Contribution to a Rock Block Slide Examination by a Model of Mutual Transformation of Point Clouds

Basic objective of this article is to find out whether the rock block on which the castle of Crni kal is situated sticked once to the Kraški rob wall. The result is given on the basis of comparison of forms of both presumed contact surfaces represented by a great number of points determined in space. This cloud of points has been captured by 3D terrestrial laser scanning. On the basis of assessment of geological and morphological characteristics of the Crni kal rock block and the Kraški rob wall 12 characteristic pairs of corresponding (matching) points were collected, one pair consisting of two points, each from its own wall. By use of a method called 12-parameter affine transformation, transformation parameters of one cloud transformation into the other one were calculated. Since for such a transformation 4 pairs of points are enough, and there were even 12 pairs of points used in order to provide better results, the socalled least square method (LSM) was used. By the so obtained transformation vector the reference point cloud of the Crni kal rock block was transformed, for a size of the vector move back, into a cloud of transformed points which should match the reference point cloud of the Kraški rob wall. The comparison of a reference point cloud of Kraški rob and a cloud of transformed points showed that the rock block of Crni kal slid in a S-SW direction for 4.7 m in form of a block failure. Static analysis of matching point clouds proved that as much as 95 % of points fell within a distance less than 0.74 m which confirmed the hypothesis that the rock block on which the castle of Crni kal was situated represented once a part of the Kraški rob wall. Prior to the 11th century at least, it split away from it and moved parallel to the wall in form of a block failure

Modeliranje ponašanja pilona mosta na probno opterećenje primjenom regresijske analize kao linearan i nelinearan proces

This paper presents the procedure for dynamic system identification regarding behaviour of bridge pylon for test load, and the numeric example had been illustrated by examination of \u27\u27Sloboda\u27\u27 bridge in Novi Sad. Since pylon shifts, occurred during test load, were long-period in nature, static GPS method had been applied for measurements. To identify dynamic process of the construction, auto-regression model with external input (ARX) had been selected. The process had been approximated as linear and non-linear. Establishing model degree had been performed by autocorrelation function and parameter significance test. It had shown that the shifts of pylon along the longitudinal axis of the bridge, occurring due to the load action, must be described as a result of non-linear process; while shifts, occurring orthogonal to longitudinal axis of the bridge, occurring due to the temperature change, are the result of linear process. Model fitting was also analyzed, observing the pylon as both rigid and deformable body. Higher percentage of fitting (alignment) had been achieved when the construction had been viewed as a deformable body.U radu je opisan postupak identifikacije dinamičkog sustava ponašanja pilona mosta na probno opterećenje, a brojčani primjer ilustriran je ispitivanjem mosta „Slobode“ u Novom Sadu. Kako su pomjeranja pilona pri probnom opterećenju dugoperiodična, za mjerenja je primijenjena statička GPS metoda. Za identifikaciju dinamičkog procesa konstrukcije izabran je autoregresijski model s vanjskim pobuđivanjem (AutoRegressive with eXternal input – ARX). Proces je aproksimiran kao linearan i nelinearan. Za utvrđivanje stupnja modela primijenjena je autokovarijacijska funkcija i test značajnosti parametara. Pokazano je da se pomjeranja pilona mosta, u smjeru duže osi, koja nastaju pod utjecajem opterećenja, moraju opisati kao rezultat nelinearnog procesa; dok su okomita pomjeranja, koja nastaju uslijed promjene temperature, rezultat linearnog procesa. Također je analizirano fitovanje modela (suglasnost) kada je pilon promatran kao kruto i kao deformatibilno tijelo. Ostvaren je veći postotak fitovanja kada je pilon promatran kao deformatibilno tijelo

Primjenjivost kontinuiranog monitoring sustava u realnom vremenu za održavanje sigurnosti važnih objekata

