With tunnel structures prefabricated in factories and excavation and construction carried out simultaneously on site, the complex construction of urban underground comprehensive utility tunnels will also be conducted like "building blocks." An underground comprehensive utility tunnel under construction in Chengdu, Sichuan Province, has for the first time in China adopted integrated construction combining segmented prefabrication and tunnel boring machine assembly, marking that China's urban underground comprehensive utility tunnel construction is expected to enter a modular phase.

　　The reporter learned from CCCC Second Harbor Engineering Co., Ltd., headquartered in Wuhan, that this urban underground comprehensive utility tunnel project, located in Chenghua District of Chengdu, is about 1.2 kilometers long. After completion, pipelines and cables for sewage, water transmission, water distribution, power, and communications will be installed in the tunnel.

　　Underground comprehensive utility tunnels concentrate numerous pipelines and cables for urban water supply, heating, power, communications, and other services in underground tunnel corridors. They can avoid the "road zipper" phenomenon of repeated road excavation, extend the service life of pipelines, and are therefore called the city's "hidden infrastructure project."

　　Zhang Shikui, chief engineer of the Chengdu Urban Construction Company of CCCC Second Harbor Engineering Bureau, introduced that compared with the traditional comprehensive utility tunnel methods of open-cut foundation pits, on-site pouring, and backfilling, this "building block" method uses multiple patented technologies to prefabricate all main structures of the comprehensive utility tunnel in a factory. Drawing on construction principles such as tunnel shield tunneling, it integrates soil excavation, mobile support, segment installation, and backfilling, achieving simultaneous jacking, excavation, and assembly.