Journal ArticleDOI
Soil deformation measurement using particle image velocimetry (PIV) and photogrammetry
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A deformation measurement system based on particle image velocimetry (PIV) and close-range photogrammetry has been developed for use in geotechnical testing as mentioned in this paper.Abstract:
A deformation measurement system based on particle image velocimetry (PIV) and close-range photogrammetry has been developed for use in geotechnical testing. In this paper, the theory underlying this system is described, and the performance is validated. Digital photography is used to capture images of planar soil deformation. Using PIV, the movement of a fine mesh of soil patches is measured to a high precision. Since PIV operates on the image texture, intrusive target markers need not be installed in the observed soil. The resulting displacement vectors are converted from image space to object space using a photogrammetric transformation. A series of validation experiments are reported. These demonstrate that the precision, accuracy and resolution of the system are an order of magnitude higher than previous image-based deformation methods, and are comparable to local instrumentation used in element testing. This performance is achieved concurrent with an order of magnitude increase in the number of meas...read more
Citations
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Journal ArticleDOI
Characterization of Fracture Process in Sandstone: A Linear Correspondence Between Acoustic Emission Energy Density and Opening Displacement Gradient
TL;DR: Wang et al. as discussed by the authors defined the fracture process zone (FPZ) as the region of inelastic deformation surrounding the crack tip, and a variety of experimental techniques have been used to study the FPZ, including acoustic emission (AE) and morié interferometry.
Journal ArticleDOI
Shear banding and strain softening in plane strain extension: physical modelling
TL;DR: In this paper, a series of plane strain model experiments was achieved in natural (1 g) and increased (ng) gravity field (geotechnical centrifuge) with dry and moist sand as well as with dry-and moist sand-clay mixtures.
Proceedings ArticleDOI
Uplift Resistance of Buried Pipelines at Low Cover-Diameter Ratios
TL;DR: In this article, a series of full-scale and centrifuge tests at the Schofield Centre, University of Cambridge were conducted to evaluate the impact of shear on the uplift resistance of backfill soil.
Journal ArticleDOI
Similarity of soil variability in centrifuge models
TL;DR: The soil specimen in a centrifuge model is subject to spatial variability depending on the method of sample preparation and the stress field induced by the centrifugal acceleration, even though it... as mentioned in this paper.
Journal ArticleDOI
Development of a fault simulator for soils under large vertical stress in a centrifuge
TL;DR: In previous earthquakes due to faulting, especially reverse faulting with large discontinuous ground displacement under large earth pressure, have triggered severe damages of structures observed in previous earthquakes as mentioned in this paper.
References
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Journal ArticleDOI
Particle-Imaging Techniques for Experimental Fluid Mechanics
TL;DR: A review of these methods can be found in articles by Lauterborn & Vogel (1984), Adrian (1986a), Hesselink (1988), and Dudderar et al..
Proceedings ArticleDOI
A four-step camera calibration procedure with implicit image correction
Janne Heikkilä,Olli Silven +1 more
TL;DR: This paper presents a four-step calibration procedure that is an extension to the two-step method, and a linear method for solving the parameters of the inverse model is presented.
Proceedings ArticleDOI
Calibration procedure for short focal length off-the-shelf CCD cameras
Janne Heikkilä,Olli Silven +1 more
TL;DR: A camera calibration procedure intended for a 3D measurement application is presented, paying attention to the various error sources, and notices that a more complete camera model is needed to explain all the error components.
Journal ArticleDOI
A review of instrumentation for measuring small strains during triaxial testing of soil specimens
TL;DR: In this article, the authors present a survey of small-strain measuring devices and their modes of operation, benefits, capabilities, and limitations, as well as a classification of internal and external measuring devices.