Abstract:

The overall stability of the foundation pit itself and the stability of the underground utility lines and buildings around the foundation pit are of great importance. In the paper, the variation of the axial force of the steel bracings of Beisong station of Line 1 of Shijiazhuang Metro is presented, and the causes for the variation of the axial force are analyzed in terms of the surrounding environment, the cutting and supporting of the foundation pit and the construction of the main structure of the station. Conclusions drawn are as follows: 1) The higher the temperature, the greater the axial force of the steel bracing; the lower the temperature, the smaller the axial force of the steel bracing; 2) The axial force of the steel bracing under axial load is reduced due to the axial load applied on the neighboring steel bracings; 3) As long as the strength of the main structure of the uncompleted station reaches the designed concrete strength, the main structure of the uncompleted station can be used as the support for the foundation pit to replace the steel bracings.

Key words: Shijiazhuang Metro, station, foundation pit, steel bracing, axial force variation