Providing a conceptual model of the underground space as a urban development catalyst Using the grounded theory

Aims & backgrounds: Over time, cities are confronted with a number of natural and artificial problems such as lack of green and open spaces, high density and lack of recreational spaces, which in some cases can be reasonably efficient use of subsurface spaces. Builders of subsurface space are the urban development catalyst. Methodology: The purpose of this study is qualitative and fundamental research which is done by the approach of data theory. In order to analyze documentary studies, it is a cross-sectional and in-depth analysis of the content and method of gathering documentary study and in-depth interviews. Nvivo software was used for data analysis and coding Findings: After studying documents and interviewing experts and analyzing data qualitatively with respect to the number of citations (237 citations), 29 initial codes of the subsurface constructor were extracted as urban development catalyst, 5 of which were perceptual, visual, morphological, service and functional codes. Core codes and the three components of activity, body, and imagination as the main constituents of subsurface space as drivers of urban development are interactive and mutually beneficial Conclusion:The conceptual model of the constituents of subsurface space as a urban development catalyst shows that the component of subsurface activity and citizens' perceptions of these spaces lead to services such as security and safety. The component of citizen perceptions and perceptions leads to the identification of items such as fit, human scale, comfort, and so on in urban subsurface spaces. The interaction between activity and body comprises two important factors of land use and transport, and such as land use mixing and access hierarchy, leading to the enhancement of the performance of underground space as urban development catalyst.