.g., differential frost heave, thaw settlement, slope instability, frost mounds, icing, river ice scouring, and pipeline floating) along buried pipelines in permafrost regions and summarizes and prospects the major progress in the research on mechanisms, analysis methods, model test, and field monitoring based on publications of studies of key energy pipelines in permafrost regions. This review will provide scholars with a basic understanding of the challenging freezing-thawing hazards encountered by energy pipelines in permafrost regions, as well as research on the stability and mitigation of pipeline foundation soils plagued by freezing-thawing hazards in permafrost regions under a warming climate and degrading permafrost environment.

scholarly journals Towards A Geo-Hydro-Mechanical Characterization of Landslide Classes: Preliminary Results

2020 ◽  
Vol 10 (22) ◽  
pp. 7960
Author(s):  
Federica Cotecchia ◽  
Francesca Santaloia ◽  
Vito Tagarelli
Keyword(s):  
Risk Mitigation ◽  
Mitigation Strategies ◽  
Slope Instability ◽  
Mitigation Measures ◽  
Economic Losses ◽  
Landslide Risk ◽  
Multidisciplinary Analysis ◽  
Risk Mitigation Strategies ◽  
Landslide Mechanisms

Nowadays, landslides still cause both deaths and heavy economic losses around the world, despite the development of risk mitigation measures, which are often not effective; this is mainly due to the lack of proper analyses of landslide mechanisms. As such, in order to achieve a decisive advancement for sustainable landslide risk management, our knowledge of the processes that generate landslide phenomena has to be broadened. This is possible only through a multidisciplinary analysis that covers the complexity of landslide mechanisms that is a fundamental part of the design of the mitigation measure. As such, this contribution applies the “stage-wise” methodology, which allows for geo-hydro-mechanical (GHM) interpretations of landslide processes, highlighting the importance of the synergy between geological-geomorphological analysis and hydro-mechanical modeling of the slope processes for successful interpretations of slope instability, the identification of the causes and the prediction of the evolution of the process over time. Two case studies are reported, showing how to apply GHM analyses of landslide mechanisms. After presenting the background methodology, this contribution proposes a research project aimed at the GHM characterization of landslides, soliciting the support of engineers in the selection of the most sustainable and effective mitigation strategies for different classes of landslides. This proposal is made on the assumption that only GHM classification of landslides can provide engineers with guidelines about instability processes which would be useful for the implementation of sustainable and effective landslide risk mitigation strategies.

scholarly journals Numerical Simulation of Frost Heave in Soils around the Buried Oil Pipeline in Island Talik Permafrost Region

2014 ◽  
Vol 6 ◽  
pp. 714818 ◽  
Author(s):  
Zaiguo Fu ◽  
Bo Yu ◽  
Yu Zhao ◽  
Yasuo Kawaguchi
Keyword(s):  
Heat Transfer Process ◽  
Temperature Fields ◽  
Frost Heave ◽  
Permafrost Region ◽  
Site Management ◽  
Oil Pipeline ◽  
Frost Heaves ◽  
Different Thickness ◽  
Capacity Method ◽  
Permafrost Regions

A systematic method to obtain the freezing characteristics and the amounts of frost heave in the soils around a buried oil pipeline in island talik permafrost region is presented on the basis of the simulation of soil temperature fields and a classic segregated potential frost heave model. The finite thermal effect domain and the equivalent heat capacity method were adopted to analyze the heat transfer process with phase change. The calculation parameters were derived from the China-Russia Crude Oil Pipeline engineering. The developments of the annual maximum freezing circles and frost penetrations emerging in typical years within the pipeline operation life cycle under different oil temperature, different thickness of thermal insulation layer, and different water content of soils were investigated. The maximum frost heaves in four typical sections of island talik were predicted. The results can be used to further mechanical calculation and can provide references for risk evaluation and site management of the buried pipelines in island talik permafrost regions.

Pipelines in permafrost: geotechnical issues and lessons 12010 R.M. Hardy Address, 63rd Canadian Geotechnical Conference.

