finite element modelling of unpaved road reinforced with geosynthetics

Abstract The technique of soil mechanical stabilization, using geosynthetics, is extensively used in the construction of unpaved roads with a low volume of traffic. Unpaved roads consist of unbound granular bases overlying cohesive subgrades. When built on weak subgrades, these roads are subject to problems like excessive rutting and mud-pumping, increasing maintenance costs and usually leading to periodic interruptions to traffic. Particularly, the field applications of geosynthetic reinforcement placed above a weak subgrade can markedly improve the performance of these roads decreasing permanent vertical deformations, increasing lateral restraint ability, which results in increased pavement service life or reduced base thickness to carry the same number of load repetitions. This paper focuses on providing a numerical investigation using a bi-dimensional Finite Element Method (FEM), using ABAQUS software, to analyze the improvement of reinforced unpaved road under repeated wheel traffic load conditions in terms of aggregate base course thickness saving

Soil Geosynthetic Interaction: Design Parameters from Experimental and Theoretical Analysis

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Valorization of artichoke wastewaters by integrated membrane process

In this work an integrated membrane system was developed on laboratory scale to fractionate artichoke wastewaters. In particular, a preliminary ultrafiltration (UF) step, based on the use of hollow fibre membranes, was investigated to remove suspended solids from an artichoke extract. The clarified solution was then submitted to a nanofiltration (NF) step. Two different 2.5 × 21 in. spiral-wound membranes (Desal DL and NP030) with different properties were investigated. Both membranes showed a high rejection towards the phenolic compounds analysed (chlorogenic acid, cynarin and apigenin-7-O-glucoside) and, consequently, towards the total antioxidant activity (TAA). On the other hand, the Desal DL membrane was characterized by a high rejection towards sugar compounds (glucose, fructose and sucrose) (100%) when compared with the NP030 membrane (4.02%). The performance of selected membranes in terms of permeate flux, fouling index and water permeability recovery was also evaluated. On the base of experimental results, an integrated membrane process for the fractionation of artichoke wastewaters was proposed. This conceptual process design permitted to obtain different valuable products: a retentate fraction (from the NP030 membrane) enriched in phenolic compounds suitable for nutraceutical, cosmeceutical or food application; a retentate fraction (from the Desal DL membrane), enriched in sugar compounds, of interest for food applications; a clear permeate (from the Desal DL membrane) which can be reused as process water or for membrane cleaning.Conidi, C.; Cassano, A.; García Castelló, EM. (2014). Valorization of artichoke wastewaters by integrated membrane process. Water Research. 48:363-374. doi:10.1016/j.watres.2013.09.047S3633744

A stress transfer model to predict the pullout resistance of extruded geogrids embedded in compacted granular soils

Pullout tests are necessary in order to study the interaction behaviour between soil and geosynthetics in the anchorage zone, hence, the test results have direct implications in the design of reinforced soil structures. This paper presents an evaluation of the soil-geogrid interaction, conducted to quantify the contributions of the frictional and the bearing components of the pullout resistance of geogrids. Based on the data obtained by authors, a stress transfer model has been implemented to predict the results of large-scale pullout tests using the load transfer curves approach. In particular, in the proposed stress transfer model the geometry of the elements on which the bearing resistance mobilizes, the soil dilatancy effects, the geogrid extensibility and the interference phenomena (between transversal bearing members) are taken into account. The comparison between theoretical and experimental results shows a good agreement, thus confirming the reliability of the proposed approach

Finite Element Modelling of Unpaved Road Reinforced with Geosynthetics

Abstract The technique of soil mechanical stabilization, using geosynthetics, is extensively used in the construction of unpaved roads with a low volume of traffic. Unpaved roads consist of unbound granular bases overlying cohesive subgrades. When built on weak subgrades, these roads are subject to problems like excessive rutting and mud-pumping, increasing maintenance costs and usually leading to periodic interruptions to traffic. Particularly, the field applications of geosynthetic reinforcement placed above a weak subgrade can markedly improve the performance of these roads decreasing permanent vertical deformations, increasing lateral restraint ability, which results in increased pavement service life or reduced base thickness to carry the same number of load repetitions. This paper focuses on providing a numerical investigation using a bi-dimensional Finite Element Method (FEM), using ABAQUS software, to analyze the improvement of reinforced unpaved road under repeated wheel traffic load conditions in terms of aggregate base course thickness saving