Research on the Bearing Behavior of PHC Pipe Piles in Soft Soil Layer by Vacuum Combined Surcharge Preloading though Field Test and Numerical Simulation.

Based on a thermal power plant project in Guangzhou, this paper studied the vertical load bearing performance of PHC pipe piles in Nansha area through the static load test of single pile and the test record of PHC pipe piles. Combined with ABAQUS software, the displacement field of surrounding soil during pile driving is simulated, and the influence of pile diameter on pile displacement field is analyzed. The results showed that pre-treatment of the soft soil layer by vacuum combined surcharge preloading reduce the settlement of the pile foundation, which was twice as much as that without pre-treatment when the pile top load reaches the design load of 3000 kN.The pile diameter had a great influence on the displacement of the soil. The maximum horizontal displacement of the soil around the pile caused by soil compaction of 400mm pipe pile was 45% smaller than that of 600mm PHC pipe pile. It can provide a reference basis for the design of PHC pipe piles for the formation conditions of the underlying rock in the deep and weak soil layer.