Reverse modelling of natural rock joints using 3D scanning and 3D printing

The distance between Hemse church and the fields of Mästermyr on the Swedish Island of Gotland is about eight kilometers. The distance or rather the proximity between these two places is given importance in this filmed research article. In the 1930s, a farmer found a wooden chest in Mästermyr containing hundreds of forged tools and other artefacts. During a restoration of the Romanesque Hemse church in the 1890s, reused parts of a stave church were discovered in the wooden floor. The hypothetical question that is investigated in this study is whether the tools from Mästermyr were used in the construction of Hemse stave church in the early 1100’s? This filmed article analyzes and compares the traces of toolmarks in Hemse stave church and the woodworking tools from the Märstermyr finding. Through a forensic examination involving 3D scanning with structured light, 3D printing and reconstruction of tools and woodworking procedures, it is revealed that several toolmarks in the stave church correspond to the characteristics of woodworking tools in the Mästermyr find. The tool's shape, dimensions and mode of operation are traced in its negative imprint in the stave church’s oak wood.

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Quantitative evaluation of mechanical properties of the natural rock joints for analyzing behavior of structures in discontinuous rock masses.

Doboku Gakkai Ronbunshu ◽

10.2208/jscej.1999.624_231 ◽

1999 ◽

pp. 231-243 ◽

Cited By ~ 3

Author(s):

Yujing JIANG ◽

Mitsuo NAKAGAWA ◽

Tetsuro ESAKI

Keyword(s):

Mechanical Properties ◽

Quantitative Evaluation ◽

Rock Joints ◽

Rock Masses ◽

Natural Rock ◽

Discontinuous Rock

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Class Ratio Transform with an Application to Describing the Roughness Anisotropy of Natural Rock Joints

Advances in Civil Engineering ◽

10.1155/2020/5069627 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14

Author(s):

Rui Yong ◽

Lei Huang ◽

Qinkuan Hou ◽

Shigui Du

Keyword(s):

Roughness Parameter ◽

Rock Joints ◽

Anisotropic Model ◽

Roughness Parameters ◽

Transform Method ◽

Smooth Coefficient ◽

Natural Rock ◽

Smoothing Process ◽

Regular Roughness ◽

Parameter Values

In this study, we explore the potential of class ratio transform with an application to describing the roughness anisotropy of natural rock joints. Roughness smooth coefficient, used for suitably smoothing the roughness parameter values to realize an anisotropic model, is proposed to represent the apparent anisotropy of surface roughness. The geometric irregularities of roughness parameters in polar plots allow transforming to a regular roughness asperity pattern, which can be readily approximated by the ellipse function. The joint roughness coefficients in different orientations of natural rock joints were measured and revealed to be identical after applying the smoothing process using the class ratio transform method. The results show that the roughness smooth coefficient increases with sample size but decreases as azimuthal interval narrows. This method demonstrates the ability in describing the roughness anisotropy and inferring the roughness parameters Z2, Rp, and θmax∗/C+12 D.

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Scale Dependence of Waviness and Unevenness of Natural Rock Joints through Fractal Analysis

Geofluids ◽

10.1155/2020/8818815 ◽

2020 ◽

Vol 2020 ◽

pp. 1-18

Author(s):

Yingchun Li ◽

Shengyue Sun ◽

Hongwei Yang

Keyword(s):

Surface Roughness ◽

Rock Joint ◽

Fractal Dimensions ◽

Window Size ◽

Scale Dependence ◽

Rock Joints ◽

Joint Surface ◽

Triangular Prism ◽

Natural Rock ◽

Waviness And Unevenness

The scale dependence of surface roughness is critical in characterising the hydromechanical properties of field-scale rock joints but is still not well understood, particularly when different orders of roughness are considered. We experimentally reveal the scale dependence of two-order roughness, i.e., waviness and unevenness through fractal parameters using the triangular prism surface area method (TPM). The surfaces of three natural joints of granite with the same dimension of 1000 mm×1000 mm are digitised using a 3D laser scanner at three different measurement resolutions. Waviness and unevenness are quantitatively separated by considering the area variation of joint surface as grid size changes. The corresponding fractal dimensions of waviness and unevenness in sampling window sizes ranging from 100 mm×100 mm to 1000 mm×1000 mm at an interval of 100 mm×100 mm are determined. We find that both the fractal dimensions of waviness and unevenness vary as the window size increases. No obvious stationarity threshold has been found for the three rock joint samples, indicating the surface roughness of natural rock joints should be quantified at the scale of the rock mass in the field.

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