The Study Of Compacting Effect By Static Piling Driving And The Analysis Of Measured Data

Static piling is now widely used in civil engineering, especially in some buildings of soft clay foundation, because of its well-known pile body quality, high construction efficiency, relative lower cost, and no pollution of noisy and slurry, etc. But as a type of soil compaction piling, static piling often causes negative effects on adjacent buildings if no proper measures are adopted. As human environmental protection consciousness gradually strengthens, more and more attention has been given for soil compaction effects caused by static piling.Based on the previous studies, the following studies has been done in this paper, including:1. Based on Vesic cavity expansion theory, unified analytical solutions of cylindrical and spherical cavity expansion problems with the initial radius are proposed for Tresca materials and Mohr-Coulomb materials. For Tresca strain-softening materials, unified analytical solutions are also deduced assuming softening curve is hyperbola.2. The influences of initial radius ratio and softening coefficient on stress and displacement field for Tresca materials are studied during cylindrical cavity expansion. Analysis results show that plastic zone radius, radial displacement, radial stress and ultimate pressure decline with the increase of initial radius ratio, and that radial stress and ultimate pressure increase with the increase of softening coefficient.3. The influences of initial radius ratio and softening coefficient on the excess pore water pressure for Tresca materials are studied during cylindrical cavity expansion. Analysis results show that the excess pore water pressure and its influencing range decline with the increase of initial radius ratio. For Tresca strain-softening materials, the excess pore water pressure in plastic zone is dependent of the softening coefficient, plastic zone radius and pore water pressure coefficient. As the softening coefficient increases, the excess pore water pressure increases, and the excess pore water pressure in elastic zone has no relation with the softening coefficient.4. Some laws and conclusions are obtained by many measured data of horizontal displacement and excess pore water pressure from San-Li Ting pile driving project.5. Based on the measured data, excess pore water pressure caused only by single driving pile is obtained. The theoretical results and the measured data are compared.