Montana State engineer wins NSF grant to study the effects of melting permafrost on structures

BOZEMAN - The National Science Foundation recently awarded a civil engineer at Montana State University a grant to explore how melting permafrost might damage structures such as buildings and roads built upon it.

Permafrost is a layer of soil, rock or sediment that remains frozen for two or more consecutive years. It is found in regions with cold climates, such as the Arctic, sub-Arctic and high mountain areas, including some regions of western Montana. Permafrost can extend down from a few meters to hundreds of meters below Earth's surface.

The NSF awarded the $981,000 grant, titled "Collaborative Research: Multiscale Characterization of Permafrost and Frozen Soil Properties: Bridging Micro-and Macro-Scales," to principal investigator Mohammad Khosravi from the Department of Civil Engineering in MSU's Norm Asbjornson College of Engineering and to Ali Khosravi, an assistant professor in civil and environmental engineering at Auburn University.

"Approximately 85% of Alaska is underlain by permafrost, and much of the infrastructure built there relies on the strength of the frozen ground for stability," Khosravi said. "With rising temperatures due to climate change, we're witnessing permafrost degradation, which threatens the structural integrity of roads, buildings and other infrastructure."

Melting permafrost could also affect oil and gas pipelines in Alaska, he said: "As the ground settles unevenly, differential settlement can occur, which may compromise the structural integrity of the pipelines."

Khosravi and three MSU doctoral students will work with Ali Khosravi, Mohammad's twin brother, on the grant. The scientists hope to better understand the complex interactions between climate, unfrozen soil and permafrost, and they hope the data will provide insights into how climate change accelerates permafrost degradation.

Mohammad Khosravi said this deeper understanding will enable more accurate predictions of the resulting loss in soil volume, structural cohesion and the erosion of coastal and riverbank bluffs. Additionally, he said, this information will improve risk assessments for existing infrastructure and planned developments on permafrost, as well as inform the design of future infrastructure, including more robust foundations that extend deeper into the permafrost.

But how deep below the surface would be deep enough?

To answer that, the team will conduct experiments in collaboration with the University of California-Davis using an NSF-funded geotechnical centrifuge facility to simulate various environmental conditions - including temperature fluctuations and water infiltration due to precipitation. The centrifuge, which measures 18 meters in diameter (about 60 feet), generates gravitational force, or g-force, by spinning at high speeds, allowing the team to study the effects of different parameters on permafrost degradation and evaluate the effects of climate change on the frozen ground.

"The centrifuge makes the soil heavier, so it replicates stress conditions that you have in the field," Mohammad Khosravi said. He added that the centrifuge also effectively accelerates time, allowing the scientists to compress years of permafrost behavior into hours, something that is essential for studying long-term effects. Additionally, the controlled environment enables precise manipulation of factors like temperature and infiltration, ensuring accurate simulations of natural conditions.

"You can measure temperature changes in the soil, water content and soil stiffness," Khosravi said. "This allows us to observe how different materials respond and how their properties evolve throughout the process."

Two of the three MSU doctoral students will travel to UC-Davis to conduct the centrifuge experiments.

"Structures and infrastructure are already failing due to permafrost degradation," Khosravi said. "This is an urgent issue that demands immediate attention, and we must develop effective solutions to prevent further damage."