Indicators of urban underground space development for implementing sustainability

`Sustainable Development (SD)´ has become a guideline and value to be pursued for few decades. However, it is difficult to balance the development of economic, social and environmental sectors at the same time, especially in urban cities. Recently, underground development has been suggested as a solution to problems caused by rapid urbanization. In this study, the role of underground space in urban areas is evaluated as an effective method towards SD and 22 appropriate indicators are proposed as results. The use of underground structures can contribute to sustainability in four ways: by (a) creating additional open spaces above the ground, (b) consuming energy efficiently, (c) providing strong protection from severe weathers or natural hazards, and (d) enhancing overall environmental quality. Among the conventional approaches, measuring overall sustainability, indicators associated with underground development were identified, and also weights between them were calculated. Data were collected from interviews and the analytic hierarchy process conducted by experts including professionals and researchers in related fields. These research findings offer an alternative strategy considering underground space to achieve sustainable development as well as to provide an analysis tool for ongoing projects.