The numerical analysis of the cross passage of large diameter shield tunnel beneath the river

The construction of the cross passages of twin shield tunnel is confronted with high uncertainty and huge risk. Ground freezing method is widely used for passages excavation in sandy ground condition when the tunnel is under the water. Earlier studies usually concerned the effectiveness of the freezing program, such as the space between the the freezing pipes or the temperature variation in the frozen soil. In this paper, the structure force of the cross passage of a large diameter shield tunnel beneath the river is discussed. A 3-dimensional numerical method is described to calculate the stress of the frozen soil and the internal force of the cross passage lining. The critical situations in construction and operation phases and the key mechanical parts are recognized. The safety of the design scheme is checked.