The Lanshulin Tunnel, a key part of the Qinhuangdao–Shenyang Expressway, runs 35 meters below a 600-year-old section of the Ming Great Wall. Preventing construction damage to this cultural treasure was both a major challenge and top priority. To protect the site, the team replaced blasting with excavation and implemented an integrated system of investigation, monitoring, and early warning. Using precise, meticulous methods, they completed the infrastructure project while preserving the historic monument.