Multisensory and BIM-Integrated Digital Twin to Improve Urban Excavation Safety

Urban excavation is an indispensable process for many construction activities such as road paving, house building, and pipe rehabilitation. However, the everincreasing complexity of underground utilities (e.g., water mains, gas lines, and sewage pipes) in urban environments challenges the safety of urban excavation, posing tremendous risks of potential collision and damage accidents. By obtaining real-time excavation information and high-fidelity simulation to evaluate safety risks, digital twin (DT) has an unexplored potential to improve urban excavation safety (UES). This research aims to investigate how a DT for urban excavation can be developed and used to improve UES. First, a multisensory solution is proposed to equip the physical excavators with the capability to precisely estimate their three-dimensional (3D) poses based on the kinematic model and social spider algorithm (SSA). Second, a building information model (BIM) of buried utilities and a 3D model of the excavators are integrated to form a dynamic virtual model that mirrors the actual excavation process. Third, based on the physical-virtual coupling DT, a real-time safety control method is proposed to proactively monitor urban excavation, dynamically assess collision risk, and timely warn against unsafe behaviors. A system prototype was developed and applied in a case study in Shandong, China. Results show that the system can precisely twin the pose of the excavator, increasing the estimation accuracy of the translation by at least 4.0 cm. The system can display the dynamic spatial position of the excavator and the buried pipes in 3D and automatically guide the excavator to operate safely in real-time, thereby avoiding potential collision accidents.