Rapid urbanization results in the great development of underground facilities. This is underlined by the rapidly increasing number of metro lines, utility tunnels, water conveyance tunnels, underground stations, underground cities, underground garages, and underground storages for water, grains, data devices, etc. High utilization of urban underground space (UUS) requires Intensive Construction Technology (ICT).

3D Printing represents one of the emerging technologies in the age of digitization and intelligence. It has been drawing the attention of scientists in many fields, including civil engineering.

Concrete structural failures generally initiate with cracks. Effective control of cracks is the key to ensure the safety and durability of concrete structures.