Stiffness of Soil–Geosynthetic Composite under Small Displacements: I. Model Development

Abstract

While significant emphasis has been placed on the quantification of soil-geosynthetic properties under failure conditions, studies of properties that are suitable for characterizing this interaction under serviceability conditions have been limited. Also, most geosynthetic properties are currently defined in isolation rather than under the confinement of soil. The purpose of this study is to develop a soil-geosynthetic interaction framework that, with a single and repeatable parameter, can capture the stiffness of a soil-geosynthetic composite under small displacements. The soil-geosynthetic interaction model developed in this study involves well-established force equilibrium differential equations. However, the constitutive relationships and boundary conditions were specifically selected so that the model results in a closed-form analytical solution. Since the analytical solution involves a single parameter, its use may be particularly suitable for specification and the design of structures such as stabilized roadways. This parameter, referred to as the stiffness of the soil-geosynthetic composite, or SG C K , captures both the tensile characteristics of the geosynthetic and the shear behavior of the soilgeosynthetic interface. Experimental procedures to quantify SG C K were developed as part of this study. The results of a pilot experimental program, conducted using tailor-made soil-geosynthetic interaction equipment, are presented in the paper. These results confirm the suitability of the assumptions and outcomes of the model. A companion paper provides the results of a comprehensive experimental program with particular emphasis on the evaluation of the repeatability of the results and on the sensitivity of the assumptions and outcomes of the model to variables that impact SG C K .

Lessons Learned on Geosynthetics Applications in Road Structures in Silesia Mining Region in Poland

“…Detailed analysis of the values for the calculated pavement elastic modules indicated that the pavement and the subsoil were of high rigidity, which is in agreement with the assumptions made by Zornberg et al [39] and Sudarsanan, et al [40]. At the same time, in the section of increased deflections (i.e., from 323 + 800 km to 324 + 00 km-southern section), the value of modules was reduced.…”

Interaction Between a Lateritic Soil and a Non-woven Geotextile in Different Moisture Conditions

“…Fannin and Raju (1993) used strain gages to check the longitudinal deformation along the geosynthetic. Authors such as Palmeira (2009), Ferreira and Zornberg (2015), Bathurst and Ezzein (2017), and Zornberg et al (2017) also presented different proposals and more complex approximations for the calculation of the confined stiffness of the geosynthetics using pullout tests. These approximations appear to be significantly better for the calculation of confined deformation of the geotextile than the calculation of the deformations directly by the displacement between two consecutive points.…”

Optimal placement of reinforcement in piggyback landfill liners

“…Consequently, neither failure strain nor strength were considered when a suitable model geogrid was selected. Zornberg et al (2017) showed using a parameter defined as the stiffness of the soil-geosynthetic composite that both confined stiffness and interface shear strength (a function of bond) are required to describe the behaviour of reinforced granular materials at small strain. Consequently, the remaining two fundamental geogrid properties, stiffness and bond, were of importance when selecting a model geogrid for centrifuge testing.…”