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Fortier, Richard

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Fortier

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Richard

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Université Laval. Centre d'études nordiques

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ncf10363691

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Geophysical and geotechnical characterization of a sensitive clay deposit in Brownsburg, Québec

2017-05-24, Bélanger, Karine, Locat, Ariane, Fortier, Richard, Demers, Denis

The results of a geophysical and geotechnical investigation in a sensitive clay deposit affected by numerous landslide scars in Vases Creek Valley near Brownsburg, Quebec, Canada are presented herein. The main objective of this investigation was to assess the suitability of electrical resistivity measurements in marine clay deposits for mapping out areas prone to flowslides. In addition to a 1.6 km-long electrical resistivity tomography (ERT) carried out perpendicular to the axis of the Vases Creek Valley, six piezocone penetration tests and five boreholes with sampling were also performed along the geophysical survey line. Moreover, standard geotechnical parameters and pore water salinity, as well as electrical resistivity of undisturbed clay samples were measured in the laboratory. According to the correlations found between the remoulded shear strength, the pore water salinity and the electrical resistivity, clay samples with salinity below 6.2 g/l are characterized by remoulded shear strength below 1 kPa and electrical resistivity above 2.8 and 10 m measured respectively in the field and in the laboratory. In such conditions, sensitive clay deposits can be prone to flowslides if all other criteria are also met. Based on this resistivity limit value, only one small area of nonsensitive clay was identified in the interpretative stratigraphic cross-section assessed from the field investigation. Otherwise, the deposit is entirely composed of sensitive clay. The ERT is a promising geophysical tool for the delineation of areas prone to large landslides in eastern Canada

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Topical collection : hydrogeology of a cold-region watershed near Umiujaq (Nunavik, Canada)

2020-03-06, Ouellet, Michel, Therrien, René, Lemieux, Jean-Michel, Fortier, Richard, Molson, John W. H.

A cold-region watershed located in the discontinuous permafrost zone near Umiujaq (Nunavik, Canada) was studied in order to increase understanding of the subarctic water cycle and permafrost dynamics. This essay gives an overview of the research, summarised in a collection of six papers that: respectively characterize the physical three-dimensional cryo-hydrogeological system, present a detailed water balance of the watershed, characterize groundwater and surface-water hydrogeochemistry, describe the application of a tracer method to determine groundwater fluxes, develop a two-dimensional numerical model identifying impacts of groundwater flow on permafrost dynamics, and present a parameter sensitivity analysis. The work serves as a guide for developing site characterization plans at similar permafrost-impacted sites and for evaluating their groundwater resource potential.

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Curvature sensing using a hybrid polycarbonate-silica multicore fiber

2020-12-21, Morency, Steeve, Bilodeau, Guillaume, Fortier, Richard, Messaddeq, Younès, Bernier, Martin, Boilard, Tommy

We report on the development of a novel hybrid glass-polymer multicore fiber integrating three 80 µm polyimide-coated silica fibers inside a 750 µm polycarbonate cladding. By inscribing an array of distributed FBGs along each segment of silica fiber prior to the hybrid fiber drawing, we demonstrate a curvature sensor with an unprecedented precision of 296 pm/m−1 around 1550 nm, about 7 times more sensitive than sensors based on standard 125 µm multicore fibers. As predicted by theory, we show experimentally that the measured curvature is insensitive to temperature and strain. Also, a more precise equation to describe the curvature on a simple bending setup is presented. This new hybrid multicore fiber technology has the potential to be extended over several kilometers and can find high-end applications in 3D shape sensing and structural health monitoring.

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Atmospheric carbon mineralization in anindustrial-scale chrysotile mining waste pile

2018-06-12, Horswill, Micha, Beaudoin, Georges, Larachi, Faïcal, Maldague, Xavier, Duchesne, Josée., Nowamooz, Ali, Therrien, René, Lemieux, Jean-Michel, Fortier, Richard, Dupuis, J. Christian, Constantin, Marc, Molson, John W. H.

Magnesium-rich minerals that are abundant in ultramafic mining waste have the potential to be used as a safe and permanent sequestration solution for carbon dioxide (CO2). Our understanding of thermo-hydro-chemical regimes that govern this reaction at an industrial scale, however, has remained an important challenge to its widespread implementation. Through a year-long monitoring experiment performed at a 110 Mt chrysotile waste pile, we have documented the existence of two distinct thermo-hydro-chemical regimes that control the ingress of CO2 and the subsequent mineral carbonation of the waste. The experimental results are supported by a coupled free-air/porous media numerical flow and transport model that provides insights into optimization strategies to increase the efficiency of mineral sequestration at an industrial scale. Although functioning passively under less-than-optimal conditions compared to laboratory-scale experiments, the 110 Mt Thetford Mines pile is nevertheless estimated to be sequestering up to 100 tonnes of CO2 per year, with a potential total carbon capture capacity under optimal conditions of 3 Mt. Annually, more than 100 Mt of ultramafic mine waste suitable for mineral carbonation is generated by the global mining industry. Our results show that this waste material could become a safe and permanent carbon sink for diffuse sources of CO2.

