Frost Depth Research Articles

Effect of Culverts on the Thermal Regime of a Railway Embankment

A common issue for Canadian railway operators is the development of localized frost heave near railway culverts, which leads to nonuniform deformation of the track surface and degradation of the track geometry, damages the track component, and affects the quality of rides in railway operations. Frequent maintenance including placing wooden shims between rail and ties and often the reduction of train speeds are required to ensure safe operating conditions. Given the future expected climate patterns, freeze–thaw cycles are anticipated to become more frequent, and therefore, a greater understanding of their effect on the changing ground thermal regime under railway embankments is essential. This paper investigates the effects of culverts and insulation layers on changing the temperature regime of the ground during the winter–spring period through numerical modeling in TEMP/W (version 2019) two-dimensional (2D) and three-dimensional (3D) software. The model was calibrated using actual field measurements collected from an instrumented section of the track that has suffered from frost heaves at the proximity of a culvert. Using the results from 2D simulation, the effect of culverts on extending the frost zone, in both horizontal and vertical directions, was quantified. In addition, the effects of shape, installation depth, and the number of culverts on the frost penetration depth were discussed. Using TEMP/W 3D results, the most appropriate configuration to install the culverts was studied to minimize frost penetration.

A Fiber Optic Sensor for Monitoring the Spectral Alterations and Depth in Ex Vivo and In Vivo Cryosurgery

This article discusses how to monitor the freezing depth during cryotherapy using a fiber optic array sensor. The sensor was used to measure the backscattered and transmitted light from frozen and unfrozen ex vivo porcine tissue and in vivo human skin tissue (finger). The technique exploited the variations in optical diffusion properties of the frozen and unfrozen tissues to determine the extent of freezing. Ex vivo and in vivo measurements yielded comparable results, despite spectral variations attributable to the hemoglobin absorption peak in the human frozen and unfrozen tissues. However, because the spectral fingerprints of the freeze-thaw process in the ex vivo and in vivo experiments were similar, we could extrapolate the maximum depth of freezing. Therefore, this sensor has the potential to be utilized for monitoring cryosurgery in real time.

Frost Mitigation Techniques for Tunnels in Cold Regions: The State of the Art and Perspectives

Tunnels located in cold regions are vulnerable to frost damage resulting from the special atmosphere, which directly threatens the safety of the tunnel structure and operation. Frost problems of tunnels in cold regions have not been fundamentally resolved. This paper reviews design theory and the frost mitigation techniques currently used in the design, construction and maintenance of cold region tunnels. The depths of freezing and thawing and frost heaving force are the key indexes of design theory. Insulation is the main design technology used to prevent frost heaving and thawing, and the active heating technology has also been applied in practice. In construction, reducing the heat of hydration and blasting by specific winter construction techniques can prevent tunnel freeze–thaw damages. In operation, the restoration of drainage systems, the reinforcement of structures and the reinstallation of freezing-prevention systems are effective measures to treat frost problems. Finally, some constructive suggestions and opinions are put forward to improve the service performance of tunnels.

The frost heave characteristics of a coarse-grained volcanic soil quantified by particle image velocimetry

The increasing use of the seasonally frozen and permafrost regions for civil engineering constructions and the effects of global warming on these regions have stimulated research on the behaviors of frozen soils. In the present study, the frost heave characteristics of a coarse-grained soil with volcanic nature was experimentally investigated. A large soil tank model was established in laboratory for this purpose. The effects of temperature boundary, external water supply, and water transfer type on the frost heave characteristics of the volcanic soil were studied, through a series of frost heave tests. The particle image velocimetry (PIV) technique was used to quantify the full field deformation of the soil specimen. The results suggest that temperature gradient inside the soil specimen is the driving force for the migration of pore water and vapor. The largest increment in water content generally agrees well with the frost penetration depth. The contribution of vapor to the frost heave of the soil specimen is typically small. The applied seeding method, selected subset size, image-object space calibration, and calculation processes ensured accurate PIV results. Discussions regarding the presented experimental investigation and the employment of PIV technique for quantifying frozen soil deformation are summarized. These findings and discussions can provide valuable insights into the frost heave behavior of the studied soil in particular, as well as promote the application of PIV for frozen soil engineering.