2011 ◽  
Vol 48 (9) ◽  
pp. 1412-1431 ◽  
Author(s):  
James M. Oswell
Keyword(s):  
Slope Stability ◽  
Frost Heave ◽  
Terrain Mapping ◽  
Upheaval Buckling ◽  
Technical Developments ◽  
History Of ◽  
Key Issues ◽  
Thaw Settlement ◽  
Design Construction ◽  
Permafrost Regions

Geotechnical input to the design, construction, and operations of pipelines in permafrost may differ significantly from that for pipelines in temperate terrain. The general remoteness and terrain fragility of permafrost regions are key issues that challenge the geotechnical input. Specific geotechnical issues that necessitate input include pipeline routing, slope stability, thaw settlement and frost heave, ditching, buoyancy control, upheaval buckling. and others. This paper examines the history of pipeline development in Canada north of the 60th latitude and highlights some key design issues and some of the technical developments over the past 40 years of design, construction, and operations of pipelines in permafrost regions. Advances have been made in areas such as geothermal modeling, slope stability assessments, terrain mapping technologies, thaw settlement and frost heave prediction, and predicting and monitoring pipeline strain demand.

Remedying embankment thaw settlement in a warm permafrost region with thermosyphons and crushed rock revetment

2012 ◽  
Vol 49 (9) ◽  
pp. 1005-1014 ◽  
Author(s):  
Wei Ma ◽  
Zhi Wen ◽  
Yu Sheng ◽  
Qingbai Wu ◽  
Dayan Wang ◽  
...  
Keyword(s):  
Crushed Rock ◽  
Permafrost Region ◽  
Permafrost Degradation ◽  
Remedial Measures ◽  
Two Phase ◽  
Permafrost Warming ◽  
Railway System ◽  
Thaw Settlement ◽  
The Stability ◽  
Permafrost Regions

Due to the special engineering geology characteristics of permafrost, construction in permafrost regions tends to result in serious permafrost-related engineering problems. Thaw settlement induced by permafrost degradation is the principal challenge for railway construction on the Qinghai-Tibetan Plateau. It threatens the stability and safety of the railway system, especially in warm and ice-rich permafrost regions. Thaw settlement in section DK1139+780 along the Qinghai-Tibetan railway is a potential risk to the safety of the railway, and a combination of closed thermosyphons and crushed rock revetment was used to remedy permafrost warming and thaw settlement of the embankment. Based on ground temperatures and embankment deformations observed at this site since 2002, the effects of the remedial measures were evaluated. The results show that the remedial measures lowered the ground temperature and raised the permafrost table. The crushed rock slope protection acted as an insulation layer and reduced heat flux into the embankment. The thermosyphons lowered the permafrost temperature and had a good cooling effect on the underlying permafrost. The results show that the remedial measures using two-phase thermosyphons and crushed rock revetment decreased the settlement of the embankment and improved the stability of the railway system.

scholarly journals Modeling Epidemic Spread among a Commuting Population Using Transport Schemes

Mathematics ◽  
2021 ◽  
Vol 9 (16) ◽  
pp. 1861
Author(s):  
Daniela Calvetti ◽  
Alexander P. Hoover ◽  
Johnie Rose ◽  
Erkki Somersalo
Keyword(s):  
Network Model ◽  
Transport Theory ◽  
Optimal Transport ◽  
State Level ◽  
Compartment Model ◽  
Census Bureau ◽  
Mitigation Strategies ◽  
Mitigation Measures ◽  
Metapopulation Model ◽  
Infection Dynamics

Understanding the dynamics of the spread of COVID-19 between connected communities is fundamental in planning appropriate mitigation measures. To that end, we propose and analyze a novel metapopulation network model, particularly suitable for modeling commuter traffic patterns, that takes into account the connectivity between a heterogeneous set of communities, each with its own infection dynamics. In the novel metapopulation model that we propose here, transport schemes developed in optimal transport theory provide an efficient and easily implementable way of describing the temporary population redistribution due to traffic, such as the daily commuter traffic between work and residence. Locally, infection dynamics in individual communities are described in terms of a susceptible-exposed-infected-recovered (SEIR) compartment model, modified to account for the specific features of COVID-19, most notably its spread by asymptomatic and presymptomatic infected individuals. The mathematical foundation of our metapopulation network model is akin to a transport scheme between two population distributions, namely the residential distribution and the workplace distribution, whose interface can be inferred from commuter mobility data made available by the US Census Bureau. We use the proposed metapopulation model to test the dynamics of the spread of COVID-19 on two networks, a smaller one comprising 7 counties in the Greater Cleveland area in Ohio, and a larger one consisting of 74 counties in the Pittsburgh–Cleveland–Detroit corridor following the Lake Erie’s American coastline. The model simulations indicate that densely populated regions effectively act as amplifiers of the infection for the surrounding, less densely populated areas, in agreement with the pattern of infections observed in the course of the COVID-19 pandemic. Computed examples show that the model can be used also to test different mitigation strategies, including one based on state-level travel restrictions, another on county level triggered social distancing, as well as a combination of the two.

