The world's population has been increasing in recent years. The development of underground space can effectively expand the living space and improve the quality of human lives. In the development process of underground space, the construction of urban tunnels has become a critical issue. Since the "Metropolitan Line" of London completed in 1863, subway construction has become a symbol of urban development, and subways are being built in many cities around the world. Under weak geological conditions, the construction and operation of the subway will interact with the surrounding environment. For example, the construction of tunnels near existing buildings and underground pipelines will affect existing facilities and the surrounding environment. Moreover, during the construction and operation of tunnels in soft soil, the ground settlement around the tunnel will adversely affect the adjacent buildings. Research related to this is currently mainly one-way research (or single-direction research), and there are few studies on the interaction between the subway and the surrounding environment under construction or operation.

Under the modern and complicated urban environment, clarifying the interaction mechanism and mutual influence mechanism between the urban tunnel and the surrounding environment is of considerable significance to the construction and operation of the tunnel, and the protection of surrounding buildings. Therefore, doing related research is urgent to develop reasonable plans and measures to deal with related challenges.

This Special Issue aims to publish original theoretical research articles, review articles, and case studies related to the interaction between urban tunnels and the surrounding environment under weak geological conditions. We particularly welcome papers related to the interaction between the construction and operation of urban tunnels and surrounding facilities, advanced urban tunnel construction technology, subway protection, and reinforcement technology, and the protection of facilities around the tunnel.

Potential topics include but are not limited to the following:

• Interaction between the construction and operation of urban tunnels and surrounding facilities (such as buildings, underground pipelines, pile foundations)
• Advanced urban tunnel construction technology
• Characteristics of soft urban soil (such as characteristics of freeze-thaw soil, vibration characteristics)
• Subway protection and reinforcement technology
• Protection of facilities around the tunnel (such as buildings, underground pipelines, pile foundations)