Numerical Analysis of Catenary Load Transfer Platform for Geopier-Supported Embankment

Column-supported embankments provide a rapid means of construction in areas where subsurface consists of fine-grained soft soils. A load transfer platform (LTP) is usually provided at the base of the embankment to even out differential settlement and minimize overall deformation of the embankments. The mechanism of load transfer in geosynthetic-reinforced LTPs (GRLTP) supported on columns is, in general, poorly understood. Especially, the case of soil arching within the embankment fill from which the proportion of the embankment load that is transferred to the columns and to the subsoil is determined. A well instrumented full- scale test embankment incorporating a catenary GRLTP and supported by rammed aggregate piers (geopiers) was built in Malaysia. The results of the numerical analysis and its relation to field data are presented along with implications for arching ratio. Overall, the relatively simple elastic-perfectly plastic Mohr-Coulomb constitutive model was able to capture the essential embankment/load transfer platform behavior based on conventional data regarding material properties and subsurface conditions. The arching ratio assumed in the design of catenary load transfer platform based on the British design method is significantly higher than that indicated by the field-calibrated numerical analysis and the field measurements.