Visco-elastic consolidation subsequent to pile installation

Driven piles normally generate excess pore pressures in the surrounding soi l. Dissipation of the pore pressures following driving is predicted current ly by available elastic theory. However, viscosity is pronounced for many s oft clays, therefore, its effect should be suitably accounted for. The grad ual increase in pile capacity is dominated by the dissipation of excess por e pressure as has been widely explored both experimentally and theoreticall y. To predict the load-settlement response, the variation of pile-soil stif fness with the dissipation of pore pressure must also be quantified. This p aper presents closed form solutions for the radial consolidation of the soi l around a driven pile, assuming that the: soil skeleton deforms viscoelast ically. The solutions are theoretically valid for any initial distribution of excess pore pressure. However, the current study is focussed on the loga rithmic variation of the initial pore pressure with radius, due to the expa nsion of a cylindrical cavity in an ideal elastic, perfectly plastic soil. The overall pile response measured from three cases has been used to backfi gure the time-dependent variation of the two key facets: shear modulus and strength. The back analysis shows that variation of the two key facets can be well predicted with the presented radial consolidation theory. (C) 2000 Elsevier Science Ltd. All rights reserved.