Statement of Task
An ad hoc committee of the National Academies will conduct a study to explore the potential advantages of underground development in the urban environment, to identify the research needed to take advantage of these opportunities, and to develop an enhanced public and technical community understanding of the role of engineering of underground space in the sustainability of the urban built environment, specifically the minimization of consumption of nonrenewable energy resources, construction materials, and negative impact on the natural, built, and social environments. In particular the study will:
• Summarize current geological and geotechnical engineering knowledge about underground development in the urban environment and how utilization of underground could increase sustainability, including knowledge of geologic site characterization, construction and geotechnical monitoring techniques, energy requirements, use of excavated materials, and lifecycle costs and benefits of underground infrastructure development.
• Identify the research needed to capitalize on opportunities for enhancing sustainable urban development through underground engineering, in the following areas:
• Underground characterization, prediction of the geologic environment, and ground response critical for successful design and construction of underground projects and critical facilities to maximize sustainability and resiliency;
• Construction and monitoring methodologies and enhanced excavation
of stakeholders, each with potentially different and sometimes opposing needs, interests, governing structures, and resources.
Refining the definition of sustainability as it applies to underground development was the first task undertaken by the study committee. Earlier work illustrates the difficulty defining terms such as “sustainability” and even “urban” (e.g., Shaffer and Vollmer, 2010). The concept of “Sustainable Development” was described by the World Commission on Environment and Development in 1987 as “meeting the needs of the present without compromising the ability of future generations to meet their own needs” (UN, 1987). Terms such as “resilience” are often related to sustainability (e.g., NRC, 2011). The present study committee considers the maintenance of quality of life as part of sustainability, and it recognizes that incorporating sustainability into societal management practice must occur at many scales—from the global and national down to the individual project scale. Defining sustainability as part of implementable urban systems at the local level becomes more difficult because the term becomes infused with