scholarly journals Geostructural and Geomechanical Study of the Piastrone Quarry (Seravezza, Italy) Supported by Photogrammetry to Assess Failure Mode

Geosciences ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 64
Author(s):  
Sabrina Bonetto ◽  
Gessica Umili ◽  
Anna Maria Ferrero ◽  
Rodolfo Carosi ◽  
Matteo Simonetti ◽  
...  
Keyword(s):  
Rock Mass ◽  
Failure Modes ◽  
Three Dimensional ◽  
Point Clouds ◽  
Orientation Data ◽  
Rock Mass Characterization ◽  
Rock Bridges ◽  
Survey Techniques ◽  
Ornamental Stone ◽  
The Stability

The use of non-contact-techniques for rock mass characterization has been growing significantly over the last decade. However, their application to stability assessment of ornamental stone has not yet received much attention from researchers. This study utilizes rock mass data both in terms of slope orientations and degree of fracturing obtained from a point cloud, a set of three-dimensional (3D) points representing a rock mass surface, to (1) investigate the influence of geostructures at different scales and (2) assess quarry stability by determining areas susceptible to different failure types. Multi-resolution point clouds are obtained through several photogrammetric survey techniques to identify important structural elements of the site. By integrating orientation data of discontinuity planes, obtained with a traditional survey, and of traces, outlined on point clouds, several joint sets were identified. Kinematic tests revealed various potential failure modes of the rock slope. Moreover, an analysis of the influence of the discontinuity strength determined by the presence of rock bridges was carried out. The study revealed that the strength of the quarry face is governed by the presence of rock bridges that act to improve the stability condition of the rock fronts.

scholarly journals Rock Mass Characterization by UAV and Close-Range Photogrammetry: A Multiscale Approach Applied along the Vallone dell’Elva Road (Italy)

Geosciences ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 436
Author(s):  
Maria Migliazza ◽  
Maria Teresa Carriero ◽  
Andrea Lingua ◽  
Emanuele Pontoglio ◽  
Claudio Scavia
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Small Scale ◽  
Stability Conditions ◽  
Multiscale Approach ◽  
Rock Mass Characterization ◽  
Geometrical Data ◽  
Close Range ◽  
The Stability ◽  
Kinematic Mechanisms

Geostructural rock mass surveys and the collection of data related to discontinues provide the basis for the characterization of rock masses and the study of their stability conditions. This paper describes a multiscale approach that was carried out using both non-contact techniques and traditional support techniques to survey certain geometrical features of discontinuities, such as their orientation, spacing, and useful persistence. This information is useful in identifying the possible kinematics and stability conditions. These techniques are extremely useful in the case study of the Elva valley road (Northern Italy), in which instability phenomena are spread across 9 km in an overhanging rocky mass. A multiscale approach was applied, obtaining digital surface models (DSMs) at three different scales: large-scale DSM of the entire road, a medium-scale DSM to assess portions of the slope, and a small-scale DSM to assess single discontinuities. The georeferenced point cloud and consequent DSMs of the slopes were obtained using an unmanned aerial vehicle (UAV) and terrestrial photogrammetric technique, allowing topographic and rapid traditional geostructural surveys. This technique allowed us to take measurements along the entire road, obtaining geometrical data for the discontinuities that are statistically representative of the rock mass and useful in defining the possible kinematic mechanisms and volumes of potentially detachable blocks. The main purpose of this study was to analyse how the geostructural features of a rock mass can affect the stability slope conditions at different scales in order to identify road sectors susceptible to different potential failure mechanisms using only kinematic analysis.

scholarly journals A modified method of discontinuity trace mapping using three-dimensional point clouds of rock mass surfaces

2020 ◽  
Vol 12 (3) ◽  
pp. 571-586
Author(s):  
Keshen Zhang ◽  
Wei Wu ◽  
Hehua Zhu ◽  
Lianyang Zhang ◽  
Xiaojun Li ◽  
...  
Keyword(s):  
Rock Mass ◽  
Three Dimensional ◽  
Point Clouds ◽  
Modified Method ◽  
Trace Mapping

Comparing traditional geomechanical and remote sensing techniques for rock mass characterization 

2021 ◽  
Author(s):  
Angela Caccia ◽  
Biagio Palma ◽  
Mario Parise
Keyword(s):  
Rock Mass ◽  
Point Cloud ◽  
Laser Scanning ◽  
Quantitative Description ◽  
Present Contribution ◽  
Rock Mass Characterization ◽  
Rock Face ◽  
Remote Sensing Techniques ◽  
The Stability ◽  
Processing Techniques

