The Mechanical Performance of Shear Key of Immersed Tube Tunnel with Differential Foundation Settlement

Abstract

A fiber Bragg grating (FBG) based sensor network was developed to monitor the strain distributions within immersed tube tunnel shear key, which was subjected to differential settlements. An improved packaging and installation method of the quasi-distributed sensor system was utilized, which not only ensured a high sensor survival rate but also achieved accurate measurement of axial strains. Based on the monitoring results, the stress variations of shear keys of the immersed tunnel joint, which originate from the buckling caused by the longitudinal differential siltation at seabed and the surface defects, were analyzed in detail.