Improving the effectiveness of the injectable waterstop used for the segmented joint of immersed tunnel

摘要

The immersed tunnel of Hong Kong-Zhuhai-Macao Bridge (HZMB)rncontains 219 segmented joints, 60% of which are placed at water depthrnover 40m and each segmented joint is of circumferential length ofrnapproximately 90 m. To ensure the watertightness, the improvement ofrnusing the injectable waterstop was attempted and no leakage was foundrnin the 5.664 km long tunnel up to now. The ways of improvement werernelaborated in this paper and the conclusion drawn is that therneffectiveness of watersealing can be achieved by looking at the systemrncovering the structure and foundation of each tunnel element. Further,rnthe elongation of the injectable waterstop that may lead to waterrnpassage was controlled by using permanent prestressing tendonsrnlongitudinally to confine the opening of the segmented joint.