Abstract: Combined with a project in Guangzhou, the whole model of two-dimensional finite element is established through the diaphragm wall, inner supporting and soil layer. The numerical simulation of deep foundation excavation under the construction process is carried through. Research shows that：With excavation depth increasing, the horizontal displacements of retaining structures increase and the location of the maximum values changes from the top to middle of the retaining structures. The horizontal displacement curves of the retaining structures have a “bow shape”. The monitoring results are compared with the measurement values. The supporting construction plays an important role on the decrease of the horizontal displacement of the pile. The maximum horizontal displacement is 24.6 mm without supporting constructions. And the elasticity modulus of soils has great impact on the foundation displacement. The result can provide valuable references for the design and construction of similar projects.

Key words: deep foundation pit; horizontal displacement; numerical simulation; soft soil