地铁基坑混凝土支撑轴力监测预警误判原因分析

Analysis of the Causes for Precaution-Misjudging the Axial Forces of Concrete Struts in Subway Foundation Pits

结合石家庄市地铁基坑工程的设计和施工方案,对混凝土支撑轴力监测原理进行了介绍,在对基坑施工过程中轴力监测数据变化进行分析的基础上,对导致监测预警误判的原因进行了分析,主要是由于混凝土硬化收缩产生的附加力及外部温度变化修正考虑不周全所导致,并就确保基坑混凝土支撑轴力监测数值的可靠性提出了建议。

With the design and construction schemes of the foundation pits for the Shijiazhuang City Subway as practical examples,the monitoring principle for the axial forces of concrete struts is introduced in the paper.Upon the basis of analyzing the change in the monitored data about the axial forces of concrete struts in the course of the construction of the foundation pits,the causes for the precaution misjudgment are analyzed.It is found that the misjudgment chiefly results from the insufficient consideration of the additional forces coming from the hardening and contracting of concrete and the amendment for the change in temperature outside.Some corresponding suggestions to help ensure the reliability of the monitored data for the the axial forces of concrete struts are proposed in the paper as well.