Load recovery mechanism of arching within piled embankments using discrete element method and small scale tests

Abstract

In this paper, small scale tests and 3D discrete element method (DEM) simulations are proposed to explore the load recovery mechanism of arching within unreinforced piled embankments. Comparisons between numerical and physical samples in regards to efficiency response, volumetric deformation and displacement characteristics are conducted to verify the DEM which is an effective way to capture the load transfer mechanism of piled embankments. The validation of the numerical tool is performed for different sand densities and pile patterns with small scale tests. Experimental tests results confirm that the load recovery stage in dense sand for equivocal triangular patterns reaches at a low value of displacement in comparison with square patterns. The results also show that the load recovery phases can be accurately modeled with DEM. The peak efficiency of the equilateral triangular sample is sharper and its strain-softening behavior is more significant. Also, the results show that the failure mechanism above pile heads is analogous to that of a circular shallow foundation, although vertically mirrored and similar to shallow foundations, the failure mechanism is dependent on the soil state, including relative density and mean stress. The discrete nature of the utilized numerical model for soil allows a good description of the evolution of the load recovery stage and contact forces within the granular material considering the kinematic of the arching process.