INFLUENCE OF EXCAVATION PROCESS IN SAND ON ERECT COLUMN PILES

The erect column piles have an important effect on the stability of the foundation pit. Based on the three-dimensional explicit finite-difference program, this paper analyzes the impact of the tension force, the location of the maximum tension force and the heave of piles on the column piles with consideration of the interaction between soil and piles. It is shown that the influence of the excavation on the erect column piles has an obvious spatial characteristic, with the maximum influence on the center pile and the minimum on the corner pile. The tension force is induced by excavation, the location of the maximum value moves upward of the column pile, and finally stops at half of the effective insertion depth of pile foundation, the maximum tension force of the center pile in pile group is larger than that of a single pile; the heave of the pile top increases with the numbers of piles, and then decreases when the pile number is increased to a certain value.