A Study On Pore Water Pressure And Time Effect Of Pile Bearing Capacity Caused By Penetration Of Prestressed Concrete Pile

Prestressed concrete pile was developed based on the technology of precompressing and spuning concrete. For its advantage of cheapness, reliability and convenience, it is extensively applied nowadays.Firstly, associated with practical engineering problems, in-situ tests are conducted to study the pore pressure, tip resistance, static piling forces, bearing capacity with time during and after pile installation. Experimental results are obtained on the generation and dissipation of pore pressure, time effect of bearing capacity, etc.Secondly, based on the cavity expansion theory presented by Vesic, an equation for calculating instantaneous pore pressure is proposed. According to the solution for dissipation of pore pressure, the rules for generation and dissipation of pore pressure are analyzed. The influence of radial distance, elastic modulus, pore pressure coefficient, undrained strength, horizontal consolidation coefficient are discussed. According to the effective stress theory and the failure form of soil-pile interface, an analytical solution is proposed for calculating the bearing capacity of pile with time, and the influence of relative parameters are also discussed.Finally, by comparison of theoretical analysis and measured results, the rules presented in this paper for the generation and dissipation of pore pressure, and the time effect of bearing capacity are verified. The difference between the theoretical and observations is analyzed and assessed. The work completed in this paper provides some theoretical and practical grounds for the application of static pile installation.