Core Points - The Beijing East Sixth Ring Road renovation project has been completed and opened to traffic after five years of construction, allowing vehicles to traverse the urban sub-center through an underground tunnel [1][2] - The project is a key initiative for Beijing, spanning approximately 16.3 kilometers, with a 7.4-kilometer shield tunnel being a critical component [1] - The tunnel is the deepest in Beijing at 75 meters and one of the longest shield highway tunnels in China, overcoming significant construction challenges [1][2] Construction Challenges - The construction team developed two large-diameter shield machines, "Jinghua" and "Yunhe," to tackle technical difficulties such as shallow cover starting and high-risk hoisting [2] - The project utilized self-developed synchronous double-liquid grouting technology to control ground settlement to millimeter-level precision, filling a gap in China's large-diameter slurry shield tunnel technology [2] - Intelligent ventilation technology was implemented to monitor various data in real-time, improving air quality within the tunnel and achieving over 80% purification efficiency [2] Significance - The East Sixth Ring Road serves as a vital link connecting key areas such as Shunyi, Daxing, Yizhuang, and both Beijing Capital International Airport and Beijing Daxing International Airport [2] - The completion of the project is expected to enhance traffic coordination in the Beijing-Tianjin-Hebei region and improve the overall transportation service level in Beijing [2]