Full-Scale Interface Friction Testing of Geotextile-Based Flood Defence Structures

Abstract

Open-topped woven polypropylene cellular containers filled with dense granular ballasts are often used as emergency flood defence structures. The effectiveness of these systems is highly dependent on the interaction with their bedding surface. The characteristics of the foundation will often govern the system’s overall resistance to applied loading imposed by retained floodwater. However, the frictional relationship between polypropylene bulk bag flood defences and common bedding surfaces has not been extensively investigated. This study aims to reduce the reliance on arbitrary static friction coefficients by measuring and presenting actual data obtained through quantitative testing. This study presents the results of full-scale field testing to quantify the frictional resistance generated between filled polypropylene bulk bags and seven common bedding surfaces. Findings resulting from testing each interface scenario are expressed as coefficients of static friction. Test interfaces affording high frictional resistance comprised an unmade gravel road (µ = 0.74) and grass (µ = 0.64). Contrastingly, interfaces generating significantly lower frictional resistance were steel floated concrete (µ = 0.40) and polypropylene plastic (µ = 0.40). Test interfaces involving asphalt (µ = 0.54) and tamped concrete (µ = 0.56–0.58) were also investigated. This study recommends new friction coefficients necessary to characterise the structural stability analysis of bulk bag flood defences with greater accuracy. Practical advice based on experimental observation and field design experience is also given.

Operational risk management – Measurement and evaluation of friction coefficients for geotextile sandbags for flood protection

“…That underlines the already stated assumption: the higher measurement inaccuracy due to surface condition leads to higher friction coefficients compared to laboratory conditions. The comparison of present results to former studies shows good conformity [7,11]. However, one former investigation in general presents lower results compared to the assumed results on this investigation.…”

“…Investigation on polypropylene bulk bags with a weight of approximately 650 kg for several friction coefficients was conducted, in which a friction coefficient from polypropylene on gravel road with μ = 0.74, on grass with μ = 0.64, on steel with μ = 0.40, on asphalt μ = 0.54, on tamped concrete μ = 0.56 and on polypropylene itself μ = 0.40 was assumed [7]. A general recommendation to use μ = 0.25 as friction coefficient for every calculation, independent of the surface and the boundary condition, was made [8].…”

Role of Wind, Ground Surface, and Slope in Plastic Waste Movement on Terrestrial Environments

“…There is a conclusive argument concerning plastic friction against the ground's surface. When the plastic reaches the surface, the rank of the ground surface must be concrete asphalt road as the smoothest one, followed by grass and cut grass based on simulation of Woven Polypropylene Plastic (bulk bag material) on different ground surface to hold the flood [28]. Further research on observing actual events in the field relating to plastic transport on land by the wind is still required to determine the probability of plastic entering water bodies.…”

Approximation method for the sewer drainage effect for urban flood modeling in areas without drainage-pipe data

“…The existing method reduces water mass in the process of runoff generation, while the new method deducts the water quantity after the rainwater flows to the road, which is much closer to the actual case (Li et al, 2020;Klipalo et al, 2022). In this study, a hydrodynamics-based urban flood model was adopted as a standard for comparison with the two methods.…”