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.This work was partially funded by the Swiss National Science Foundation (FNS-138015 and FNS-144040 Projects), the Spanish Ministry of Economy and Competitiveness (MINECO) and EU FEDER under Projects TEC2011-28201-C02-02 and TIN2014-55413-C2-2-P, the Spanish Ministry of Education, Culture and Sport in the framework of the Programa Estatal de Promocin del Talento y su Empleabilidad en I + D + i under project PRX14/00100 and by the Generalitat Valenciana under Project ACOMP/2014/136

Diseño de un sistema de control estadístico de procesos para el deshidratado de manzana en empresa SURFRUT

146 p.En este presente informe se propone el diseño de sistema de control estadístico de los procesos para el deshidratado de manzana en empresa Agroindustrial Surfrut, ubicada en la ciudad de Romeral. La primera parte corresponde a la descripción del lugar de aplicación del proyecto, en la cual se detallan las características de la empresa y el entorno en la cual está ubicada esta industria. Luego a ello se formaliza la problemática a abordar, exponiendo los elementos y antecedentes que justifican el diseño de un sistema de control estadístico de los procesos para la empresa. El segundo capítulo presenta la forma con la cual será abordada la problemática, indicando en términos teóricos el significado y uso de las herramientas estadísticas a utilizar para el proyecto de diseño. Indicando además la justificación del uso de las herramientas y posteriormente la metodología a seguir para el cumplimiento de los objetivos. Ya definido lo anterior, en el capítulo tres, se desarrolla un diagnóstico profundo y actual de la organización, en la cual se señalan las causas que afectan el funcionamiento que tiene la empresa en la producción de manzanas deshidratadas y en especial se define el proceso crítico en términos de calidad. El capítulo cuatro presenta el desarrollo de la propuesta de diseño del sistema control estadístico de los procesos, en la que se detallan los pasos seguir en la generación de las herramientas estadísticas y como éstas se conjugan en un sistema de información. El capítulo cinco describe la elaboración del diseño experimental al proceso de selección de color, en el cual se sugieren mejoras en la configuración de la máquina y se establecen eficiencias en el equipo. Por último, se presentan las implicancias operativas y económicas que conlleva el diseño de control estadístico, en conjunto con el desarrollo del diseño experimental, relacionando a ambos con los costos y beneficios en la implementación de la propuesta. Además se analizan los resultados del estudio y se definen diferentes propuestas para el mejor funcionamiento de los procesos críticos en términos de calidad

Rock Mass Characterization of Karstified Marbles and Evaluation of Rockfall Potential Based on Traditional and SfM-Based Methods; Case Study of Nestos, Greece

Rockfall consists one of the most harmful geological phenomena for the man-made environment. In order to evaluate the rockfall hazard, a variety of engineering geological studies should be realized, starting from conducting a detailed field survey and ending with simulating the trajectory of likely to fail blocks in order to evaluate the kinetic energy and the runout distance. The last decade, new technologies, i.e., remotely piloted aircraft systems (RPAS) and light detection and ranging (LiDAR) are frequently used in order to obtain and analyze the characteristics of the rock mass based on a semi-automatic or manual approach. Aiming to evaluate the rockfall hazard in the area of Nestos, Greece, we applied both traditional and structure from motion (SfM)-oriented approaches and compared the results. As an outcome, it was shown that the semi-automated approaches can accurately detect the discontinuities and define their orientation, and thus can be used in inaccessible areas. Considering the rockfall risk, it was shown that the railway line in the study area is threaten by a rockfall and consequently the construction of a rockfall netting mesh or a rock shed is recommended.This work was partially funded by the University of Alicante (vigrob-157 and GRE18-05 Projects), the Spanish Ministry of Economy and Competitiveness (MINECO) and EU FEDER under Project TEC2017-85244-C2-1-P

DSE

Disponible en Github: https://github.com/adririquelme/DSEDiscontinuity Set Extractor (DSE) is programmed by Adrián Riquelme for testing part of his PdD studies. Its aim is to extract discontinuity sets from a rock mass. The input data is a 3D point cloud, which can be acquired by means of a 3D laser scanner (LiDAR or TLS), digital photogrammetry techniques (such as SfM) or synthetic data. It applies a proposed methodology to semi-automatically identify points members of an unorganised 3D point cloud that are arranged in 3D space by planes

Economic assessment of converting a pressurised water distribution network into an off-grid system supplied with solar photovoltaic energy

