Field tests of 3D laser scanning in urban excavation

When developing deep excavations in urban environments, a critical concern is the influence of construction-related ground movements on neighboring facilities and utilities. Ground movements may cause structures supported by the affected ground to deform and possibly be damaged. It is important to predict and control the extent and distribution of ground movements that result from constructing underground space. Currently, engineers can estimate ground movements using a combination of semi-empirical methods based in part on past performance data and the results from model simulation using numerical analysis. However these sophisticated analyses require accurate as-built construction staging data which most projects lack. The traditional approach of collecting field information is both labor-intensive and time-consuming. A system capable of gathering accurate as-built data in a timely manner would be highly beneficial for controlling and predicting ground movements in urban excavation sites. Significant developments in information technology are opening new ways to collect better as-built construction field data. A research team at the University of Illinois at Urbana-Champaign has been exploring the use of 3D laser scanning technology in urban excavation. Funded by National Science Foundation, this research field-tests the 3D laser scanning technology at urban sites in the Chicago area and explores better integration between engineering and construction field controls. This paper reports preliminary findings of the project, which include data from a five-month tracking of an urban construction site. It demonstrates the potential integration of 3D excavation data with finite analysis tools.