High-resolution photogrammetry to measure physical aperture of two separated rock fracture surfaces

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外文摘要：Photogrammetry,reconstructing three-dimensional(3D)models from overlapping two-dimensional(2D)photos,finds application in rock mechanics and rock engineering to extract geometrical details of reconstructed objects,for example rock fractures.Fracture properties are important for determining the mechanical stability,permeability,strength,and shear behavior of the rock mass.Photogrammetry can be used to reconstruct detailed 3D models of two separated rock fracture surfaces to characterize fracture roughness and physical aperture,which controls the fluid flow,hydromechanical and shear behavior of the rock mass.This research aimed to determine the optimal number of scale bars required to produce high-precision 3D models of a fracture surface.A workflow has been developed to define the physical aperture of a fracture using photogrammetry.Three blocks of Kuru granite(25 cm×25 cm×10 cm)with an artificially induced fracture,were investigated.For scaling 3D models,321 markers were used as ground control points(GCPs)with predefined distances on each block.When the samples were well-matched in their original positions,the entire block was photographed.Coordinate data of the GCPs were extracted from the 3D model of the blocks.Each half was surveyed separately and georeferenced by GCPs and merged into the same coordinate system.Two fracture surfaces were extracted from the 3D models and the vertical distance between the two surfaces was digitally calculated as physical aperture.Accuracy assessment of the photogrammetric reconstruction showed a 20-30 μm digital control dis-tance accuracy when compared to known distances defined between markers.To attain this accuracy,the study found that at least 200 scale bars were required.Furthermore,photogrammetry was employed to measure changes in aperture under normal stresses.The results obtained from this approach were found to be in good agreement with those obtained using linear variable displacement transducers(LVDTs),with differences ranging from 1 μm to 8 μm.

外文关键词：

PhotogrammetryPhysical apertureRock fracturePredefined distancesMarkers

作者：

Masoud Torkan、Mateusz Janiszewski、Lauri Uotinen、Alireza Baghbanan、Mikael Rinne

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作者单位：

Department of Civil Engineering,Aalto University,Espoo,Finland

Department of Mining Engineering,Isfahan University of Technology,Isfahan,Iran

基金：

State Nuclear Waste Management Fund(VYR)Ministry of Economic Affairs and Employment of Finland on the Finnish Research Program on Nuclear Waste Management KYT2018 aMinistry of Economic Affairs and Employment of Finland on the Finnish Research Program on Nuclear Waste Management KYT2018 aNational Nuclear Safety and Waste Management Research ProgramNational Nuclear Safety and Waste Management Research ProgramNational Nuclear Safety and Waste Management Research Program

项目编号：

KYT 1/2021KYT 1/2022SAFER2028SAFER 25/2023MIRKASAFER 42/2023CORF

出版年：

2024

DOI：

10.1016/j.jrmge.2023.10.003

岩石力学与岩土工程学报(英文版)

中国科学院武汉岩土力学所中国岩石力学与工程学会武汉大学

岩石力学与岩土工程学报(英文版)

CSTPCD

影响因子：0.404

ISSN：1674-7755

年,卷(期)：2024.16(8)