Early warning of slope instability will enable evacuation of vulnerable people and timely repair and maintenance of critical infrastructure. However, currently available warning systems are too expensive for wide-scale use or have technical limitations. The acoustic emission (AE) monitoring approach using active waveguides (i.e. a steel tube with granular backfill surround installed in a borehole through a slope), in conjunction with the Slope ALARMS AE measurement system, has the potential to be an affordable early warning system for slope instability. However, the challenge has been to develop strategies to interpret and quantify deformation behaviour from measured AE. The development of an approach to quantify slope deformation behaviour from measured AE will enable the AE monitoring system to provide early warning of slope instability through detecting, quantifying and communicating accelerations in slope movement. Field monitoring and full-scale physical modelling have been conducted to characterise the AE response from the system to both reactivated slope movements and first-time slope failure. Definitive field evidence has been obtained showing AE monitoring can measure slope movements and generated AE rates are proportional to slope displacement rates, which was confirmed through comparisons with both conventional inclinometer and continuous ShapeAccelArray deformation measurements. A field monitoring case study demonstrated that the AE approach can detect very slow slope movements of 0.075 mm/day. In addition, the concept of retrofitting inclinometer casings with active waveguides to convert the manually read instrument to a real-time monitoring system has been demonstrated using a field trial. Dynamic strain-controlled shear tests on active waveguide physical models demonstrated that AE monitoring can be used to quantify slope displacement rates, continuously and in real-time, with accuracy to within an order of magnitude. Large-scale first-time slope failure experiments allowed the AE response to slope failure to be characterised. AE was detected after shear deformations of less than a millimetre in previously un-sheared material, and AE rates increased proportionally with displacement rates as failure occurred. The AE rate-displacement rate relationship can be approximated as linear up to 100 mm/hour and shear surface deformations less than 10-20 mm. At greater velocities and larger deformations the gradient of the relationship progressively increases and is best represented using a polynomial. This is because complex pressure distributions develop along the active waveguide analogous to a laterally loaded pile, and the confining pressures increase. Variables that influence the AE rate-displacement rate relationship have been quantified using physical model experiments and empirical relationships. A framework has been developed to allow AE rate-displacement rate calibration relationships to be determined for any AE system installation. This provides a universal method that can be used by practitioners when installing AE systems, to calibrate them to deliver alarm statuses/warning levels that are related to slope displacement rates. Use of this framework has been demonstrated using a case study example, and decision making protocols have been suggested that use trends in alarms with time to trigger decisions, which could be to send an engineer to inspect the slope, manage traffic, or evacuate people.

Track stiffness is the one of the most critical parameters of the track structure. Its evaluation is important to assess track quality, component performance, localised faults and optimise maintenance periods and activities. Keeping the track stiffness within acceptable range of values is connected with keeping the railway network in a satisfactorily performing condition, allowing thereby upgrade of its capacity (speed, load, intensity). Current railway standards are changing to define loading and stiffness requirements for improved ballasted and ballastless performance under high speed train traffic. In recent years various techniques have been used to measure track deflection which have been also used to validate numerical models to assess various problems within the railway network. Based on recent introduction of the Video Gauge for its application in the civil engineering industry this project provides the proof of effective applicability of this DIC (Digital image correlation) tool for the accurate assessment of track deflection and the calculation of track stiffness through its effective applicability in various track conditions for assessing the stiffness of various track forms including track irregularities where abrupt change in track stiffness occur such as transition zones and rail joints. Attention is given in validation of numerical modelling of the response of insulated rail joints under the passage of wheel load within the goal to improve track performance adjacent to rail joints and contribute to the sponsoring company s product offering. This project shows a means of improving the rail joint behaviour by using external structural reinforcement, and this is presented through numerical modelling validated by laboratory and field measurements. The structural response of insulated rail joints (IRJs) under the wheel vertical load passage is presented to enhance industry understanding of the effect of critical factors of IRJ response for various IRJ types that was served as a parametric FE model template for commercial studies for product optimisation.