Seasonally freeze–thaw changes on the Qinghai–Tibet plateau and their possible causes

AbstractKnown as the “roof of the world”, 50%–56% area of the Qinghai–Tibet Plateau (QTP) is covered by seasonal frozen ground (SFG), which has an important impact on local and global climate change, terrestrial ecosystems, and regional energy and hydrological cycles. In this study, long‐term observational data of air and soil water (precipitation and soil moisture) and heat [surface air temperature (SAT) and soil temperature (ST)] at 30 meteorological stations were used to study the temporal and spatial changes of SFG and their possible causes for the central‐eastern QTP (CEQTP). The results showed that latitude and altitude are the key factors affecting the spatial distributions of seasonal freeze–thaw activities of CEQTP. The stations with deeper freeze depths and more freeze days are mainly located in high‐altitude and high‐latitude regions, and those with shallower freeze depths and fewer freeze days are mainly located in the low‐altitude and low‐latitude regions of the southern QTP. This may be the reason that latitude and altitude are the key factors determining the temperature distribution on the CEQTP. SAT, ST, precipitation, and soil moisture are all significant correlations with the freeze depth, freeze days, freeze start date (FSD) and thaw end date (TED), and the abrupt change years of them are also consistent; they are the important factors affecting the freeze–thaw changes (FTCs) of SFG. Among them, ST is the key factor influencing the FTCs of SFG, and the variations of monthly average soil temperature (MAST) at 0–320 cm depths are the inverse of those of the monthly average freeze depth and freeze days during the year. Using the MAST data at 0–320 cm depths and the 0°C ST threshold, the soil freeze–thaw processes at different depths on the CEQTP are revealed. Affected by global warming, SAT and ST at different depths on the CEQTP have shown the upward trends since the 1980s. Additionally, precipitation and soil moisture have also increased substantially, especially since the late 1990s. Enhancement of warming and wetting conditions from the land surface to the deep soil have accelerated the thawing of SFG, and led to the delay of FSD and the advance of TED, which further caused the reduction of freeze depth and freeze days of SFG on the QTP, especially since the late 1990s.

Role of Temperature Gradient and Soil Thermal Properties on Frost Heave

In cold regions, the soil temperature gradient and depth of frost penetration can significantly affect roadway performance because of frost heave and thaw settlement of the subgrade soils. The severity of the damage depends on the soil index properties, temperature, and availability of water. While nominal expansion occurs with the phase change from pore water to ice, heaving is derived primarily from a continuous flow of water from the vadose zone to growing ice lenses. The temperature gradient within the soil influences water migration toward the freezing front, where ice nucleates, coalesces into lenses, and grows. This study evaluates the frost heave potential of frost-susceptible soils from Iowa (IA-PC) and North Carolina (NC-BO) under different temperature gradients. One-dimensional frost heave tests were conducted with a free water supply under three different temperature gradients of 0.26°C/cm, 0.52°C/cm, and 0.78°C/cm. Time-dependent measurements of frost penetration, water intake, and frost heave were carried out. Results of the study suggested that frost heave and water intake are functions of the temperature gradient within the soil. A lower temperature gradient of 0.26°C/cm leads to the maximum total heave of 18.28 mm (IA-PC) and 38.27 mm (NC-BO) for extended periods of freezing. The maximum frost penetration rate of 16.47 mm/hour was observed for a higher temperature gradient of 0.78°C/cm and soil with higher thermal diffusivity of 0.684 mm2/s. The results of this study can be used to validate numerical models and develop engineered solutions that prevent frost damage.

GEOTECHNICAL STUDY AND CALCULATION OF THEFOUNDATION LAND FOR THE LOCATION OF RAISING CHICKENS FARM

The geotechnical study resulted from the need to know the foundation land in order to properly place the investment and includes the geotechnical exploration works performed in the site area, with the aim of providing the data necessary to solve the basic problems specifying the aspects related to: the stratification of the land on the site; physical-mechanical characteristics of existing soils; admissible pressures at different foundation levels; probable settlements; framing of field excavations; frost depth; seismic framing; hydrogeological data.