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Rapid groundwater recharge dynamics determined from hydrogeochemical and isotope data in a small permafrost watershed near Umiujaq (Nunavik, Canada)

2020-01-25, Cochand, Marion, Barth, Johannes (Johannes A. C.), Therrien, René, Geldern, Robert van, Lemieux, Jean-Michel, Fortier, Richard, Molson, John W. H.

Hydrogeochemical data are used to better understand recharge dynamics and to support a hydrogeological conceptual model in a 2-km2 watershed in a discontinuous permafrost zone in Nunavik, Canada. The watershed contains an upper (surficial) and lower aquifer within Quaternary deposits, above and below a marine silt layer containing ice-rich permafrost mounds. The analysis is based on water samples from precipitation, groundwater monitoring wells, ground ice in permafrost mounds, thermokarst lakes and a perennial stream. Groundwater geochemistry in both aquifers reflects young, poorly evolved waters, with mainly Ca-HCO3 water types and low mineralisation ranging from 11 to 158 mg/L total dissolved solids (TDS), implying short pathways and rapid travel times of a year or less. While relatively low, TDS signatures in groundwater and surface water show increasing values downgradient. Groundwater isotope values (δ18OH2O and δ2HH2O) are often strongly influenced by snowmelt, while those of thermokarst lakes show evidence of evaporation. Recharge along the cuesta contributes to a transverse component of groundwater flow within the valley with higher TDS and δ13CDIC values influenced by open-system weathering. Even where permafrost-free, the marine silt unit has a strong confining effect and plays a more important role on recharge dynamics than the discontinuous permafrost. Nevertheless, the vulnerability of these types of hydrogeological aquifer systems is expected to increase due to rapid recharge dynamics associated with the gradual loss of the confining effect of permafrost. This hydrogeochemical data set will be useful as a baseline to document impacts of permafrost degradation on the hydrogeological system.

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Thermal effect of rainwater infiltration into a replicated road embankment in a cold environmental chamber

2018-12-21, Liu, Weibo, Chen, Lin, Yu, Wenbing, Fortier, Richard, Lu, Yan, Zhang, Mingyi, Hu, Da

A laboratory experiment was performed to investigate the thermal effect of rainwater infiltration into a one-half scale replicated road embankment built on artificial permafrost subjected to four 15-day freeze-thaw cycles and several rainfall events during thaw periods in a cold environmental chamber. The ground temperature, water content, and heat flux were monitored at different depths at three key locations in the road subbase. Based on the experimental results, the rainwater infiltration has a significant heating effect on the shallow subbase layers down to a depth no more than 30 cm. The heat transfer in the road embankment is directly correlated to the amount of rainfall. Moreover, rainwater infiltration has different heating effects according to the locations in the road subbase. The most important heating effect is underneath the embankment slope, the second one in the embankment shoulder, and the third one underneath the concrete pavement. The changes in temperature, moisture, and heat flux in the road subbase due to the rainwater infiltration are delayed and attenuated with the increase in depth. Even if the road subbase was frozen at these depths, moisture changes in the road subbase as deep as 60 cm were observed. The volumetric unfrozen water content in the road subbase and subgrade depends on the ground temperature and exhibits hysteretic behavior during cooling and warming cycles. The observed variations in heat flux are related to the changes in temperature and moisture in the road subbase. For road embankments located in permafrost environments, the thermal effect of rainwater infiltration into the road subbase may lead to permafrost degradation at depth.

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Coupled cryo-hydrogeological modelling of permafrost dynamics near Umiujaq (Nunavik, Canada)

2020-02-12, Therrien, René, Lemieux, Jean-Michel, Dagenais, Sophie, Fortier, Richard, Molson, John W. H.

