Abstract: The finite element method with harden soil model are employed to conduct sensitivity study of various design parameters such as predrilling loosen effect, embedded length of retaining piles in rigid stratum, and elastic module of ground improvement layer in upper soft and lower hard strata in Singapore. The results show the following: (1) Predrilling will loosen the surrounding soil of the retaining wall to provide condition for retaining wall construction. (2) The increase of elastic module of ground reinforcement layer will increase the bending moment of retaining wall, hence, the elastic module of ground reinforcement layer should be within a certain range. (3) It is essential to vary the input parameters within a reasonable range, and sensitivity analysis should be conducted for the parameters to ensure the safety of the project.

Key words: deep foundation pit, upper soft and lower hard strata, finite element method, predrilling, embedded length, ground reinforcement, harden soil model