Geosynthetics have increasingly been used in geotechnical engineering applications due to their numerous benefits, including the cost-effectiveness, reliability and contribution to sustainability. When employed in transport infrastructure projects, geosynthetics may perform a variety of functions, leading to increased stability and longevity of the system. This paper describes a laboratory study carried out using a large-scale direct shear test apparatus to characterise the direct shear behaviour of the interfaces between a recycled construction and demolition (C&D) material and two geosynthetics (a geogrid and a geocomposite) subjected to cyclic normal loading. The direct shear tests were performed under a constant shear displacement rate, while the normal loading varied cyclically at predefined frequency and amplitude values. Direct shear tests under static normal loading were also performed for comparison purposes. Test results have shown that the interface shear strength and dilation behaviour tend to decrease under cyclic normal loading and are influenced by the applied frequency and amplitude. The peak and large displacement shear strengths of the interface with the geogrid exceeded those reached when the geocomposite was used, which may be attributed to more effective interlocking of the aggregates within the geogrid apertures.
Ground-Penetrating Radar (GPR) provides high-resolution, non-invasive insights into the subsurface, making it an essential tool for assessing climate change impacts and managing infrastructure in Arctic and sub-Arctic environments. This review examines GPR applications in mapping and characterizing cold-region features to enhance our understanding of the Critical Zone at high latitudes. Specifically, we focus on permafrost, including its active layer and embedded ice structures, as well as glaciers and front moraine, ice sheets, and snow cover. Furthermore, driven by advancements in miniaturization and energy efficiency, we extend our review to GPR-based subsurface exploration on the Moon and Mars, where environmental conditions and frozen geomorphological structures share similarities with terrestrial cold regions. Finally, we highlight the interconnection between hardware and software advancements and the expanding applications of GPR in cryospheric research.
This study assesses the vulnerability of Arctic coastal settlements and infrastructure to coastal erosion, Sea-Level Rise (SLR) and permafrost warming. For the first time, we characterize coastline retreat consistently along permafrost coastal settlements at the regional scale for the Northern Hemisphere. We provide a new method to automatically derive long-term coastline change rates for permafrost coasts. In addition, we identify the total number of coastal settlements and associated infrastructure that could be threatened by marine and terrestrial changes using remote sensing techniques. We extended the Arctic Coastal Infrastructure data set (SACHI) to include road types, airstrips, and artificial water reservoirs. The analysis of coastline, Ground Temperature (GT) and Active Layer Thickness (ALT) changes from 2000 to 2020, in addition with SLR projection, allowed to identify exposed settlements and infrastructure for 2030, 2050, and 2100. We validated the SACHI-v2, GT and ALT data sets through comparisons with in-situ data. 60% of the detected infrastructure is built on low-lying coast (< 10 m a.s.l). The results show that in 2100, 45% of all coastal settlements will be affected by SLR and 21% by coastal erosion. On average, coastal permafrost GT is increasing by 0.8 degrees C per decade, and ALT is increasing by 6 cm per decade. In 2100, GT will become positive at 77% of the built infrastructure area. Our results highlight the circumpolar and international amplitude of the problem and emphasize the need for immediate adaptation measures to current and future environmental changes to counteract a deterioration of living conditions and ensure infrastructure sustainability.
Although soil stabilization with cement and lime is widely used to overcome the low shear strength of soft clay, which can cause severe damage to the infrastructures founded on such soils, such binders have severe impacts on the environment in terms of increasing emissions of carbon dioxide and the consumption of energy. Therefore, it is necessary to investigate soil improvement using sustainable materials such as byproducts or natural resources as alternatives to conventional binders-cement and lime. In this study, the combination of cement kiln dust as a byproduct and zeolite was used to produce an alkali-activated matrix. The results showed that the strength increased from 124 kPa for the untreated clay to 572 kPa for clay treated with 30% activated stabilizer agent (activated cement kiln dust). Moreover, incorporating zeolite as a partial replacement of the activated cement kiln dust increased the strength drastically to 960 and 2530 kPa for zeolite ratios of 0.1 and 0.6, respectively, which then decreased sharply to 1167 and 800 kPa with further increasing zeolite/pr to 0.8 and 1.0, respectively. The soil that was improved with the activated stabilizer agents was tested under footings subjected to eccentric loading. The results of large-scale loading tests showed clear improvements in terms of increasing the bearing capacity and decreasing the tilt of the footings. Also, a reduction occurred due to the eccentricity decreasing as a result of increasing the thickness of the treated soil layer beneath the footing.