scholarly journals Design of COVID-19 staged alert systems to ensure healthcare capacity with minimal closures

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Haoxiang Yang ◽  
Özge Sürer ◽  
Daniel Duque ◽  
David P. Morton ◽  
Bismark Singh ◽  
...  
Keyword(s):  
Hospital Admissions ◽  
Optimal Strategies ◽  
Mitigation Strategies ◽  
Mitigation Measures ◽  
Public Confidence ◽  
Proof Of Concept ◽  
Alert System ◽  
System Safety ◽  
Reducing Costs ◽  
Restrictive Measures

AbstractCommunity mitigation strategies to combat COVID-19, ranging from healthy hygiene to shelter-in-place orders, exact substantial socioeconomic costs. Judicious implementation and relaxation of restrictions amplify their public health benefits while reducing costs. We derive optimal strategies for toggling between mitigation stages using daily COVID-19 hospital admissions. With public compliance, the policy triggers ensure adequate intensive care unit capacity with high probability while minimizing the duration of strict mitigation measures. In comparison, we show that other sensible COVID-19 staging policies, including France’s ICU-based thresholds and a widely adopted indicator for reopening schools and businesses, require overly restrictive measures or trigger strict stages too late to avert catastrophic surges. As proof-of-concept, we describe the optimization and maintenance of the staged alert system that has guided COVID-19 policy in a large US city (Austin, Texas) since May 2020. As cities worldwide face future pandemic waves, our findings provide a robust strategy for tracking COVID-19 hospital admissions as an early indicator of hospital surges and enacting staged measures to ensure integrity of the health system, safety of the health workforce, and public confidence.

scholarly journals Assessing Soil Loss by Water Erosion in a Typical Mediterranean Ecosystem of Northern Greece under Current and Future Rainfall Erosivity

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2002
Author(s):  
Stefanos Stefanidis ◽  
Vasileios Alexandridis ◽  
Chrysoula Chatzichristaki ◽  
Panagiotis Stefanidis
Keyword(s):  
Open Source ◽  
Soil Loss ◽  
Renewable Resource ◽  
Mitigation Strategies ◽  
Mitigation Measures ◽  
Mediterranean Ecosystem ◽  
Rainfall Erosivity ◽  
Negative Consequences ◽  
Northern Greece ◽  
Erosion Risk

Soil is a non-renewable resource essential for life existence. During the last decades it has been threatened by accelerating erosion with negative consequences for the environment and the economy. The aim of the current study was to assess soil loss changes in a typical Mediterranean ecosystem of Northern Greece, under climate change. To this end, freely available geospatial data was collected and processed using open-source software package. The widespread RUSLE empirical erosion model was applied to estimate soil loss. Current and future rainfall erosivity were derived from a national scale study considering average weather conditions and RCMs outputs for the medium Representative Concentration Pathway scenario (RCP4.5). Results showed that average rainfall erosivity (R-Factor) was 508.85 MJ mm ha h−1 y−1 while the K-factor ranged from 0.0008 to 0.05 t ha h ha−1 MJ−1 mm−1 and LS-factor reached 60.51. Respectively, C-factor ranged from 0.01 to 0.91 and P-factor ranged from 0.42 to 1. The estimated potential soil loss rates will remain stable for the near future period (2021–2050), while an increase of approximately 9% is expected by the end of the 21th century (2071–2100). The results suggest that appropriate erosion mitigation strategies should be applied to reduce erosion risk. Subsequently, appropriate mitigation measures per Land Use/Land Cover (LULC) categories are proposed. It is worth noting that the proposed methodology has a high degree of transferability as it is based on open-source data.

