Research On The Bearing Capacity Of PHC Pile And Numerical Simulation In Cretaceous Argillaceous Siltstone Region

For the PHC pile’s outstanding features, such as high bearing capacity, good stability, small settlement, high mechanization degree, strong adaptability, short duration, low cost, high operational safety, it is widely used in a large number of high-rise buildings, housing, utilities,industrial constructions, equipment foundations, long-span bridges, ports and other projects.With it’s own characteristic and that under different construction conditions of PHC pile, the pile load-transfer theory, PHC pile compaction effect theory and plugging effect theory are analyzed.Combined with practical work, by selecting PHC500AB125 and PHC400AB95 for vertical compressive static load test, comparing the differences of the settlement’s standard calculative value and experimental value under the effect of the loads, it analyzes the pile’s rebound curves law in the unloading process. According the bearing capacity destruction test of 3 Φ500 piles, it turns out that the destruction pattern of PHC pile is the whole shearing destruction in the Cretaceous Argillaceous siltstone area.By establishing PHC pile’s finite element model using ABAQUS, performing numerical simulations for PHC pile’s compression strength of single pile, comparing the load-settlement relation curves from pile static load test and numerical simulation results, analyzing the change law of pile top resistance and pile side friction resistance, it shows that the numerical simulation of single pile vertical bearing capacity test is feasible.The current pile foundation checking code takes the deformation of pile top as one of valuation criteria for pile foundation’s ultimate bearing capacity which bears some relation to pile shaft compression. With different parameters of pile length and pile diameter, the pile compression is different under the same amount load on the pile top. This paper puts forward the method to improve the ground bearing capacity by enhancing pile stiffness with core concrete and reducing the pile top deformation under the effect of loads, which is validated through finite element model analysis. By comparing the numerical analysis for different levels of core concrete,pile lengths, and pile diameters, it arrives at reduction of pile shaft compression and pile top settlement after filling the PHC pile’s core. The results show that the filling core method has some effect on reduction of pile top settlement and practical significance.By studying the changing law of soil around the pile under the load test, it analyzes the deformation characteristic of pile side and pile top soil and the critical depth of pile end soil with the deformation influence.