Development of a test setup for piled embankment modelling

This paper outlines the design and development of a trapdoor test setup used to simulate the effect of a geosynthetic reinforcement on the load distribution in a timber piled embankment. Geosynthetic-reinforced pilesupported embankment (GRPSE) is a common foundation method for both roads and railways on soft subsoil. Timber piling allows for a solution with lower carbon footprint than concrete or steel piling. The removal of concrete pile caps further reduces the footprint but increases the requirements of the geosynthetic reinforcement. The purpose of the trapdoor test setup is to find the best suited number, placement, stiffness, and strength of the layers of geosynthetic reinforcement for different embankment heights and pile spacings. The tested embankment model consists of a vertical cross section of the embankment between two adjacent piles, assuming plane strain. The test is performed under Earth’s gravity. A hydraulically controlled trapdoor mechanism in between the two pile heads acts as the deformed subsoil. The trapdoor is composed of several segments to model a non-horizontal top surface of the displaced subsoil. Displacements are captured using optical measurement techniques to confirm and study the arch formation. The arching efficacy is quantified by pressure cells on each of the two pile heads. Though the primary application is timber piled embankments, the test results can be extrapolated to GRPSE designs in general.Funder: Statens väg- och transportforskningsinstitut (VTI); Branschsamverkan i grunden (BIG);ISBN för värdpublikation: 978-89-952197-7-5