Modelling helical screw piles in clay using a transparent soil

A transparent synthetic soil consisting of fumed silica particles and a pore fluid with matched refractive index has been used to represent clay in a physical model of the installation and undrained load-deflection performance of helical screw piles in a deep installation condition. A digital camera captures images during installation and load-deflection testing, allowing the use of Particle Image Velocimetry (PIV) techniques to compute displacement fields around the piles. This experimental method is being used to assess the effect of the helical plate spacing ratio on the failure mode and load deflection performance of single and multi-helical plate screw piles loaded in tension and compression, at a constant strain rate. Initial results are presented indicating significantly differing behaviour with respect to the configuration of the helical screw pile. The precision of the PIV output is significantly better than in previous analyses conducted using transparent soils in similar non-intrusive modelling scenarios. © 2010 Taylor & Francis Group, London