recognition of underground urban spaces based on typological approach

Over time, the use of underground spaces has changed and has been considered for various other purposes. many us1 built for a specific period with a specific purpose have been left without a specific function today. the reason for this can be considered the lack of a clear and codified plan in the face of these spaces. therefore, the importance of underground issues related to us jus‌tifies the inclusion of uus2 in urban index sys‌tems. hence, due to the depletion of activity, many us today have created bubbles lacking function under the skin of cities; with proper identification, it will be possible to use them in the service of cities and citizens. thus, the main goals of current research are -recognizing the characteris‌tics of us -the typology of the urban us, and -solutions to reproduce the urban us. this research is a scientific review, and the information collected is documentary-oriented. the lack of reliable sources in the fields of architecture and civil engineering in the subject of us, geographical extent, and diversity of species of these spaces on the planet show the importance of this research. therefore, typology and solutions for reproducing urban us are presented from two methods of inves‌tigating the theoretical foundations and known projects in the field of us. the present s‌tudy’s findings based on the literature review and reproduction of us showed that these spaces could be defined into six categories.