Settlement control of Qiantang River embankments during undercrossing of EPB shield tunnels

The earth pressure balance (EPB) shield has been widely used in construction of cross-river tunnels, and it is difficult to protect the embankments during crossing. Based on the construction of Hangzhou No. 1 subway tunnel under crossing Qiantang River, a tunnel-soil-levee interaction nonlinear finite element model is established. Through analyzing the characteristics of displacement and deformation, it is found that the settlement of embankment is mainly caused by deformation and displacement of soils when the shield traverses the embankment. Considering the significance of the embankment, some practical and effective measures are suggested for the earth pressure balance shield. The field test results show that the numerical analysis reflects the basic characters of construction. The settlement caused by releasing methane before construction is significantly greater than that of numerical analysis, and the releasing methane has a huge impact on the ground settlement and structural safety. Attention should be paid to similar projects.