Target Reliability Approach to Study the Effect of Fiber Reinforcement on UCS Behavior of Lime Treated Semiarid Soil

Abstract

This paper evaluates the effectiveness of stabilizing expansive soil with two different types of fibers, Fiber Mesh® (FM) and Fiber Cast® (FC), in conjunction with chemical stabilization. The intention of this study is to evaluate the effect of these fibers and lime in stabilizing expansive soil by improving its UCS behavior. The effect of varying lengths (6 mm and 12 mm) and amounts (0.2, 0.4 and 0.6% dosage by weight of soil) of FC and FM fibers and curing periods (0, 7, 28, 60, 120, 180 and 360 days) on the UCS and on secant modulus of a semi-arid expansive soil, in the presence of lime, was investigated. The main focus of this paper is on the determination of optimum fiber reinforcement parameters (in terms of fiber type, length and dosage) for the stabilization of expansive soil in terms of UCS, which is of a prime importance in soil stabilization projects for practicing engineers. In deterministic optimization, the uncertainties associated with subgrade soil of the pavement system are not explicitly taken into account. Hence, resulting optimal solutions may lead to reduced reliability levels of the pavement. Therefore, this paper also focuses on determining the optimum amounts of reinforcement for desired UCS performance of lime blended expansive soil using target reliability approach (TRA). The experimental data was used to develop a parabolic model using factors such as, length and dosage of fiber types to predict UCS as a response variable. In addition, it was concluded that the TRA can be successfully employed in expansive soil stabilization applications in determining the optimum length and dosage of fiber reinforcements.

Effect of polypropylene fibre reinforcement on the consolidation, swell and shrinkage behaviour of lime-blended expansive soil

“…These fibres were obtained from Propex operating company, LLC, United Kingdom and their chemical and physical properties are given in Table 1 as a part of supplemental materials. The amount of fibres was limited to 0.6% by dry weight of soil from workability perspective relying on earlier studies (Millar and Rifai 2004;Puppala et al 2006;Malekzade and Bisel 2012;Moghal et al 2016Moghal et al , 2017aMoghal et al , 2017b.…”

“…Regression analysis is one of the most widely used methods to relate dependent variables with independent variable (Sridharan and Nagaraj 2000;Işık 2009; Vinod and Bindu 2010; Tiwari and Ajmera 2012; Prasad 2013; Moghal et al 2017aMoghal et al , 2017b. In the present study, linear regression analysis is applied to experimental data.…”

“…Moghal et al (2016) recommended the two exponential best fit equations for estimating the hydraulic conductivity of lime-fibre-treated expansive soils in terms of dosage and length for different polypropylene fibre materials. Further, Moghal et al (2017b) reported the influence of length and dosage of fibre reinforcement on unconfined compressive strength (UCS) values through a non-linear regression equation, based on the experimental data measured after 28 and 360 days curing periods on expansive soil. In another extended study, Moghal et al (2017a) proposed two non-linear best fit equations for estimating the California Bearing Ratio (CBR) of lime-treated fibre-reinforced expansive soil in terms of amount and fibre length relying on laboratory experimental data.…”

“…In another extended study, Moghal et al (2017a) proposed two non-linear best fit equations for estimating the California Bearing Ratio (CBR) of lime-treated fibre-reinforced expansive soil in terms of amount and fibre length relying on laboratory experimental data. Moghal et al (2016Moghal et al ( , 2017aMoghal et al ( , 2017b considered these regression equations and employed target reliability approach (TRA) to obtain the optimum amounts of fibre reinforcement (for different fibre types) satisfying hydraulic conductivity, UCS and CBR behaviour of lime blended expansive soil for respective applications.…”

Probabilistic Bearing Capacity of a Pavement Resting on Fibre Reinforced Embankment Considering Soil Spatial Variability

“…There is a huge possibility that the mixing of fibres with soil may not be uniform, which may lead to the randomness in fibre reinforced soil. Very few probabilistic and reliability based studies are available on fibre reinforced soil (Ranjan et al, 1996;Moghal et al, 2016;Diab et al, 2017;Moghal et al, 2017;. Johari and Kalantari (2016) carried out a probabilistic analysis of slope stability of embankment reinforced with discrete polypropylene fibre.…”