Abstract: Considering the effects of various factors on inner-bracing stiffness, including the initial deflection, the second-order effect of compression and bending in the inner-bracing, the interaction between the inner-bracing and diaphragm wall, the deformation of diaphragm wall, etc., an effective stiffness calculation method for the inner-bracing was put forward for diaphragm wall and inner-bracing system. Taking the excavation engineering of a Beijing subway station project as a case study, the excavation process was simulated with ABAQUS finite element software, incorporating both the current standard support stiffness and the effective support stiffness. The simulation results were then compared with the measured data. The results show thateffective stiffness calculation method for the inner-bracing accords with the real force and deformation state of the foundation pit support system.

Key words: excavation engineering, diaphragm walls, inner-bracing, inner-bracing stiffness, effective stiffness