Tunnels in the Cold: How Warmth Affects Their Lifespan

Tunnels in chilly areas often face a big problem: frost heave. This is when the ground swells due to freezing and thawing. To tackle this, an insulation layer is usually added. However, this layer does not last forever. It wears down over time due to repeated freezing and thawing, as well as temperature changes. This wear and tear can greatly affect how reliable these tunnels are. To understand this better, a study focused on a tunnel in the Qinghai-Tibet Plateau. This region is known for its cold temperatures. The study looked at what might happen over the next 50 years if temperatures rise by 2. 6 degrees Celsius or 4 degrees Celsius. These temperature increases are based on predictions. The study examined how the thickness of the frozen and thawed layers, the temperature around the tunnel, and the stress on the surrounding rock would change. It considered two situations: one where the insulation layer deteriorates and one where it does not. The study used a method called the Monte-Carlo method to figure out how these changes would affect the tunnel's reliability. The findings were clear: when the insulation layer deteriorates, the thickness of the frozen and thawed layers, the temperature, and the stress on the surrounding rock all increase. This happens whether the temperature rises by 2. 6 degrees Celsius or 4 degrees Celsius. As a result, the tunnel's reliability decreases. Specifically, with a 2. 6-degree Celsius increase, reliability drops by about 4. 5%. With a 4-degree Celsius increase, it drops by about 6. 3%. This study highlights an important point: as temperatures rise, the challenges for cold region tunnels grow. It is crucial to consider these factors when planning and maintaining tunnels in such areas. The impact of climate change on infrastructure is real and needs to be addressed proactively. Engineers and planners must think critically about how to build and maintain tunnels that can withstand these changes.