Three-dimensional behavior of biaxial geogrid in a piled embankment: numerical investigation

Abstract

Biaxial geogrid in current research is oversimplified, and the 1 three-dimensional orthotropic nature of the biaxial geogrid has not been fully 2 understood in numerical investigations. A comparative study on three modeling 3 approaches for the biaxial geogrid is presented in this paper, including the isotropic 4 membrane model, the orthotropic membrane model and the truss element model. It 5 shows that the orthotropic membrane model yields practically identical results of the 6 maximum geogrid tension when compared with the truss element model, whereas the 7 isotropic membrane model tends to yield values that are approximately 33% larger. A 8 parametric study shows that the pile spacing has the strongest influence on the 9 maximum geogrid tension. The comparison of four analytical methods with the 10 orthotropic membrane model shows that the BS8006 (2010), EBGEO (2011) all 11 greatly overestimate the geogrid tension, while the method presented by Zhuang et al. 12 (2014) results in closer agreement.13

Multilayered low-strength geogrid-reinforced piled embankment

“…When subjected to stresses that are perpendicular to the horizontal plane, the gegrid may take the shape of a membrane so that the tensile forces guarantee the static equilibrium of the sheet (Briancon and Villard, 2008). As a result, modelling the geogrid inclusion as a continuous membrane has proven to simulate the overall response of the geogrid-reinforced piled embankment reasonably (Gu et al, 2016;Hussein and Meguid, 2016;Liu et al, 2007;Saad et al, 2006;Zhuang and Wang, 2015). The biaxial geogrid in this paper is represented using four-node, full integration, 3D membrane elements and is modelled as an orthotropic elastic material with the non-zero stiffness only in two orthogonal directions (Zhuang and Ellis, 2014).…”

“…Generally, single or multiple layers of geogrids are installed just above the pile head to increase the load transfer to the piles and to reduce the total and differential settlements (Ariyarathne and Liyanapathirana, 2015;Chen et al, 2016;Deb and Mohapatra, 2013;Huang and Han, 2009;Lu and Miao, 2015;Xing et al, 2014;Zhang et al, 2016;Zhuang and Wang, 2015;. The tensile force of the geogrid is directly related to the service performance of the geogrid.…”

“…Some guidelines for the calculation of the tensile force of geogrids in reinforced piled embankments have been developed in the past decades (BSI, 2010;GGS, 2011;Van Eekelen et al, 2011Ellis, 2014, 2016;. However, due to the complexity of the reinforced piled embankments, some of these methods are based on a wide range of conservative assumptions that give rise to conflicting results, particularly with respect to the degree of the load transfer and stress-strain developed in the geogrid (Abdullah and Edil 2007;Chen et al, 2010;Russell and Pierpoint, 1997;Stewart and Filz, 2005;Zhuang and Wang, 2015). There are no clear uniform code guidelines available for the design of geogrid in reinforced piled embankments.…”

“…However, full 3D numerical modelling can usually be very complicated, needs computers with a high processing power and also can be extremely time consuming depending on the complexity of the problem (Ariyarathne et al, 2012). Therefore, for practical limitation, many researchers have used the unit cell concept and 3D column model to study the performance of piled embankments (Bhasi and Rajagopal, 2014;Jenck et al, 2009;Yoo, 2010;Yoo and Kim 2009;Zhuang and Wang, 2015).…”

Full-scale model study on variations of soil stress in geosynthetic-reinforced pile-supported track bed with water level change and cyclic loading

“…The foundation of the pile-supported track bed is commonly improved by an array of piles with caps on them. The additional improvement such as the application of a geogrid reinforcement layer is also considered in some embankments (Han and Gabr 2002;Heitz et al 2008; van Eekelen et al 2012avan Eekelen et al , 2012bvan Eekelen et al , 2013Zhuang and Wang 2015;Chen et al 2016b;Wang et al 2018a).…”