<p>Analysis of the stability conditions of rock masses starts from detailed geo-structural surveys based on a systematic and quantitative description of the systems of discontinuities. Traditionally, these surveys are performed by implementing the classical geomechanical systems, available in the scientific literature since several decades, through the use of simple tools such as the geological compass to measure dip and dip direction directly on the discontinuity systems, and to fully describe their more significant physical characteristics (length, spacing, roughness, persistence, aperture, filling, termination, etc.). In several cases, this can be difficult because the discontinuities, or even the rock face, cannot be easily accessible. To have a complete survey, very often the involvement of geologists climbers is required, but in many situations this work is not easy to carry out, and in any case it does not cover the whole rock front.</p><p>Today, to solve these problems, traditional geomechanical surveying is implemented by innovative remote techniques using, individually or in combination, instruments such as terrestrial laser scanners and unmanned aerial vehicles to build a point cloud.</p><p>This latter permits to extract very accurate data on discontinuities for stability analyses, based on areal and non-point observations. In addition, the point cloud allows to map sub-vertical walls in their entirety in much shorter times than traditional surveying.</p><p>At this regard, two rock slopes were detected in the Sorrento Peninsula (Campania, southern Italy) with techniques that include traditional mapping, dictated by the guidelines of the International Society for Rock Mechanics, and the remote survey, through laser scanning and drone photogrammetry. The data obtained were processed automatically and manually through the Dips, CloudCompare and Discontinuity Set Extractor softwares.</p><p>In the present contribution we highlight the limits and advantages of the main data collection and the processing techniques, and provide an evaluation of the software packages currently available for the analysis and evaluation of discontinuities, in order to obtain a better characterization of the rock mass.</p>

Study of the Three-Dimensional Global Limit Equilibrium Method Applied to the Stability of Rock Slope

2012 ◽  
Vol 249-250 ◽  
pp. 1099-1102
Author(s):  
Yi Sheng Huang ◽  
Jian Lin Li
Keyword(s):  
Rock Mass ◽  
Stability Analysis ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Limit State ◽  
Three Dimensional ◽  
Limit Equilibrium Method ◽  
Equilibrium Method ◽  
The Stability ◽  
Loose Rock

Amending the normal stress over the slip surface based on the stress field by numerical analysis, applying the three-dimensional global limit equilibrium method to the stability analysis of tension-slackened rock mass in the right bank of Yagen hydropower station. Stability analysis shows that if do not take any measures, the loose rock mass stability can cater to the Specification demand, but some small sliders is in the limit state under the water and earthquake condition, if use the cutting slope and unloading scheme, the whole loose rock mass and the all small sliders can meet the Specification standard stability requirements.

Seismic attenuation spectra in rock mass characterization; a case study in open‐pit mining

Geophysics ◽  
1986 ◽  
Vol 51 (2) ◽  
pp. 302-323 ◽  
Author(s):  
R. P. Young ◽  
J. J. Hill
Keyword(s):  
Rock Mass ◽  
Three Dimensional ◽  
Seismic Attenuation ◽  
Phase Iii ◽  
Open Pit ◽  
Open Pit Mining ◽  
Rock Masses ◽  
Rock Mass Characterization ◽  
Fracture Anisotropy

The application of engineering geophysics to the characterization of rock masses is exemplified through a case study of three phases of a research project into the design of efficient blasting systems in open‐pit mining. Seismic experiments are used before and after mine blasting to monitor the efficiency of explosions in terms of rock fragmentation. Spectral analysis of seismic signals, after they have been used to interrogate rock masses, is used to compute preblast and postblast attenuation and velocity parameters. The results show that fragmentation efficiency of a mine blast and fracture anisotropy of a rock mass can be quantified in terms of three‐dimensional (3-D) attenuation spectra and polar anisotropy diagrams. These seismic data are correlated with the blast design and the energy used by the excavating dragline machine to dig to rock mass. An overview of the seismic attenuation technique and instrumentation used in the project (phases I and II) is given. A case study from phase III highlights the scope and interpretation of the relationship between excavation parameters and seismically characterized blasting efficiency.

Seismic noise monitoring of a small rock block collapse test

2020 ◽  
Vol 224 (1) ◽  
pp. 207-215
Author(s):  
Marco Taruselli ◽  
Diego Arosio ◽  
Laura Longoni ◽  
Monica Papini ◽  
Luigi Zanzi
Keyword(s):  
Rock Mass ◽  
Seismic Noise ◽  
Broad Band ◽  
Rock Block ◽  
Spectral Content ◽  
Rock Bridges ◽  
Spectral Density Matrix ◽  
Polarization Characteristics ◽  
The Stability ◽  
Value Decomposition

SUMMARY We tested the capability of seismic noise to monitor the stability conditions of a small rock block that we forced to fail in four following stages. Ambient vibrations were recorded with a broad-band 3C seismometer placed on top of the block and were processed to analyse their spectral and polarization characteristics with diverse algorithms. To analyse the spectral content of the records, we applied the multitaper method while seismic noise polarization features were investigated by means of the singular value decomposition of the Hermitian spectral density matrix. Numerical modelling was found to add limited value because of the uncertainty in estimating correctly spatial and mechanical features of the rock bridges between the block and the rock mass. Nevertheless, a modelling exercise we performed is in agreement with previous post-failure observations according to which unstable rocks may be coupled to the stable rock mass by rock bridges covering only a few per cent of the total surface of the fractures. Our analyses confirm that, when approaching final collapse, there is a trend of the block eigenmodes towards lower frequencies and show that polarized bands become narrower.

