Application of Bamboo Joint Pile in Strengthening Composite Foundation of Variable Cross-Section Screw Pile

The composite foundation with variable cross-section compacted screw pile was conducted in soft soil area. When the stacking height reaching 5～6 m, which was below the design height of 11 m, the ground subsidence occurred and the maximum subsidence was about 1.30 m. The grid frame column had a large deformation, and the maximum horizontal displacement was more than 680 mm, which led to the material shed in an ultra dangerous state. Bamboo joint pile was used to reinforce the composite foundation of variable cross-section compacted screw pile. By reasonably arranging the driving direction of bamboo joint pile, adopting long auger and stress release hole, the influence of soil squeezing effect of bamboo joint pile on original compacted screw pile, side column cap and foundation pile was reduced. After the pile sinking, the characteristic value of the vertical bearing capacity of the single bamboo joint pile was not less than 740 kN, which meet the design requirements. The reinforced bamboo pile composite foundation+ raft meet the design requirements of surcharge.