Frost-susceptible Soils Research Articles

Modeling Wicking Fabric Inhibition Effect on Frost Heave

The deterioration of roads in cold regions can result in unsafe driving conditions and high maintenance costs. Frost heaving is regarded as one of the main reasons for road degradation. Generally, frost heave is caused by water migrating from the unfrozen zone to the freezing front, where it is then transformed into an ice lens. Frost heave can be reduced by removing frost-susceptible soil, raising the temperature, or removing water from the soil. Among these methods, the most economical and practical approach is to reduce the water content. Recently, an innovative geotextile known as wicking fabric (WF) has been used to drain water from unsaturated conditions and minimize frost heaving. The objective of this study was to evaluate the inhibition effects of WF on frost heave under different experimental conditions in the freezing process. In this study, a thermo-hydro-mechanical (THM) coupled numerical model is proposed to simulate the freezing process of subgrade soil with WF. The evaporation model is used to simply describe the water absorption characteristics of WF. The numerical model was validated by comparing the simulation results with the experimental results of the wicking fabric model (WWF) and the non-wicking fabric model (NWF). Additionally, parametric analysis was conducted to examine the effectiveness of WF in reducing frost heave under various experimental conditions. As a result, the freezing process of soil installed with WF was accurately simulated by the proposed model. WF showed inhibition effects on frost heave under various experimental conditions. The results indicate the following: (1) Compared to Touryo soil (a high frost-susceptible clay-sand soil), WF inhibited frost heave more effectively in Tomakomai soil (a medium frost-susceptible lean clay), while the inhibition effect of WF in Fujinomori soil (a medium frost-susceptible lean clay) was limited. (2) WF has a more significant frost heave inhibition effect at a slower cooling rate in the freezing process. (3) The further the WF is installed from the groundwater level (GWL), the greater its impact on inhibiting frost heave.

New Methods for Predicting Strain Demand of Arctic Gas Pipelines across Permafrost under Frost Heave Displacement

With increasing gas resource development in the Arctic region, gas pipeline installations in permafrost regions are becoming important. Frost heave of pipeline foundation soils may occur when a chilled gas pipeline passes through unfrozen areas with frost-susceptible soils. The stress and strain behaviors caused by the differential frost heave will directly affect the safety of the pipeline. A nonlinear finite element model (FEM) computing the mechanical responses of the buried gas pipeline subjected to frost heave load was established and successfully validated with the results of a large-scale indoor pipe-soil interaction experiment carried out in Caen in France. Utilizing C# language and object-oriented visual programming techniques, a new customized parametric strain calculation software was developed. The effects of pipe diameter, pipe wall thickness, pipe internal pressure, and peak soil resistance on the longitudinal strain of X60, X70, and X80 steel pipes have been investigated quantitatively. For the first time, a fitting semiempirical equation and trained backpropagation neural network (BPNN) for predicting pipeline strain demand subjected to frost heave load were proposed based on 2688 groups of FEM results. The comparison results have proved their high accuracy and lower running time cost. The proposed new methods can be applied in the strain-based pipeline design and safety evaluation of pipelines in service. It is in the hope of supplementing existing theory and identifying new approaches for arctic gas pipeline installations.

Heat and Mass Transfer by Vapour in Freezing Soils

Vapour mass transfer is often underestimated when designing the bases for structures in frost susceptible soils. Intensive and long-term vapour transport may lead to excessive frost heaving and associated issues. A vapour transport model and the algorithm of its calculation is presented in this study based on the results of experimental freeze–thaw cycles of nine soil samples with varied density. The temperature field distribution, air voids volume and the energy comprising latent heat for the phase transition and heat extracted during the temperature drop are the main parameters for determining the vapour velocity and the amount of ice formed. According to the results, the average speed of vapour transport in frozen soils was about 0.4 m/h. The amount of ice built in 1 h during uniaxial freezing due to the saturated vapour pressure difference was 1.64 × 10−5–3.6 × 10−⁵ g/h in loose samples and 1.41 × 10−⁶ g/h to 5.61 × 10−⁷ g/h in dense samples of 10 cm diameter and 10 cm high sections. The results show that vapour mass transfer can increase the risk of ice growth and related problems.

