Parametric evaluation of relevant parameters affecting the soil-geosynthetic interaction under small displacement

Abstract

Geosynthetic products have been used for soil reinforcements purposes for the past couple of decades. The Civil Engineering industry, more specifically the transportation and geotechnical engineering sectors, have experienced a significant increase in the adoption of geosynthetics into their structures. Within these two sectors, the use of geosynthetic can be attributed to two major engineering groups: 1.) reinforced retaining walls and steep slopes, and 2.) stabilized flexible pavement systems. Although both of these systems use geosynthetics for its performance improvement benefits, the mechanisms involved in each are different. When geosynthetics are used in retaining walls, they are incorporated into the design based on their limit state properties which are known to provide soil-reinforcement. On the other hand, when geosynthetics are used in flexible pavements, they are incorporated into the design based on the properties of the soil-geosynthetic composite under small-displacements. Geosynthetics in flexible pavements are known to provide stabilization to the pavement structure as a whole; therefore, these geosynthetics serve a stiffening function. Currently in the engineering practice, there is no real parameter to quantify, or just to simply understand, what are the factors involved in the performance improvement based on the stiffening function provided by the soil-geosynthetic reinforcements. In an attempt to quantify the stiffness property, a soil geosynthetic composite (SGC) model was developed at the University of Texas at Austin. This model successfully characterized the stiffness of the soilgeosynthetic composite under small displacements and provided good correlation with field evaluation. The downside of this experimental model to determine the “stiffness of the soil-geosynthetic composite,” is that it requires a very labor and material intensive large-scale soil-geosynthetic interaction test under every condition at which the stiffness parameter is desired. This thesis focused on doing a parametric evaluation of the relevant testing parameters that affect the experimental stiffness of the soil geosynthetic composite by using smaller-scale equipment that requires less than 10% of the labor and materials required for the large-scale testing equipment. The parametric evaluation conducted from the small-scale tests showed that the stiffness property obtained experimentally from the small-scale test can be used for comparative purposes when characterizing the improvements in performance of the stabilized flexible pavement systems.