TH 241 Column-Supported Embankment

Abstract

A pile-supported embankment constructed on TH 241 near St. Michael, MN was instrumented with 48 sensors, including strain gages on the piles and on the geogrid, as well as earth pressure cells and settlement systems near the base of the embankment. Pile supported embankments are relatively novel structures employed largely at bridge approaches and highway expansions where soft soils would otherwise lead to unacceptably large differential settlements. The structure typically consists of a number of capped piles, well-compacted gravel, and one or more layers of geogrid reinforcement above the piles. Analyses of the data suggest that the redistribution of the embankment load to the piles occurs within and above the so-called load transfer platform, a 1 m layer of geogridreinforced gravel. Arching seemed to take place within the embankment, such that the stress at the top of the platform was concentrated above the piles.