This study assesses the seismic fragility curves of in-service piled bridge abutments on liquefaction-prone soils and evaluates an optimal countermeasure within the vulnerability framework. Seismic fragility curves, accounting for varying ground motion intensities, assess the seismic risk and describe abutment damage through settlement measurements. The ageing abutment performance is estimated by integrating a corrosion model into fragility curves. The impact of different sheet pile positions on the seismic performance of in-service piled bridge abutments is analysed, and the optimal pile position is discussed. The developed fragility curves provide a rapid and effective risk assessment tool for the seismic performance of in-service abutments and guide liquefaction remedial measures.
In this study, the seismic resilience of granular column-supported road embankments on liquefiable soils is examined to enhance the understanding and seismic design of resilient transportation infrastructure. A nonlinear dynamic analysis of embankments on liquefiable soils is performed, and the results are validated against centrifuge test data. In the assessment, a functional analysis framework encompassing fragility, vulnerability, and restoration functions is employed to evaluate the robustness and recovery of embankments. The resilience of embankments is quantified by the comprehensive life-cycle resilience index (R), which considers various factors, such as the embankment height, the liquefiable soil thickness, and the area replacement ratio (AR) of granular columns. A simplified design method is proposed that involves a model for rapidly assessing the resilience state of embankments under varying seismic intensities. The analysis highlights the essential role of granular columns in mitigating liquefaction-induced damage during seismic events, improving robustness, and recovering postearthquake functionality, and a practical and reliable tool is developed for assessing embankment resilience across diverse seismic scenarios.
While plastic has been recognized as one of the top ten notable advancements of the 20th century, extensive utilization of plastic in its various forms has evolved into a complex concern with respect to environmental protection. The large amount of waste plastic and its low biodegradability is driving the research effort seeking alternatives to recycling plastic waste into construction materials, and recycled plastic utilization as a valuable alternative to soil, asphalt, and concrete appears to be one of the more promising solutions for beneficial use of plastic waste. Recent progress on recycled plastic utilization in transportation infrastructure systems, including content, size, shape, mechanism, effectiveness, and its applicability to soil, asphalt, and concrete, is outlined in this review paper. The effects of recycled plastic addition on the mechanical properties of soil, asphalt, and concrete are also discussed in detail. The potential for environmental disturbance and possible implementation difficulties in understanding the progress of recycled plastics utilization has also been investigated.
Extreme rainfall occurred in July 1996 over the Saguenay Region, some 200 km north of Quebec City. With about 1000 land -slides, seven damaged dams, one dike failure, washed out road sections, tens of bridges damaged or destroyed, 1700 properties destroyed or damaged and several casualties, this event was one of the most important natural disasters in Canada. Detailed geotechnical investigations permitted better understanding of the soils involved, mainly sensitive clays and their superficial crust, including their behaviour in landslides, the erosion processes, impacts on infrastructure and sediment deposition.
The past four decades have seen extensive development of the winter sport industry in the French Alps and several hundred ropeway transport systems have been installed in areas where mountain permafrost may be present. Due to current climatic change and the ensuing permafrost degradation, the vulnerability of these infrastructures to destabilization may increase. Therefore, there is a real potential for instabilities to develop on ropeway transport systems in the Alps, requiring a better understanding of these processes. This study investigates the relation between permafrost and infrastructure stability in the French Alps, seeking to understand the evolution of this phenomenon over the past decades. This was done by following a two-step analysis. At first, the infrastructure elements built on modeled permafrost-affected areas were inventoried at the scale of the French Alps in order to get an overview of the possible vulnerabilities. Then, our study presents a detailed historical inventory of damage to infrastructure over the past three decades in different geomorphologic contexts. Overall, in the French Alps, there are almost 1000 infrastructure elements located in permafrost areas among which 12 (i.e., 24 infrastructure elements) were identified to have been subject to repeated instances of disruption and deterioration and most of the damages recorded were in areas where permafrost degradation is fully expected (ice-rich terrain). Infrastructure recovery costs may be significantly high, making this issue a relevant consideration to be included in the design process.