scholarly journals The bridge piers sagging problem under permafrost subbase degradation conditions and the possible solution

2020 ◽  
Vol 7 (3) ◽  
Author(s):  
Sergey Tomilov ◽  
Alexander Sim ◽  
Pavel Grinev
Keyword(s):  
Traffic Safety ◽  
High Stress ◽  
Bridge Piers ◽  
Permafrost Soil ◽  
Permafrost Degradation ◽  
Deep Foundation ◽  
Engineering Structures ◽  
Permafrost Soils ◽  
Building Engineering ◽  
Frost Boil

Permafrost soils are common for extensive areas of our country and when building engineering structures in such conditions, it is necessary to take into account the factor supporting subbase on the permafrost soil, which may initially have high stress-related characteristics. But the permafrost degradation phenomenon with frost retreat no less common. It can be happening both for natural reasons due to global warming, and for man-made reasons, when interference during construction and further the structure itself initiates subsoil frost retreat. For the most part, permafrost soils lose their strength and elastic properties during the frost retreat, turning into an almost liquid consistency, which entails the failure of the supports in the bearing capability and position stability. With the road network development and the bridge’s construction in the northern regions at the end of the 60s — early 70s of the XX century, the first principle of the design was widely applied. It was for use and maintenance of the subsoil in a frozen state, which means not require a deep foundation required. However, after 20 — 30 years of operation, cases of unexpected and significant bridge piers sagging began to be noted, as it turned out, was the result of permafrost soils frost retreat to the entire depth of the foundation. It was also noted that in some cases the bridge piers sagging is preceded by its frost boil phenomena, which appear shortly before piers sinking and almost complete failure. In this article case of an unexpected bridge piers failure examined on a specific bridge. After 30 years of proper functioning, pierces received such significant sagging, so in just three years that got to the point when it’s not only traffic safety but the cohesiveness of the entire structure. And before that, a frost boil was noted at some of the bridge pierce. The purpose of this study is to analyze the frost boil mechanism and sagging of the bridge pierce’ foundations due to the progressive permafrost degradation and to suggest restoring and maintaining ways for pierces’ operation capacity. Overall, the reasons and principles of permafrost subbase degradation were analyzed in this paper. through calculations using a specific example, significant sagging and bridge pierce bearing capability loss observations were justified and substantiated the effectiveness of the proposed in this article structural reinforcement measures.

scholarly journals Soil deformation model analysis in the processing of the geotechnical monitoring results

2021 ◽  
Vol 266 ◽  
pp. 03014
Author(s):  
Vladimir Syasko ◽  
Aleksander Shikhov
Keyword(s):  
Russian Federation ◽  
Frozen Soil ◽  
Permafrost Soil ◽  
Deformation Model ◽  
Soil Deformation ◽  
Engineering Structures ◽  
Geotechnical Monitoring ◽  
Permafrost Soils ◽  
The Russian Federation ◽  
Hydrocarbon Deposits

Much of the territory of the Russian Federation is located in the permafrost soil area. The developed hydrocarbon deposits make a significant contribution to the budget of the Russian Federation. Therefore, ensuring trouble-free operation of engineering structures and these fields is the most crucial task. Frozen soil deformation leads to violations in the operation of structures, which entail economic harm and significant environmental problems. This article provides a brief overview of the leading causes of deformations of engineering structures built on permafrost soils. The methods currently used to stabilize the frozen soil deformation are considered, and the directions for solving this problem are proposed.

scholarly journals Analysis of the causes of engineering structures deformations at gas industry facilities in the permafrost zone

2021 ◽  
Vol 249 ◽  
pp. 377-385
Author(s):  
Gennadii Vasiliev ◽  
Anton Dzhaljabov ◽  
Igor Leonovich
Keyword(s):  
Multicomponent System ◽  
Individual Characteristics ◽  
Raw Material ◽  
Permafrost Zone ◽  
Permafrost Soil ◽  
Material Base ◽  
Engineering Structures ◽  
Gas Industry ◽  
Geological Conditions ◽  
Permafrost Soils

Construction of oil and gas infrastructure facilities on permafrost soils is the most important task of increasing the raw material base of the entire fuel and energy industry in Russia. Permafrost soil is a complex, multicomponent system, state of which depends on many factors. Buildings and structures built under such conditions, on the one hand, have a complex thermal effect on permafrost soils, and on the other hand, they perceive the consequences of changes in the characteristics of such soils. This situation leads to the fact that buildings and structures on permafrost soil during their life cycle are subject to complex and poorly predictable deformations. Article presents the results of a study for various degradation processes of permafrost soils that can be implemented at construction sites of industrial facilities. Analysis of the deformations causes for engineering structures at the gas industry in the permafrost zone is carried out. Series of reasons causing such deformations have been investigated. Comprehensive criterion for assessing changes in permafrost-geological conditions of industrial sites is proposed. It is suggested to apply the method of calculating the individual characteristics for the temperature regime of the territory to monitor and assess the conditions of heat exchange and predict changes in the geocryological conditions of permafrost soil.

