Population increase has led to the growth of crowded, dense and congested cities, which has, in turn, resulted in the development at altitude and underground. Despite the benefits of crowded populations, such congestion has posed a threat to human quality of life. The concept of viability, in response to this concern, addresses the objective and subjective qualities that people expect from the environment. New subsurface developments, which are mainly due to the increase in density and congestion in cities, has paid less attention to human biodiversity below the ground but to the functional aspects. Reduction of social oversight, security, ventilation, lighting and humidity control, readability, and orientation are among the most important challenges of this type of development. The need to create and popularize the use of dynamic and community-oriented public spaces in the subsurface has been the impetus for this research. In order to provide a model for improving livability in subterranean public spaces of cities, the collected qualitative data were analyzed simultaneously by a documentary method (basic analysis) and grounded theory approach (complementary analysis). The data were collected employing a documentary approach and semi-structured interview. The Nvivo software was used for qualitative data analysis and coding. From the combination of baseline and complementary analyses, such elements as performance-accessibility, perceptual, identity, environment, and resilience components were identified and studied which are the key components that make up a livable subsurface. Also, the grounded theory was used to present the model. Based on the questions raised in the interview process, 989 referrals were made. Following multiple revisions and integration of codes based on similarity during several stages of data summarization, 02 initial codes and 7 axial codes were extracted and after discovering the causal relationships, a livable subsurface space model based on the snowflake pattern was presented.