基坑支护工程大多数是按照临时结构设计，一般使用期限为1年，但有些深基坑因各种原因造成停工，导致再开工时部分基坑支护结构存在超期使用的情况。预应力锚索作为保障基坑支护稳定性的主要受力构件，超期使用基坑再次施工时需对锚索预应力的损失情况进行分析，以确保基坑安全。本文讨论了锚索预应力损失的原因、变化规律，并提出了对超期基坑锚索预应力损失的分析思路。

Most of the foundation pit support projects are designed according to temporary structure, and the service life is usually one year. However, some deep foundation pits are shut down due to various reasons, which leads to the overuse of some foundation pit support structures during the restart period. Prestressed anchor cable is the main force component to ensure the stability of foundation pit support. It is necessary to analyze the loss of prestress of anchor cable when the foundation pit is reconstructed in excess of time in order to ensure the safety of foundation pit. This paper discusses the causes and changing rules of prestressing loss of anchor cables, and puts forward the analysis ideas of prestressing loss of anchor cables in overdue foundation pits.

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