LIVESTOCK FARM LOCATION OF PIGS REPRODUCTION BASED ON THE GEOTECHNICAL STUDY

The geotechnical study resulted from the need to know the foundation land in order to properly place the investment and includes the geotechnical exploration works performed in the site area, with the aim of providing the data necessary to solve the basic problems specifying the aspects related to: the stratification of the land on the site; physical-mechanical characteristics of existing soils; admissible pressures at different foundation levels; probable settlements; framing of field excavations; frost depth; seismic framing; hydrogeological data.

ЭРОЗИОННЫЕ ПРОЦЕССЫ ПРИ СТОКЕ ТАЛЫХ ВОД НА ЮГЕ ЕВРОПЕЙСКОЙ ЧАСТИ РОССИИ

Purpose: to determine the regularities of melt water runoff and soil erosion on the chernozems of Rostov region for a long-term observation period of 1970–2021. Methods. Field experiments were carried out on slopes on compacted arable land (perennial and winter crops) and loose arable land (autumn ploughing). Measuring of melt water runoff and precipitation during the period of snow melting and soil washout was carried out on the water balance site of Stepnoy village Rostov region. The main physical and water-physical properties of soil during the snow melting period (freezing depth, moisture content of the upper soil layer 0.30 cm, water permeability) were studied according to generally accepted methods. Results. An analysis of field observations for the period from 1970 to 2021 was carried out for the parameter “snow water reserves before melting + precipitation during the snow melting period”, which averaged 47.8 mm over 52 years on compacted arable land and 43.15 mm on loose arable land, the runoff coefficient was higher on compacted arable land and amounted to 0.25 and 0.10, respectively; with appearance of surface runoff of 10.6 t/ha, this indicator increased to 5.9 and 20.7 t/ha on loose arable land, respectively. Mathematical analysis of the data made it possible to establish the relationship between the values of runoff, soil washout and water reserves in snow, the depth of soil freezing and water permeability during the runoff period. Conclusions. Long-term studies (52 years) found that there is a greater accumulation of water in snow on compacted arable land than on loose arable land, while the runoff coefficient was 2.5 times higher on compacted arable land, but the plants retain soil particles on compacted arable land, and soil washout on average over the years with the manifestation of surface runoff, was 10.6 t/ha, while on loose arable land this figure increased to 20.7 t/ha. The relationship between runoff rate, soil washout and water reserves in snow, the depth of soil freezing and water permeability during the runoff has been determined.

Modern studies of the cryosphere of the Zeravshan and Gissar Ranges (Tien Shan)

The paper presents brief results of the modern studies of the cryosphere of the Zeravshan and Gissar ranges. Also the rate of decrease in the area of glaciers over the last almost a hundred years and the presence and degradation of permafrost during that time were considered. The actual description of the methodic for estimation of the depth of the ground freezing based on air temperature and snow thickness data were also given. An experience of application of this method for estimating the depth of ground freezing on the mountain slopes in order to compile the maps of the permafrost zone of the Zeravshan and Gissar ranges was described.

Особенности проявления эрозии в пределах овражно-балочного водосбора

Purpose: to determine patterns of formation of hydrographic network elements depending on the melt-and rainwater runoff and soil losses. Materials and methods. The studies were carried out in the upper reaches of the Bolshoy Log gully system, which is a part of the land use of the experimental farm “Polevoy” of the Federal Rostov Agrarian Research Center, with an area of 2070 hectares, of which more than 70 % is arable land. Soils are ordinary chernozems of varying degrees of erosion. The standard methods of research and the method of pins were used on runoff plots. Results. Within the catchment area, the amount of runoff and hydraulic indicators of water courses are greatly influenced by the agricultural background and the soil surface condition from which meltwater flows, and the intensity of erosion processes is influenced by the depth of soil freezing, the moisture content of topsoil, water storage in snow, snowmelt intensity. The water sprays are concentrated along the gullies, where the soil is washed out over time, and they pass into the category of hollows, then into ravines and gullies, forming a hydrographic network in the gully-ravine catchment area. The most intensive meltwater runoff was observed over the years: in 1988 – 33.8 mm, 2003 – 63.9 mm, 2006 – 24.6 mm, 2014 – 14.3 mm, 2017 – 19.3 mm, 2023 – 10–14 mm. In the variants with reclamation protective forest plantations and hydraulic structures, the runoff was 5–12 mm less than in the control and it retained in the forest belt. The mathematical data analysis made it possible to determine the relationship between the runoff rate and soil loss in the gully-ravine catchment, depending on the distance from the watershed. Conclusions. On the gully-ravine catchment, the sheet wash smoothly turns into a linear one and forms hollows and valleys. The final link of the catchment area are ravines and gullies. During the peak periods of meltwaters, the water flow velocity on flat sections of the slope is 0.33–0.46 m/s, and along the hollows – 0.57–0.83 m/s.

