CCTV News: Railways are the country's steel artery. The Northeast Railway Line crosses the frozen soil layer and the snowstorm zone. Railway builders use innovative technologies to solve the world problem of frozen soil roadbed settlement, injecting new impetus into the economic development of high-altitude areas. Let’s take a look at the engineering testers who “escorted” the railway construction in the cold north.

Anchor Xing Kaichen: The anchor experiences a new position and the labor is the most glorious. Now I am located at the construction site of the Yichun section of the northernmost high-speed railway under construction in China - the Harbin-Iraq High-speed Railway Pilot Project. The job I want to experience today is called a railway engineering tester. The one standing next to me is my team leader today. Hello, Master Du. Master Du, my first question is what kind of job is the railway engineering tester?

Senior Engineer of China Railway 22nd Bureau Du Chunrui: Escort the quality of our railway engineering projects.

The Hagrid High-speed Railway is the northernmost high-speed railway under construction in China and is also China's first trunk railway crossing the permafrost area. The lowest temperature throughout the year can reach minus 40°. After completion, it can effectively strengthen the economic ties between the northern region and the developed inland areas, promote the revitalization of old industrial bases, and create a new engine for economic growth in the Northeast. Engineering testers shoulder the heavy responsibility of geological surveying and full process quality control, and are known as the "rail escort".

Concrete rebound detection is a method of estimating concrete strength by bounced against the concrete surface by bounced on the bounce rod and measuring the distance from the heavy hammer. Using the rebound value as an indicator related to strength, it can estimate the strength of concrete.

In the construction of railways, it is normal to open roads and build bridges when passing through mountains and encountering water. Because they are the people who build roads, there is almost no road under their feet. Our testers are not only "escortists" but also "pioneers". They often shuttle through deep forests or wilderness mountains to collect test samples.

Frozen soil is a variety of rocks and soils containing ice, which are rheological. Construction projects in frozen soil areas face two dangerous problems: frost swelling and melting.

Experts not only travel through mountains and rivers, break ice and shaving soil, but also need to master advanced professional knowledge.

High moisture content frozen soil can easily cause subgrade settlement deformation or frost swelling damage when temperature changes. After more than 8 hours of testing, we came up with the results that the staff can determine the type of roadbed filler based on the moisture content of the permafrost and formulate corresponding construction plans to ensure the project quality and durability of high-speed railways.