This paper presents the results of a study on the effectiveness of porous overlays on urban highways. Permeable Friction Course (PFC) is a layer of porous asphalt applied to the top of conventional asphalt highways at a thickness of around 50 mm. PFC is often installed for safety and noise benefits, and is being seen as an emerging technology for meeting environmental requirements for stormwater discharge. The first objective of the study was to determine the impact of porous asphalt on the quality of stormwater runoff on highways with a curb and gutter drainage system. The quality of highway stormwater runoff was monitored before and after the installation of PFC on an eight-lane divided highway in the Austin, Texas area for 2 years. Observed concentrations of total suspended solids from PFC are 92% lower than those in runoff from the conventional pavement. Concentration reductions are also observed for nitrate/nitrite and total amounts of phosphorus, copper, lead, and zinc. The data shows that the results with curb and gutter are consistent with past results where runoff sheet flowed onto vegetated shoulders. The effect of two different binder compositions is also compared, showing an increase in zinc when recycled rubber is used. The second objective focuses on the drainage capabilities of PFC. While porous overlays can reduce stormwater accumulation on roadways, capacity at high rainfall intensities is limited. Installing subgrade underdrains within PFC could further improve stormwater conveyance. This research attempts to model the hydraulic profile of runoff as it approaches an underdrain with varying flow rates and grades. The results could assist TxDOT in the sizing and configuration of drains based on rainfall intensity and roadway geometry. / text

The drainage behaviour of sports pitches is not well understood nor has performance been measured in the past. Within planning authorities there is a perceived contribution of pitch water discharge to local flood risk; whereby all the rainfall surface runoff is rapidly channelled through the drainage system to the pitch outfall. However, empirical evidence from industry suggested that this may not be a realistic assumption from observations of low drainage volumes yielded from pitch drainage systems. Furthermore, discharge constraints imposed have in many cases resulted in grossly over-designed off-line drainage attenuation systems for new sports developments through lack of understanding. In contrast, sports pitches indeed have the potential to enhance the attenuation performance of the subsoils and provide localised effective management of surface water runoff, and a significant storage volume if designed appropriately The findings in this thesis confirm that pitch bases demonstrate the key functions that are in fact reflected in the design requirements of Sustainable Urban Drainage Systems (SuDS). This PhD research project was conducted to investigate and document the performance of common pitch construction and drainage systems to better characterise the key drainage mechanisms that occur and control the flow of surface rain water through the pitch to the discharge outfall. The project developed a triangulated approach to the investigations, comprising: field measurements of climate and discharge behaviour at a range of artificial and natural turf pitches in England; laboratory physical model testing of pitch component hydraulics; and predictive mathematical modelling of how a pitch system may be expected to perform hydraulically based on key material and system drainage principles. The field monitoring systems were developed as part of the research, as was bespoke laboratory physical simulation of a pitch construction. It was found that very variable yields (% out versus % in) of water were detected from the monitored field sites. The values varied across a range of < 1 to 88%, with the natural turf providing higher yields in general. The antecedent weather patterns did not show a clear relationship with yield as might have been expected. However, it was not always possible to retrieve detailed information on the subsoil conditions or hydraulic capability reducing the conclusiveness of the discharge flow measurements. The scaled laboratory testing of pitch materials established the importance and magnitude of barriers to percolation of surface water through the layers of the pitch constructions, in particular artificial pitch profiles. It was found that a significant proportion of the total rainfall head was required to instigate percolation of surface water through the carpet and into the pitch i.e. breakthrough head. In addition, several constituent pitch materials exhibited water retention characteristics that reduced that rate of free percolation of surface water through the pitch profile. The net impact is to reduce the net available head of water to further drive flow through the layers to the pipe network drainage system. A conceptual hydraulic model, developed from the literature, was further developed into a simple numerical model. The model was informed by parameters determined from the laboratory measurements and key groundwater drainage flow theory to attempt to replicate a pitch drainage system. It was envisaged that the models would be validated by the field data, although this proved challenging as a result of the field data variability and the multivariate nature of the influences on flows measured. A key finding of the modelling was further establishing the likely head of water generated at the interfaces between the bottom of the granular sub-base and the pipe collection drainage system beneath. This resulted in limited pipe infiltration and low total flows to the outfall, further corroborating the project field results and the anecdotal observations from practitioners. The combined unique data sets provide a refined model for sports pitch drainage to both reinforce understanding and inform practical design and operation.

