Analysis and control of ground settlement of embankments in construction of cross-river shield tunnels

Slurry shield has been widely used in construction of cross-river tunnels. One big challenge is how to traverse the embankment without impacting its regular service and safety. Based on the field settlement monitoring data in construction of Hangzhou Qingchun Road cross-river tunnel, ground settlements induced by shield tunneling under greenfield and the embankment are compared. The results show that the settlements of the embankment are larger, for which for the shielding disturbance to the surrounding soils, the complexity of the embankment structure, the vehicle travelling on the embankment and sustained rainfall are accounted. Peck equation’s applicability to predict the ground settlements due to shield tunneling in Hangzhou is evaluated, and the values of the ground trough-width parameter and the volume loss in this project are suggested. By combining the successful experience of crossing the embankment in this tunnel, some practical and effective measures are suggested for slurry shield to traverse the embankment. These results will provide a scientific reference for the design and construction of similar shield tunnels in practice.