Tunnels have saved us from hours of detours into mountains and rocky surfaces for decades. However, it is not the only technique to shorten time and develop new roads that connect cities with each other. In this regard, it is worth telling how China once again demonstrates its ability to transform the landscape with a technique that seems straight out of a science fiction movie: literally cut mountains in half to build roads. Explosives, giant excavators and millimeter planning are what is needed to divide rock formations hundreds of meters high.
How the technique works. After a geological study Thoroughly determining the composition of the mountain and planning cuts so that they do not compromise the stability of the terrain, engineers use controlled explosives to create the first fractures, followed by specialized heavy machinery that can dig tens of meters deep per day.
The remaining walls are stabilized with metal mesh, shotcrete and drainage systems to prevent slipping. Although it is also true that there is not a single clean pit, since the usual thing is to excavate in phases, in terraces or stepped benches that open from top to bottom. The final result is a clean passage through the mountainwith vertical walls up to 200 meters high that look like someone with a giant knife has gone through them.
A technique in multiple regions of China. These ‘cut walls’ can be seen mainly in the mountainous provinces of GuizhouYunnan and Sichuan, where karst terrain and complicated rock formations made traditional tunnel construction impractical. High-profile projects such as the Guiyang-Qianxi Highway or the Taihang Mountain Pass have turned hours-long journeys into minutes-long journeys. It has also been used in the construction of the high speed railway that connects Beijing with Guangzhou, where several sections cross mountains literally split in half.
The last great example: Huajiang. The most recent and spectacular case is once again in Guizhou, within the S57 Liuzhi-Anlong highway, where these cutting techniques coexist with one of the most ambitious bridges ever built. The Huajiang Canyon Bridge opened on September 28, 2025 and was presented by China Railway (CREC) as the highest bridge in the world by distance between the roadway and the river, with a height of 625 meters, a length of 2,890 meters and a main span of 1,420 meters. According to China Dailyreduces the canyon crossing from about an hour to just two minutes.
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Why are tunnels not used?. The decision to cut rather than drill often comes due to technical criteria and specific economics. In terrain with a high concentration of groundwater or unstable rock formations, building tunnels can be more expensive and risky than direct cutting.
Additionally, maintenance of an open passage is considerably easier than that of a tunnel, which requires constant ventilation, lighting and drainage systems. In low-lying mountains, cutting also allows for the greater proliferation of heavy vehicles, especially in an economy so dependent on road freight transportation.
Beyond China. Although China has perfected and popularized this technique, it is not the only country that uses it. Norway uses similar methods in its fjords, where the characteristics of the terrain make cutting more viable than drilling (although in this country we also have spectacular tunnel projects under construction such as Rogfast). In the United States, the Cumberland Gap Pass in the Appalachians was created using cutting techniques, although on a smaller scale. However, no country matches the ambition and scale of Chinese projects, which have turned mountain cutting into an art.
Environmental impact. Although the benefits of using this technique are evident, especially in the aspect of economic development and its effectiveness in connecting remote regions, this technique also generates some debate. around the environmental impact.
And this type of construction can end up destroying local ecosystems, altering natural drainage patterns or fragmenting wildlife habitats, not to mention the amount of dust and noise during its construction that can generate millions of tons of waste. It should also be said that it is not the most used technique, since tunnels continue to be the preference except in exceptional cases.
Cover image | Zhang Meifang and r/Damnthatsinteresting
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