No description available.

This thesis treats virtual sensing for fatigue assessment of steel bridges. The purpose is to develop avirtual sensing method to use in the fatigue assessment process. The aim for the virtual sensing method is to only depend on strain measurements located on the bridge structure. The service life of bridges is often limited by fatigue and amending bridge design to improve fatigue resistance was developed in the 1970s. There are several bridges in Sweden, Europe and other countries that have exceeded their theoretical service life with regard to fatigue, and the need to replace them isboth a environmental and economical issue. The bridge over Rautasjokk north of Kiruna, Sweden is a specific example where the theoretical service life is limited by fatigue. Uncertainties in the theoretical fatigue assessment of bridges can be reduced by measuring strains atthe fatigue critical details, and therefore lead to a longer theoretical service life. Monitoring is, however,an expensive method and the procedure of installation and administration requires working time, and monitoring can only provide information at the gauge location. Hence, it is of great interest to optimizethe monitoring system. Virtual sensing is a method that could provide an alternative to conventionalmeasuring techniques. Virtual sensing combine measurement data with information from a model. Virtual sensing for fatigue assessment of the Rautasjokk Bridge was evaluated developing two methods. Both methods uses a finite element model of the bridge combined with strain measurements. The measurements were obtained on February 14 2018 and included a time signal and strain variations at six different locations of the structure. The accuracy of the virtual sensing methods were evaluated by comparing the fatigue damage of virtual sensing with the fatigue damage calculated using measured strains. The fatigue calculations were based on methods presented in the Eurocode EN-1993-1-9. The first method was based on the idea to find a relation between groups of stress ranges for two gauge locations on the bridge. The stress ranges were established by loading influence lines obtained from the finite element model with a fictitious train and the difference between two gauges was stored in a vector, the correlation vector. The correlation vector was applied on the measured stress ranges of the first gauge to estimate the actual stress ranges of the second gauge. No relation between groups of stress ranges for different loading cases was found and the correlation vector method for virtual sensing is not a sufficiently accurate method to apply in the fatigue assessment of the Rautasjokk Bridge. The second method was based on finding a relation between each stress range instead of a group of stress ranges. Influence lines from the finite element model were used to find a relation between each stress range of two gauges. Their relation was stored in a matrix, the correlation matrix. The matrix was applied on the measured stress ranges of the first gauge to estimate the actual stress ranges of the second gauge. The correlation matrix method for virtual sensing estimate the fatigue damage sufficiently accurate at the bridge locations where local stress ranges have the greatest impact on the fatigue damage. Results obtained through virtual sensing only include the same parameters that were used as inputs in the method. A credible virtual sensing method is crucial in order to achieve reliable results. In general, a virtual sensing method requires an extent amount of input data to validate its reliability. Further studies are required to investigate how the uncertainties of the correlation matrix affect the fatigue assessment.

Hundreds of thousands of landslides occur every year around the world impacting on people's lives. Monitoring techniques able to foresee imminent collapse and provide a warning in time useful for action to be taken are essential for risk reduction and disaster prevention. Acoustic emission (AE) is generated in soil and rock materials by rearrangement of particles during displacement or increasing damage in the microstructure preceding a collapse; therefore AE is appropriate for estimation of slope deformation. To overcome the high attenuation that characterise geological materials and thus to be able to monitor AE activity, a system called Slope ALARMS that makes use of a waveguide to transmit AE waves from a deforming zone to a piezoelectric transducer was developed. The system quantifies acoustic activity as Ring Down Count (RDC) rates. In soil applications RDC rates have been correlated with the rate of deformation, however, the application to rock slopes poses new challenges over the significance of the measured AE trends, requiring new interpretation strategies. In order to develop new approaches to interpret acoustic emission rates measured within rock slopes, the system was installed at two trial sites in Italy and Austria. RDC rates from these sites, which have been measured over 6 and 2.5 years respectively, are analysed and clear and recurring trends were identified. The comparison of AE trends with response from a series of traditional instruments available at the sites allowed correlation with changes in external slope loading and internal stress changes. AE signatures from the limestone slope at the Italian site have been identified as generated in response to variations in the groundwater level and snow loading. At the conglomerate slope in Austria, AE signatures include the detachment of small boulders from the slope surface caused by the succession of freeze-thaw cycles during winter time. Consideration was also given to laboratory testing of specific system elements and field experiments. A framework towards strategies to interpret measured acoustic emission trends is provided for the use of the system within rock slopes.

