Abstract:

Pit soil rebounding during excavation will cause piles rebound and produce lateral friction in pit.Three-dimensional finite element analysis method was conducted to study the behavior of single pile and pile group under excavation. Results show that the rebounding displacement of single pile can be divided into two parts, namely, one is caused by the rebounding of soil around the pile and the other is caused by the rebounding of the bearing layer. The rebounding displacement and the degree of lateral friction of central pile were reduced by the shielding effects of outer piles. The relative reduction in rebounding displacement in 5×5 pile group increased with the increase of relative bearing stiffness ratio, and this kind of variation depended on the pile location in the group. Based on three cases studied, the larger the number of piles in a group, the greater the shielding effects presented. The number of piles had greater influence on shielding effect than pile spacing.

Key words: excavation, rebounding displacement, single pile, pile group