Определение эффективных рассеивающих свойств среды в процессе криодеструкции с помощью сапфирового криоаппликатора

The task of monitoring the condition of the tissue during its cryodestruction is extremely relevant for cryosurgery. Previously, the concept of a sapphire cryoprobe was proposed, which makes it possible to detect diffusely scattered light from a tissue during an ice ball formation. This probe combines the advantages of sapphire as a promising material for cryosurgery, as well as the possibility of assessing the depth of tissue freezing in the contact area. The use of several light source channels inside the applicator, spaced at different distances from the detector channel, makes it possible to analyze the scattering properties of the medium using the methods of diffusion theory. In this paper, we consider the influence of the position and number of analyzed source channels on the signals recorded by the detector channel and the determined effective scattering coefficient of a two-component medium consisting of an iceball and unfrozen tissue. Differences in the scattering coefficient obtained for various channel configurations are shown, as well as the advantages of analyzing a large number of channels to describe the effective properties of the medium with a complex iceball boundary.

Monitoring of Seasonal Variations in Ground Temperature

The paper considers the problem of monitoring seasonal changes in soil temperature in northern and mountainous areas in the light of ongoing climate changes. To study seasonal changes in soil temperature, a model site of the Moscow State University Meteorological Observatory was used with the ability to monitor air temperature, snow cover thickness, and ground freezing temperature and depth, which was a prototype of a system for monitoring the state of permafrost soils used in the Arctic and mountain territories. The paper presents the results of monitoring seasonal changes in soil temperature based on the results of numerical modeling of the penetration of seasonal fluctuations in soil temperature in 2014-2017 in MATLAB environment at the model site of the MSU Meteorological Observatory. The results of numerical simulation of the penetration of seasonal temperature fluctuations in the ground at the MSU meteorological site in 2014-2017 in the MATLAB environment are in good agreement with the thermometry data and, therefore, the developed calculation scheme shows fairly good simulation results. This makes it possible to use the calculation scheme to assess the thermal state of frozen soils and assess the stability of foundations and buildings and linear structures located on them in the conditions of the North and mountainous territories. Therefore, the presented methodology can serve as a good help for monitoring and preventing the destruction of the studied structures in the conditions of climate warming.

Monitoring of seasonal variations in ground temperature at the observation site of Lomonosov MSU

The paper considers the problem of monitoring seasonal variations of ground temperature in northern and mountainous areas in the light of ongoing climate changes. To study seasonal variations of ground temperature, a model site of the Moscow State University Meteorological Observatory was used with the ability to monitor air temperature, snow cover thickness, and ground freezing temperature and depth, which was a prototype of a system for monitoring the state of permafrost soils used in the Arctic and mountain territories. The paper presents the results of monitoring seasonal variations of ground temperature based on the results of numerical modelling of the propagation of seasonal fluctuations of ground temperature in 2014-2017 in MATLAB environment which are in good agreement with the thermometry data and, therefore, the developed calculation scheme shows fairly good simulation results. This makes it possible to use the calculation scheme to assess the thermal state of frozen grounds and the stability of foundations and buildings and linear constructions located on them in the conditions of the North and mountainous territories. Therefore, the presented methodology can serve as a good help for monitoring and preventing the destruction of the observed structures in the conditions of climate warming.

