Application of grillage shaped diaphragm wall in support of revetment project of immersed tube tunnel

Based on introducing the commonly used revetment retaining structures of excavated foundation trench of the immersed tube tunnel and combined with a specific project, the earth pressure and structural design of grillage shaped diaphragm wall (GSDW) are studied. A simplified method for the GSDW is proposed and it is compared with the finite element method (FEM). From the comparison, the moment calculated by the simplified method is larger than that by the FEM, and the displacement is on the contrary. The causes are the ignorance of the spatial effects of the GSDW and the relatively larger equivalent stiffness respectively. Due to the geometry of the GSDW, the distribution of the diaphragm walls has typical spatial characteristics. For example, the inner vertical wall bears a greater level of moment while the outer vertical wall bears a less one. So we can optimize the reinforcement of the GSDW through the analysis of the moment distribution laws. As for the stress characteristics and design calculation method of the GSDW, the spatial effects are seldom taken into consideration. Further discussions and more researches of the deformation method are needed. This study may provide reference for the design of the GSDW.