Evaluation of additional confinement for three-dimensional geoinclusions under general stress state

Abstract

17The three-dimensional cellular geoinclusions (e.g. geocells, scrap tires) offer all-around 18 confinement to the granular infill materials, which improves their strength and stiffness. The 19 accurate evaluation of extra confinement offered by these geoinclusions is inevitable for 20 predicting their performance in the field. The existing models to evaluate the additional 21 confinement are based on either plane-strain or axisymmetric stress states. However, these 22 geoinclusions are more likely to be subjected to the three-dimensional stresses in actual 23 practice. This note proposes a semi-empirical model to evaluate the additional confinement 24 provided by cellular geoinclusions under the three-dimensional stress state. The proposed 25 model is successfully validated against the experimental data. A parametric study is conducted 26 to investigate the influence of input parameters on additional confinement. The results reveal 27 that the simplification of the three-dimensional stress state into axisymmetric or plane-strain 28 condition has resulted in inaccurate and unreliable results. The extra confinement offered by 29 the geoinclusion show substantial variation along the intermediate and minor principal stress 30 directions depending on the intermediate principal stress, infill soil and geoinclusion 31 properties. The magnitude of additional confinement increases with an increase in the 32 geoinclusion modulus. The findings are crucial for the accurate assessment of the in-situ 33 performance of three-dimensional cellular geoinclusions. 34 35

Remediation of a Railway Embankment Using Geocells and Deep Soil Mixing - A Numerical Analysis

“…The input values of the strength and stiffness parameter of equivalent material were determined according to [6], [7], and [8], considering the beaviour of crushed stone to be governed by the Duncan-Chang non-linear constitutive model [9]. Increasing of the values of the strength and deformation parameters of the filling material is considered due to the 3D stress state in the individual cell pocket [10]. The development of the apparent cohesion c r depends on the increased lateral stress ∆ σ3 arising in the soil inside the cell due to the membrane stress induced by the wall of the cell.…”

“…The elastic modulus of the Duncan-Chang model in loading conditions E i is given by equation (10), where n is a modulus exponent and P t is the atmospheric pressure which is used to normalise the stress inputs. The values M = 450 MPa, d 0 = 0.24 m, K e = 725, n = 0.43 and K p = 3 were used in this presented analysis.…”

Finite Element Modeling of the Dynamic Response of Critical Zones in a Ballasted Railway Track

“…The mitigation techniques that improve the stiffness or strength of granular layers may prove more effective for critical zones with stiff subgrade than critical zones with soft subgrade. For instance, 3D geoinclusions such as geocells, which improve the properties of granular layers through confinement (Punetha et al, 2020b), are more beneficial for critical zones with a stiff subgrade.…”

Full-scale laboratory testing of a geosynthetically reinforced soil railway structure

“…Geogrids are proven to be a practical solution used under the ballast to reduce the permanent deformation for railways Singh, et al, 2020;Punetha, et al, 2020). In the last 2 decades, geosynthetically reinforced soils (GRS) emerged as a reliable transportation infrastructure mitigation strategy.…”