Discontinuity spacing analysis in rock masses using 3D point clouds

The complete characterization of rock masses implies the acquisition of information of both, the materials which compose the rock mass and the discontinuities which divide the outcrop. Recent advances in the use of remote sensing techniques – such as Light Detection and Ranging (LiDAR) – allow the accurate and dense acquisition of 3D information that can be used for the characterization of discontinuities. This work presents a novel methodology which allows the calculation of the normal spacing of persistent and non-persistent discontinuity sets using 3D point cloud datasets considering the three dimensional relationships between clusters. This approach requires that the 3D dataset has been previously classified. This implies that discontinuity sets are previously extracted, every single point is labeled with its corresponding discontinuity set and every exposed planar surface is analytically calculated. Then, for each discontinuity set the method calculates the normal spacing between an exposed plane and its nearest one considering 3D space relationship. This link between planes is obtained calculating for every point its nearest point member of the same discontinuity set, which provides its nearest plane. This allows calculating the normal spacing for every plane. Finally, the normal spacing is calculated as the mean value of all the normal spacings for each discontinuity set. The methodology is validated through three cases of study using synthetic data and 3D laser scanning datasets. The first case illustrates the fundamentals and the performance of the proposed methodology. The second and the third cases of study correspond to two rock slopes for which datasets were acquired using a 3D laser scanner. The second case study has shown that results obtained from the traditional and the proposed approaches are reasonably similar. Nevertheless, a discrepancy between both approaches has been found when the exposed planes members of a discontinuity set were hard to identify and when the planes pairing was difficult to establish during the fieldwork campaign. The third case study also has evidenced that when the number of identified exposed planes is high, the calculated normal spacing using the proposed approach is minor than those using the traditional approach.

Datasets and results of the research [Discontinuity spacing analysis in rock masses using 3D point clouds]

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Characterization of rock slopes through slope mass rating using 3D point clouds

Rock mass classification systems are widely used tools for assessing the stability of rock slopes. Their calculation requires the prior quantification of several parameters during conventional fieldwork campaigns, such as the orientation of the discontinuity sets, the main properties of the existing discontinuities and the geo-mechanical characterization of the intact rock mass, which can be time-consuming and an often risky task. Conversely, the use of relatively new remote sensing data for modelling the rock mass surface by means of 3D point clouds is changing the current investigation strategies in different rock slope engineering applications. In this paper, the main practical issues affecting the application of Slope Mass Rating (SMR) for the characterization of rock slopes from 3D point clouds are reviewed, using three case studies from an end-user point of view. To this end, the SMR adjustment factors, which were calculated from different sources of information and processes, using the different softwares, are compared with those calculated using conventional fieldwork data. In the presented analysis, special attention is paid to the differences between the SMR indexes derived from the 3D point cloud and conventional field work approaches, the main factors that determine the quality of the data and some recognized practical issues. Finally, the reliability of Slope Mass Rating for the characterization of rocky slopes is highlighted.

Rock map of the Yellow River (Huang He) expedition, China, 1925-1927 : Sheet 2

This layer is part of a set of georeferenced, raster images of the manuscript, paper map set entitled: Ch'ing-Hai upper Yellow River expedition : Rock and Simpson, 1925-27, [cartography by J.F. Rock]. Scale 1:250,000. This layer image is of Sheet II [of 10] covering a portion of the Yellow River (Huang He) region in eastern Qinghai Sheng and southern Gansu Sheng, China. The map set details the route and surrounding environs of the Arnold Arboretum's "Western China" expedition led by Joseph Rock, 1924-1927. The set covers a portion of the Yellow River (Huang He) region in south central China (Qinghai, Gansu, and Sichuan shengs (a portion of historic Tibet)). It shows features, labeled variously in English, Chinese, Wade-Giles transliteration, and Tibetan, including: rivers, streams, lakes, mountains, gorges, valleys, plateaus, plains, cities, towns, villages, provincial capitals, county seats, passes, monasteries, ruin sites, native tribe locations, and more. Relief is shown by hachures, spot heights, and landform drawings. The original manuscript map set is part of the Harvard College Library, Harvard Map Collection. "Joseph Rock traced his travels for the [Arnold] Arboretum's [Western China] 1924-1927 expedition in a colorful, hand-drawn map entitled 'Ch'ing-Hai upper Yellow River expedition.' The pen-and-ink drawing was made on ten sheets that when joined form a single, irregularly-shaped map, approximately six by eight feet in size. The individual sheets are numbered, using roman numerals; on sheet VII is a second title, 'Choni Territory, Upper and Lower T'ieh-Pu country and route to Sung-Pan, J. F. Rock, 1925-1927.' Topographical and other features are identified using a combination of English, Chinese characters, Wade-Giles transliterations and Tibetan script. Rock's attractive cursive style and use of hachures, spot heights, and landform drawings to depict relief add character to the map." -- Text from the Arnold Arboretum Web site.

