Journal of Cold Regions Engineering

The mechanistic–empirical (ME) design guide developed under the National Cooperative Highway Research Program represents a true change in the approach to engineering road structures. Changes in material properties with seasonal variations in moisture and temperature condition, which influence the mechanical response of the materials and hence the structural response of road layers, forced reliance on empirical measures to predict performance. These empirical functions will require calibration to ensure the prediction model is responsive to local conditions including adopted construction practice. The performance of pavements in cold regions clearly reveal the need to properly measure the distribution of stresses, strains, moisture, and thermal regimes, within road layers over a period of time. This paper presents the design, implementation, and use of a practical road instrumentation monitoring system capable of capturing all structural and environmental data for roadways. This proposed road installation scheme is simple yet effective in generating data that could be used to calibrate a host of design M-E and visco-elastic models including the new AASHTO design guide. Details include selection of sensors, data acquisition systems, data processing techniques, and some actual data.

Pedestrian safety on parking lots and sidewalks is a main concern under adverse winter conditions because of the reduced friction level caused by snow and ice contaminations. Although there is an intuitive understanding that the risk of slipping is related to the friction level of a pavement surface affected by snow and ice, there is limited knowledge on the underlying relationship and how friction level is affected by various factors such as contaminant type and amount, pavement type, and other factors. Knowledge of this relationship with the contaminant types, coefficient of friction, and risk of slipping is essential for establishing cost-effective level of service policy and standards for winter maintenance of these transportation facilities. This paper summarizes the results of a field study investigating the friction characteristics and associated slipping risk levels of different contaminant pavement surfaces under a variety of weather conditions. A large number of field tests were conducted on three common pavement structures—asphalt concrete, interlocked brick, and Portland cement concrete—with a variety of surface contaminants such as unplowed snow, plowed snow, slush, and ice. It was found that pavement surfaces of major contaminant types have distinctive ranges of friction and slipping risk levels, and they could be inferred from each other, suggesting the feasibility of establishing a friction-based service standard.

The purpose of this study is to establish a numerical simulation model that addresses the combined thermal-hydraulic-mechanical process of frost heave. Of the several practical frost heave estimation theories, the authors adopt Takashi’s equation, which has been successfully applied to one-dimensional frost heave estimation. In this paper, Takashi’s equation is used to assess the frost heave ratio during freezing. Takashi’s equation is expanded for a two-dimensional evaluation by introducing an anisotropic parameter to distribute the frost heave ratio in different directions. This model couples Fourier’s law for heat transfer and Darcy’s law for unfrozen water flow. Latent heat is seriously evaluated by equivalent heat capacity method. For the thermal and hydraulic processes, this model considers temperature- and pressure-dependent hydraulic conductivity by an empirical equation. Both saturated and unsaturated conditions are addressed in this model. A finite-element method is adopted, and the time domain solution employed is the widely accepted Crank–Nicolson method. Specifically, it is assumed that the pore water pressure head and water content at freezing are zero. In this situation, it is not necessary to consider the hydraulic condition during the freezing process because it is accepted that Takashi’s equation can deal with the hydraulic process of freezing. Future complex and detailed models will require a more complete understanding and formulation of the processes in freezing zone; however, this is outside the scope of this paper. Finally, in order to demonstrate the applicability of this model, simple examples and simulations are provided.

Snow as a construction material has been used for centuries, with igloos among the first examples. Each winter, snow and ice villages, buildings, and artwork are built in many places around the world. Machine-made snow manufactured by snow guns is commonly used for constructions made of snow. However, only a few basic studies on machine-made snow have been published. Knowledge based on experience and studies on natural snow constitute the basis for constructions made using snow and ice. Through material tests on machine-made snow used for construction, data on important physical and mechanical properties have been established that aim to improve and optimize safe constructions made from snow. Strength tests have been performed using two different qualities of machine-made snow. Specimens used for testing were cut out from one block of snow that had a coarse-grained structure with clusters of ice in the snow and from one block of snow with a fine-grained and homogeneous structure. The density for each tested snow sample was measured and strength tests were performed at different deformation rates to investigate the relationship between mechanical properties and deformation rate or strain rate. The load response curves achieved from the strength tests were used to evaluate compressive strength, Young’s modulus, and the residual modulus. The results show that compressive strength increases with increasing density. Increasing compressive strength with an increasing strain rate was also observed for fine-grained snow quality specimens, whereas no similar tendency was observed for coarse-grained snow. The residual modulus increased with an increasing strain rate up to a certain critical value for the fine-grained machine-made snow specimens. Regression analysis was used to investigate whether any dependence was observed between the calculated mechanical properties; no further relationship between the mechanical and the physical properties was noticed.

A continuous snow fence of 50% porosity, 130 m in length, and 4.0 m height was installed to overcome the snowdrift problems at Banihal Top (Jammu and Kashmir, India) in the Himalayan region. The avalanche sites, which affect the north and south Portals of the Jawahar Tunnel, have catchment areas near Banihal Top. The width of mountainous ridge at this site is about 60 m except within a central depression area where the width is about 200–250 m. Snow mass is eroded from the southern windward slope and deposited on the northern leeward slope toward the Kashmir valley during the winter. The rates of erosion and deposition of snow are controlled by snow characteristics, the snow surface roughness, terrain features, and the snow fence configuration. The snow at Banihal Top is wet in nature and snow deposition due to snow drifting is found to be about $105{\mathrm{m}}^3$ per running meter of snow fence having a height of 4.0 m. The storage capacity of this snow fence is higher than that of previously installed snow fences of 3.0 and 3.5 m heights. The extension of deposited snow on the leeward side of the snow fence is found to be 15–17 times the snow fence height; this is comparatively smaller than the extension of drifted snow mass reported in Western countries. It is observed that the nose of the drifted snow profile is shifted toward the snow fence with a reduction of the snow fence porosity due to snow riming. Change in porosity due to snow riming of the fence reduces its capacity but it serves to accumulate more snow if the riming happened after the aerodynamic equilibrium state is reached. The snow fence has reduced the snow mass accumulation in the formation zone of the avalanche site. It has also helped to prevent blockage of the national highway NH-1 A and the North Portal of the Jawahar Tunnel in Jammu and Kashmir, India.