Journal of Cold Regions Engineering

Current application rate guidance for liquid deicers is limited for low to moderate temperatures (below −9.4°C, 15.0°F and −9.4°C–3.9°C, 15.0°F–25.0°F) and light snow conditions (<2.5 cm/h, 1.0 in./h; <10.2 cm, 4.0 in. in 24 h). The performance of liquid deicers has been mainly studied in laboratory environments, but findings do not directly translate to highly diverse and variable conditions experienced in the field. Thus, the objective of this study is to expand liquid application rate guidance using observed field data and practitioner experience. A survey of practice was conducted to gather agencies’ liquid application guidance and practice, and to identify sites for field data collection. Data collection consisted of route information and field data, in terms of weather, roadway conditions, materials, application rates, and performance measures during storms. Fourteen agencies from six states submitted data for 22 routes, resulting in field data for 167 winter storms. Commonly used application rates were identified and shared with 12 practitioners who have extensive experience in using liquid applications. Practitioners provided feedback, validated observed application rates, recommended adjustments, and raised awareness about specific conditions. The results of this study are given in tables, with application rate guidance for different liquid applications by pavement temperature range, pavement temperature trend, roadway surface condition, and chemical material.

In recent years, permafrost warming has adversely affected the performance of infrastructure projects in northern Canada. The common construction practice in these permafrost-underlain areas is to use the pile foundation for building and infrastructure rather than using shallow foundations. Thus, the influence of warming permafrost on the loading capacity of pile foundations is critical for evaluating forthcoming changes under a warming climate. The present study was performed to assess the influence of temperature and loading rate on the adfreeze strength of piles in permafrost soil. A series of uniaxial compressive tests on wooden piles drilled into frozen soil were carried out at various temperatures, mimicking the conditions in warming permafrost. The results demonstrated that an increase in strain rate led to an increase in the adfreeze strength of piles. Moreover, the wooden piles exhibited peak adfreeze strength at a displacement of less than 2 mm for most temperature and deformation rate combinations. Interestingly, although the adfreeze strength of piles increased as temperatures cooled below −1°C, a transition phase between −3°C and −4.5°C was observed in which the adfreeze strength decreased. It could be noted that failure occurred in the wooden piles at temperatures colder than −5°C rather than frozen soil failure at these temperatures. These variations in the adfreeze strength were related to soil temperature, unfrozen water content, and the adhesive bonds at the interface between the frozen soil and pile.

The objective of this study is to evaluate the impacts of two commonly used temperature databases, Parameter-elevation Relationships on Independent Slopes Model (PRISM) and Topography Weather (TopoWx), on the quantity and distribution of snowmelt in the Missouri River Basin simulated by a new macroscale grid-based model for two representative flood and drought years. The model incorporates a unique LEGO-fashion framework to account for within-grid heterogeneity. The snowmelt simulations were compared with the SNOw Data Assimilation System (SNODAS) estimates, indicating that both data sets provided comparable snowmelt with the SNODAS data (R² > 0.91). Comparison of the modeling results revealed that both data sets provided comparable magnitude and distribution of the average monthly snowmelt. However, the average daily snowmelt varied up to 16.9% and the snowmelt variations were more pronounced in the areas with complex topography. The simulations suggested that even nuances in the snowmelt coverage led to significant changes in the simulated snowmelt quantity.

Abstract

Nowadays, chitosan biopolymer has received much research attention in geoenvironmental practices like soil erosion reduction, hydraulic conductivity, and heavy metal absorption in contaminated soil. Nevertheless, the effect of chitosan incorporation on freeze–thaw resistance of soft clays has not been evaluated comprehensively. In this research, different concentrations (2%, 4%, 6%, and 8%) of biocompatible chitosan, which is synthesized from the waste of shrimp shells, are utilized to investigate its potential in resistance of clay specimens subjected to 1, 2, 3, 6, 12, and 24 freezing and thawing cycles. The results demonstrate that the stress–strain behavior and compressive strengths of the specimens significantly depend on the amount of added chitosan solution. The unconfined compressive strength grows as the chitosan content increases from 2% to 6%. The 8% chitosan destroys the balance in the overall electrical neutrality of the mixture and does not make a noticeable influence in comparison to 6%. Moreover, the interparticle interactions are strongly linked to the curing time and moisture content of specimens, and chitosan solution can provide an extra interaction among clay particles in the early days. Increasing the curing time for the treated specimens leads to an increase in compressive strength while its efficiency remains constant over time. The durability index used to quantify the resistance of the treated specimens to freeze–thaw damage reveals that by three freezing and thawing cycles, the index reduces to 0.64 and 0.66 for samples in optimum and saturated water contents, respectively. This reduction will be negligible for higher cycles (e.g., 0.53 and 0.50 for 24 cycles). In addition, according to the analysis by scanning electron microscopy, the number of freezing and thawing cycles has a substantial influence on enlarging the voids and clay disintegration, which damages the stabilized soft clays.