Frost heave and frost susceptibility of soils on the projected railway Moscow–Kazan

Frost heave and factors which affect it are considered on the projected railway Moscow– Kazan. That region is intensively developed; however, frost heave hasn’t been well studied in there, especially at the present climatic conditions. Results of field studies of frost heave properties of grounds on monitoring sites along the railway Moscow–Kazan are presented; they include physical properties of grounds, depth of seasonal freezing, grounds thermal mode, groundwater dynamics, snow cover thickness and basic characteristics of frost heave.

Effect of freezing and thawing on soil permeability: newly equipment and experimental results

In a cold climate design of dams, clay barrier liners on landfills, and structures on frost-susceptible soils is a challenge for geotechnical engineers. During service life of the structures a frost heave may reach 15-20% of the depth of a frost penetration and an uplift movement are accompanied by the formation of layered or lattice cryogenic texture. When thawing, macro- and micropores are formed instead of ice lenses. Basically pores are oriented predominantly along frost front. They are a reason of horizontal water permeability increase, consequently, reduce of stability of the slopes and decrease of the effectiveness of the landfill clay barrier liners. The paper presents a new apparatus for studying water permeability and frost heave of soils which allows to carry out horizontal or/and vertical permeability tests (along and across layered cryogenic texture) after assigned number of freeze-thaw cycles without withdrawal of a soil sample from apparatus. The results for clay and fine sand samples are obtained. Clay and fine sand samples showed an increase of horizontal hydraulic conductivity after 2 - 4 freeze-thaw cycles. Relationship between water flow velocity and hydraulic gradient for non-Darcian and Darcian flow is obtained as a result of vertical permeability tests of clay samples in unfrozen state.

Frost susceptibility of soils―A confusing concept that can misguide geotechnical design in cold regions

Frost susceptibility of soils―A confusing concept that can misguide geotechnical design in cold regions

A Proposal of Standard Test Method for Frost Susceptibility of Soil

A recommendation of a standard test method for frost susceptibility of soil is proposed. The recommendation is required in order to have a design technique of common and equivalent quality not only in domestic but international practice. This topic is one of the essential and current objectives of Technical Committee 216 (ISSMGE) and has been discussing to the present. The purpose of the proposed recommendation test method is defined, different methods from several countries are compared, necessary and common articles are selected and some items are specified to discuss. It is expected that this proposal would take a role to be a draft suggestion to promote discussion and achieve a final recommendation.

THE INNOVATIVE LABORATORY EQUIPMENT FOR ASSESSMENT OF A FROST HEAVE PHENOMENON OF THE SOILS

The impact of the freezing-thawing process on soils, accompanied by frost heaving and changes of physico-mechanical properties and water permeability, leads to a decrease in the reliability of the designed structures such as dams, landfill caps, pavements. The existing apparatuses for the study of frost heaving are systematized according to their purpose (measured parameters), design features and experimental conditions. The authors pointed out the directions for improving laboratory equipment and presented developed innovative equipment for studying both the frost heave and its consequences. The article presents apparatuses for testing of frost-susceptible soils with the ability to manage the freezing front movement and water migration from the thawed to the freezing parts of soil. A laboratory equipment for studying the water permeability of soils along and across the ice lenses in subject to cyclic freezing and thawing is presented. Taking into account the dependence of criteria of frost-susceptibility of soils on experimental conditions, the authors propose a new approach to assessing the impact of frost heave phenomenon on designed structures. According to the approach the preparation of the laboratory research program and the analysis of their results are carried out using data obtained from numerical modeling both of the laboratory equipment and of the designed constructions.

Soil Moisture Variations in Frozen Ground Subjected to Hydronic Heating

Full-scale thawing experiments, performed on three types of homogenous, initially frozen soils, were carried out during late winter 2011 and repeated in 2012. An auxiliary heat source (hydronic heating) was employed to initiate and expedite the thawing process. The corresponding phase change, soil temperature increase, and variations in bound and unbound water content were monitored during the experiments. The resulting thermal response have been published in an earlier paper by the authors. In the current paper, the remaining results are presented. This includes spatial and temporal soil moisture variations and resulting thaw rates. Results from both experiments show similar trends. Generally, frost-susceptible soils, such as silty sand, contain more water and thaw slower relative to coarser soils, such as gravelly sand. Very porous soils (uniform gravel) with low water content thaw comparatively slower. Thaw rates compiled from soil moisture records correspond well with similar based on soil temperature. The degree of water redistribution and migration is higher in silty sand compared with coarser soils. These processes are more prominent in the uppermost layer for all soils examined.

