Abstract: A case study is conducted on the Ping′anli station of the Beijing metro line 19 to implement advance piperoof support for mined metro stations in dense building areas of prosperous cities using the ultrashallowburied piperoof cover method. A mechanical model and calculation method are established for advance piperoof support using theoretical derivation, numerical simulation, field tests, and practice summaries. The stress and deformation mechanism of the pipe roof are analyzed and validated, and the equipment and technology of piperoofing in limited space are optimized and summarized. Practical results show the following: (1) The piperoof cover method can fulfill the requirements of stress and deformation for the advance support of ultrashallowburied mined tunnels and can be combined with the pilebeamarch method for mined station construction. (2) The elastic thin plate theory and calculation method can meet the actual working conditions requirements and provide a theoretical basis for designing and constructing mined metro stations using the ultrashallowburied piperoof cover method. (3) The piperoof support technology is characterized by high mechanization and construction efficiency, making it suitable for limited space construction in prosperous cities.

Key words: piperoof support, mined metro station, ultrashallowburied piperoof cover method, piperoof test, elastic thin plate theory