CHEN Xiang-sheng, FU Yan-bin, CHEN Xi, XIAO Hui, BAO Xiao-hua, PANG Xiao-chao, WANG Xue-tao
With the rapid development of the Chinese economy at the beginning of the 21st century, above-ground space resources have become increasingly saturated, and cities are faced with rapid expansion. With the construction of tunnels, metro stations, and complex underground projects, underground engineering structures exhibit unique characteristics, such as micro deformation, small spacings, large sections, deep buried depths, high precision, extended distances, and large sizes. These projects face three significant technical problems:water, softness, and deformation. These factors are difficult to predict and lead to challenges for underground construction technology and equipment. Therefore, this paper reviews and analyzes the technical progress and innovation in underground engineering in recent years, particularly construction technology, construction equipment, and digitalization technology. Displacement and deformation control techniques for water-rich strata in soft soil were analyzed in detail. The ground freezing technology of water-rich strata and comprehensive auxiliary construction control techniques for shield tunnels passing beneath metro tunnels are proposed. Typical super underground engineering equipment with green, intelligent, and independent intellectual property rights, which integrate artificial intelligence, the Internet of Things, and other leading-edge and core technologies for equipment, were described. The characteristics of modern underground space digitalization technology were established based on the following aspects:design, construction, monitoring, operation, maintenance, and application. The construction of a visual underground space information platform is the basis of achieving "transparent underground space" through co-construction and sharing of underground space information. The advanced forecasting and control of adverse geological, environmental disasters can ensure underground engineering safety. A control and management system based on the Internet of Things, big data, and other modern information technologies is critical in constructing the security of smart city infrastructure. Future underground engineering should strengthen the application of digital intelligence technology and achieve refinement, digitization, intelligence, and information of the entire construction.