scholarly journals Stability Analysis of Irregular Cavities in Tunnel Using Geomagic-COMSOL Coupling Method

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Shangqu Sun ◽  
Chengshuai Qin ◽  
Hongbo Wang ◽  
Liping Li ◽  
Yongliang Huang
Keyword(s):  
Stability Analysis ◽  
Plastic Strain ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Equivalent Plastic Strain ◽  
Point Clouds ◽  
Computational Error ◽  
Geometrical Shape ◽  
Scanning Method ◽  
The Stability

The erosion of soluble rock and transformation of groundwater result in the high irregularity of cavities in tunnel. At present, however, karst cavities are mainly simplified as circular, rectangular, or elliptical shape in the numerical simulation. The purpose of this paper is to propose a new method to analyze the stability of irregular cavities. First of all, we used the drilling laser scanning method to reconstruct the three-dimensional point clouds model of irregular cavities. Furthermore, we proposed the method of determining the point density to reduce the computational error under the premise of ensuring the accuracy in engineering scale. We also developed the Geomagic-COMSOL coupling numerical method to conduct the stability analysis of irregular cavities. The results demonstrated that the geometrical shape of karst cavities has great effects on the deformation and mechanical properties of the surrounding rock. The displacement and equivalent plastic strain of simplified cavities exhibited symmetric characteristics, while those of irregular cavities are highly randomly distributed. We noted that a greater displacement value and more intensive plastic strain can be triggered by irregular cavities shape, compared with the simplified cavity shape. The results also showed that the larger displacement occurred at the long-edge part, while the plastic zone was concentrated at the sharp turning angle of the irregular cavities.

scholarly journals DIGITAL SURVEY TECHNIQUES FOR THE DOCUMENTATION OF WOODEN SHIPWRECKS

2016 ◽  
Vol XLI-B5 ◽  
pp. 237-242 ◽  
Author(s):  
E. Costa ◽  
C. Balletti ◽  
C. Beltrame ◽  
F. Guerra ◽  
P. Vernier
Keyword(s):  
Cultural Heritage ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Point Clouds ◽  
Point Of View ◽  
Principal Type ◽  
Recording Technique ◽  
Survey Techniques ◽  
Roman Age ◽  
Digital Survey

Nowadays, researchers widely employ the acquisition of point clouds as one of the principal type of documentation for cultural heritage. In this paper, different digital survey techniques are employed to document a wooden ancient shipwreck, a particular and difficult kind of archaeological finding due to its material characteristics. The instability of wood and the high costs of restoration do not always offer the opportunity of recovering and showing the hull to researchers and public and three-dimensional surveys are fundamental to document the original conditions of the wood. The precarious conditions of this material in contact with air could modify the structure and the size of the boat, requiring a fast and accurate recording technique. The collaboration between Ca' Foscari University and the Laboratory of Photogrammetry of Iuav University of Venice has given the possibility to demonstrate the utility of these technology. We have surveyed a sewn boat of Roman age through multi-image photogrammetry and laser scanner. Point clouds were compared and a residual analysis was done, to verify the characteristics and the opportunity of the two techniques, both of them have allowed obtaining a very precise documentation from a metrical point of view.

scholarly journals UNDERWATER PHOTOGRAMMETRY AND 3D RECONSTRUCTION OF MARBLE CARGOS SHIPWRECK

2015 ◽  
Vol XL-5/W5 ◽  
pp. 7-13 ◽  
Author(s):  
C. Balletti ◽  
C. Beltrame ◽  
E. Costa ◽  
F. Guerra ◽  
P. Vernier
Keyword(s):  
Image Processing ◽  
Digital Image Processing ◽  
Digital Image ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Point Clouds ◽  
Archaeological Survey ◽  
Technical Documentation ◽  
Survey Techniques ◽  
Essential Prerequisite

Nowadays archaeological and architectural surveys are based on the acquisition and processing of point clouds, allowing a high metric precision, essential prerequisite for a good documentation. Digital image processing and laser scanner have changed the archaeological survey campaign, from manual and direct survey to a digital one and, actually, multi-image photogrammetry is a good solution for the underwater archaeology. This technical documentation cannot operate alone, but it has to be supported by a topographical survey to georeference all the finds in the same reference system. In the last years the Ca' Foscari and IUAV University of Venice are conducting a research on integrated survey techniques to support underwater metric documentation. The paper will explain all the phases regarding the survey’s design, images acquisition, topographic measure and the data processing of two Roman shipwrecks in south Sicily. The cargos of the shipwrecks are composed by huge marble blocks, but they are different for morphological characteristic of the sites, for the depth and for their distribution on the seabed. Photogrammetrical and topographical surveys were organized in two distinct methods, especially for the second one, due to the depth that have allowed an experimentation of GPS RTK’s measurements on one shipwreck. Moreover, this kind of three-dimensional documentation is useful for educational and dissemination aspect, for the ease of understanding by wide public.

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