In recent years, there has been significant advancement in monitoring sciences, especially due to the continued development of measuring equipment. Consequently, continuous real-time monitoring of integrity of significant structures, like buildings, bridges, dams, as well as the movement of slopes, landslides and volcanoes has become possible. This paper presents the usefulness of continuous real-time monitoring system that is able to combine geodetic, geotechnical and meteorological sensors to match the needs of the monitoring project. At the experimental polygon, we have installed four points; one reference and three observation points, all based on global navigation satellite system (GNSS) sensors. For every point, we acquire location in sense of coordinate Y, X and H in the local coordinate system, which allows observing any movements and deformations on observation points. Moreover, the characteristics of experimental polygon correspond to observing structures and also any changes on the Earth’s surface. The real-time visualization of acquired data enables us to decide on further measures in the shortest possible time, which reflects in major safety, as well as in the avoidance of severe damage. On the basis of 20 minutes of measurements, executed every 24 hours, we have calculated that it is possible to detect, with a 99.73% probability, all displacements larger than 1.2 mm and relative movements larger than 3 mm. The monitoring results and regression lines indicate that displacements for two points are no more than 1 mm, while on one we have obtained displacement of approximately 7 mm in a time period of only three months. The results obtained are significant and confirm the necessity of continuous real-time monitoring systems.U posljednjih nekoliko godina, došlo je do velikog napretka u znanosti o nadzoru (monitoringu), posebice zbog kontinuiranog razvoja mjerne opreme. Prema tome, kontinuirani real-time nadzor integriteta značajnih objekata, kao što su zgrade, mostovi, brane, pomicanje padina, klizišta i vulkana, postao je moguć. Ovaj rad opisuje korist kontinuiranog monitoring sustava u realnom vremenu koji omogućava kombiniranje geodetskih, geotehničkih i meteoroloških senzora kako bi se odgovorilo potrebama monitoringa. Na eksperimentalnom poligonu su instalirana četiri mjerna mjesta; jedna referentna i tri promatrane točke, a sve se zasniva na globalnom navigacijskom satelitskom sustavu (GNSS). Za svaku točku može se odrediti položaj u lokalnom koordinatnom (Y, X, H) sustavu koji omogućuje praćenje pomicanja i deformacija na mjernim mjestima. Štoviše, karakteristike eksperimentalnog poligona odgovaraju opažanim strukturama kao i bilo kakvim promjenama na površini Zemlje. Real-time vizualizaciju prikupljenih podataka omogućuje odlučivanje o daljnjim mjerama u najkraćem mogućem roku, što se odražava boljom zaštitom radi sigurnosti, kao i izbjegavanjem ozbiljnih šteta. Na temelju 20 minutnih mjerenja, koje se vrši 24 sata na dan, izračunato je da je moguće s 99,73 % vjerojatnosti otkriti sva pomicanja veća od 1,2 mm, a relativna pomicanja veća od 3 mm. Rezultati monitoringa i regresijska analiza pokazuju da pomicanja dvaju mjernih mjesta nisu veća od 1 mm, a za jedno mjesto je dobiven pomak od oko 7 mm u vremenskom periodu od samo tri mjeseca. Dobiveni rezultati su značajni i potvrđuju nužnost kontinuiranih real- time monitoring sustava

Analiza utjecaja pogrešaka pomoćnih veličina pri određivanju geometrijskih popravaka duljina

