In the towering mountains of southwestern China lies an engineering marvel that quietly narrates a tale of human wisdom and courage—Shimen Tunnel. This tunnel is not only a monumental achievement in China's transportation history but also a shining gem in the world of tunnel construction. Behind this tunnel lies a legendary story that spans millennia, about how ancient craftsmen used their ingenuity and bravery to carve a passage through the daunting natural environment.
In the fourth year of Yongping during the Eastern Han Dynasty (61 AD), Emperor Ming of Han, Liu Zhuang, ordered the construction of the Baoxie plank road to strengthen control and development of the western regions. This road was not only a crucial link between Guanzhong and Hanzhong but also a strategic point vital for maintaining national unity and stability. However, the construction faced unprecedented difficulties. The road was blocked by mountain rocks, presenting a significant challenge to the craftsmen.
According to the "Compilation of Baogu Valley Relics," when faced with these obstacles, the craftsmen employed a primitive but ingenious method called the "fire-setting and water-quenching" technique. They would first pile up large amounts of firewood and ignite it to heat the rocks until they were extremely hot. Then, they would rapidly cool the rocks with cold water, exploiting the thermal expansion and contraction properties of the rocks to weaken them, making excavation easier. This method, though primitive, demonstrated remarkable creativity and courage, showcasing the ancient craftsmen's wisdom and determination.
However, this method has not been without controversy. Some later scholars questioned its effectiveness, arguing that it was difficult to control the damaged areas and that the rock surfaces might not be smooth enough. Despite these doubts, the successful excavation of Shimen Tunnel remains a significant milestone in China's tunnel history. It not only solved the transportation bottleneck but also provided invaluable experience and lessons for future tunnel construction.
After years of arduous efforts, the Shimen Tunnel was finally completed in 62 AD. The tunnel is 16 meters long, 3.45-3.75 meters high, and 4.1-4.4 meters wide, allowing modern small cars to pass through with ease. It became the most crucial section of the "Difficult Road to Shu" and a key point controlling the Hanzhong Plain and Sichuan. The idiom "Repairing the plank road openly while secretly crossing the Chencang" refers to the Baoxie Road. This idiom not only reflects the clever use of ancient military strategies but also highlights the Shimen Tunnel's strategic importance in military history.
The successful excavation of the Shimen Tunnel is a testament to the intelligence and bravery of ancient craftsmen and marks a significant breakthrough in China's tunnel construction history. It provided valuable experience and insights for future projects and left us with a precious cultural heritage. Let us remember this history, inherit that spirit, and continue to write new chapters in China's transportation development.
Today, the Shimen Tunnel has become a stunning attraction, drawing countless visitors to experience its historical grandeur and significance. The spirit of self-reliance and hard work embodied in its construction continues to inspire us to move forward and create a better future.