Rock map of the Yellow River (Huang He) expedition, China, 1925-1927 : Sheet 3

This layer is part of a set of georeferenced, raster images of the manuscript, paper map set entitled: Ch'ing-Hai upper Yellow River expedition : Rock and Simpson, 1925-27, [cartography by J.F. Rock]. Scale 1:250,000. This layer image is of Sheet III [of 10] covering a portion of the Yellow River (Huang He) region in eastern Qinghai Sheng and southern Gansu Sheng, China. The map set details the route and surrounding environs of the Arnold Arboretum's "Western China" expedition led by Joseph Rock, 1924-1927. The set covers a portion of the Yellow River (Huang He) region in south central China (Qinghai, Gansu, and Sichuan shengs (a portion of historic Tibet)). It shows features, labeled variously in English, Chinese, Wade-Giles transliteration, and Tibetan, including: rivers, streams, lakes, mountains, gorges, valleys, plateaus, plains, cities, towns, villages, provincial capitals, county seats, passes, monasteries, ruin sites, native tribe locations, and more. Relief is shown by hachures, spot heights, and landform drawings. The original manuscript map set is part of the Harvard College Library, Harvard Map Collection. "Joseph Rock traced his travels for the [Arnold] Arboretum's [Western China] 1924-1927 expedition in a colorful, hand-drawn map entitled 'Ch'ing-Hai upper Yellow River expedition.' The pen-and-ink drawing was made on ten sheets that when joined form a single, irregularly-shaped map, approximately six by eight feet in size. The individual sheets are numbered, using roman numerals; on sheet VII is a second title, 'Choni Territory, Upper and Lower T'ieh-Pu country and route to Sung-Pan, J. F. Rock, 1925-1927.' Topographical and other features are identified using a combination of English, Chinese characters, Wade-Giles transliterations and Tibetan script. Rock's attractive cursive style and use of hachures, spot heights, and landform drawings to depict relief add character to the map." -- Text from the Arnold Arboretum Web site.

Rock map of the Yellow River (Huang He) expedition, China, 1925-1927 : Sheet 4

This layer is part of a set of georeferenced, raster images of the manuscript, paper map set entitled: Ch'ing-Hai upper Yellow River expedition : Rock and Simpson, 1925-27, [cartography by J.F. Rock]. Scale 1:250,000. This layer image is of Sheet IV [of 10] covering a portion of the Yellow River (Huang He) region in eastern Qinghai Sheng, China. The map set details the route and surrounding environs of the Arnold Arboretum's "Western China" expedition led by Joseph Rock, 1924-1927. The set covers a portion of the Yellow River (Huang He) region in south central China (Qinghai, Gansu, and Sichuan shengs (a portion of historic Tibet)). It shows features, labeled variously in English, Chinese, Wade-Giles transliteration, and Tibetan, including: rivers, streams, lakes, mountains, gorges, valleys, plateaus, plains, cities, towns, villages, provincial capitals, county seats, passes, monasteries, ruin sites, native tribe locations, and more. Relief is shown by hachures, spot heights, and landform drawings. The original manuscript map set is part of the Harvard College Library, Harvard Map Collection. "Joseph Rock traced his travels for the [Arnold] Arboretum's [Western China] 1924-1927 expedition in a colorful, hand-drawn map entitled 'Ch'ing-Hai upper Yellow River expedition.' The pen-and-ink drawing was made on ten sheets that when joined form a single, irregularly-shaped map, approximately six by eight feet in size. The individual sheets are numbered, using roman numerals; on sheet VII is a second title, 'Choni Territory, Upper and Lower T'ieh-Pu country and route to Sung-Pan, J. F. Rock, 1925-1927.' Topographical and other features are identified using a combination of English, Chinese characters, Wade-Giles transliterations and Tibetan script. Rock's attractive cursive style and use of hachures, spot heights, and landform drawings to depict relief add character to the map." -- Text from the Arnold Arboretum Web site.