Les crues – telles que les laves torrentielles – engendrées dans les torrents lors de fortes précipitations peuvent mobiliser de grande quantité de sédiments. Lorsqu'elles atteignent les zones urbanisées, elles peuvent mettre en dangers à la fois les personnes et les biens. Les approches visant à réduire le risque torrentiel se basent largement sur des seuils intensité-durée de pluie qui déterminent les conditions minimum de déclenchement d’une lave torrentielle. Pourtant, ces seuils sont sujets à une forte variabilité liée, non seulement aux différences inter-sites, mais aussi à la méthode appliquée lors de leur établissement. De plus, ils peuvent entraîner des fausses prédictions, l’intensité et la durée de l’épisode de pluie n’étant pas les seules variables explicatives. Ce travail de thèse vise (i) à fournir un cadre méthodologique rigoureux pour l’établissement des seuils de pluie afin de limiter les sources de variabilité, et (ii) à améliorer leurs performances en considérant à la fois les facteurs de déclenchement et de prédisposition. Il s’appuie sur les données d’un observatoire des crues torrentielles, mis en place dans les Alpes françaises en 2011 sur les torrents très actifs du Manival et du Réal. Dans un premier temps, les images et mesures hautes-fréquences collectées entre 2011 et 2016 ont été analysées afin de détecter et de caractériser les crues torrentielles. Pour appréhender la diversité des écoulements observés, une classification phénoménologique a été proposée. Dans un second temps, la condition minimum intensité-durée de pluie requise pour déclencher une lave torrentielle a été établie. La sensibilité du seuil à la définition d’un épisode de pluie a été évaluée. Dans un troisième temps, un modèle de régression logistique a été implémenté pour discriminer les épisodes de pluies critiques qui n’ont pas engendré de lave torrentielle. Il a permis de sélectionner les variables explicatives les plus pertinentes. Finalement, des pistes de travail ont été avancées pour (i) passer de conditions critiques établies à une échelle locale vers une échelle régionale, en perspective d’une application au sein d’un système d’alerte dédié aux risques hydrométéorologiques, et (ii) passer des conditions de déclenchement d’une lave torrentielle dans la zone de production sédimentaire aux conditions de propagation jusqu'aux zones à enjeux. / Flows – such as debris flows – caused by heavy rainfalls in torrents can mobilise a huge amount of sediments. When they reach the urbanised areas, they may endanger the people’s safety or cause damages. Approaches aimed at mitigating torrential risk widely rely on rainfall intensity-duration thresholds which determine the minimum debris-flow triggering conditions. However, these thresholds suffer from a high variability related not only to inter-site differences but also to the method applied to design them. In addition, they are likely to cause false prediction because the intensity and the duration of the rainfall event are not the only explanatory variables. This PhD research work aim (i) to provide a rigorous methodological framework for designing rainfall threshold in order to limit the variability sources, and (ii) to improve their performances by including both the triggering and the predisposing factors. It is supported by field observations stemming from high-frequency monitoring stations installed since 2011 on two very active debris flow-prone torrents in the French Alps: the Manival and the Réal. First, the images and data gathered between 2011 and 2016 were analysed in order to detect and characterise the sediment laden-flows. To deal with the variety of recorded flows, a phenomenological classification was performed. Second, the minimum intensity-duration threshold for debris-flow triggering was assessed. The threshold sensitivity to the rainfall event definition was estimated. Third, a logistic regression model was used to discriminate the critical rainfall events which do not lead to a debris flow. It makes it possible to select the most relevant explanatory variables. At last, several avenues of work were proposed (i) to move the knowledge of debris-flow initiation conditions from a local to a regional level, with a view to application in a warning system dedicated to hydrometeorological risks, and (ii) to improve the ability to predict, not the debris-flow triggering in the production zone, but the debris-flow propagation up to the area concerned.

