Model Pile Installation by Vertical Water Jet in Clay

Abstract

Pile installation by water jetting relies extensively upon empirical methods. For more scientific approaches, improvements have to be made in identifying the erosion processes that occur within the zone of soil adjacent to the pile. This paper addresses the problem of offshore pile installation in saturated clay by examining the mechanisms associated with water jet techniques. Parameters controlling installation geometry and pile embedment depth within the seabed are established based on tests carried out in laboratory physical scale using downward vertical water jets in highly compressible clay. Observations and measurements indicate that the geometry of the smeared and fluidized zone is constrained to two pile diameters, the eroded cavity under the pile tip is controlled by the nozzle jet Reynolds number, and the penetration embedment depth is a function of pile mass and applied water flowrate. It is demonstrated that penetration embedment depth is a function of pile mass and applied water flowrate. Based on the laws of similarity and statistical analysis, an equation is proposed for the maximum embedment depth of piles in clay, which is described as a function of pile geometry and mass, nozzle Reynolds number of water jet, along with the fluid and soil properties.