ABSTRACT
Multiple fixed lengths anchors are widely used as a support of deep excavation walls. Due to their high capacity, even in weak soil conditions, they may be used to support walls of launching and receiving shafts or portals of tunnels. Like conventional ground anchors, these structures have to be prestressed. Typically, it is achieved by using multiple stressing jacks, which provide independent control of lock-off load in each fixed length. However, due to the convenience, using of one stressing jack and prestressing of one after another is also popular. The paper presents results of tests performed on one two-fixed-lengths ground anchor with unseparated fixed lengths which were conducted to determine early-stage procedure of prestressing in an infrastructural project. The results were implemented into a numerical analysis to calibrate the model and simulate the procedure of prestressing. The conducted tests show losses in lock-off forces which were observed in every loading step. Author suggests that load losses caused by prestressing with singular stressing jack should be considered in specified anchor loading design individually to provide required level of reliability.
