Wyniki wyszukiwania - BazTech

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Przyczyny uszkodzeń warstw asfaltowych nawierzchni, lokalizacja osłabionych miejsc za pomocą systemu GPR

Wutke M.

Drogownictwo

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2017

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nr 12

401--406

PL

W artykule przedstawiono potencjalne przyczyny uszkodzeń warstw asfaltowych nawierzchni przed upływem okresu gwarancyjnego, określone na podstawie specjalistycznych badań: w trakcie realizacji kontraktu, terenowych oraz laboratoryjnych. Omówiono praktyczne zastosowanie metody GPR celem lokalizacji osłabionych miejsc warstw asfaltowych na podstawie map powierzchniowych stałych dielektrycznych.

EN

The article presents potential causes of damages of asphalt pavement layers before the end of the warranty period, determined on the basis of specialized researches: during the contract, during the site works and laboratory researches. The practical application of the GPR method has been discussed in order to locate weakened areas of asphalt layers based on surface maps of dielectric constants.

2

Zastosowanie transformaty curvelet w przetwarzaniu danych z georadaru GPR

Wójcik W., Cięszczyk S., Ławicki T., Miaskowski A.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 9b

249-252

PL

Technika GPR (Ground Penetrating Radar) służy do nieinwazyjnego określania obiektów oraz ich właściwości będących pod powierzchnią określonego materiału. Otrzymany obraz GPR zawiera informację użyteczną i szereg zakłóceń utrudniających interpretację wyników. Artykuł prezentuje zastosowanie transformaty curvelet jako narzędzia pomocnego we wskazaniu lokalizacji poszukiwanych obiektów.

EN

Ground Penetrating Radar (GPR) is used for non-invasive determination of objects and their properties under the surface of a material. The resulting GPR scan contains information useful and a number of distortions that hinder interpretation of results. The article presents the application of curvelet transform as a tool helpful in indicating the location of objects searched.

3

Surface NMR survey on Hansbreen Glacier, Hornsund, SW Spitsbergen (Norway)

Turu V.

Landform Analysis

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2012

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Vol. 21

57-74

EN

Glaciers are widely spread on polar and sub-polar regions but also on middle latitude mountains, where cold-dry type glaciers, polythermal glaciers and temperate-wet glaciers are respectively present. Polythermal glaciers have a cold-ice layer (temperature below the pressure melting point) overriding a temperate-ice layer. Nineteen magneticc resonance soundings were done following a 3 Kmprofile on Hansbreen front. Resistivity on the glacier surface, magnetic susceptibility of rocks, electromagnetic noise and total earth's magnetic field measurements confirm that the MRS survey took place in the best conditions. MRS data show different signals amplitudes at the Larmor frequency according to the loop dimension. In a very high electrical resistive context (greater than 2 Mega Ohms meter for glacier ice) the surveyed depth is directly related to the loop area. For small loops (30msquare loop) amplitudes around 50 nV are common as well as some decay time (T*2) above 300 ms. Enlarging the loop size (60 m square loop) it is possible to observe a decrease of the signal amplitude at the Larmor frequency (E0 less than 20 nV) but also the time decay (100 ms greater than =T*2 greater than 40 ms). Increasing loop sizes (90 and 120msquare loops), a slight increase in amplitude at the Larmor frequency, close to 30 nV, is observed with very high time decays (T*2 greater than 500 ms). Ground Penetrating Radar surveys were carried out in Hansbreen at the same location as theMRSsurveyed zone. Available GPR data show a water content of 2,5% on the cold-ice layer (the first 35 m depth) and 2% of water content on the temperate- ice layer but a 4%of water content can also be detected. Both geophysical methods are not convergent because some water content on ice has too short relaxation times being undetectable with conventionalMRSdevices. In that sense the low T*2 time decays data from large MRS loops elucidates that at the temperate-ice layer water flows by seepage through veins and microfractures at a very low rate toward the glacier bottom and a large amount of free water is close to the cold/temperate transition surface. In the cold-ice layer large T*2 time decays are common because water flows through fissures or karstic like conduits. In summary, combining the MRS and GPR techniques gives glaciologists a powerful toolkit to elucidate water flow-paths on glaciers, supercooled meltwater content and subglacial water or aquifers.