Rock map of the Yellow River (Huang He) expedition, China, 1925-1927 : Sheet 9

This layer is part of a set of georeferenced, raster images of the manuscript, paper map set entitled: Ch'ing-Hai upper Yellow River expedition : Rock and Simpson, 1925-27, [cartography by J.F. Rock]. Scale 1:250,000. This layer image is of Sheet IX [of 10] covering a portion of the Yellow River (Huang He) region in southern Gansu Sheng and northwestern Sichuan Sheng, China, including parts of Baishui Jiang and Pai Ho (Gar He). The map set details the route and surrounding environs of the Arnold Arboretum's "Western China" expedition led by Joseph Rock, 1924-1927. The set covers a portion of the Yellow River (Huang He) region in south central China (Qinghai, Gansu, and Sichuan shengs (a portion of historic Tibet)). It shows features, labeled variously in English, Chinese, Wade-Giles transliteration, and Tibetan, including: rivers, streams, lakes, mountains, gorges, valleys, plateaus, plains, cities, towns, villages, provincial capitals, county seats, passes, monasteries, ruin sites, native tribe locations, and more. Relief is shown by hachures, spot heights, and landform drawings. The original manuscript map set is part of the Harvard College Library, Harvard Map Collection. "Joseph Rock traced his travels for the [Arnold] Arboretum's [Western China] 1924-1927 expedition in a colorful, hand-drawn map entitled 'Ch'ing-Hai upper Yellow River expedition.' The pen-and-ink drawing was made on ten sheets that when joined form a single, irregularly-shaped map, approximately six by eight feet in size. The individual sheets are numbered, using roman numerals; on sheet VII is a second title, 'Choni Territory, Upper and Lower T'ieh-Pu country and route to Sung-Pan, J. F. Rock, 1925-1927.' Topographical and other features are identified using a combination of English, Chinese characters, Wade-Giles transliterations and Tibetan script. Rock's attractive cursive style and use of hachures, spot heights, and landform drawings to depict relief add character to the map." -- Text from the Arnold Arboretum Web site.

Rock map of the Yellow River (Huang He) expedition, China, 1925-1927 : Sheet 5

This layer is part of a set of georeferenced, raster images of the manuscript, paper map set entitled: Ch'ing-Hai upper Yellow River expedition : Rock and Simpson, 1925-27, [cartography by J.F. Rock]. Scale 1:250,000. This layer image is of Sheet V [of 10] covering a portion of the Yellow River (Huang He) region in eastern Qinghai Sheng and southern Gansu Sheng, China. The map set details the route and surrounding environs of the Arnold Arboretum's "Western China" expedition led by Joseph Rock, 1924-1927. The set covers a portion of the Yellow River (Huang He) region in south central China (Qinghai, Gansu, and Sichuan shengs (a portion of historic Tibet)). It shows features, labeled variously in English, Chinese, Wade-Giles transliteration, and Tibetan, including: rivers, streams, lakes, mountains, gorges, valleys, plateaus, plains, cities, towns, villages, provincial capitals, county seats, passes, monasteries, ruin sites, native tribe locations, and more. Relief is shown by hachures, spot heights, and landform drawings. The original manuscript map set is part of the Harvard College Library, Harvard Map Collection. "Joseph Rock traced his travels for the [Arnold] Arboretum's [Western China] 1924-1927 expedition in a colorful, hand-drawn map entitled 'Ch'ing-Hai upper Yellow River expedition.' The pen-and-ink drawing was made on ten sheets that when joined form a single, irregularly-shaped map, approximately six by eight feet in size. The individual sheets are numbered, using roman numerals; on sheet VII is a second title, 'Choni Territory, Upper and Lower T'ieh-Pu country and route to Sung-Pan, J. F. Rock, 1925-1927.' Topographical and other features are identified using a combination of English, Chinese characters, Wade-Giles transliterations and Tibetan script. Rock's attractive cursive style and use of hachures, spot heights, and landform drawings to depict relief add character to the map." -- Text from the Arnold Arboretum Web site.

