Research on Prestress Variation Law of Anchor Bolt in Soft Rock Deep Foundation Pit
With the rapid development of urban underground space,prestressed anchor bolts had been widely used as active support structures in foundation pit slope support engineering.However,there is still a lack of understanding of the short-term and long-term changes after anchor anchoring,especially the prestress distribution along the course and its variation law.In order to explore the law of prestress in anchor bolt,in this paper,based on the distributed fiber Bragg grating sensing technology,the in-situ monitoring and experimental analysis of loading process and post-anchoring prestress change were carried out.Additionally,the influencing factors were analyzed and summarized.The results showed that the short-term prestress decreased sharply after anchoring,which was mainly caused by anchoring and relaxation of anchor bar.And loss rate of short-term prestress could reach 20%.The distribution of anchor prestress can be divided into three parts:free section,transition section and anchorage section according to its stress conditions,and with the increase of time,the distribution of anchor prestress along the route would undergo significant changes.
deep foundation pitdistributed fiber Bragg gratingloss of prestressanchor boltfield monitoring
NETL
NSTL
万方数据
