Confined Space and Inner-City Projects—Future Challenge and Opportunity for Diaphragm Walling

Diaphragm walls are known as underground structural elements commonly used as retention systems for excavation pits and shafts and permanent foundation walls or elements. One can anticipate that global urbanization and increasing demands on environmental considerations will need to be accommodated in underground space in the future. These trends show an increasing requirement for diaphragm walling in even more complex conditions, especially in inner-city applications with limited space. Complex conditions in terms of space limitations, especially for inner-city jobsites, require specifically adapted solutions for slurry, spoil, reinforcement and concrete handling and the related logistics to ensure smooth production. Furthermore, one focus will be given to the QA/QC topics of the production process. Real-time installation control, data transfer and reporting systems become more and more important. Therefore, the paper will describe the construction method and the sequence of activities required for the construction of diaphragm wall systems. It will also describe the main equipment that will be needed to execute these works under various conditions. In addition to the general description of the system and the required equipment, the paper will show some site examples for infrastructure projects with their specific solutions when working under space restrictions.