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Saunier P., Fourmont S., Mlynarek J., Jung A.,Stafford R.

Successful tailings dewatering design using multilinear drainage geocomposites

This article, published by the Mining Engineering Magazine from Society for Mining, Metallurgy & Exploration Inc. (SME) presents the design of DRAINTUBE® multi-linear drainage geocomposites for tailings dewatering.

 

Fourmont S., Riot M.

Improving railway drainage with multilinear geocomposites

Drainage ferroviaire

 

In this article published by the Geosynthetics Magazine, the authors Stephan Fourmont, Business Development Manager at AfitexTexel, and Mathilde Riot, Technical and R&D at Afitexinov, assert, through three illustrative cases studies, that significantly improving railway drainage is possible using multi-linear drainage geocomposites, such as DRAINTUBE®.

Read the full article below or on the website of Geosynthetics Magazine.

 

 

Duquet J.B., Sarbach C., Fourmont S.

Design of reinforcement geosynthetics in landfill piggyback expansion

The construction of a vertical expansion of existing waste disposal facilities (piggyback landfills) involves the use of reinforcement geosynthetics to address differential settlements and stability issues that will be reactivated under the load of the new cell. The challenge is to guarantee the integrity of the new liner system.

This article published in the Geosynthetics Magazine - IFAI presents the extension project of an old landfill and the main design steps to select the appropriate GEOTER reinforcement geosynthetic.

 

Damiano L., Steinhauser E.

A guide for specifying drainage geocomposites

ASTM D7931 standard provides a guideline for calculating engineering properties related to drainage geocomposites that can be used by designers and engineers throughout multiple industries. The calculation methodologies for products like multi-linear drainage geocomposites do not change. Designing with innovative products can decrease the required transmissivity and increase the factor of safety of the drainage layer, allowing for opportunities to meet more stringent regulations.

Fourmont S., Pellez JC.

Innovative mechanically stabilized earth walls with geotextiles geocells

Structures reinforced with geosynthetics consist in increasing the mechanical performance of a soil (mainly shear resistance) by associating it with flexible geosynthetics inclusions. One of the important issues in the construction of geosynthetic reinforced walls is the supply of natural backfill materials with the required properties needed for the stability of the wall. Indeed, unlike geosynthetics that exhibit stable properties due to extensive quality controls during the manufacturing process, soil matrix will vary from a site to another and even from the beginning to the end of the excavation work. It influences the soil stability itself and also the soil-geosynthetic interface. As it minimizes the influence of soil characteristics on the stability of the reinforced structure, M3S geotextile geocells make possible, in addition to the construction of reinforced structures with complex shapes, to reuse the soil material excavated on-site to build the wall, including those with very poor geotechnical characteristics. This publication presents the M3S cellular system and its mechanical and functional characteristics. It also gives a case study on the construction in 2019 of two MSE walls as part of the A71 motorway bypass on the APRR network, France.

Khoueiry N., Briançon L., Daouadji A., Riot M.

Developed full-scale cyclic plate load and traffic load tests for unpaved roads on soft subgrade and reinforced with geosynthetics

With the expansion of urban areas, the construction on soft subgrade becomes a more often issue due to excessive settlement, especially for roads network. Nowadays, the tradition soft soil replacement solution is substituted by stabilization solutions to reduce the surface settlement. Geosynthetics (GSYs) are used to stabilize base course over soft subgrade under unpaved roads. GSYs improve this structure by the following mechanisms : lateral restraint and reinforcement of base course aggregates, tension membrane effect in rutted areas, and reduction of mixing between subgrade and base soils. With the reinforcement addition, the mechanisms developed at the interface become even more complex. It is important to identify and clarify these mechanisms in order to propose an efficient design method for this kind of structure. A large-scale laboratory test was designed and developed to characterize the GSYs effects and the reinforcement mechanisms in unpaved roads. An unpaved road platform was subjected to cyclic plate load. The platform consisted of a soft subgrade layer supporting a base course layer and placed in a box of 1.9 m of large, 1.8 m of length and 1.1 m of height. The composition of soft soil, the installation and the quality control procedure are detailed in this paper. The surface rutting, the subgrade settlement and the vertical stress distribution were monitored during the loading cycles. Moreover, the GSY strain was monitored using the fibre optic technology. Six tests were performed; two repeatability tests and four reinforced and unreinforced tests with different base course thicknesses. The tests performed proved the repeatability of the experimental protocol. Moreover, it is concluded that the used GSY has a negligible effect if the base course thickness is equal or higher than 350 mm. On the other hand, for a base course thickness of 220 mm, the geogrid reinforcement provides a surface rutting reduction of 22%, and a subgrade central vertical stress reduction of 30%. In comparison with the empirical and the analytical design methods from the literature, we conclude that these methods overestimate the base course thickness for unreinforced platform. These experiments consist in a preparation program to a full-scale experiment, with a cyclic Traffic load applied on the unpaved road surface, using the Simulator Accelerator of Traffic (SAT) machine developed at INSA Lyon.

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