A two-dimensional (2D) cryo-hydrogeological numerical model of groundwater flow, coupled with advective-conductive heat transport with phase change, has been developed to study permafrost dynamics around an ice-rich permafrost mound in the Tasiapik Valley near Umiujaq, Nunavik (Québec), Canada. Permafrost is degrading in this valley due to climate warming observed in Nunavik over the last two decades. Ground temperatures measured along thermistor cables in the permafrost mound show that permafrost thaw is occurring both at the permafrost table and base, and that heat fluxes at the permafrost base are up to ten times higher than the expected geothermal heat flux. Based on a vertical cross-section extracted from a 3D geological model of the valley, the numerical model was first calibrated using observed temperatures and heat fluxes. Comparing simulations with and without groundwater flow, advective heat transport due to groundwater flow in the subpermafrost aquifer is shown to play a critical role in permafrost dynamics and can explain the high apparent heat flux at the permafrost base. Advective heat transport leads to warmer subsurface temperatures in the recharge area, while the cooled groundwater arriving in the downgradient discharge zone maintains cooler temperatures than those resulting from thermal conduction alone. Predictive simulations incorporating a regional climate-change scenario suggest the active layer thickness will increase over the coming decades by about 12 cm/year, while the depth to the permafrost base will decrease by about 80 cm/year. Permafrost within the valley is predicted to completely thaw by around 2040.

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Semi-automated filtering of data outliers to improve spatial analysis of piezometric data

2015-04-19, Therrien, Pierre, Tremblay, Yohann, Comeau, Guillaume, Therrien, René, Talbot Poulin, Marie-Catherine, Lemieux, Jean-Michel, Fortier, Richard, Molson, John W. H.

The identification and removal of data outliers remains a major challenge for spatial analysis of piezometric data. In this context, a simple semi-automated procedure for filtering outliers of depth to static water level was developed and used as a part of a regional groundwater-mapping project in the Québec Metropolitan Community, Québec, Canada. Following a few basic steps of data control, potential outliers were detected using two simple automated steps: (1) identifying water levels that are deeper than the 99th percentile of a high-reliability dataset compiled by groundwater professionals and assumed to adequately represent depths to static water level, and (2) using moving averages within a search radius of 250 m calculated around each well. All detected potential outliers were visually examined in a geographic information system and compared to neighbouring data before being kept or discarded. To evaluate the efficiency of the procedure, exploratory statistics, histograms and semi-variograms of the initial, intermediate and filtered datasets were compared to the high-reliability dataset. Objective interpolation was then performed using ordinary kriging. A cross-validation analysis showed a less biased and more accurate interpolation after applying the proposed outlier filtering procedure. Qualitative knowledge of the hydrogeological settings is an important component of this procedure which combines advantages of both manual and automated processing, making the procedure adaptive and easy to use. The final outcome of the proposed procedure is an improved interpolation map of depth to static water level along with minimised and low squared estimation errors.

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A WebGIS to support GPR 3D data acquisition : a first step for the integration of underground utility networks in 3D city models

2017-10-27, Losier, Louis-Martin, Fortier, Richard, Tabarro, Paulo, Pouliot, Jacynthe

For the planning and sustainable development of large cities, it is critical to accurately locate and map, in 3D, existing underground utility networks (UUN) such as pipelines, cables, ducts, and channels. An emerging non-invasive instrument for collecting underground data such as UUN is the ground-penetrating radar (GPR). Although its capabilities, handling GPR and extracting relevant information from its data are not trivial tasks. For instance, both GPR and its complimentary software stack provide very few capabilities to co-visualize GPR collected data and other sources of spatial data such as orthophotography, DEM or road maps. Furthermore, the GPR interface lacks functionalities for adding annotation, editing geometric objects or querying attributes. A new approach to support GPR survey is proposed in this paper. This approach is based on the integration of multiple sources of geospatial datasets and the use of a Web-GIS system and relevant functionalities adapted to interoperable GPR data acquisition. The Web-GIS is developed as an improved module in an existing platform called GVX. The GVX-GPR module provides an interactive visualization of multiple layers of structured spatial data, including GPR profiles. This module offers new features when compared to traditional GPR surveys such as geo-annotated points of interest for identifying spatial clues in the GPR profiles, integration of city contextual data, high definition drone and satellite pictures, as-built, and more. The paper explains the engineering approach used to design and develop the Web GIS and tests for this survey approach, mapping and recording UUN as part of 3D city model.

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Flexible trans-jacket inscription of fiber Bragg gratings for directional distributed sensing

2019-08-29, Morency, Steeve, Fortier, Richard, Messaddeq, Younès, Bernier, Martin, Trépanier, François, Boilard, Tommy

An array of 18 FBGs spectrally distributed over 70 nm was written in a polyimide-coated fiber, with a single uniform phase-mask, by applying strain on the fiber prior to exposition. This flexible method will be used to develop directional sensor for distributed sensing based on a hybrid glasspolymer multicore fiber.