WEATHER CONDITIONS DURING THE CONSTRUCTION OF DEFENSIVE LINES IN CHUVASHIA DURING THE GREAT PATRIOTIC WAR

Based on archival materials and scientific literature, the article studies weather conditions in the territory of the Chuvash Republic during the construction of defensive lines during the Great Patriotic War. The relevance of the chosen topic is due to insufficient exploration degree of this aspect in the scientific literature. The novelty of the research consists in attracting new sources: tables of meteorological and agro-meteorological observations TM-1 and BSH-1 made by meteorological stations of Alatyr, Kanash, Poretskoye, Cheboksary in late 1941 – early 1942. The purpose of the work is to study the air temperature values, snow cover height and soil freezing depth in Chuvashia in the winter of 1941–1942 based on the analysis of different groups of historical sources: 1) documents of the authorities controlling the progress of construction; 2) memories of the builders of defensive lines and their relatives; 3) observation data of air temperature, precipitation, snow cover height, depth of soil freezing compiled by weather stations in the territory of the republic and in neighboring cities. Comparison of information obtained from different sources helped to conclude about their reliability and determine in what weather conditions the construction of defensive structures in the territory of the republic took place during the Great Patriotic War. Comparison of historical sources of different groups does not confirm the data on the air temperature below –44°C during the construction period in the territory of Chuvashia. It should be taken into consideration that the minimum temperature indicators refer to the night time when the work was not carried out. The construction lasted a long time, and if we keep in mind the period from October 1941 to February 1942, then the weather was different within these time limits and it is impossible to accurately define only one value of air temperature. It can be unequivocally stated that winter of 1941–1942 was one of the coldest in the XX century.

Thermal-mechanical properties of polystyrene insulation board under defect condition and their influence on lining structure of conveyance channel

The seasonal frozen soil area in the north of China has a low temperature in winter, and laying an insulation board is an effective method for mitigating the frost-heaving damage to the lining structure of the conveyance channel. However, the insulation board has a certain defect rate during installation and later operation, which changes its thermodynamic and mechanical properties, thus affecting the safety of the lining structure. In this study, an expanded polystyrene insulation board was adopted and its thermal-mechanical properties were examined under the condition of defects. Then, the effect of the insulation board with defects on the lining structure was analyzed by conducting numerical simulations, taking a conveyance channel of a Jiaodong water diversion project as an example. The experimental results showed that with the increase in freeze–thaw times and decrease in defect size, the moisture content and thermal conductivity of the insulation board with defects increased. After 28 freeze–thaw cycles, compared with the complete insulation board, the moisture content and thermal conductivity of the insulation board with 20-mm defect decreased by 21.63% and 4.33%, respectively. With the increase in freeze–thaw times and defect size, the elastic modulus and compressive strength of the insulation board with defects decreased. After 45 freeze–thaw cycles, compared with the complete insulation board, the elastic modulus and compressive strength of the insulation board with 20-mm defect decreased by 17.76% and 6.67%, respectively. The numerical simulation results showed that when air media existed in the defects, the deformation and stress change of lining were not distinctive. When ice media were present in the defects, the larger the defect size, the larger the freezing depth of the channel, the larger the normal frost-heaving displacement of the lining surface, the greater the possibility of tensile damage of the lining inside, and the more significant the outward expansion trend of the canal slope lining. In the middle of a shady slope, compared with the complete insulation board, the average freezing depth of the insulation board with 20-mm ice defect increased by 2.29 times, the maximum normal frost-heaving displacement increased by 4.50 times, and the normal frost-heaving stress and tangential freezing stress increased by 16.86 and 7.47 times, respectively. These results can provide a theoretical reference for the safe and efficient operation of water diversion projects in dry and cold regions.

Математическое моделирование процесса промерзания грунтов земляного полотна железных дорог в условиях холодного климата

Purpose: Mathematical model for studying the process of soil freezing given moisture migration is developed. Numerical modeling of temperature mode of railway subgrade at non-stationary pro-cess in cold climate conditions is performed. Methods: Numerical implementation of the model is performed by mathematical module processing in COMSOL Multiphysics program, which’s based on partial differential equations (PDE), with finite element method. The model reliability is con-firmed by the comparison with previous experimental data and the results of simulation by other authors. Results: Calculation results on the developed model basis show the best correlation with experimental data in comparison with the results for other models. Calculation example and calcu-lation results for subgrade temperature mode in freezing-thawing fifth cycle are presented. The analysis of soil freezing depth change and soil temperature fluctuation change by depth by fifth year are carried out. Practical significance: The developed mathematical model makes it possible to predict soil freezing depth, taking into account moisture migration, including freezing and thawing depth changes caused by climate warming. The developed model can be used both, to study the mechanism of subgrade temperature mode distribution at freezing and thawing, and to improve subgrade construction for to protect it from soil frost heaving.

