1,721,008 research outputs found
A rugged FBG-based pressure sensor for water level monitoring in dikes
Full text linkThis paper describes the implementation of an FBG sensor to measure water levels in a dike. The sensor is based on a 3D-printed mechanical transducer through which the external pressure is converted into longitudinal strain exerted on the fiber. An additional FBG integrated within the sensor measures temperature and is used to compensate for the temperature effects on the first FBG. By employing an aluminum alloy case, the sensor is suitable for operations in harsh environments and rough installation procedures. Four sensors of this kind have been successfully tested on a real scale dike at the Water Proof Holland facility in The Netherlands.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Hydraulic Structures and Flood RiskWater Resource
Integrated Geomorphological Mapping of Emerged and Submerged Coastal Areas based on the Coupling of Terrestrial and Marine Datasets
No full textA deeper understanding of the processes acting on the coastal areas is crucial for coastal hazard assessment and mapping. To this aim, integrated geomorphological investigations of emerged and submerged areas resulting in geomorphological mapping represent an innovative way to provide the necessary knowledge for preventing hazards and reducing risks. An example is provided from the north-western coast of Malta (central Mediterranean Sea)
Landslide-geomorphosite assessment in the Dolomites (Italy): Application of a newly implemented method
Full text linkThis paper aims at the definition of new geoheritage criteria to identify and assess landslides as geomorphosites. As first application of a newly implemented methodological approach, we propose a comparative evaluation of landslide geomorphosites in the Dolomites, north-eastern Italy. We quantitatively assess each site by using standard criteria well-established in geoheritage studies and newly defined ones related to risk perception, anthropic signature, and climate change. These new criteria aid in defining the most useful geomorphosites for educating visitors regarding themes such as landslide hazard and risk, the consequences of human activities on landslide triggering and development, and landslide activity in response to warming climatic conditions. In previous studies, geomorphosite assessment was not performed for landforms of one kind as opposed to any kinds of landforms within a specific geographic area. For the first time, we analyse a landform of a kind – namely landslides, as geomorphosites in a defined region, using old and newly defined criteria that can be applied to a variety of other landforms. Our methodology highlights the scientific importance of the definition of landslides as geomorphosites, emphasises how their consequences on human activities and the environment can be disseminated to the public, and can be applied for geomorphosite assessment of any other geomorphological landform
Fiber optic sensor with improved sensitivity for acoustic detection of rockfalls
No full textThis short note summarizes the activity about the development and optimization of a fiber optic sensor for ultrasonic acoustic sensing to the aim of rockfall detection. The sensor is described and its viability to rockfall is discussed and experimentally validated. An improved design of the sensor, with double responsivity, is also proposed
Optical fiber sensor for simultaneous measurement of hydrostatic pressure and temperature in soil embankments
No full textFiber optic sensor for hydrostatic pressure and temperature measurement in riverbanks monitoring
No full textGeomorphological analysis of the historic landslide of Sottrù (Badia Valley, Italy) reactivated on December 13, 2012
No full textThe historic landslide of Sottrù, located in the Badia Valley (Autonomous Province of Bolzano), was reactivated on 13 December 2012 after a long period of dormancy. According to historic documents, the previous activation dates back to June 1821. At that time, the slope was mobilised after a period of persistent rain and snow melt causing the damming of the Gadera stream. After snowmelting, in June 1827 the natural dam collapsed flooding meadows and villages down valley. In December 2012, the landslide was partly reactivated, showing the first slow movements on the 13th and more rapid displacements on the 14th. A detailed geomorphological survey of the landslide was carried out during summer 2014. A surficial highly permeable level (in-situ or reworked till) has been found laying on top of a thick sequence of clays, shales and marls, both over the landslide body and the surrounding areas. From the landslide scar uphill, the hydrographic pattern is extremely irregular, made of discontinuous drainage lines indicative of higher infiltration rate than superficial run off. The comparison between the current morphology and the pre-2012 one has not evidenced any movement within the historic source area, while relevant displacements occurred at two lateral zones whose dynamics caused the partial collapse of the central part of the landslide, originating a second, lower crown. Since the previous activation (1821), the landslide has been dormant for quite a long period, i.e. 191 years, and its last activation occurred during a season where landslides are usually not frequent. Temperature and precipitation time series, recorded at the nearby meteorological station of La Villa, have been analysed for the last 27 years. It has been found out that November 2014 had many rainy days, three of which with precipitation amounts ranging from 30 to 50 mm. The rainiest day (November 29) was suddenly followed by a dramatic drop below 0°C of maximum and minimum air temperatures, lasting until the 13th of December i.e., the landslide activation day. This probably caused the freezing of the soil which at that time was snow free and completely saturated. Moreover, it is possible that the 13-day period below 0°C enabled also the freezing of a spring located in the lower part of the slope nearby the village of Sottrù thus blocking groundwater drainage, leading to the onset of a confined-aquifer condition and, ultimately, to the rapid increase of pore water pressure inside the clay-rich landslide material. This hypothesis has been made also in consideration of similar events occurred in the Dolomites (e.g., in Zoldo Valley in 1991). However, in order to confirm this hypothesis, geophysical and geotechnical analysis would be needed
On the use of OFDR for high-spatial resolution strain measurements in mechanical and geotechnical engineering
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