Method of Reducing Energy Consumption for Heating Frost-Susceptible Soil around Chilled Underground Pipeline

Abstract This article is devoted to the calculation and optimization of the engineering protection of cold underground condensate pipelines using heat-tracing cable in frost-susceptible soils in We...

Ground subsidence and heave over permafrost: hourly time series reveal interannual, seasonal and shorter-term movement caused by freezing, thawing and water movement

Abstract. Heave and subsidence of the ground surface can offer insight into processes of heat and mass transfer in freezing and thawing soils. Additionally, subsidence is an important metric for monitoring and understanding the transformation of permafrost landscapes under climate change. Corresponding ground observations, however, are sparse and episodic. A simple tilt-arm apparatus with logging inclinometer has been developed to measure heave and subsidence of the ground surface with hourly resolution and millimeter accuracy. This contribution reports data from the first two winters and the first full summer, measured at three sites with contrasting organic and frost-susceptible soils in warm permafrost. The patterns of surface movement differ significantly between sites and from a prediction based on the Stefan equation and observed ground temperature. The data are rich in features of heave and subsidence that are several days to several weeks long and that may help elucidate processes in the ground. For example, late-winter heave followed by thawing and subsidence, as reported in earlier literature and hypothesized to be caused by infiltration and refreezing of water into permeable frozen ground, has been detected. An early-winter peak in heave, followed by brief subsidence, is discernible in a previous publication but so far has not been interpreted. An effect of precipitation on changes in surface elevation can be inferred with confidence. These results highlight the potential of ground-based observation of subsidence and heave as an enabler of progress in process understanding, modeling and interpretation of remotely sensed data.

The Cyclical Structure of the Isotopic Diagram of a Lithalsa and Its Radiocarbon Age, Sentsa River Valley, Eastern Sayan

This paper reports on the nature and history of the mineral-rich frost heave mounds—lithalsas—developed on the first terrace of the Sentsa River in Okinsky District of Buryatia. An ice core of the lithalsa was exposed by drilling of a 20-m borehole. The most typical feature of the isotopic diagrams, which we obtained for the ice core, is their cyclical pattern illustrating isotope minima at depths of about 3–5 m, 9–12 m, and 18–21 m, separated by two distinct isotope maxima. Most likely, this demonstrates the cyclicity of the triple flooding of the growing frost heave mound and the subsequent active evaporation of lake-march waters, which are the main source of moisture for the lithalsa ice core. Based on the detailed radiocarbon dating of organic material from the upper horizons of the highest and surrounding lithalsas, we determined the time of their formation. Organic material in drained frost-susceptible soils was intensely accumulated during the period from 0.5 to 0.2 ka BP. This is the time of the beginning of the formation of permafrost, active ice-formation, and the associated frost heave and lithalsa growth. The age of at least three of four mounds studied is not older than 200 years, it coincides with the cooling at the beginning of the 19th century.

The Influence of Nanosilica on Unconfined Compressive Strength of Frost-Susceptible Soil

In engineering practice there are numerous methods to improve the mechanical properties of subsoil. The paper presents the analysis of changes in the unconfined compressive strength of frost-susceptible soils stabilised with nanosilica (NS). Tests were conducted on samples of fine-grained soil at the maximum dry density (MDD) and optimum moisture content (OMC). Four variants of samples were prepared: soil without additive, soil with 1% NS, soil with 3% NS and soil with 5% NS. Due to the frost-susceptible character of the soil, tests were conducted on non-frozen samples and on samples subjected to ten cycles of freezing and thawing. Cyclic freezing and thawing of soil mixtures allowed for determination of the additive effectiveness in the temperature conditions encountered during the winter season. Based on the research results of unfrozen samples, it was determined that the addition of nanosilica leads to the increase in their unconfined compressive strength. On the other hand, the strength of pure soil samples after ten cycles of freezing and thawing decreased. This is a commonly known trend that results from the soil and soil mixtures freezing. However, in the same conditions, the unconfined compressive strength of samples stabilised with nanosilica demonstrated a significant increase with the increase of the additive content. The highest values were noted for samples stabilised with 5% addition of nanosilica. In order to explain the obtained results, further tests are required. However, the preliminary research has shown the effectiveness of nanosilica as an independent additive stabilising frost-susceptible soils, although it is not commonly used in engineering practice.