Practical Applications

The freeze–thaw cycles change the geotechnical properties of soft clays and result in a further alteration in soil structure and loss of strength. These effects should be considered for a safe design in cold regions, particularly those underlined by permafrost. This research is performed to investigate and quantify the behavior of using an environmentally friendly material known as chitosan, which is one of the low-cost biopolymers extracted from discarded crustacean shells. In soft soils, the size of pores is approximately large (4–5 μm) and cycles of freezing and thawing cause an extra increase in the size of the voids. Mixing 6% chitosan at the optimum water content and curing for 28 days cause the chitosan to react with clay minerals and reduce the size of the voids to approximately 2–3 μm, resulting in a solid structure that is 90% more durable than the untreated soils.

This manuscript presents and discusses the results of an experimental study on the deformation behavior, strength, and microstructural development of cemented paste backfill (CPB) with chloride-bearing antifreeze (calcium chloride, CaCl₂) in subzero environments. CPB samples with CaCl₂ at various concentrations (0, 5, 15, and 35 g/L) were cured at different subzero temperatures (−1, −6, and −12°C) that represent temperatures to which CPBs may be exposed in mines located in permafrost or cold regions. Unconfined compressive strength (UCS) tests were conducted after specific curing time (7, 28, 60, and 90 days). Moreover, microstructural analyses and monitoring experiments (for volumetric water content and matric suction) were performed. The results showed that the addition of calcium chloride antifreeze reduced the strength of CPB and had a significant impact on its stress–strain behavior and microstructural characteristics. Furthermore, it was also found that the strength of CPB decreased with an increase of calcium chloride concentration and subzero curing temperature. These findings provide important guidance for mine backfilling work of CPB with chloride-bearing antifreeze additives and productivity improvement in subzero environments.

Ice gouging is one of the critical threats to the subsea pipelines crossing the Arctic and neighboring shallow waters. The burial of subsea pipelines is considered a viable solution to protect them against ice gouging attacks. The pipeline is usually buried below the deepest recorded ice gouges in that specific geographical location but is still threatened by subgouge soil deformation that is extended down the ice tip due to the shear resistance of the seabed soil. Determination of the subgouge soil deformations is a challenging design aspect that usually requires costly experimental and numerical studies to ensure the structural integrity of the buried pipeline against ice gouging. In this paper, an alternative and cost-effective methodology has been proposed using the group method of data handling (GMDH) to simulate the horizontal and vertical subgouge soil deformation profiles in the sandy seabed. Ten GMDH models (GMDH 1 to GMDH 10) were defined by using the governing input parameters comprising the soil depth ratio, the gouge depth ratio, the shear strength of seabed soil, the attack angle, the frontal berm height ratio, the horizontal and vertical loads, and the ice dynamics. The results from the best GMDH models were compared with the artificial neural network and empirical approaches, which showed a robust performance.

