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 Marine Rapid Environmental Assessment in the Gulf of Taranto: a multiscale approach

2016 ◽  
Vol 16 (12) ◽  
pp. 2623-2639 ◽  
Author(s):  
Nadia Pinardi ◽  
Vladyslav Lyubartsev ◽  
Nicola Cardellicchio ◽  
Claudio Caporale ◽  
Stefania Ciliberti ◽  
...  
Keyword(s):  
Surface Waters ◽  
Large Scale ◽  
Eastern Mediterranean ◽  
Small Scale ◽  
Multiscale Approach ◽  
Mesoscale Variability ◽  
Large Scale Circulation ◽  
Eddy Field ◽  
Multiscale Sampling ◽  
Circulation Structure

Abstract. A multiscale sampling experiment was carried out in the Gulf of Taranto (eastern Mediterranean) providing the first synoptic evidence of the large-scale circulation structure and associated mesoscale variability. The mapping of the mesoscale and large-scale geostrophic circulation showed the presence of an anticyclonic large-scale gyre occupying the central open ocean area of the Gulf of Taranto. On the periphery of the gyre upwelling is evident where surface waters are colder and saltier than at the center of the gyre. Over a 1-week period, the rim current of the gyre undergoes large changes which are interpreted as baroclinic–barotropic instabilities, generating small-scale cyclonic eddies in the periphery of the anticyclone. The eddies are generally small, one of which can be classified as a submesoscale eddy due to its size. This eddy field modulates the upwelling regime in the gyre periphery.

scholarly journals Transient Analysis of Grout Penetration With Time-Dependent Viscosity Inside 3D Fractured Rock Mass by Unified Pipe-Network Method

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1122 ◽  
Author(s):  
Zizheng Sun ◽  
Xiao Yan ◽  
Rentai Liu ◽  
Zhenhao Xu ◽  
Shucai Li ◽  
...  
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
High Efficiency ◽  
Fractured Rock ◽  
Time Dependent ◽  
Pipe Network ◽  
Fractured Rock Mass ◽  
Network Method ◽  
The Stability ◽  
Dependent Viscosity

Grouting is widely used for mitigating the seepage of underground water and enhancing the stability of fractured rock mass. After injection, the viscosity of the grout gradually increases until solidification. Conventional multifield analysis models ignoring such effects greatly overestimate the penetration region of the grout and the stability of the grouted rock structures. Based on the 3D unified pipe-network method (UPM), we propose a novel numerical model considering the time-dependent viscosity of the grout, therein being a quasi-implicit approach of high efficiency. The proposed model is verified by comparing with analytical results and a time-wise method. Several large-scale 3D examples of fractured rock mass are considered in the numerical studies, demonstrating the effectiveness and robustness of the proposed method. The influence of the time-dependent viscosity, fracture properties, and grouting operation methods are discussed for the grout penetration process.

Application Discussion on the Bifurcation and Nonlinear Dynamic Theory in Mines

2013 ◽  
Vol 448-453 ◽  
pp. 3843-3846
Author(s):  
Chuan Peng Wang ◽  
Long Hao Dong ◽  
Zhi Chao Tian
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Dynamic Theory ◽  
Physical Property ◽  
Progressive Damage ◽  
Linear Dynamics ◽  
Non Linear ◽  
Safety Production ◽  
Research Procedure ◽  
The Stability

Mining is a large-scale and highly complex misalignment system. The progressive damage and disorder development of the rock mass distort as well as the development that the rock mass evolution curve changes from the linear constant speed stage to the distortion stage which is accelerated by misalignment threaten the safety production in mines seriously. Therefore, the research on the rock mass distortion destroys plays an important part in guaranteeing the safety production in mines. This article elaborates the non-linear dynamics branch theory in detail, analyzes the branch phenomenon in slow change and stress-strain of rock mass according to its characteristics and advances the research procedure of the non-linear dynamics branch theory in mining. Moreover, it establishes the dynamic model according to the physical property of system and determines the stability of system using the branch theory.

