Modelling analysis of the influence of shield crossing on deformation and force in a large diaphragm wall

The effect of a shield crossing an existing underground infrastructure needs to be evaluated, yet there are few studies on this subject. In this study, to model the influence of a shield crossing on a large diaphragm wall, a detailed three-dimensional numerical model with special methods considering the effects of the panel joints and the shield crossing has been developed. The panel joints have been simulated by a HINGE mode of the connection type, and the effect of shield crossing has been realized by modelling the excavated concrete using the solid elements, which interact with the surrounding soils that have been simulated with the ground springs. After analysing the characteristics of the deformation, maximum and minimum principal stresses, vertical and circumferential bending moments in the diaphragm wall, the maximum deformation, and the largest maximum and minimum principal stresses are at the perimeter of the shield tunnel. Further, for the bending moment, the largest negative vertical and circumferential bending moments are at the perimeter of the shield tunnel, yet the largest positive vertical and circumferential bending moments are distributed around the perimeter of the shield tunnel. For the largest tensile stress and vertical bending moment, there are large changes in the diaphragm wall around the shield tunnel, which is detrimental to the diaphragm wall. Considering the effect of the shield crossing, the diaphragm wall should be reinforced according to the results of the numerical analysis during the design and construction stages.