Interdisciplinary challenges in design of windblown sand barriers around desert railways

Ultra-long transnational railway megaprojects are currently being planned. Along their route, they cross different environments and are subjected to related specific environmental actions. In particular, they increasingly cross arid and desert regions, e.g. One Belt-One Road (8.000 km), or Arab Railway Network (30.000 km). In these regions, railways are vulnerable to sand blown by the wind. Several failure cases recently occurred because of windblown sand, e.g. along Mecca-Medina railway in Saudi Arabia, the Keetmanshoop-Luderritz railway in Namibia. Railways projects have technical complexity, resulting from components in civil works, railway equipment, rolling stock, signaling technologies. Windblown sand is the key, driving issue in the design of all these components. SMaRT is a multidisciplinary and intersectoral research project funded by Horizon 2020 research and innovation programme. It aims at tackling the challenges posed by windblown sand in the design of railways infrastructures. The SMaRT consortium includes geomorphologists, applied mathematicians, wind engineers, civil engineers. Companies in the fields of civil constructions, signaling systems, railway equipment express their industrial needs. The present paper summarizes the approach to windblown sand developed by SMaRT. In a problem setting approach, we consider windblown sand as an environmental action, similarly to wind or snow actions. We categorize its effects into Sand Ultimate Limit States (e.g. train derailment) and Serviceability Limit States (e.g. ballast contamination). In the design perspective, we propose a semi-probabilistic quantitative prediction of the incoming windblown sand drift. We conceive innovative windblown sand barriers, we assess their performances by computational simulations and wind tunnel tests.