Distance measurement results are hampered by systematic and accidental errors. The influence of systematic errors is reduced or eliminated mostly through the entering of appropriate corrections or through the use of a particular measurement method. A large number of different sources of corrections may be divided into three groups, namely into meteorological, geometric and projection corrections. In this paper, exclusively geometric corrections are explored. The determination of geometric corrections and the elimination of their influence upon measurement results demands knowledge or measurement of various auxiliary parameters. Auxiliary parameters are also hampered by accidental errors, which under the law of propagation of errors affect the precision of the distance measured adjusted for geometric corrections. These are all generally known facts, but due to reasons unknown to the authors, the problematics exposed in this paper have not yet been treated in literature. This paper presents an analysis of the impact of auxiliary parameters on the precision of measured distances that have been adjusted for geometric corrections. Knowing the precision of a distance adjusted in this manner is significant, as the previously listed effects are present in the daily implementation of surveying tasks in the field of precise geodetic measurements and in the calibration of electronic instruments used to measure distances. This paper also presents a detailed example of calculating the impact of geodetic sources and their standard deviations on the precision of an electronically measured distance. In addition, this paper can also serve as a detailed general instruction manual for everyday professional application during precision distance measurements.Rezultati mjerenja duljina opterećeni su sustavnim i slučajnim pogreškama. Utjecaj sustavnih pogrešaka smanjuje se ili eliminira najčešće unošenjem odgovarajućih popravaka ili metodom mjerenja. Veliki broj različitih izvora popravaka može se podijeliti u tri skupine, i to: meteorološke, geometrijske i projekcijske popravke. U ovom radu obrađene su samo geometrijske popravke. Određivanje geometrijskih popravka i eliminiranje njihovih utjecaja iz rezultata mjerenja zahtijeva poznavanje ili mjerenje različitih pomoćnih veličina. Pomoćne veličine su, također, opterećene slučajnim pogreškama koje prema zakonu o rasprostiranju pogrešaka utječu i na točnost duljine popravljene za geometrijske popravke. Ovo su opće poznate činjenice, ali iz autorima nepoznatih razloga, problematika izložena u ovom radu nije do sada tretirana u stručnoj literaturi. U radu je prikazana analiza utjecaja pomoćnih veličina na točnost mjerene duljine koja je popravljena za geometrijske popravke. Poznavanje točnosti ovako popravljene duljine je važno, jer su navedeni utjecaji svakodnevno prisutni pri realizaciji geodetskih zadataka iz područja preciznih geodetskih mjerenja, kao i pri umjeravanju elektroničkih instrumenata za mjerenje duljina. Također, prikazan je i detaljan primjer računanja utjecaja geometrijskih izvora i njihovih standardnih odstupanja na točnost elektronički izmjerene duljine. Stoga, rad može poslužiti i kao detaljne, opće upute za svakodnevnu profesionalnu primjenu prilikom preciznih mjerenja duljina

Visualisation of the 3D geodata models and their application

U radu se opisuju 3D modeli geopodataka i njihova primjena. Na geodetskim planovima i topografskim kartama najčešće se primjenjuju metode prikaza terena (reljefa) pomoću kota i izohipsi. Međutim, sa pojavom novih tehnologija mijenja se način vizualizacije i naglašava koncept 3D modela geopodataka. Pritom, koriste se različiti pojmovi: digitalni model visina (DMV), digitalni model terena (DMT), digitalni model površi (DMP) i drugo. Infrastruktura i 3D modeli geopodataka su standardizovani, ali se vizualizacija i detaljnost sadržaja mijenja i usklađuje prema namjeni i razmjeri prikaza. Primjena 3D modela geopodataka u digitalnom obliku (raster ili vektor) postaje sve više aktuelna i putem interneta. Zato je važno razlikovati navedene pojmove i odlike 3D modela geopodataka kao i mogućnosti njihove primjene.This paper describes the 3D geodata models and their application. On geodetic plans and topographic maps commonly applied methods of terrain (relief) by spots elevation and contour lines. However, with the advent of new technologies the way of the visualisation is changing and highlights the concept 3D geodata model. Namely, there are different concepts: digital elevation model (DEM), digital terrain model (DTM), digital surface model (DSP) and so on. Infrastructure and 3D geodata models are standardized, while the visualization and details of information change and adjust the needs and aspect ratio display. Application of 3D geodata models in digital format (raster or vector) is becoming increasingly topical over the internet. Therefore, it is important to distinguish between certain concepts and features of 3D geodata models and the possibility of their application

Preliminary Analysis of Quality of Contour Lines Using Smoothing Algorithms

In this paper several well-known filtering techniques were compared in the purpose of automatic line generalization. The used methods for line simplification are digital first order low-pass filter, Savitzky-Golay (SG) filter and Whittaker filter. Two versions of the algorithm for line feature generalization were tested, from source scale 1:25 000 towards target scale of 1:100 000 and from source scale 1:25 000 towards scale of 1:50 000. Also, GPS data filtering for the target scale 1:50 000 was tested. The first version of the algorithm considers that there are no control data, and the filtering parameter is dictated by the desired accuracy for the target scale. The second version involves control data in the target scale. This means that the optimal value for the filtering parameter is the value for which the difference between input and control data is the smallest. Analysis showed that the SG filter yielded the best results in general. The proposed filters can be considered as a new solution for automated cartographic line simplification

