DFI Traveling Lecture

"Do's and Don'ts in Lateral Stabilization of Soils Using Deep Foundation Elements"

Presented by: Jesus Gomez, Ph.D, P.E., DGEP

Vice President at GEI Consultants

Besides their main application to support vertical and lateral loading from a superstructure, deep foundation elements are often subject to lateral loading from the soil itself. In some cases, the foundation elements may need to resist lateral movement of the soil during a potential lateral spreading event in a seismic area, or they may potentially be subject to lateral movement when installed near or below a slope.

This presentation discusses potential situations where deep foundation elements may be required to withstand lateral soil movements. A theoretical, simple slope instability case will be used to illustrate the various steps of analysis, including assessment of movement profile, development of the foundation reaction-displacement function, evaluation of the slope and foundation stability. This example depicts suitable methods of analysis of these systems and will be used to highlight analysis flaws that are often seen in practice.

Several case histories will also be presented that include lateral “squeezing” of soft soils located under or near the edge of an embankment and its effect on driven piles; mitigation of lateral squeeze using drilled foundations; design and testing of augered cast-in-place piles to withstand a lateral spreading event; and slope stabilization using micropiles. Design and construction of these systems, most of which were recently completed, will be discussed in some detail.