关键词: PBA法地铁车站, 横向管棚, 荷载－梁理论, 传递矩阵法, 弹性地基梁, 简支梁, 固支梁

Abstract: The pipe roof support can be used in metro station with rectangular crosssection constructed by PBA method in advance. The transverse pipe roof is densely arranged in PBA mined metro station with rectangular crosssection. Firstly, the simplified methods and calculation mechanisms of elastic foundation beam, simply supported beam and clamped beam of the "loadbeam model" of pipe roof are summarized. And then, the three models of elastic foundation beam, simply supported beam and clamped beam are used to calculate the stress and deformation of pipe roof of Ping′anli Station on Beijing Metro Line No. 19, and the calculation results are compared with monitoring results. Finally, the influence factor analysis is carried out on stress and deformation of pipe roof of different projects with different geological parameters. The research results show that: (1) The bending moments and midspan deflections calculated by elastic foundation beam model are between the results calculated by clamped beam model and simply supported beam model, and the results calculated by the elastic foundation beam and the simply supported beam model are more consistent with the measured data; however, the models of simply or clamped supported beam can not reflect the deflection at the sidewall and the influence of the formation parameters and the pipe thickness. (2) The maximum bending moment occurs in the midspan of simply supported beam, thus the security can be ensured by using midspan moments of simply supported beams. (3) The excavation span and soil thickness (load) affect the bending moment and deflection of pipe roof greatly, and the influence of span is greater. (4) The foundation bed coefficient and pipe thickness affect the bending moment of pipe roof little, while they can reduce the deflection to a certain extent.

Key words: PBA metro station, transverse pipe roof, loadbeam theory, transfer matrix method, elastic foundation beam, simply supported beam, clamped beam