Permafrost Hazard of MoHe-DaQing Crude Oil Pipeline

2013 ◽  
Vol 734-737 ◽  
pp. 2659-2663
Author(s):  
Yun Bin Ma ◽  
Dong Jie Tan ◽  
Hong Yuan Jing ◽  
Quan Xue ◽  
Cheng Zhi Zhang
Keyword(s):  
Crude Oil ◽  
The Other ◽  
Frost Heave ◽  
Permafrost Soil ◽  
Buried Pipeline ◽  
Soil Frost ◽  
Plastic Deformations ◽  
Oil Pipeline ◽  
Thaw Settlement ◽  
Slope Instabilities

The crude oil pipeline from MoHe to DaQing (hereafter called Mo-Da pipeline) is part of China-Russia oil pipeline. Mo-Da pipeline is the first pipeline that through high latitude cold regions of China. The pipeline is in so complicated geography environment that many kinds of permafrost hazard are easily to happen including frost heave, thaw settlement, slope instabilities, and collapse and so on. The pipeline and the permafrost act and react upon one another. On one hand, soil frost heave and thaw settlement can produce extra stresses on pipe walls, which may result in centralized stresses and plastic deformations under certain conditions, even causes pipeline faults. On the other hand, buried pipeline will disturb ambient environment and then degrade the permafrost soil and finally impact safety of the pipeline. This paper mainly introduces the permafrost hazards of Mo-Da pipeline and demonstrates some methods for monitoring the influence of permafrost.

Emerging mitigation measures and strategies are needed for riverine ecology to ensure sustainable hydropeaking production in Norway 

2021 ◽  
Author(s):  
Jo Halvard Halleraker ◽  
Mahmoud S. R. Kenawi ◽  
Jan Henning L’Abée - Lund ◽  
Anders G. Finstad ◽  
Knut Alfredsen
Keyword(s):  
Biological Indicators ◽  
Ecological Impacts ◽  
Mitigation Strategies ◽  
Mitigation Measures ◽  
National Database ◽  
Political Agenda ◽  
Regulated Rivers ◽  
Hydropower Production ◽  
Multiple Pressures ◽  
Environmental Requirements

<p><strong>Riverine biodiversity</strong> is threatened with severe degradation from multiple pressures worldwide. One of the key pressures in European rivers are hydromorphological alterations. Rehabilitation of river habitats is accordingly high on the political agenda at the start of UN decade of ecological restoration (2021-2030).</p><p><strong>Water storage</strong> for hydropower production (HP) has severe impacts on aquatic ecology in Norway, with more than 3000 water bodies designated as heavily modified due to hydropower. Norway is the largest hydropower producer in Europe with a huge amount of high head storage schemes. Ca 86 TWh of this is storage hydropower, which constitutes more than 50% of the total in Europe. This makes Norway a potentially significant supplier of hydropeaking services. Flexible hydropower operations are crucial for EUs Green Deal in balancing electricity from renewable intermittent power generation such as wind and solar. </p><p>Many Norwegian <strong>HP licenses</strong> were issued before modern environmental requirements evolved. Few are re-licensed with emerging strategies to mitigate hydropeaking. Still, there seems to be a common understanding of relevant mitigation strategies emerging between many large hydropower producers. For example, flow ramping from hydropower tailrace water with direct outlet into fjords or other lake reservoirs may be less environmentally harmful than outlet into riverine habitat.In this study, we have assessed the Norwegian hydropower portfolio of more than 1600 HP facilities constructing a national database focusing on the knowledge base for assessing potential downstream hydropower ecological impacts. The ecological severity of such flow ramping and the restoration/mitigation potential, may depend on;</p><p> </p><p>About 51 % of the HPs (ca<strong> 80TWh</strong>) have tailrace into shorter rivers (<1 km) or directly into fjords or lake/reservoirs. Many of the largest HPs are in this category (e.g 50 HP> 500 MW). Close to 800 HP might have downstream impacts on rivers (> 0.5 km; about 49 % of all HP, in total of ca<strong> 56 TWh</strong>). Probably <strong>> 3 000 km of regulated rivers</strong> in Norway therefor might need more ecosystem-based mode of HP operation. <strong>Flow ramping analysis: </strong> Ecosystem-based HP operational rules are established in a selection of sustainably managed Norwegian rivers, still with significant baseload production (0.35-0.76 - TWh annual prod). However, eco-friendly mode of operation seems to be rare as our analysis indicate that flow ramping with potential ecological degradation seems widespread in many rivers. Surprisingly, even in many with operational ramping restriction as required mitigation.Our database may be further improved and updated (with e.g. more flow ramping data and biological indicators) and serve as a basis for a national hydropeaking strategy, and hence make more of the Norwegian hydropower portfolio in line with the EUs sustainability taxonomy.</p>

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