Finite-element analysis of arching in highway piled embankments subjected to moving vehicle loads

This paper presents a simplified finite-element model, based on which the arching in highway piled embankments subjected to moving vehicle loads is investigated. The analyses demonstrated that the pile spacing was a more sensitive factor than embankment height, whose increase from 2·0 to 3·0 m led to a 60–68% increase of the normalised maximum settlement at the base of the embankment. The effect of moving vehicle loads was of particular interest, increasing the normalised maximum settlement and vertical stress at the base of the embankment by approximately 23% and 19%, respectively, compared to the static situation. The influence height of soil arching related to the pile spacing and embankment height was investigated, and showed that the vertical extent of arching was within a normalised distance of 2·0 from the base of the embankment. Factors of the embankment properties – that is, elastic modulus, friction angle, dilation angle and cohesion – were examined and showed that the cohesion was a most sensitive factor, whose increase from 1 to 10 kPa reduced the normalised maximum settlement and vertical stress by approximately 56% and 42%, respectively. Also shown was that the increase in the velocity of a moving vehicle from 30 to 120 km/h slightly increased the normalised maximum settlement and vertical stress by approximately 9% and 10%, respectively. Finally, a modified analytical method was developed by considering the additional vertical stress induced by moving vehicle loads based on the Boussinesq equation, whose solution was found to be in good agreement with the finite-element results.