Rock map of the Yellow River (Huang He) expedition, China, 1925-1927 : Sheet 6

This layer is part of a set of georeferenced, raster images of the manuscript, paper map set entitled: Ch'ing-Hai upper Yellow River expedition : Rock and Simpson, 1925-27, [cartography by J.F. Rock]. Scale 1:250,000. This layer image is of Sheet VI [of 10] covering a portion of the Yellow River (Huang He) region in eastern Qinghai Sheng, southern Gansu Sheng, and northwestern Sichuan Sheng, China. The map set details the route and surrounding environs of the Arnold Arboretum's "Western China" expedition led by Joseph Rock, 1924-1927. The set covers a portion of the Yellow River (Huang He) region in south central China (Qinghai, Gansu, and Sichuan shengs (a portion of historic Tibet)). It shows features, labeled variously in English, Chinese, Wade-Giles transliteration, and Tibetan, including: rivers, streams, lakes, mountains, gorges, valleys, plateaus, plains, cities, towns, villages, provincial capitals, county seats, passes, monasteries, ruin sites, native tribe locations, and more. Relief is shown by hachures, spot heights, and landform drawings. The original manuscript map set is part of the Harvard College Library, Harvard Map Collection. "Joseph Rock traced his travels for the [Arnold] Arboretum's [Western China] 1924-1927 expedition in a colorful, hand-drawn map entitled 'Ch'ing-Hai upper Yellow River expedition.' The pen-and-ink drawing was made on ten sheets that when joined form a single, irregularly-shaped map, approximately six by eight feet in size. The individual sheets are numbered, using roman numerals; on sheet VII is a second title, 'Choni Territory, Upper and Lower T'ieh-Pu country and route to Sung-Pan, J. F. Rock, 1925-1927.' Topographical and other features are identified using a combination of English, Chinese characters, Wade-Giles transliterations and Tibetan script. Rock's attractive cursive style and use of hachures, spot heights, and landform drawings to depict relief add character to the map." -- Text from the Arnold Arboretum Web site.

Rock map of the Yellow River (Huang He) expedition, China, 1925-1927 : Sheet 7

This layer is part of a set of georeferenced, raster images of the manuscript, paper map set entitled: Ch'ing-Hai upper Yellow River expedition : Rock and Simpson, 1925-27, [cartography by J.F. Rock]. Scale 1:250,000. This layer image is of Sheet VII [of 10] covering a portion of the Yellow River (Huang He) region in southern Gansu Sheng and northwestern Sichuan Sheng, China, including parts of Bailong Jiang and Tao He. Sheet VII includes a separate title: 'Cho-ni Territory, Upper and Lower T'ieh-Pu country and route to Sung-P'an, J. F. Rock, 1925-1927.' The map set details the route and surrounding environs of the Arnold Arboretum's "Western China" expedition led by Joseph Rock, 1924-1927. The set covers a portion of the Yellow River (Huang He) region in south central China (Qinghai, Gansu, and Sichuan shengs (a portion of historic Tibet)). It shows features, labeled variously in English, Chinese, Wade-Giles transliteration, and Tibetan, including: rivers, streams, lakes, mountains, gorges, valleys, plateaus, plains, cities, towns, villages, provincial capitals, county seats, passes, monasteries, ruin sites, native tribe locations, and more. Relief is shown by hachures, spot heights, and landform drawings. The original manuscript map set is part of the Harvard College Library, Harvard Map Collection. "Joseph Rock traced his travels for the [Arnold] Arboretum's [Western China] 1924-1927 expedition in a colorful, hand-drawn map entitled 'Ch'ing-Hai upper Yellow River expedition.' The pen-and-ink drawing was made on ten sheets that when joined form a single, irregularly-shaped map, approximately six by eight feet in size. The individual sheets are numbered, using roman numerals; on sheet VII is a second title, 'Choni Territory, Upper and Lower T'ieh-Pu country and route to Sung-Pan, J. F. Rock, 1925-1927.' Topographical and other features are identified using a combination of English, Chinese characters, Wade-Giles transliterations and Tibetan script. Rock's attractive cursive style and use of hachures, spot heights, and landform drawings to depict relief add character to the map." -- Text from the Arnold Arboretum Web site.

