On January 16, the Aimin Tunnel on the Harbin-Mudanjiang Passenger Dedicated Line officially broke through, laying the foundation for the opening and operation of the entire line.

The 292.995-kilometer Harbin-Mudanjiang Passenger Dedicated Line is an important component of the rapid passenger transport network in Northeast China. It starts in Harbin and ends in Mudanjiang, with a designed speed of 250 kilometers per hour, forming a major transport corridor from the port of Suifenhe in eastern Heilongjiang Province to the port of Manzhouli in the Inner Mongolia Autonomous Region.

The Aimin Tunnel is located in China's cold region, where the extreme minimum temperature can reach minus 35 degrees Celsius. It is a tunnel with an extremely high risk rating in China's severe cold region, and construction faced technical challenges such as frost heave prevention, snow damage prevention, and winter construction. The tunnel passes through multiple loose sedimentary layers, Tertiary mudstone and sandstone strata, and other formations, with Grade V and Grade VI surrounding rock accounting for 95% of its length.

After field surveys and verification, the relevant construction units established a technical research team. For the creeping geology in the tunnel's entrance section, they adopted the measure of “anti-slide pile protection + surface grouting”; for the interbedded sand and mudstone section between No. 1 inclined shaft and No. 2 inclined shaft, they used methods such as full-curtain grouting, thereby improving the self-stability of the soil layer and ensuring safe excavation.