Hummocks in alpine tundra, northern British Columbia, Canada: distribution, morphology and organic carbon composition

Hummocks develop by cryoturbation in fine-grained frost-susceptible soils and their stage of maturity may affect the translocation of organics in Cryosols. This study examines the distribution and morphology of hummocks in the Chuck Creek Trail Valley (northern British Columbia) and determines the quantity, distribution, and composition of organic matter in their soils. Hummocks occupy about 5%–20% of the valley and their morphology is largely affected by their silt content. Cryoturbated intrusions, radiocarbon dated to 2814 and 1648 cal year B.P., suggest that hummock development was initiated during the cooler late Holocene. Hummocks have an average soil organic carbon density of 16.3 kg m−2 in the uppermost 1 m, with 62% stored in the top 25 cm. Organics are mainly present as particulate organic matter in the O-horizon (25%–80%), characterized by degradable alkyl C and O/N-alkyl groups, but occur as mineral-associated organic matter (96%–98%) composed of recalcitrant aromatic and aliphatic C groups in the underlying B and C horizons. Minor differences in organic content and composition occur between hummock tops and troughs, and between hummocks showing different stages of maturity. In the absence of an observed frost table, contemporary hummock activity is attributed to seasonal freezing and thawing.

Thermo-hydro-mechanical modeling of frost heave using the theory of poroelasticity for frost-susceptible soils in double-barrel culvert sites

Abstract The upward movement of soil due to the formation of ice lenses, known as frost heave, is detrimental to buried utilities, pavement structures and building foundations. In this paper, a fully coupled thermo-hydro-mechanical model was presented in the framework of the theory of poroelasticity and a porosity rate function aiming to predict frost heave, temperature distribution and pore water pressure in frost-susceptible soils. The model was verified by experimental and field data and applied to predict frost heave in two double-barrel concrete culvert sites in Manitoba, Canada. It was concluded that the insulation and non-frost-susceptible backfill can be used to effectively decrease frost heave and corresponding differential deformations at the road surface.

Physical Responses to Anthropogenic Disturbance on a Runway in the Canadian High Arctic

Background: The McGill Arctic Research Station (MARS) runway on Axel Heiberg Island, Nunavut, has been subject to intense compaction from aircrafts since the 1960’s, causing alterations to the landscape across time and space. This study investigated the thermal, hydrological and physical responses of repeated aircraft compaction of the runway to characterize its vulnerability to land use, and the effects of long-term and repeated compaction. Methods: In late July and early August 2018, the island’s summer thaw season, topographic, soil, hydrological and frost table data were collected along four transects across the MARS runway. Results: Topography and effective porosity differences caused by compaction were found to affect soil moisture contents, leading to the observed differential frost heaving and insulation properties of soil across the runway. Soil was found to be mostly silt on and off disturbed areas, indicating that compaction does not affect grain-size but rather pore space and soil bulk density. The frost table mapping suggested statistically significant variations in depth of the frost table across undisturbed, disturbed, and indirectly disturbed areas, showing that compression from aircrafts has both direct and indirect spatial impacts on the hydrogeomorphic system. Furthermore, this research examined possible solutions to mitigate thaw consolidation of the runway. Limitations: The method of probing used to determine frost table depths introduced significant error to the data. Probing discrepancies arose between people probing and between sampling days, as techniques differed and/or improved. Future studies should consider using electrical resistance tomography to map the frost table, as this would eliminate inconsistencies. Furthermore, while pore size distributions were inferred based on grain-size and extent of compaction, subsequent studies should consider a quantitative approach to pore space analysis. Conclusion: This study suggests that aircraft travel to the remote McGill Arctic Research Station causes spatially and temporally significant changes in the local hydrogeomorphology, especially in fine-grained and wet, frost-susceptible soils. Thaw consolidation, which results indicate is caused by the direct and indirect effects of soil compaction, compromises the prolonged use of the runway.

