| Résumé | Winter roads are seasonal structures that only exist in the winter – they run over frozen land and frozen water surfaces (lakes, rivers). These roads can only open once the segments running over ice covers have achieved a thickness deemed safe enough to accommodate the weight of the vehicles expected to travel on them. A review of documented cases is presented in which reinforced ice was used for real operational scenarios as well as in field studies – these include a description of construction and/or deployment procedures. A review of laboratory investigations on reinforced ice is also provided, with a succinct account of the loading modes and types of testing that have been done, as well as their outcome. The difference between macroscopic and microscopic reinforcement is outlined, with examples. A distinction is made between the concepts of ice ‘failure’, linked with ‘first crack’, and breakthrough, as well as between linear and planar macroscopic reinforcement. Resistance to deformation of reinforced ice, the importance of bonding between ice and reinforcement materials, and the resistance to breakthrough are aspects that have been addressed by previous investigators. The outcome of a computational modeling exercise, aimed at assessing resistance to ice failure for linear reinforcement (lumber and steel), under specific assumptions, offers guidance in the choice of material size, type, spacing, aspect ratio and depth in the ice cover. Options for deployment procedures include: i) laid onto the ice, ii) in the water before freeze-up, iii) inserted through and below the ice, and iv) inserted into the ice surface. Breakthroughs are complex phenomena involving a sequence of radial and circumferential cracks. Retrieval of reinforcement after the winter road season is over is another aspect that warrant attention in a planning scheme, but very little information was found in that regard. Determining the bearing capacity of reinforced ice is seen as an outstanding challenge in being able to implement a safe and effective reinforcement procedure. The solution could be to perform real-scale, fully controlled ice testing, and most importantly, allow for breakthrough to be achieved, so as to avoid overly conservative designs. A simple reinforcement procedure would have to be devised beforehand, further guided by adequate computational modeling. This would lead the way toward guidelines on implementation. |
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