Finite-element analysis of a piled embankment with reinforcement and subsoil

Abstract

Zhuang & Ellis (2014) considered predictions of reinforcement tension in a piled embankment from BS 8006 (BSI, 2010 and 2012), comparing the results with finite element model predictions. In keeping with BS 8006 any contribution from the subsoil beneath the embankment was ignored. This paper extends that work by also considering the potentially beneficial contribution of a lightly overconsolidated clay subsoil layer, both in the finite element predictions and as a simple modification to the BS 8006 predictive method. It is assumed that there is no 'working platform' (granular) material below the pile cap level, and that the water table in the subsoil does not drop, since either of these factors would be likely to significantly reduce the ability of the subsoil to carry load from the embankment. As anticipated the subsoil support reduces reinforcement tension. When compared to the finite element results the proposed modified BS 8006 prediction is quite accurate. The BSI (2012) modified prediction is 'best' (but sometimes slightly unconservative), whilst the BSI (2010) modified prediction is conservative in all cases considered.

A Design Chart for the Analysis of the Maximum Strain of Reinforcement in GRPEs Considering the Arching and Stress History of the Subsoil

“…The soil arching and tension membrane effects play an important role in the load transfer mechanism of GRPEs. A large number of experimental and numerical studies on this topic have been conducted by many researchers [1][2][3][4][5][6][7][8].…”

“…Zhuang et al [10] presented that subsoil has a major contribution to the overall vertical equilibrium of GRPEs. Zhuang and Ellis [7] demonstrated the nonnegligible bearing capacity of subsoil in long-term conditions, and the support of subsoil reduced the reinforcement tension. Therefore, a design that does not take into account the bearing capacity of the subsoil may become overly conservative.…”

“…In this paper, a new design method for GRPEs was developed under the framework of Hewlett and Randolph's [2] soil arching model and the BS8006 [14] reinforcement method modified by Zhuang and Ellis [5,7]. Additionally, the design method incorporated the settlements of subsoil considering different stress histories.…”

Calculation model and bearing capacity optimization method for the soil settlement between piles in geosynthetic-reinforced pile-supported embankments based on the membrane effect

“…Zhuang and Ellis. [ 10 , 11 ] analyzed the British standard BS 8006 published in 2010 and the 2012 amended version respectively through the finite element method. The results show that the BSI 2012 modified prediction is ‘best’ (but sometimes slightly unconservative), whereas the BSI 2010 modified prediction is conservative in all cases considered.…”

Geosynthetic reinforcement of pile-supported embankments

“…To this day, Geosynthetic-Reinforced Pile-Supported Embankment (GRPSE) is a technique, which is studied using field or full-scale experimental cases (Le Hello, 2007;Briançon and Simon, 2012;Briançon and Dias, 2015 ;Nunez et al, 2013 ;Xing et al, 2014 ;Chen et al, 2016), 1×g small-scale models at a scale of 1/N (Jenck et al, 2005, Jenck et al, 2007, Eskişar et al, 2012, Van Eekelen et al (2012a, b, 2015) and centrifuge modelling at a scale1/N and a g-level equals to N (Ellis and Aslam, 2009;Blanc et al, 2013;Girout et al, 2014). These physical modelling tests have been often supplemented by numerical analyses (Le Hello and Villard, 2009;Girout et al, 2014or Han-Jiang et al, 2014Zhuang and Ellis, 2016;Zhuang and Wang, 2015; . Some standard and design guidelines like EBGEO (2011) have been examined by Blanc et al (2014), for which the vertical displacement of a GR strip between two piles is compared with the physical modelling results.…”