Оценка влияния сезонно-действующих охлаждающих устройств на теплофизические процессы грунтов основания железнодорожной насыпи

Construction in the regions of the Far North is characterised by numerous natural barriers, the presence of permafrost soils in the foundations of structures, the lack of infrastructure and extreme natural and climatic conditions. Thus, the most urgent task both in design and construction, and in further operation of transport infrastructure in the Arctic regions is to ensure reliability of the foundation of the structure.To ensure reliability of structures designed on permafrost soils, it is necessary to carry out thermophysical calculations and make forecasts of the influence of temperature processes on the foundation soils.The territory of the permafrost soils (PFS) occupies a large part of Russia, therefore, expanding the possibilities of using these regions for development of the transportation network is an important strategic task for the state. Today, in accordance with the Strategy for Spatial Development of the Russian Federation for the period up to 2025, the Arctic zone of the Russian Federation is a priority region in terms of economic growth and strategic impact.The article analyses the impact of the technology of seasonally operating cooling devices on the foundation soils of Salekhard- Nadym section of the Northern Latitudinal Railway line (Kilometre points 2825+00 - PK 2830+00). The effectiveness of seasonally operating cooling devices on permafrost soils of the railway embankment foundation is shown in combination with heat­insulating material. The advantages and disadvantages of seasonally operating cooling devices are summarised.Строительство в районах Крайнего Севера характеризуется большим количеством естественных природных преград, наличием многолетнемёрзлых грунтов в основаниях сооружений, отсутствием инфраструктуры и экстремальными природно-климатическими условиями. Таким образом наиболее актуальной задачей как при проектировании и строительстве, так и при дальнейшей эксплуатации путей сообщения в районах Заполярья является обеспечение надёжности основания сооружения.Для обеспечения надёжности сооружений, проектируемых на многолетнемёрзлых грунтах, необходимо проведение теплофизических расчётов и составление прогнозов влияния температурных процессов на грунты основания.Территория распространения многолетнемёрзлых грунтов (ММГ) занимает большую часть России, поэтому расширение возможностей использования этих регионов для развития сети путей сообщения является важной стратегической задачей для государства. На сегодняшний день, в соответствии со Стратегией пространственного развития Российской Федерации на период до 2025 года, приоритетным регионом, с точки зрения экономического роста и стратегического влияния, является Арктическая зона Российской Федерации.В данной статье проанализировано влияние технологии сезоннодействующих охлаждающих устройств на грунты основания участка Салехард–Надым железнодорожной линии «Северный широтный ход» (ПК 2825+00 – ​ПК 2830+00). Показана эффективность работы сезонно-действующих охлаждающих устройств на многолетнемёрзлые грунты основания железнодорожной насыпи в совокупности степлоизолирующим материалом. Сделан вывод о достоинствах и недостатках сезонно-действующих охлаждающих устройства

