A new apparatus for direct shear and pull-out tests was conceived to study the soil-geosynthetic and the geosynthetic-geosynthetic interaction: it consists of a testing box, having a contact area of 0.1 m2, with vertical and horizontal loads applied by an electronically controlled two-axis testing machine. Different types of geogrids (both uniaxially and biaxially oriented) were tested. Two different types of soil were used: silty sand and gravel. Particularly,direct shear tests were run using different testing rates (varying from 0.1 to 5.0 mm/min). The second part of the research concerned triaxial tests, using a very large cell (0.82 m height and 0.35 m diameter) and the same gravel soil. These tests were performed with and without the geogrid reinforcements. The direct shear tests have demonstrated that the rate of displacement does not influence significantly the soil-geosynthetic interaction. On the other hand, the triaxial tests have emphasized that the geosynthetic inclusion give a not negligible cohesion to the whole mass and determine peculiar modes of failure.

Dykes, or levees, are structures designed and constructed to keep the water in a river within certain bounds in the event of a flood. In relation with climate change, more frequent floods, of higher intensity, can be expected due to anthropogenic emissions of greenhouse gases into the atmosphere. The objective of this review paper is to address the many ways in which geosynthetics contribute to sustainable construction of dykes and thus to water systems management. This review paper, prepared by the four Technical Committees and the Sustainability Committee of the International Geosynthetics Society, briefly describes geosynthetics and their function, dykes and dyke failure modes, before presenting the main focus of the use of geosynthetics for the design and construction of durable dykes to ensure the protection of life and infrastructure. The optimization of dyke construction with geosynthetics to increase their resilience not only results in performance advantages, but also in economic advantages. The way geosynthetics can contribute to mitigating greenhouse gas emissions for a sustainable river management is discussed. This is done not only by allowing more economic construction methods to be implemented, but also solutions with increased resilience to face the extreme stresses related to climate change, while at the same time bringing about a positive contribution to the reduction of greenhouse gas emissions during the construction process itself. Finally, it is shown that by following state of the art standards and design practice any possible risk associated with the use of geosynthetics in dykes can be mitigated.

Geosynthetics are man‐made products manufactured to meet specific functions in earthworks and geotechnical projects, such as dams, levees, canals, dikes and other structures commonly found in agricultural engineering. Thanks to the Memorandum of Understanding between the International Geosynthetics Society (IGS) and the International Commission on Irrigation and Drainage (ICID), collaborative efforts are being undertaken to generate awareness of geosynthetics in agriculture. In the Workshop on ‘Applications of geosynthetics to irrigation, drainage and agriculture’ held at the 23rd International Congress of the ICID in Mexico City on 8 October 2017, a group of delegates from the IGS contributed with a series of presentations introducing various functions and applications of geosynthetics. The authors gave an overview of how geosynthetic products are designed and tested to ensure they will fulfil their intended function, focusing on applications to irrigation, drainage and agriculture. A few key considerations were identified as being critical to ensure proper performance of geosynthetic materials, in geotechnical projects in general and in agriculture in particular. The present paper is intended to provide a summary of these presentations. © 2018 John Wiley & Sons, Ltd.

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The use of geocells in base reinforcement of structural fill allows confinement of the soil from lateral spreading, therefore preventing shear failure and increasing the soil bearing capacity.Geocell are typically loaded by the live loads on the surface and the overall structure is tensioned while the underlying foundation soil settles. Geocells are regularly used for soil confinement on steep slopes to prevent severe erosion. The geocells are sometimes installed even over slippery geomembranes to contain and reinforce the cover soil.The geocells in these applications should withstand high tensile stresses both in the strands and the junctions without breaking and sliding down the slope. A need for more accurate and specific geocells testing is needed by the design engineers when designing such a critical applications. The testing procedures appropriate for geocells will be investigated, performed and analyzed in this paper. The description of the above tests and some preliminary results are presented and discussed. A final proposal for test standards concerning geocells will be presented for consideration by the existing geosynthetics testing committees.