The Π-Formed Diaphragm Wall Construction for Departure and Reception of Shield Machine

In the design of shield tunnels, it is important to determine the structure of the diaphragm wall in order to achieve the required retaining wall structure pattern. In this paper, the stabilization effect of a new diaphragm wall structure (Π-formed diaphragm wall) is investigated based on model experiments and numerical simulations. By varying the length of the wing wall and its angle to the end wall, it is possible to discuss the effect of different styles of Π-formed diaphragm wall on the support of the soil behind the wall during the departure and reception of the shield machine, the effect of the wing wall on the internal force distribution of the diaphragm wall generated during excavation, the effect of the excavation of the shield machine on the internal force distribution of the diaphragm wall, and the ground settlement during the departure and reception of the shield machine in different construction stages. Π-formed diaphragm walls can effectively support the soil behind the wall and reduce the major principal stresses generated during excavation. The maximum value of the major principal stress in the wing wall of the Π-formed diaphragm wall increases with the length of the wing wall, and the damage to the concrete of the diaphragm wall tends to occur on the outside rim of the wing wall.