Snow sintering involves the formation of bonds between snow particles and is critically important in the construction of snow pavements in polar regions. In areas where the temperature never exceeds −20°C, such as the South Pole, snow sintering occurs so slowly that the construction of a seasonal snow runway is impractical. To accelerate the rate of sintering at the South Pole, discoloration of the snow surface with a liquid dye has been considered, but has not been demonstrated in practice. This is because of the high financial cost of proving new technologies in logistically challenging polar environments. In order to demonstrate the potential of liquid dye as a sintering accelerant for snow pavement construction, this study was aimed at measuring the sintering of manufactured snow samples stored in a mobile cold room. The manufactured snow was treated with 0%, 1%, 2%, and 3% (by mass) liquid dye and then allowed to sinter in a simulated South Pole environment. The sample temperature, density, and compressive strength were measured before dye application, as well as after 1, 5, 11, 15, and 20 days of sintering following application of the dye. The manufactured snow samples exhibited particle size distribution, density, and rate of strength gains that were consistent with those of processed polar snow. This finding allows conceptual snow research to be confidently and conveniently performed in nonpolar environments prior to being verified at the South Pole. The results also showed that 2% to 3% (by mass) of inert liquid black dye significantly increased the temperature, density, and compression strength of the manufactured snow samples. Consequently, it was concluded that liquid dye solutions have the potential to allow the construction of a seasonal snow runway at the South Pole, if this is deemed to be environmentally acceptable. In the future, these findings must be verified using real snow in a polarlike environment.

Ice load is one of the main loads that needs to be considered in the design and construction of wading bridges (bridges whose piers are submerged in water) in cold regions, and ice velocity, area, and thickness are the main parameters that affect ice load. A noncontact measurement technology based on the “ scale method” was proposed to realize small-range monitoring of river ice by laying calibration grids on the ice surface. The “bounding rectangle method” and Harris corner detection were used to accurately identify the area and velocity of a single ice drift. Also, the thickness of ice drift was estimated by statistical analysis. Considering the Huma River basin in the Daxing’an Mountains as the research object, field tests were performed to determine the flow ice parameters. The results indicate that noncontact measurement technology can accurately identify the velocity and area of ice drift and has wide application prospects, thereby providing a reference for the structural design and safety evaluation of wading bridges in cold areas.

In hydro-environmental and natural resource studies, Alaska is characterized by sparse hydrologic data. The state’s hydrologic data set could be increased by using a nonintrusive gauging method, large-scale particle image velocimetry (LSPIV), which is limited in its current application to a single camera. This study seeks to assess the feasibility of using multiple cameras to diversify the conditions in which LSPIV may be applied. Using specialized software and the deployment of multiple cameras, we compared multiple-camera LSPIV discharge measurements with those determined by using an RDI River Pro acoustic Doppler current profiler and accepted single-camera practices used with LSPIV. The results indicate the feasibility of using multiple cameras, with additional work. Furthermore, the data indicate the possibility of an empirical relationship between the velocity index (α) and aspect ratio (B/H, width divided by average depth).

Abstract

Sump pumps protect below-grade structures from water damage by pumping water from a sump well to the surface through vertical discharge pipes. However, after draining the sump well, the discharge pipes typically remain water-saturated, which is problematic whenever the discharge pipe is exposed to freezing conditions that cause damage from the expansion of freezing water. Current methods to protect discharge pipes from freezing include heat tape or routing the discharge pipe through a conditioned space. This study presents a theoretical analysis and hydraulic experiments for a new method using pneumatic evacuation immediately after each pump activation. The results demonstrate the feasibility of this new method for vertical pipe lengths up to 3.05 m (10 ft), pipe diameters up to 52.6 mm (nominally 2 in.), compressed air with a minimum pressure of 138 kPa (20 psi), and a minimum duration of 10 s.

Practical Applications

Sump pumps are an important part of the system that keeps water from damaging basement walls and floors. Sump pumps are found in a sump well below the basement foundation. Water accumulates in the sump well and is pumped to the surface and away from the house through polyvinyl chloride (PVC) pipes. This vertical PVC pipe remains full of water from approximately the depth of the foundation to the ground surface. Often, the discharge pipe is exposed to freezing conditions and is subject to damage from the expansion of freezing water. The current methods employed to protect discharge pipes from freezing are using heat tape or routing the discharge pipe through conditioned space. At times, these methods are not possible or practical. In this study, an experiment was performed using varying pressures of compressed air at varying time durations to remove water from varying pipe diameters. The results of the experiment show that water can effectively be removed from a 2-in.-diameter 10-ft-long pipe using 20 psi compressed air for 10 s. Based on this study, the proposed method to use compressed air to remove water from below-grade sump pump discharge pipe subject to freezing is a reasonable alternative to the currently used methods.