Feasibility test of a sapphire cryoprobe with optical monitoring of tissue freezing.

This article describes a sapphire cryoprobe as a promising solution to the significant problem of modern cryosurgery that is the monitoring of tissue freezing. This probe consists of a sapphire rod manufactured by the edge-defined film-fed growth technique from Al2 O3 melt and optical fibers accommodated inside the rod and connected to the source and the detector. The probe's design enables detection of spatially resolved diffuse reflected intensities of tissue optical response, which are used for the estimation of tissue freezing depth. The current type of the 12.5-mm diameter sapphire probe cooled down by the liquid nitrogen assumes a superficial cryoablation. The experimental test made by using a gelatin-intralipid tissue phantom shows the feasibility of such concept, revealing the capabilities of monitoring the freezing depth up to 10 mm by the particular instrumentation realization of the probe. This justifies a potential of sapphire-based instruments aided by optical diagnosis in modern cryosurgery.

Trends in soil frost formation in a warming maritime climate and the impacts on urban flood risk

The most severe urban flooding in cold maritime climates is due to the co-action of long-duration rainfall, snowmelt, and soil frost. Increasing winter air temperature due to climate change is projected to change the magnitude and frequency of rain-on-snow (RoS) events and increase the number of freeze–thaw cycles and midwinter snowmelt. While daily rainfall records are readily available, less is known about the infiltration and frost formation within urban soils. Thus, there is uncertainty on how warming winter conditions may affect urban flood risk and the climate resilience of cities. The aim of this study was, therefore, to assess soil frost formation in the past 70 years in the maritime city of Reykjavík, Iceland (64° N, 21° W), and its co-action with runoff generation, and the potential implications on urban flood risk. To that end, the daily thermal and hydraulic conditions of the soil were simulated using the Simultaneous Heat and Water (SHAW) model dating back to 1949, calibrated based on hourly observations from 2007. Model simulations indicated that the minimum soil temperature at 10 cm depth has been warming at a rate of 0.015 °C/year in the past seven decades. Climate warming is also noted in a steady decline in frost depth and the duration of soil frost each winter (p-value < 0.05). However, the freezing season has shortened so that the timing of maximum frost coincides more with the timing of maximum RoS and snowmelt events. Furthermore, RoS events during frost have the capacity to produce larger runoff volumes than rainfall or snowmelt alone based on the joint frequency analysis of winter events using the copula method. This, combined with increasing volume during RoS events, suggests that winter floods may intensify in the next decades, which urges re-thinking urban stormwater management in cold climates.

Calculation method and model tests of pile frost jacking for railway overhead contact systems in permafrost regions

One of the major challenges encountered in electrification reconstruction project of Golmud-Lhasa section of Qinghai-Tibet railway of China is ensuring the frost jacking stability of the pile foundation of overhead contact system mast (OCSM). To evaluate the resisting frost jacking performance of OCSM pile in permafrost regions, a theoretical model of OCSM pile in permafrost soils under the effect of frost heave was constructed based on superposition principle and deformation coordination relationship between the pile and soil. The model was solved by using the finite difference method combined with MATLAB. Then, large scale model tests were performed to investigate the thermodynamic behaviors of OCSM piles with different sections (equal section circular pile, straight cone cylindrical pile and curved cone cylindrical pile) in the permafrost soils under freeze-thaw actions, after which the theoretical model were validated. It was found that distribution curves of pile axial force obtained by the calculation method is basically consistent with model test results in the overall trend, implying that the calculation model is reasonable and feasible. During soil freezing, the pile is under tension as a whole, and the axial force is greatest near the depth of frost penetration. The maximum value of tangential frost-heave stress occurs near the ground surface. The total tangential frost heaving force of the curved cone cylindrical pile is the smallest, and the effect of resisting frost jacking is the best. These research results can provide a reference for resisting frost jacking design of OCSM pile in permafrost regions.