The measurement of planar displacements of sand grains

Andrawes, K Z; Butterfield, R.

doi:10.1680/geot.1973.23.4.571

Cited by 21 publications

(9 citation statements)

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“…For deformation monitoring, it was introduced in 1963 using X-ray images [20]. Then, in the early 1970s, a stereo-photogrammetric technique was proposed which was later used to measure planar displacement of sand grains [21,22].…”

Section: Photogrammetrymentioning

confidence: 99%

A comparative study of techniques of distant reconstruction of displacement and strain fields using the DISTRESS simulator

Hassan

Dyskin

MacNish

et al. 2016

Optik

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Reconstruction and monitoring of displacement and strain fields is an important problem in engineering. We analyze the remote and nonobtrusive methods of strain measurement based on photogrammetry and Digital Image Correlation (DIC). The method is based on covering the photographed surface with a pattern of speckles and comparing the images taken before and after the deformation. In this study, a comprehensive literature review and comparative analysis of photogrammetric solutions is presented. The analysis is based on a specially developed Digital Image Synthesizer To Reconstruct Strain in Solids (DISTRESS) Simulator to generate synthetic images of displacement and stress fields in order to investigate the intrinsic accuracy of the existing variants of DIC. We investigated the Basic DIC and a commercial software VIC 2D, both based on displacement field reconstruction with post processing strain determination based on numerical differentiation. We also investigated what we call the Extended DIC where the strain field is determined independently of the displacement field. While the Basic DIC and VIC 2D are faster, the Extended DIC delivers the best accuracy of strain reconstruction. The speckle pattern is found to be playing a critical role in achieving high accuracy for DIC. Increase in subset size for DIC does not significantly improves the accuracy, while the smallest subset size depends on the speckle pattern and speckle size. Increase in the overall image size provides more details but does not play significant role in improving the accuracy, while significantly increasing the computation cost.

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Section: Photogrammetrymentioning

confidence: 99%

A comparative study of techniques of distant reconstruction of displacement and strain fields using the DISTRESS simulator

Hassan

Dyskin

MacNish

et al. 2016

Optik

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“…X-ray radiography (Roscoe et al 1963), stereo-photogrammetry (Butterfield et al 1970;Andrawes and Butterfield 1973), computer based image processing (Taylor et al 1998) and photoelasticity (Drescher and De Jong 1972) are some of the pioneering observational methods that have been developed. Many modern non-invasive visualisation methods adopted in geotechnical research originate from embryonic techniques such as these; albeit benefiting from the considerable level of new technology at our disposal enabling increased measurement capabilities.…”

Section: Visualisation In Geotechnical Modellingmentioning

confidence: 99%

Quantification of Optical Clarity of Transparent Soil Using the Modulation Transfer Function

Black

Take

2015

Geotech. Test. J.

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Transparent synthetic soils have been developed as a soil surrogate to enable internal visualization of geotechnical processes in physical models. Transparency of the soil dictates the overarching success of the technique; however, despite this fundamental requirement, no quantitative framework has yet been established to appraise the visual quality of transparent soil. Previous approaches to assess and optimize transparency quality included an eye chart assessment method, although this approach is highly subjective and operatordependent. In this paper, an independent method for quantitatively assessing the optical quality of transparent soil is proposed based on the optical calibration method, Modulation Transfer Function (MTF). The work explores this hypothesis and assesses the potential for MTF to quantify the optical quality of transparent soils for a number of aspects including (i) optimum oil blend ratio, (ii) depth of viewing plane, and (iii) temperature. The results confirmed that MTF offers a robust and reliable method to provide an independent quantitative measure of the optical quality of transparent soil. The impact of reduced soil transparency and the ability to track speckle patterns-thus accuracy and precision of displacement measurement-was correlated with MTF to evaluate the permissible viewing depth of transparent soil.

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“…173 Techniques for the measurement of deformations and soil 174 transport in geotechnical models have developed significantly in 175 recent years. Early studies by Butterfield et al (1970) and 176 Andrawes and Butterfield (1973) reported the use of stereo pho-177 togrammetry, in which individual particle movements as seen For each physical simulation, there were four 232 total scans associated with each test; two scans, one from each 233 side of the model levee were obtained so that a scan of the entire 234 surface could be obtained by the scanner. Two initial scans were 235 obtained following the completion of construction of the model 236 levee, but prior to turning on the flow of water.…”

Section: Conventional Visualization Methodsmentioning

confidence: 99%

New Visualization Method to Evaluate Erosion Quantity and Pattern

Kamalzare

Zimmie

Cutler

et al. 2016

Geotechnical Testing Journal

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3The objective of this research is to develop tools that would improve the understanding of the 4 process of levee failure because of erosion and reduce the risk of failure. Hydraulic erosion is a 5 complicated phenomenon and depends on many different parameters. To improve design 6 criteria for levees, embankments, and earthen structures, the development of realistic 7 computer models that can simulate the erosion process is necessary. Verification of these 8 computer simulations, as with any simulation, is a necessity. In this research, a large number 9 of physical levee erosion tests were performed at 1g and at high g's using a geotechnical 10 centrifuge. Centrifuge tests were performed to simulate real (prototype) size levees, and thus 11 to obtain a more realistic model. The erosion was modeled physically in detail. Conventional 12 three-dimensional scanning was used to precisely verify the calculated dimensions of initial 13 and final computer model geometries, but did not yield interim data or measurements of the 14 quantity of eroded soil during the tests. A Kinect device was used to scan and evaluate the 15 volume of eroded soil and variation of the shape of the channels as a function of time. Three-16 dimensional images were obtained, and variations of different parameters were plotted. 17 Various quantities were measured as a function of time. Based on recorded videos and 18 pictures taken during the tests, it was discovered that the Kinect results agreed well with the 19 physical models. The Kinect is a low-cost sensor, and enables the measurement of the rate of 20 soil erosion, which, if done at all, usually requires expensive equipment. The Kinect device was 21 also used in the centrifuge experiments, and functioned well in the high g environment. It is 22 believed to be the first use of a Kinect device in a centrifuge. The application of this method in 23 other laboratory experiments was also investigated. 26 Most geotechnical physical modeling facilities feature a system 27 of image capture and analysis to provide measurements of 28 deformation fields. This paper aims to describe a new technique 29 developed for identifying and characterizing the soil hydraulic 30 erosion process of levees, earthen dams, embankments, and 31 similar structures caused by overtopping incidents. Evaluations 32 have been done for levee overtopping erosion tests performed 33 at 1g and higher g level (centrifuge) conditions but are also 34 applicable in other experiments with different environments. 35 The new technique includes various advances beyond the state-36 of-the-art described previously. With the use of a new and 37 improved apparatus and software systems, improved measure-38 ment performance was achieved. This method provides the 39 capability to measure quantities that were not easy and some-40 times impossible to measure previously. This method results 41 in a step forward in measurement utility: small particle-scale 42 transportation features can be detected, allowing soil deforma-43 tion and erosio...

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The measurement of planar displacements of sand grains

Cited by 21 publications

References 0 publications

A comparative study of techniques of distant reconstruction of displacement and strain fields using the DISTRESS simulator

A comparative study of techniques of distant reconstruction of displacement and strain fields using the DISTRESS simulator

Quantification of Optical Clarity of Transparent Soil Using the Modulation Transfer Function

New Visualization Method to Evaluate Erosion Quantity and Pattern

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