Degrading permafrost threatens Arctic nature and built environment

2020 ◽  
Author(s):  
Jan Hjort ◽  
Olli Karjalainen ◽  
Juha Aalto ◽  
Sebastian Westermann ◽  
Vladimir Romanovsky ◽  
...  
Keyword(s):  
Climate Change ◽  
At Risk ◽  
High Resolution ◽  
Human Activities ◽  
Environmental Data ◽  
The Arctic ◽  
Permafrost Degradation ◽  
Engineering Structures ◽  
Near Surface ◽  
Population At Risk

<p>Arctic earth surface systems are undergoing unprecedented changes, with permafrost thaw as one of the most striking examples. Permafrost is critical because it controls ecosystem processes, human activities, and landscape dynamics in the north. Degradation (i.e. warming and thawing) of permafrost is related to several hazards, which may pose a serious risk to humans and the environment. Thaw of ice-rich permafrost increases ground instability, landslides, and infrastructure damages. Degrading permafrost may lead to the release of significant amounts of greenhouse gases to the atmosphere and threatens also biodiversity, geodiversity and ecosystem services. Thawing permafrost may even jeopardize human health. Consequently, a deeper understanding of the hazards and risks related to the degradation of permafrost is fundamental for science and society.</p><p>To address climate change effects on infrastructure and human activities, we (i) mapped circumpolar permafrost hazard areas and (ii) quantified critical engineering structures and population at risk by mid-century. We used observations of ground thermal regime, geospatial environmental data, and statistically-based ensemble methods to model the current and future near-surface permafrost extent at ca. 1 km resolution. Using the forecasts of ground temperatures, a consensus of three geohazard indices, and geospatial data we quantified the amount and proportion of infrastructure elements and population at risk owing to climate change. We show that ca. 70% of current infrastructure and population in the permafrost domain are in areas with high potential for thaw of near-surface permafrost by 2050. One-third of fundamental infrastructure is located in high hazard regions where the ground is susceptible to thaw-related ground instability. Owing to the observed data-related and methodological limitations we call for improvements in the circumpolar hazard mappings and infrastructure risk assessments.</p><p>To successfully manage climate change impacts and support sustainable development in the Arctic, it is critical to (i) produce high-resolution geospatial datasets of ground conditions (e.g., content of organic material and ground ice), (ii) develop further high-resolution permafrost modelling, (iii) comprehensively map permafrost degradation-related hazards, and (iv) quantify the amount and economic value of infrastructure and natural resources at risk across the circumpolar permafrost area.</p>

scholarly journals Engineering and geological features of the soil section of the main water pipeline route in Central Yakutia

2020 ◽  
pp. 119-131
Author(s):  
Andrei Mikhailovich Sal'va
Keyword(s):  
Rural Areas ◽  
Physical And Mechanical Properties ◽  
Engineering Structures ◽  
Southeastern Part ◽  
Industrial Facilities ◽  
Central Yakutia ◽  
Technogenic Loads ◽  
Permafrost Soils ◽  
Pipeline Route ◽  
Water Pipeline

The object of this study is the permafrost soils of the section of the route of the main water pipeline «Tabaga-Byuteidyakh» in rural areas of Central Yakutia, spanning approximately 28 kilometers. Permafrost soils are widely developed in the Southeastern part of Central Yakutia, and are located on the Leno-Amginsky interfluve. They lie in the upper part of the geological section and are underlying on the lane of the main water pipeline route, as well as fall into the foundations of engineering structures of industrial facilities and hydraulic engineering construction. The study is based on a complex of field engineering and geological surveys, as well as laboratory studies of the physical and mechanical properties of rocks. The article discusses the features of the composition, structure and properties of rocks in this area. It is noted that among the considered soils, there is a variety of granulometric types, cryogenic texture from massive to layered, with clay soils usually of higher ice content than sandy ones. Technogenic loads are also mentioned in the form of objects of the main water supply system, consisting of pumping stations, pipelines, reservoirs and channels, which lead to significant changes in the geocryological environment and surrounding landscapes.

scholarly journals Selection of sunflower and its mixtures on the permafrost soil of Central Yakutia

2021 ◽  
pp. 50-54
Author(s):  
E. S. Pestereva ◽  
S. A. Pavlova
Keyword(s):  
Nutritional Value ◽  
Animal Husbandry ◽  
Permafrost Soil ◽  
Forage Crops ◽  
Mass Flowering ◽  
Lena River ◽  
Green Mass ◽  
Feed Production ◽  
Permafrost Soils ◽  
Selection Of

Relevance. For the development of the main branch of agriculture in Yakutia — animal husbandry, one of the most pressing problems is the availability of feed. The article presents the results of research conducted at the Yakut Research Institute of Agriculture.Methods. Scientific research on the selection of sunflower mixtures with promising forage crops was carried out at site 30 “A“(on the basis of the laboratory of feed production of the YANIISKH) on the second over-floodplain terrace of the Lena River in 2018-2019.Results. The results of research on the growth and development of forage crops, the formation of yield, chemical composition and nutritional value of sunflower and its mixtures with promising annual crops are presented. High indicators for the development and yield of the tested crops were provided by sunflower mixed with corn 42.7 t/ha of green mass and sunflower mixed with Sudan grass 40.2 t/ha of green mass. The terms of sowing and harvesting of sunflower and its mixtures on permafrost soils are determined — sowing — the first decade of June, harvesting-the second decade of August before early-autumn frosts in the phase of mass flowering and throwing out panicles of the tested forage crops.

