基坑的整体稳定性及基坑周边地下管线、周边建筑物的稳定非常重要。介绍石家庄地铁1号线北宋站钢支撑施工中出现轴力频率读数仪数值变化的情况，从外部环境、基坑开挖支护以及主体工程的施工等方面分析数值波动原因。主要结论如下： 1）温度越高，钢支撑所受的轴力越大；温度越低，钢支撑所受的轴力越小。2）临近钢支撑施加轴力会减小已施加轴力的钢支撑所受轴力。3）未施工完成结构主体，只要强度达到设计混凝土强度要求，可以替代钢支撑，作为基坑支护的一部分。

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.