Les éponges d'eau douce (Porifera) produisent des spicules siliceuses dont la morphologie a une valeur taxonomique et environnementale. Les sédiments très concentrés en spicules, dénommés spongilite, sont présents en abondance dans le nord-ouest du Minas Gerais (Brésil). Ils se sont formés au cours des derniers 28000 ans. Afin d'étudier l'aptitude de ces dépôts à enregistrer les paléoenvironnements, nous avons procédé, à partir des éponges produites actuellement dans un dans un petit lac du nord-ouest du Minas Gerais (Lagoa Verde), à 2 types de calibrations. (1) Le suivi écologique de M. spinata, éponge unique du lac, a été fait au cours de son cycle de vie annuel. L'éponge produit 4 catégories de spicules en lien avec les variations saisonnières de l'équilibre entre précipitation et évaporation, de la température de l'eau et de la concentration en silicium dissout. La mise en évidence de ces relations conforte les interprétations paléoenvironnementales précédemment tirées des assemblages de spicules fossiles. (2) La composition isotopique en oxygène (δ18O) des silicates biogéniques est communément utilisée comme marqueur paléoenvironnemental. Ce marqueur n'a jamais été calibré pour les spicules d'eau douce. Nous avons testé si M. spinata précipitait ses spicules en équilibre isotopique avec l'eau du lac. La composition δ18O des spicules montre une relation thermo-dépendante positive avec la composition δ18O de l'eau, inverse de ce qui est attendu pour une précipitation à l'équilibre isotopique. Ce résultat suggère un fractionnement cinétique d'origine biologique à déterminer en vue de reconstitutions paléoenvironnementales. / Freshwater sponges (Porifera) produce siliceous spicules with taxonomic and paleoenvironmental value. Sediments with high concentrations of spicules, called spongilite, are present in NW Minas Gerais (Brazil). They formed during the last 28000 years. In order to investigate the reliability of these deposits to record past environmental changes, we proceeded to two kinds of calibration, from sponges currently produced in a small lake of NW Minas Gerais (Lagoa verde). (1) The ecology of M. spinata, the only sponge of the lake, was monitored over its annual cycle. The sponge produced 4 spicules categories in relation with seasonal changes in precipitation, evaporation, water temperature and dissolved silicon content. These relationships confirm previous paleoenvironmental reconstructions from fossil spicule assemblages. (2) The oxygen isotopic composition (δ18O) of biogenic silica is commonly used as a paleoenvironmental proxy. This proxy has never been calibrated for fresh water sponge spicules. We checked whether M. spinata formed its spicules in isotopic equilibrium with the lake water. The δ18O signature of the spicules showed a positive thermo-dependent relationship with the δ18O of the lake water, conversely to what was expected for an equilibrium precipitation. This result suggests that a biological kinetic fractionation occurred. This kinetic fractionation needs to be systematically characterized for paleoenvironmental reconstruction purpose.

Several hydraulic loadings impose earthen levees to time-dependent variably saturated seepage conditions. The main objective of this study is to improve the analysis of levees under transient seepage with the use of unsaturated soil mechanics. An extensive set of laboratory testing, field monitoring and numerical modeling are performed to analyze a silty sand setback levee located near Seattle, WA. In-situ data obtained from field monitoring are used to monitor suction and effective stress within the levee’s embankment and foundation over the past two years. Soil samples taken from the site are used to perform index, water retention, and unsaturated multi-stage triaxial tests in the laboratory. A finite element model of transient seepage under saturated-unsaturated conditions is then developed and calibrated to reasonably match the field data. The results highlight the need to consider unsaturated soil mechanics along with climatic variables and soil-atmosphere interaction when analyzing levees under transient seepage conditions.