Abstract: To control the deformation of the excavation structure and surrounding environment, the bracing options with better deformation control effect is usually adopted for deep excavation in soft soils, the horizontal brace and the raker type brace are two commonly used forms of support. At present, research on support deformation control mainly focuses on a single support form. This paper presents a deep excavation project in Pudong New Area as a case history to analyze and study the deformation control effects of two support forms under same engineering conditions. Firstly, the deformation estimation results of the two support forms were compared and verified through the Qimingxing deep excavation analysis software and the finite element numerical analysis software. Secondly, the modified numerical model is utilized to simulate and analyze the deformation of the surrounding environment caused by deep excavation. Finally, the measured monitoring data during the deep excavation construction process are compared and analyzed with the numerical simulation deformation values, and then a comprehensive comparative analysis and research on the deformation control effects of the two support forms are conducted. The results show the, under the same engineering conditions, the peak horizontal displacement and deformation trend of the soldier piles under the two support forms are approximately the same. The measured horizontal displacement of the diagonal struts is slightly greater than that of the horizontal supports; For the settlement control effect of the protected objects outside the pit, the diagonal throw brace is slightly stronger than the horizontal support.

Key words: Excavations, Strut, Deformation, Numerical Simulation Analysis, Monitoring