Probabilistic Analysis of Geosynthetic-Reinforced Unpaved Road Subject to Subgrade Variability (original) (raw)

Design and Economic Analysis of a Flexible Pavement on a Geosynthetic Reinforced Subgrade

Journal of Applied Sciences and Environmental Management, 2019

This study investigated the effect of geogrid reinforcement on the mechanical property of an unsuitable road soil with respect to appropriate placement in the pavement structure and implication on the cost of the development of the road. Sample was collected from the stockpile of an unsuitable soil material at a bridge site and subjected to identification, geotechnical strength (CBR) and chemical stabilization tests. CBR strength evaluation test was further performed on the soil sample when reinforced with the use of a geosynthetic, triaxial geogrid (Tx 160). A flexible pavement structure was designed for low, medium and heavy traffic level using three design methods with the improved soil subgrade. The corresponding relative cost advantages were also determined using the pavement thickness reduction factor. The results established the geogrid reinforcement is a better alternative to chemical stabilization of an unsuitable AASHTO A-4 soil. The design results denoted a significant pavement thickness reduction factor as a result of geogrid reinforcement within 13%-67% savings in pavement thickness for all the pavement design methods employed. The use of geogrids should, therefore, be encouraged as an economic form of improving subgrade soils for pavement works.

Geosynthetic Reinforcement for Unpaved Roads – Recent Experience

2018

Modern geosynthetic materials, including geotextiles and geogrids, are often used to generate savings in materials and time on construction projects. Geosynthetics are used as reinforcement and separation membranes for unpaved roads that are supported by low strength or unsuitable subgrades. When geosynthetics are used, unsuitable subgrades can be left in place and reduced thicknesses of road base are required. This paper reviews the design methods currently used to build geosynthetic reinforced unpaved roads and documents the validation of these design approaches. A number of recent case histories of projects in the UK and Ireland are outlined, showing the use of geotextiles and geogrids to reinforce unpaved roads founded on peat, alluvial soils, and low strength glacial tills. The cost savings achievable are commented upon and the results of performance monitoring over time are presented. The overall aim of the paper is to show how geosynthetic reinforcements can be efficiently ut...