Influence of Micro and Nanosilica on the Frost–Heave Process

Frost-heave of soils is an important problem in engineering practice. Thus, it became necessary to find an adequate method that would reduce the negative effect of this phenomenon on building structures. The paper presents the preliminary tests results of microsilica (MS) and nanosilica (NS) influence on the water freezing process in frost-susceptible soils. The selection of stabilising additives also allowed for the analysis of changes that result from their transition from micro to nanoscale. For the purposes of the experiment a test stand was constructed, that enables to analyse six samples at the same time, at inflow of water from the bottom and freezing direction from the top. The use of linear potentiometer displacement sensors allowed to measure the increase in the height of samples automatically. Additionally, the measurement stand was equipped with digital semiconductor temperature sensors, so temperature could be measured at various heights of the samples. Moreover, an array of electrodes was applied to measure the electrical conductivity of soil at various levels of samples, which enabled the analysis of changes that occur in freezing soil. The tests were conducted according to the BS 812-124:1989 standard, in three variants: soil, soil + 5% MS, soil + 5% NS. The obtained results demonstrated that the addition of microsilica reduces the occurrence of ice lenses, which in turn significantly decreases the growth in sample height. However, the addition of nanosilica completely stops the frost-heave process. Ice lens is not created, only a frost line is noticeable. Analysing the distribution of temperatures at different heights, it was noted that stabilised samples are characterised by higher temperature in comparison to the soil without additives. This means that the analysed stabilisers reduce the degree of freezing of the soil mixture. The highest temperatures were noted in samples stabilised with nanosilica. Conductivity tests also demonstrated that the smallest changes occurred in samples stabilised with nanosilica. This results from the fact that ice lenses did not occur in such samples. In order to analyse the obtained results and their interpretation thoroughly, it is necessary to perform a detailed analysis of the microstructure both of soil and of soil with stabilising additives.

Frost heave analysis of ballasted track above box culvert and its influence on train vibration

The uneven frost heave of frost-susceptible subgrade soil causes track irregularity, which highly enhances train vibration and affects the comfort and safety of railway transportation. This paper presents a coupled thermo-hydro-mechanical (THM) analysis for the freezing behavior of railway located above a box culvert. The vertical acceleration of the vehicle, an indicator of riding comfort, is predicted through a vehicle dynamic model. The results reveal that the existence of a box culvert changes the subgrade thermal pattern, leading to a deeper frost penetration depth. The frost heave amount above the box culvert is larger than the adjacent section, resulting in uneven track structure upheave and track irregularity. This frost-induced track irregularity highly affects train vibration.

Simple frost heave testing method using a temperature-controllable cell

The characteristics of frost heave have been evaluated with experimental results based on individual testing apparatus and methods even though frost heave testing methods have already been standardized in Japan and the U.S., such as through JGS 0172 and ASTM 5918. This paper introduces a simple frost heave testing method using a newly developed temperature-controllable cell. The reliability of the testing apparatus was carefully examined with various boundary temperature conditions based on a comparison between measured and calculated volumetric expansion of sandy soils when the pore water in a specimen was frozen. After temperature boundary conditions were determined, frost heave tests with frost-susceptible soils were performed along with measuring water intake. The adfreezing bond and side friction were thoroughly assessed, and a simple frost heave test method was finally established.

Water-vapor-heat behavior in a freezing unsaturated coarse-grained soil with a closed top

A series of one-side freezing experiments with closed tops were performed to illustrate moisture migration and frost heave mechanisms of the coarse-grained soil for high speed railway subgrades in cold regions, as well as silty clay and standard sand as controls. The experimental results show that the pot effect can be formed in the soils with different unsaturated porosities when their tops are closed. The vapor migration and frost heave of unsaturated soils become more significant under larger temperature gradient. Water supply can not determine the formation of the pot effect, and only influence its intensity. Vapor migration is prominent when the initial water contents of soils are low (e.g. saturation of 30%), however, the water migration is dominant when the initial moistures of soils are high (e.g. saturation of 70%). It is also found that the initial water contents of the soils only influence the in-situ frost heave amounts; however, the total frost heave amounts are related to the combined actions of soil frost susceptibility and water migration, etc.