Rock map of the Yellow River (Huang He) expedition, China, 1925-1927 : Sheet 8

This layer is part of a set of georeferenced, raster images of the manuscript, paper map set entitled: Ch'ing-Hai upper Yellow River expedition : Rock and Simpson, 1925-27, [cartography by J.F. Rock]. Scale 1:250,000. This layer image is of Sheet VIII [of 10] covering a portion of the Yellow River (Huang He) region in eastern Qinghai Sheng, southern Gansu Sheng, and northwestern Sichuan Sheng, China. The map set details the route and surrounding environs of the Arnold Arboretum's "Western China" expedition led by Joseph Rock, 1924-1927. The set covers a portion of the Yellow River (Huang He) region in south central China (Qinghai, Gansu, and Sichuan shengs (a portion of historic Tibet)). It shows features, labeled variously in English, Chinese, Wade-Giles transliteration, and Tibetan, including: rivers, streams, lakes, mountains, gorges, valleys, plateaus, plains, cities, towns, villages, provincial capitals, county seats, passes, monasteries, ruin sites, native tribe locations, and more. Relief is shown by hachures, spot heights, and landform drawings. The original manuscript map set is part of the Harvard College Library, Harvard Map Collection. "Joseph Rock traced his travels for the [Arnold] Arboretum's [Western China] 1924-1927 expedition in a colorful, hand-drawn map entitled 'Ch'ing-Hai upper Yellow River expedition.' The pen-and-ink drawing was made on ten sheets that when joined form a single, irregularly-shaped map, approximately six by eight feet in size. The individual sheets are numbered, using roman numerals; on sheet VII is a second title, 'Choni Territory, Upper and Lower T'ieh-Pu country and route to Sung-Pan, J. F. Rock, 1925-1927.' Topographical and other features are identified using a combination of English, Chinese characters, Wade-Giles transliterations and Tibetan script. Rock's attractive cursive style and use of hachures, spot heights, and landform drawings to depict relief add character to the map." -- Text from the Arnold Arboretum Web site.

Rock map of the Yellow River (Huang He) expedition, China, 1925-1927 : Sheet 10

This layer is part of a set of georeferenced, raster images of the manuscript, paper map set entitled: Ch'ing-Hai upper Yellow River expedition : Rock and Simpson, 1925-27, [cartography by J.F. Rock]. Scale 1:250,000. This layer image is of Sheet X [of 10] covering a portion of the Yellow River (Huang He) region in northeastern Sichuan Sheng, China, including the source of the Min Chiang (Min Jiang). The map set details the route and surrounding environs of the Arnold Arboretum's "Western China" expedition led by Joseph Rock, 1924-1927. The set covers a portion of the Yellow River (Huang He) region in south central China (Qinghai, Gansu, and Sichuan shengs (a portion of historic Tibet)). It shows features, labeled variously in English, Chinese, Wade-Giles transliteration, and Tibetan, including: rivers, streams, lakes, mountains, gorges, valleys, plateaus, plains, cities, towns, villages, provincial capitals, county seats, passes, monasteries, ruin sites, native tribe locations, and more. Relief is shown by hachures, spot heights, and landform drawings. The original manuscript map set is part of the Harvard College Library, Harvard Map Collection. "Joseph Rock traced his travels for the [Arnold] Arboretum's [Western China] 1924-1927 expedition in a colorful, hand-drawn map entitled 'Ch'ing-Hai upper Yellow River expedition.' The pen-and-ink drawing was made on ten sheets that when joined form a single, irregularly-shaped map, approximately six by eight feet in size. The individual sheets are numbered, using roman numerals; on sheet VII is a second title, 'Choni Territory, Upper and Lower T'ieh-Pu country and route to Sung-Pan, J. F. Rock, 1925-1927.' Topographical and other features are identified using a combination of English, Chinese characters, Wade-Giles transliterations and Tibetan script. Rock's attractive cursive style and use of hachures, spot heights, and landform drawings to depict relief add character to the map." -- Text from the Arnold Arboretum Web site.