Армирование грунтов основания вертикальными столбами из щебня в криолитозоне

Stabilization of permafrost soils of the roadbed base, constructed with assumption of thawing, thanks to improvement of their strength characteristics, requires development and selection of rational structural and technological solutions. The objective of the study was to analyze the effectiveness of use of vertical columns of crushed stone in the permafrost zone and their influence on strength characteristics of the soil base. The study has used general scientific methods, modeling, simulation and comparative analysis. This article proposes a method for improving strength properties of soil of the roadbed base within Obskaya–Salekhard section of the Northern Latitudinal Railway thanks to reinforcement of the roadbed base made with vertical columns of crushed stone, which increases stability of the structure. The proposed basic technological model of construction of the roadbed includes the following main stages: preparatory stage, 1 stage – arrangement of vertical columns of crushed stone and granular subbases, 2 stage – additional compaction with a vibratory roller in case of mismatch of stability of bearing capacity and precipitation of the base to operating standards. The studied object of the transport infrastructure was simulated both without the use of technology for reinforcing it with vertical columns of crushed stone and with its use. The stability coefficient was calculated, and the theoretical surface of embankment collapse was obtained using Midas GTS NX and Plaxis 2D software packages. The stability test of this structure was carried out both in a flat and in a threedimensional setting. The efficiency of using vertical columns of crushed stone to strengthen the embankments constructed on permafrost soils has been shown.Стабилизация многолетнемёрзлых грунтов основания земляного полотна, сооружаемого с допущением оттаивания, за счёт улучшения их прочностных характеристик требует разработки и выбора рациональных конструктивно-технологических решений. Целью исследования является анализ эффективности использования вертикальных столбов из щебня в криолитозоне и их влияния на прочностные характеристики грунтов основания. В исследовании использовались общенаучные методы, моделирование и сравнительный анализ. Предлагается метод улучшения прочностных свойств грунтов основания земляного полотна на участке Обская–Салехард Северного широтного хода за счёт армирования вертикальными столбами из щебня, что повышает устойчивость сооружения. Обосновывается принципиальная технологическая схема сооружения земляного полотна, которая включает в себя следующие основные этапы: подготовительный этап, 1 стадия – устройство вертикальных столбов из щебня и щебёночной подушки, 2 стадия – дополнительное уплотнение виброкатком в случае несоответствия устойчивости несущей способности и осадки основания нормам эксплуатации. Выполнено моделирование исследуемого объекта транспортной инфраструктуры как без использования технологии армирования вертикальными столбами из щебня, так и с её применением. Рассчитан коэффициент устойчивости иполучена теоретическая поверхность обрушения насыпи с использованием программных комплексов Midas GTS NX и Plaxis 2D. Проверка устойчивости данного сооружения велась как в плоской, так и в трёхмерной постановке. Показана эффективность использования вертикальных столбов из щебня для усиления насыпей, сооружаемых на многолетнемёрзлых грунтах

Интенсивная технология при сооружении земляного полотна в криолитозоне

[For the English abstract and full text of the article please see the attached PDF-File (English version follows Russian version)].ABSTRACT An intensive technological regime for increasing the stability of weak soils is proposed to ensure safety of the roadbed on the site with the eternally frozen base of the Northern latitudinal railway Salekhard-Nadym. It is shown that it is necessary to take into account talik zones at the design stage, which can cause various deformations. On the basis of the fundamental principles of the mechanics of frozen soils, technological regularities are established f o r increasing the strength characteristics which include the angle of internal friction and cohesion of soil with decreasing humidity and draining water from the active layer and talik beyond the construction site. The application of intensive technology for reinforcing the roadbed during the construction of routes in the permafrost zone is substantiated. Keywords: railway, safety, stability, eternally frozen soils, roadbed, intensive technologyТекст аннотации на англ. языке и полный текст статьи на англ. языке находится в прилагаемом файле ПДФ (англ. версия следует после русской версии).Предложен интенсивный технологический режим повышения стабильности слабых грунтов при сооружении земляного полотна на участке с многолетнемёрзлым основанием. На примере Северного широтного хода показана эффективность применения фундаментальных положений механики мёрзлых грунтов, установлены технологические закономерности повышения прочностных характеристик - угла внутреннего трения и сцепления грунта при уменьшении влажности и отводе воды из деятельного слоя и талика за пределы строительной площадки. Обосновано применение интенсивной технологии для упрочнения земляного полотна при строительстве путей сообщения в криолитозоне

Laser-irradiating infrared attenuated total reflection spectroscopy of articular cartilage: Potential and challenges for diagnosing osteoarthritis

