The Role of Underground Spaces in Resilience of Cities With Emphasis on Urban Facilities and Infrastructures(Case study: Mashhad Metropolis)

Population growth and economic considerations are two main urban constraints that have brought many consequences including vertical growth and increasing subsurface spaces development. Many roles, functions and abilities can be counted for subsurface spaces. Lack of land ownership, impunity and the possibility of continuity of infrastructure services, the transfer of some facilities that are harmful to urban environment to the underground level, reducing energy consumption, reducing environmental pollution, exploiting civil defense and many other issues of are among the benefits of subsurface spaces that are being deployed. In this research, using Q methodology based on the results of studies related to subsurface spaces and resiliency and the analysis of existing discursive space, a comprehensive understanding of the role of subsurface space development in resiliency of cities was obtained; then, using experts' contributions, different perspectives were identified and categorized so that they would go beyond the set of analyses presented. The findings of the research based on Q's analysis of the factor analysis indicated four approaches to the role of sub-surface development in resilient cities. The first approach reflects the continuity of services; the second approach is rescue and relief, the third approach is urban safety and security, and the fourth approach is environmental protection. In fact, in this study, the capacity of subsurface spaces that could increase the resiliency and return ability of cities against all kinds of threats and accidents was determined.