Volume 23, Issue 3 (September 2000)
Lateral Load Behavior of Jetted Piles
Water jetting can be utilized as an effective aid to impact pile driving when hard strata are encountered above the designated tip elevation. When jetting, the immediate neighborhood of the pile is first liquefied due to high pore pressure induced by the water jet and subsequently densified with its dissipation. In addition, the percolating water also creates a filtration zone further away from the pile. Hence, jetting invariably causes substantial disturbance to the surrounding soil that results in a noticeable change in the lateral deformation behavior. Currently, no definitive criteria are available to quantify the possible reduction in the lateral strength of driven piles when jetting is employed. This paper presents the results of an experimental study performed with model piles installed using (1) impact driving and (2) jetting in a sandy soil (with 10% clay) compacted to different unit weights under unsaturated as well as saturated conditions. The beam theory and polynomial approximations are used to convert measured load-strain data to conventional lateral pressure-deformation characteristics (p-y curves). Then, the effect of jetting on the lateral load behavior of piles is presented in terms of non-dimensional empirical curves. An example is also provided to illustrate how the results can be utilized to synthesize p-y curves for jetted piles based on available p-y curves for impact-driven piles in the same soil.