Challenges in underground construction

Abstract

Infrastructure construction in mega-cities poses great challenges. Most transportation systems, energy and water supplies, shopping facilities and other daily necessities require underground spaces. However, underground construction in soft ground is demanding and must be carefully undertaken with great attention to temporary works design. Additionally, in areas with a high water table, watertight construction is a primary requirement in the whole-life maintenance strategy. This paper deals with key aspects in tackling such problems. Several recent construction projects in Shanghai are used to illustrate practical solutions to these problems. In dealing with long-span underground spaces, the use of reinforced concrete is compared with a composite construction. The design procedure for supporting deep excavations is based on constructing ‘cut-and-cover’ structures. Early-age cracking in underground structures is prevented by simulation-based design and on-site monitoring. This paper also provides an example of sustainable development for infrastructure through planned maintenance, and inspection and appraisal techniques for existing infrastructure. All of the examples show the technical aspects of the work of an efficient municipal engineer.