The basic notion underlying urban underground development is that underground space is a non-renewable resource, therefore planning its use must be done in a sustainable, environmentally-responsible manner with due account taken of economic, functional, social, and legal aspects. This paper addresses issues related to the planning, siting, design, construction, operation and maintenance of underground structures in the city of Moscow. The mechanism of the interaction between an underground structure and the surrounding rock masses is described. It is shown that underground engineering can be significantly enhanced through the use of expert systems. The paper also discusses the need for changes to the legal framework for the use of urban underground space.

Nowadays, large-span underground structures can only be built at shallow depths or in hard rock since their structural strength is not great enough to bear the overburden pressure of thick overlying soil material. To build large-span structures at greater depths or in a wider range of geotechnical conditions, new technical and technological solutions must be developed. The paper discusses the possibility of using stay cable systems to enhance the load-bearing capacity and service performance of large-span underground structures. To assess the applicability of such stay cable systems for large-span underground construction, a numerical model has been developed and validated. The paper presents the results of the modeling of underground structures (20m to 50m wide) under different pressures and examines how the stress-strain behavior of the load-bearing structural elements depends on the span of the structures, the arrangement and height of pylons, and the number and arrangement of stay cables. It is shown that the use of stay cable systems can significantly improve the load-carrying capacity and performance of both individual structural elements of a large-span underground structure and the structure as a whole. The paper also discusses the possibility of using composite materials for the stay cable systems.