CONCEPT OF UNDERGROUND GAS STORAGE IN THE LIMESTONE ROCKS IN SLOVENIA

The paper provides research and results for underground storage of gas (UGSG) in limestone rocks, which were carried out in Slovenia – Central Europe. The areas was geological surveyed and in addition structural boreholes were drilled up to the depth of 350 m. The cores were logged with emphasis on stratigraphy, layering, rock joints, tectonic zones, RQD….and addition characteristics samples were taken for the laboratory rocks geomechanical characteristics investigations. In boreholes geophysical, pressiometric and hydro-geological investigations were also carried out. In the area where the researches have been carried out, limestone, dolomites and breccias are prevalent. Storage should be built for pressure between 15 and 20 MPa. Explorations confirmed that there is a possibility of building a high-pressure underground storage of gas (UGSG) and using applied mechanics for design LRC (Lined Rock Cavern) technology. The construction of underground storage facilities for natural gas storage is important in cases, where the gas supply does not meet the required capacity for operation of the thermal power plant

Surface subsidence prognosis above an underground longwall excavation and based on 3D point cloud analysis

Impacts of underground mining have been reduced by continuous environmental endeavors, scientific, and engineering research activities, whose main object is the behavior and control of the undermined rock mass and the subsequent surface subsidence. In the presented Velenje case of underground sublevel longwall mining where coal is being exploited both horizontal and vertical, backfilling processes and accompanying fracturing in the coal layer, and rock mass are causing uncontrolled subsidence of the surface above. 3D point clouds of the study were acquired in ten epochs and at excavation heights on the front were measured at the same epochs. By establishing a sectors layout in the observational area, smaller point clouds were obtained, to which planes were fitted and centroids of these planes then calculated. Centroid heights were analyzed with the FNSE model to estimate the time of consolidation and modified according to excavation parameters to determine total subsidence after a certain period. Proposed prognosis approaches for estimating consolidation of active subsidence and long term surface environmental protection measures have been proposed and presented. The C2C analysis of distances between acquired 3D point clouds was used for identification of surface subsidence, reclamation areas and sink holes, and for validation of feasibility and effectiveness of the proposed prognosis

Analysis of Dynamic Surface Subsidence at the Underground Coal Mining Site in Velenje, Slovenia through Modified Sigmoidal Function

In underground coal mining engineering, one of the most important tasks is to monitor, predict and manage the surface subsidence due to underground coal excavation. The impact of underground mining excavation reflects as subsidence of the overlying strata and the formation of surface depressions soon after excavation. The surface subsidence is one of many natural processes that exhibit a progression from small beginnings that accelerate and approach a climax over time. When detailed data is lacking, a logistic function is often used. In this paper, the analysis of the surface subsidence above underground mining sites in the Velenje Coal Mine by using a modified sigmoid function (surrogate of logistic function), with the common “S” shape, is introduced. Furthermore, the time estimation of the next and the final epoch measurement is considered

Study of Coal Burst Source Locations in the Velenje Colliery

The Velenje coal mine (VCM) is situated on the largest Slovenian coal deposit and in one of the thickest layers of coal known in the world. The thickness of the coal layer causes problems for the efficiency of extraction, since the majority of mining operations is within the coal layer. The selected longwall coal mining method with specific geometry, increasing depth of excavations, changes in stress state and naturally given geomechanical properties of rocks induce seismic events. Induced seismic events can be caused by caving processes, blasting or bursts of coal or the surrounding rock. For 2.5D visualization, data of excavations, ash content and calorific value of coal samples, hanging wall and footwall occurrence, subsidence of the surface and coal burst source locations were collected. Data and interpolation methods available in software package Surfer®12 were statistically analyzed and a Kriging (KRG) interpolation method was chosen. As a result 2.5D visualizations of coal bursts source locations with geomechanical properties of coal samples taken at different depth in the coal seam in the VCM were made with data-visualization packages Surfer®12 and Voxler®3