Abstract: To research the influence of stepped reinforcement size on pile displacement in the passive zone of deep foundation pit, we presented the concept of stepped reinforcement. On the basis of field test data of a foundation pit, we established a numerical model in which factors affecting the pile displacement such as the reinforcement shape and size are taken into consideration. Results showed that the simulation could well reflect the actual deformation of pile support system. The reinforcement in the passive zone has significant impact on the pile displacement. The optimum reinforcement effect can be obtained when the reinforcement width and depth at each step are approximately equal. Compared with other reinforcement approaches, the stepped reinforcement has obvious advantage, and is also highly feasible.

Key words: foundation pit, soft soil ground, stepped, passive zone, lateral deformation, numerical simulation