Abstract:

Some metro stations on Beijing Metro Line No.16 are constructed by PBA method, and the bottom of the concretefilled steel tubular column is embedded in the pile foundation. In the current design codes and related researches, the constraint conditions of the bottom of concretefilled steel tubular column for the bearing capacity calculation during construction of metro station by PBA method are not cleared and identified. As a result, based on the calculation method of the vertical bearing capacity of the pile foundation of railway bridges and buildings, the numerical calculation model of the bearing capacity of concretefilled steel tubular column during construction of metro station by PBA method is established, and the influence of initial eccentricity on bearing capacity of concretefilled steel tubular column and the constraint provided by the pile foundation under the steel tubular column are analyzed. The analytical results show that under the constraints of column embedded in the pile foundation at a required length and the surrounding silty clay and pebble strata, the constraint conditions of the pile foundation under the column of PBA method station can be simplified into fixed constraints.

Key words: mined metro station constructed by PBA method, concretefilled steel tubular column, bearing capacity, constraint of column end, numerical analysis