8 Dec 2025

Improved Prediction of Soil Thermal Properties Using Gated Recurrent Unit Neural Networks

Abstract: Frost actions, such as frost depth penetration and thaw weakening, are damaging to airfields and roadways in cold regions. Machine learning techniques, such as recurrent neural networks, have been applied to this problem, but with a large focus on long short term memory (LSTM) neurons. Gated recurrent units (GRUs) are similar to LSTM neurons in terms of accuracy, but are more computationally efficient, and have yet to be applied to predicting soil thermal properties. Using a hyperparameter search, an optimal architecture for a recurrent neural network based on gated recurrent units was identified. A general model using temperature, thermal conductivity, and volumetric moisture content was found to predict temperatures effectively, having an error of less than 0.25°F across all depths. For predicting thermal conductivity, a model including temperature but not moisture content was found to be effective. For moisture content, the results were inconclusive as both models were affected by similar errors. Overall, the GRU-base recurrent neural networks were found to work well for predicting soil thermal properties in high-plasticity clays, and it is recommended to further expand the training datasets to include other frost-affected soil types.

10 Oct 2025

Standard Operating Procedures for the Site Selection, Design, and Maintenance of All-Season Roads Linear Infrastructure

Abstract: Planning, designing, constructing, and maintaining all-season roads in cold regions requires navigating complex environmental, hydrologic, and geomorphologic challenges. Harsh conditions, such as permafrost, frost-susceptible soils, muskeg, and extreme cold, are compounded by limited data availability, remote locations, and fragile ecosystems. Recent Arctic strategies across the DoD have identified changing weather patterns as significant threats to infrastructure, operations, and training land management in these regions. Key risks include degrading permafrost, changes in precipitation intensity and duration, and the loss of soil bearing capacity in saturated soils, all of which are examined in detail. As the Department of Defense expands Arctic training capabilities, infrastructure investments across Alaska must balance operational goals with sustainability and resilience. This report synthesizes the military’s typical methods for constructing roads in contingency environments, identifies practices used in the construction of the Alaska-Canada Highway, and draws from consultations with training land managers, a thorough literature review, and active engineering research. The report highlights the importance of holistic design that prioritizes longevity, environmental conservation, and safety by addressing cold-region challenges, mitigation strategies, and best practices. This resource is indispensable for military units and infrastructure planners tasked with navigating the complexities of cold-region infrastructure construction and operation.