Study on bearing characteristics of large-diameter super-long grouted piles
In order to clarify the bearing characteristics and load transfer mechanism of long pile foundations in chalky soil and fine sand strata in the middle and lower reaches of the Yellow River,a systematic study was carried out by combining indoor geotechnical tests,field in-situ tests and numerical simulations relying on actual projects.A self-made large-scale straight shear instrument was used to carry out the straight shear test of chalk-concrete interface under different water con-tent conditions,and a large tonnage loading device of 36 000 kN was designed for bridge bored piles.Based on the results of the straight shear test and static loading test,the horizontal bearing capacity of foundation piles was further investigated by using the ABAQUS trial calculation to fit the parameters of the soil body and the interface.The results show that the shear strength of the silt-concrete interface decreases with the increase of silt water content,and the increase of silt water content will significantly weaken the shear effect at the interface between soil and concrete structure.The shear strength envelope of chalk-concrete interface basically conforms to the theory of Moore's Coulomb strength,and the water content of the soil body is negatively correlated with the cohesion and friction angle of the interface.On the premise that the estab-lished pile-soil vertical static load test model and the in-situ test data are in good agreement,the numerical simulation of the horizontal bearing capacity of foundation pile is carried out,and it is found that the obtained results are basically com-parable with the design scheme,which meets the specification requirements.The relevant conclusions of this paper can provide reference for related engineering design.
bored pileslarge direct shear teststatic load testnumerical analysis
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