APPLICATION OF ELECTRO-KINETICS TO EXPEDITE PILE SETUP IN KAOLINITECLAY

摘要

A significant increase in the side shear capacity over a period of time is oftenobserved in case of driven piles. This phenomenon is referred to as ‘setup’ or‘freeze’. This phenomenon cannot be predicted based on the knowledge of theengineering properties of soil. Different kinds of mechanisms have beenproposed in order to explain set-up in cohesive soils. In engineering practice,set-up is incorporated in design on the basis of empirical formulae anddepends to a large extent on personal experience and judgment of the designengineer. Set-up is a natural process which cannot be accelerated by anyexisting practice.A research was initiated to investigate the mechanism of pile set-up in clayeysoils and explore the possibility of accelerating the set-up process by anelectro-kinetic method. The system chosen for the present study consists of aprototype steel pile driven in kaolinite clay. A laboratory test program wasdeveloped at Cleveland State University in order to meet the goals of theproposed research. Results obtained from these tests are very encouragingand show pile capacity increase of 200% within the first 5 days of electricgradient application versus those that experience natural set-up. In this paper,theoretical considerations and laboratory test results are presented anddiscussed.