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>

Terrain-Forced Flows

2000 ◽  
Author(s):  
C. David Whiteman
Keyword(s):  
Large Scale ◽  
Air Flow ◽  
Windward Side ◽  
Leeward Side ◽  
Small Scale ◽  
Mountainous Terrain ◽  
Jet Streams ◽  
Thermally Driven ◽  
Degree Of Stability ◽  
The Stability

Winds associated with mountainous terrain are generally of two types. Terrain-forced flows are produced when large-scale winds are modified or channeled by the underlying complex terrain. Diurnal mountain winds are produced by temperature contrasts that form within the mountains or between the mountains and the surrounding plains and are therefore also called thermally driven circulations. Terrain-forced flows and diurnal mountain winds are nearly always combined to some extent. Both can occur in conjunction with small-scale winds, such as thunderstorm inflows and outflows, or with large-scale winds that are not influenced by the underlying mountainous terrain. Terrain forcing can cause an air flow approaching a mountain barrier to be carried over or around the barrier, to be forced through gaps in the barrier, or to be blocked by the barrier. Three factors determine the behavior of an approaching flow in response to a mountain barrier: •the stability of the air approaching the mountains, •the speed of the air flow approaching the mountains, and •the topographic characteristics of the underlying terrain. Unstable or neutrally stable air (section 4.3) is easily carried over a mountain barrier. The behavior of stable air approaching a mountain barrier depends on the degree of stability, the speed of the approaching flow, and the terrain characteristics. The more stable the air, the more resistant it is to lifting and the greater the likelihood that it will flow around, be forced through gaps in the barrier, or be blocked by the barrier. A layer of stable air can split, with air above the dividing streamline height flowing over the mountain barrier and air below the dividing streamline height splitting upwind of the mountains, flowing around the barrier (figure 10.1), and reconverging on the leeward side (section 10.3.2). A very stable approaching flow may be blocked on the windward side of the barrier (section 10.5.1). Moderate to strong cross-barrier winds are necessary to produce terrain-forced flows, which therefore occur most frequently in areas of cyclogenesis (section 5.1) or where low pressure systems (figure 1.3) or jet streams (section 5.2.1.3) are commonly found. Whereas unstable and neutral flows are easily lifted over a mountain barrier, even by moderate winds, strong cross-barrier winds are needed to carry stable air over a mountain barrier.

Stability of a Compressible Laminar Wall-Jet With Heat Transfer

1996 ◽  
Vol 118 (4) ◽  
pp. 824-828 ◽  
Author(s):  
O. Likhachev ◽  
A. Tumin
Keyword(s):  
Heat Transfer ◽  
Large Scale ◽  
Reynolds Numbers ◽  
Small Scale ◽  
Wall Jet ◽  
Boundary Layer Equations ◽  
Incompressible Boundary ◽  
Flow Approximation ◽  
Ambient Gas ◽  
The Stability

The flow of a plane, laminar, subsonic perfect gas wall jet with heat transfer through the wall was investigated theoretically. For the case under consideration the entire surface was maintained at a constant temperature which differed from the temperature of the ambient gas. The velocity and temperature distribution across the flow were calculated for a variety of temperature differences between the ambient gas and the surface. The boundary layer equations representing these flows were solved by using the Illingworth-Stewartson transformation, thus extending the classical Glauert’s solution to a thermally non-uniform flow. The effects of heat transfer on the linear stability characteristics of the wall jet were assessed by making the local parallel flow approximation. Two kinds of unstable eigenmodes coexisting at moderate Reynolds numbers are significantly affected by the heat transfer. The influence of cooling or heating on the stability of the flow was expected in view of the experience accumulated in incompressible boundary layers, i.e. heating destabilizes and cooling stabilizes the flows. Cooling of the wall affects the small scale disturbances more profoundly, contrary to the results obtained for the large scale disturbances.

scholarly journals The Challenges of Open-Pit Mining in the Vicinity of the Salt Dome (Bełchatów Lignite Deposit, Poland)

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1913
Author(s):  
Marek Cała ◽  
Katarzyna Cyran ◽  
Joanna Jakóbczyk ◽  
Michał Kowalski
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Salt Dome ◽  
Open Pit ◽  
Open Pit Mining ◽  
Stability Conditions ◽  
Mining Operations ◽  
Mass Behavior ◽  
Geological Conditions ◽  
Wall Slope

The extraction of the Bełchatów lignite deposit located in the vicinity of the Dębina salt dome requires careful planning that considers the influence of mining projects on the slope and salt dome stability conditions. The instability problem is directly related to horizontal and vertical displacement, as well as the complex geological and mining conditions. These conditions are very unique with regard to the co-occurrence of the salt dome and lignite deposits in the same area, as well as the large scale of the pit wall slope. Thus, predicting rock mass behavior and ensuring the safety of mining operations are important issues. The presented analysis focused on the influence of long-term lignite extraction on the western pit wall slope of the Bełchatów field and the salt dome’s stability conditions. This study offers a comprehensive approach to a complex geotechnical problem defined by large-scale, complex geometry, and geological conditions. The rock mass behavior and stress conditions are simulated in numerical modelling. The results of the presented analysis will be useful not only for present mining activities but also for future developments related to post-mining and recultivation plans.

