Undrained response of fiber-reinforced cohesive soils -

Abstract

The use of fiber-reinforced soils as a ground improvement alternative has gained a renewed interest in the geotechnical community in recent years. Several studies have been conducted with the objective of investigating the potential use of fibers to reinforce both clayey and sandy soils. In real practical engineering applications, it can be argued that the use of fibers is best associated with clayey soils, given the many less onerous options available for addressing granular materials and given the nature of most readily locally available borrow sources for earthworks. Furthermore, the current and evolving trend towards sustainable material sourcing has driven us to explore the use of natural fibers as reinforcing elements, rather than the more common-traditional synthetic options. In this dissertation, a comprehensive and wide-reaching experimental triaxial testing program was conducted to characterize the as-compacted, globally undrained short term behavior of clayey soil reinforced with natural fibers. Moreover, the effectiveness of current models in predicting the improvement in the undrained shear strength of cohesive soils reinforced with fibers was evaluated and incorporated in a reliability analysis that simulates a practical field application. The research is divided into two main sections. The experimental work in the first section is aimed at supplementing the deficit in the published literature on the behavior of clays that are reinforced with “natural” fibers in response to the current effort invested to embrace sustainable construction materials and solutions. It consists of laboratory triaxial tests that addressed the effect of the compaction method (impact compaction versus kneading) and that of other parameters (fiber content, fiber aspect ratio, moisture content and confining pressure) on the undrained load response of natural clay specimens that are reinforced with natural Hemp fibers. In the second section, data collected from the literature and some results retrieved from our