Abstract Objective: A prototype infrared attenuated total reflection (IR-ATR) laser spectroscopic system designed for in vivo classification of human cartilage tissue according to its histological health status during arthroscopic surgery is presented. Prior to real-world in vivo applications, this so-called osteoarthritis (OA) scanner has been tested at in vitro conditions revealing the challenges associated with complex sample matrices and the accordingly obtained sparse spectral datasets. Methods: In vitro studies on human knee cartilage samples at different contact pressures (i.e., 0.2–0.5 ​MPa) allowed recording cartilage degeneration characteristic IR signatures comparable to in vivo conditions with high temporal resolution. Afterwards, the cartilage samples were assessed based on the clinically acknowledged osteoarthritis cartilage histopathology assessment (OARSI) system and correlated with the obtained sparse IR data. Results: Amide and carbohydrate signal behavior was observed to be almost identical between the obtained sparse IR data and previously measured FTIR data used for sparse partial least squares discriminant analysis (SPLSDA) to identify the spectral regions relevant to cartilage condition. Contact pressures between 0.3 and 0.4 ​MPa seem to provide the best sparse IR spectra for cylindrical (d ​= ​3 ​mm) probe tips. Conclusion: Laser-irradiating IR-ATR spectroscopy is a promising analytical technique for future arthroscopic applications to differentiate healthy and osteoarthritic cartilage tissue. However, this study also revealed that the flexible connection between the laser-based analyzer and the arthroscopic ATR-probe via IR-transparent fiberoptic cables may affect the robustness of the obtained IR data and requires further improvements.Abstract Objective: A prototype infrared attenuated total reflection (IR-ATR) laser spectroscopic system designed for in vivo classification of human cartilage tissue according to its histological health status during arthroscopic surgery is presented. Prior to real-world in vivo applications, this so-called osteoarthritis (OA) scanner has been tested at in vitro conditions revealing the challenges associated with complex sample matrices and the accordingly obtained sparse spectral datasets. Methods: In vitro studies on human knee cartilage samples at different contact pressures (i.e., 0.2–0.5 ​MPa) allowed recording cartilage degeneration characteristic IR signatures comparable to in vivo conditions with high temporal resolution. Afterwards, the cartilage samples were assessed based on the clinically acknowledged osteoarthritis cartilage histopathology assessment (OARSI) system and correlated with the obtained sparse IR data. Results: Amide and carbohydrate signal behavior was observed to be almost identical between the obtained sparse IR data and previously measured FTIR data used for sparse partial least squares discriminant analysis (SPLSDA) to identify the spectral regions relevant to cartilage condition. Contact pressures between 0.3 and 0.4 ​MPa seem to provide the best sparse IR spectra for cylindrical (d ​= ​3 ​mm) probe tips. Conclusion: Laser-irradiating IR-ATR spectroscopy is a promising analytical technique for future arthroscopic applications to differentiate healthy and osteoarthritic cartilage tissue. However, this study also revealed that the flexible connection between the laser-based analyzer and the arthroscopic ATR-probe via IR-transparent fiberoptic cables may affect the robustness of the obtained IR data and requires further improvements

Base Soil Reinforcement with Vertical Crushed Stone Columns in Cryolithozone

Stabilization of permafrost soils of the roadbed base, constructed with assumption of thawing, thanks to improvement of their strength characteristics, requires development and selection of rational structural and technological solutions. The objective of the study was to analyze the effectiveness of use of vertical columns of crushed stone in the permafrost zone and their influence on strength characteristics of the soil base. The study has used general scientific methods, modeling, simulation and comparative analysis. This article proposes a method for improving strength properties of soil of the roadbed base within Obskaya–Salekhard section of the Northern Latitudinal Railway thanks to reinforcement of the roadbed base made with vertical columns of crushed stone, which increases stability of the structure. The proposed basic technological model of construction of the roadbed includes the following main stages: preparatory stage, 1 stage – arrangement of vertical columns of crushed stone and granular subbases, 2 stage – additional compaction with a vibratory roller in case of mismatch of stability of bearing capacity and precipitation of the base to operating standards. The studied object of the transport infrastructure was simulated both without the use of technology for reinforcing it with vertical columns of crushed stone and with its use. The stability coefficient was calculated, and the theoretical surface of embankment collapse was obtained using Midas GTS NX and Plaxis 2D software packages. The stability test of this structure was carried out both in a flat and in a threedimensional setting. The efficiency of using vertical columns of crushed stone to strengthen the embankments constructed on permafrost soils has been shown.</jats:p

The Stability of the Pheromones of Xylophagous Insects to Environmental Factors: An Evaluation by Quantum Chemical Analysis

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.Abstract—The ground and excited states of the pheromone molecules produced by xylophagous insects (the bark beetle Ips typographus L., the black fir sawyer beetle Monochamus urussovi Fisch., and the black pine sawyer M. galloprovincialis Oliv.) were modeled using a quantum chemical method utilizing DFT (density functional theory) with the B3LYP functional. The absorption wavelengths (energies) and dipole moments were calculated; the transitions of electrons from occupied to empty molecular orbitals were considered. The computed data were used to assess the stability of pheromone molecules exposed to environmental factors, such as solar radiation and humidity