ARCHING IN PILED EMBANKMENTS

Model tests and theoretical analysis were done to investigate the arching in embankments on soft ground supported by piles with cap beams and geotextiles. 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.