The growth of meteorological disturbances

1949 ◽  
Vol 45 (1) ◽  
pp. 92-98 ◽  
Author(s):  
H. Bondi
Keyword(s):  
Heat Conduction ◽  
Temperature Gradient ◽  
Lower Limit ◽  
Time Scale ◽  
Large Scale ◽  
Ideal Gas ◽  
Small Scale ◽  
Sharp Distinction ◽  
The Subject ◽  
The Stability

1. Introduction. A considerable amount of attention has been paid to the problem of determining the conditions which decide whether a liquid heated from below is stable or unstable. The motion consequent upon the disturbance of an unstable ideal gas does not, however, seem to have been treated so far, and this problem forms the subject of the present paper. Heat conduction and viscosity are at first neglected, and we are therefore dealing with the small motions of a gas slightly disturbed from a position of equilibrium under the influence of gravity. The condition for the stability of such a gas is well known, namely, the temperature gradient must be less than the adiabatic gradient. Furthermore, it is known that there is a sharp distinction between slow large-scale (meteorological) and rapidly varying small-scale (acoustical) phenomena. The present paper confirms these points and derives the time scale of meteorological phenomena. Heat conduction and viscosity are then shown to set a lower limit to the dimensions of such disturbances, while the effect of the earth's rotation is shown to be negligible.

scholarly journals LARGE VERIFICATION TESTS ON ROCK SLOPE STABILITY

1988 ◽  
Vol 1 (21) ◽  
pp. 157
Author(s):  
J.W. Van der Meer ◽  
K.W. Pilarczyk
Keyword(s):  
Large Scale ◽  
Scale Effects ◽  
Rock Slope Stability ◽  
Small Scale ◽  
Rock Slopes ◽  
Ripple Formation ◽  
Scale Test ◽  
Gravel Beaches ◽  
The Stability ◽  
Large Scale Tests

A number of large scale tests on stability of rock slopes and gravel beaches is described and compared with small scale test results. The following topics are treated: the stability of a rock armour layer, the profile formation of a berm breakwater, the profile formation of gravel beaches, including ripple formation, and reflection and overtopping on rock slopes. The general conclusion is that scale effects could not be found.

A Micromechanics-based Multiscale Approach toward Continental Deformation and Tectonic Processes

2021 ◽  
Author(s):  
Lucy (Xi) Lu ◽  
Dazhi Jiang ◽  
Adam Beall ◽  
Ake Fagereng
Keyword(s):  
Rock Mass ◽  
Rheological Properties ◽  
Rheological Behaviour ◽  
Small Scale ◽  
Multiscale Approach ◽  
Plate Boundaries ◽  
Tectonic Processes ◽  
Geological Features ◽  
Wide Range ◽  
Heterogeneous Rock

<p>The Earth’s lithosphere has abundant structures and fabrics generated by various tectonic processes. These geological features span a wide range of characteristic lengths, from crystal lattice spacing to the dimensions of lithospheric plates. Using field observations of exhumed geological features, we aim to understand the rheological behaviour of Earth’s lithosphere. However, our direct field and laboratory observations are limited to the most accessible scales, typically from outcrops to microscopes. There is therefore a significant intrinsic scale gap between direct observations and the tectonic processes operating along plate boundaries. A micromechanics-based Multi-order Power-Law Approach (MOPLA) has been developed to bridge this scale gap. MOPLA treats the heterogeneous rock mass as a continuum of rheologically distinct elements. The rheological properties and the strain rate and stress fields of the constituent elements and the composite material are computed by solving partitioning and homogenization equations self-consistently. The partitioned ‘local’ fields in individual elements are related to small-scale geological features. The ‘bulk’ fields and the homogenized rheological properties are associated with tectonic processes and the macroscopic behaviour of the heterogeneous rock mass. The algorithm of MOPLA is implemented in a MATLAB package and has been successfully applied to various studies on multiscale deformation in the lithosphere. In this work, we will introduce this multiscale approach and also briefly introduce our ongoing work on characterising the rheological behaviour of a heterogeneous subduction shear zone using MOPLA.</p>

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