Arching in Piled Embankments

TLDR

The cap‑beam‑and‑geotextile combination is proposed to reduce uneven surface settlements in pile‑supported embankments, though model‑test limitations and influencing factors are acknowledged. The study aims to develop equations and charts to quantify how geotextile tension parameters influence load transfer in pile‑supported embankments. The authors performed model tests with sand on simulated cap beams and soft ground, recorded loads, and compared them to theoretical semicylindrical sand‑arch analysis, while also developing equations and charts to evaluate geotextile tension effects. The theoretical model agreed well with experiments when no geotextile was used, but only partially matched results when a geotextile layer was present.

Abstract

Model tests and theoretical analysis were done to investigate the arching in embankments on soft ground supported by piles with cap beams and geo‐textiles. The cap‐beam‐and‐geotextile combination may alleviate the uneven surface settlements that sometimes occur in embankments supported by piles with individual square caps. In the model tests, sand was placed on simulated cap beams and soft ground. The loads on the cap beams and soft ground were recorded and compared with theoretical analysis based on equilibrium of semicylindrical sand arches. In a second series of model tests, a geotextile layer was laid on the cap beams and the soft ground prior to placement of sand. Equations and charts were developed to show the parameters affecting the tension in the geotextile and to assess the effect of geotextile on load transfer. Theoretical solution showed reasonable agreement with experimental results for cases with no geotextile but only partial agreement for cases with geotextile. The limitations of the model tests, the factors affecting the results, and alternative interpretations are discussed.