Fracture Analysis for Attaching Fiber Reinforced Composite on V-Notch Wedge Structure

2017 ◽  
Vol 909 ◽  
pp. 133-142
Author(s):  
Teng Hui Chen
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Critical Stress ◽  
High Stress ◽  
Brittle Materials ◽  
Critical Stress Intensity Factor ◽  
Fiber Reinforced ◽  
Engineering Structures ◽  
Wedge Structure

Sharp V-notches with various angles often appear in engineering structures. When being loaded, the high stress at the apex could result in crack propagation on the structure and further fracture. For this reason, safety evaluation should be emphasized for products or engineering structures with such geometric characteristics. Sharp V-notches are regarded as wedge structures that the above situations seriously and often appear on brittle materials. Regarding the stress intensity factor K of the driving force for wedge structure failure, Chen, Dunn, and Seweryn, with numerical analysis for the fracture experiment, explained that the critical stress intensity factor Kc for single isotropic material fracture could be the intensity failure specification for wedge structures. Nevertheless, V-notched brittle materials are likely to receive great stress over the surface elastic energy of the structure when being loaded, causing brittle failure at the apex. When the high-strength and light-weight composite material is attached to reinforce the surface of brittle materials, the energy is reinforced to enhance the critical stress intensity factor of the overall structure, aiming to improve the failure of brittle materials resulted from stress singularity. This paper therefore tends to discuss the effects of the composite attachment, layer, and fiber reinforced direction on the critical stress intensity factor when the structure is being fractured.

scholarly journals A stress-strain state analysis of the road transport works foundations on seasonally freezing soils

2020 ◽  
Vol 7 (4) ◽  
Author(s):  
Anatoliy Permikin ◽  
Igor Ovchinnikov ◽  
Anastasiya Gricuk
Keyword(s):  
Traffic Safety ◽  
Road Transport ◽  
Transport Infrastructure ◽  
Fine Aggregate ◽  
Negative Consequences ◽  
Soil Thickness ◽  
The Road ◽  
Operational Characteristics ◽  
On The Road ◽  
Frost Boil

This article discusses the road transport works foundations when they are located in the seasonally freezing soils zone. Some culvert aqueduct utilized structures were considered and analyzed as an example, in the scope of most common structures on the road network and that also has an insignificant weight. Some constructive solutions disadvantages of these pipes were pointed out. It is noted that the operational characteristics of nonfrost-susceptible soil decrease in the watercourse filtering process and settling small particles and reported the dependence of the relative soil frost boil on the fine aggregate percentage. As an example of the frost boil forces influence, a typical culvert aqueduct design is considered. The calculation of axial and tangential heaving forces that affect the crown of tube is performed, assuming that the bedding soil is contaminated. Based on the calculation, rise calculated value dependence graphs of the unstressed base on the soil dampness and the heaving soil thickness, and the heaving pressure on the soil dampness are presented here. Due to the insufficient value of the forces holding back against lifting, possible negative consequences of the frost boil impact forces are presented, this affects not only the culvert aqueduct operational characteristics but also the roadbed smoothness and traffic safety. Thus, the need for additional measures to prevent soil swelling under the pipe head is justified. Recommended measures to prevent excessive deformations during frost boil, as well as modern aspects of the development of such technologies, are considered. Conclusions are made about their applicability and feasibility in relation to small artificial structures of transport infrastructure.

scholarly journals Selection of sunflower and its mixtures on the permafrost soil of Central Yakutia

2021 ◽  
pp. 50-54
Author(s):  
E. S. Pestereva ◽  
S. A. Pavlova
Keyword(s):  
Nutritional Value ◽  
Animal Husbandry ◽  
Permafrost Soil ◽  
Forage Crops ◽  
Mass Flowering ◽  
Lena River ◽  
Green Mass ◽  
Feed Production ◽  
Permafrost Soils ◽  
Selection Of

Relevance. For the development of the main branch of agriculture in Yakutia — animal husbandry, one of the most pressing problems is the availability of feed. The article presents the results of research conducted at the Yakut Research Institute of Agriculture. Methods. Scientific research on the selection of sunflower mixtures with promising forage crops was carried out at site 30 “A“(on the basis of the laboratory of feed production of the YANIISKH) on the second over-floodplain terrace of the Lena River in 2018-2019.Results. The results of research on the growth and development of forage crops, the formation of yield, chemical composition and nutritional value of sunflower and its mixtures with promising annual crops are presented. High indicators for thedevelopment and yield of the tested crops were provided by sunflower mixed with corn 42.7 t/ha of green mass and sunflower mixed with Sudan grass 40.2 t/ha of green mass. The terms of sowing and harvesting of sunflower and its mixtures on permafrost soils are determined — sowing — the first decade of June, harvesting-the second decadeof August before early-autumn frosts in the phase of mass flowering and throwing out panicles of the tested forage crops.

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