Converting a water pressurised distribution network into an off-grid pumping station supplied by solar photovoltaics represents a challenge for utility managers, user demand assessments evaluate the energy generated in a solar-powered systems to establish energy consumption. This work includes quantifying potential investments and economic savings that could be achieved, as well as the payback period which results as an indicator of the suitability of adapting to a power supply utilising solar panels. A tool (UAsolar) to aid practitioners has been developed, it requires a calibrated hydraulic model to account for the energy requirements in the water delivery process of pressurised networks. The authors encourage students, professionals, and decision-makers to use this tool to identify potential efficiency gains (e.g., delivery schedule, reduction of water use) and to synchronise energy production and consumption. Users can get results with low computational time using the software on six pressurised distribution networks. Practitioners should note that the irrigation networks have sized installations with a few photovoltaic modules, while in urban pressurised networks the results show larger installations are required. In addition, irrigation network managers can match energy demand with energy production by changing consumption over time, this could reduce the quantity of modules required and remove the need for energy storage. The payback period ranges from 6.08 to 13 years for the cases where the investment is recovered—(values that show that this investment yields a high return as the lifetime of the PV modules is 25 years). However, one municipality among those studied shows that in some scenarios it is not viable to convert networks into a standalone system.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This research was funded by the Spanish Ministry of Economy and Competitiveness (MINECO) and EU FEDER under Project TEC2017-85244-C2-1-P and by the University of Alicante (vigrob-157, VIGROB-303 and GRE18-15)

A new approach for semi-automatic rock mass joints recognition from 3D point clouds

Rock mass characterization requires a deep geometric understanding of the discontinuity sets affecting rock exposures. Recent advances in Light Detection and Ranging (LiDAR) instrumentation currently allow quick and accurate 3D data acquisition, yielding on the development of new methodologies for the automatic characterization of rock mass discontinuities. This paper presents a methodology for the identification and analysis of flat surfaces outcropping in a rocky slope using the 3D data obtained with LiDAR. This method identifies and defines the algebraic equations of the different planes of the rock slope surface by applying an analysis based on a neighbouring points coplanarity test, finding principal orientations by Kernel Density Estimation and identifying clusters by the Density-Based Scan Algorithm with Noise. Different sources of information —synthetic and 3D scanned data— were employed, performing a complete sensitivity analysis of the parameters in order to identify the optimal value of the variables of the proposed method. In addition, raw source files and obtained results are freely provided in order to allow to a more straightforward method comparison aiming to a more reproducible research.This work was partially funded by the University of Alicante (vigrob-157, uausti11–11, and gre09–40 projects), the Swiss National Science Foundation (FNS-138015 and FNS-144040 projects) and by the Generalitat Valenciana (project GV/2011/044)

Clarification of the slope mass rating parameters assisted by SMRTool, an open-source software

Geomechanics classifications are used to perform a preliminary assessment of rock slope stability for different purposes in civil and mining engineering. Among all existing rock mass classifications, slope mass rating (SMR) is one of the most commonly used for slopes. Although SMR is a geomechanics classification applied worldwide, often some misapprehensions and inaccuracies are made when professionally and scientifically used. Nearly all these miscalculations involve the influence of slope geometry and the dip and direction of the discontinuities. These problems can be overcome by a systematic assessment of SMR, which allows users to understand and visualize the relative orientation between discontinuities and slope. To fulfil this purpose, a complete and detailed definition of the angular relationships between discontinuities and slope are included in this paper, clarifying the assessment of the SMR parameters. Additionally, a Matlab-based open-source software for SMR (SMRTool) calculation is presented, avoiding miscalculations by automating the calculations and showing the graphical representation of slope and discontinuities. Finally, a general explanation of the method for the use of SMR is reviewed, stressing the common source of errors when applying this classification. The performance, benefits and usefulness of SMRTool are also illustrated in this paper through a specific case study.This work has been supported by the University of Alicante under the projects GRE14-04 and GRE17-11, the Spanish Ministry of Economy and Competitiveness (MINECO), the State Agency of Research (AEI) and the European Funds for Regional Development (FEDER) under projects TEC2017-85244-C2-1-P and TIN2014-55413-C2-2-P, and the Spanish Ministry of Education, Culture and Sport under project PRX17/00439 and CAS17/00392

Use of High-Quality and Common Commercial Mirrors for Scanning Close-Range Surfaces Using 3D Laser Scanners: A Laboratory Experiment

Three Dimension (3D) laser scanners enable the acquisition of millions of points of a visible object. Terrestrial laser scanners (TLS) are ground-based scanners, and nowadays the available instruments have the ability of rotating their sensor in two axes, capturing almost any point. Since many sensors can only operate in a vertical position, they cannot capture points located beneath themselves. Consequently, these instruments are generally unable to capture data in a vertical descending direction. Moreover, since the device positioning has certain requirements of space and terrain stability, it is possible that specific regions of interest are outside the reach of the laser. A possible solution is to address the laser beam towards the desired direction by means of a mirror. Common mirrors are very cheap; therefore, they are easy to manipulate and to substitute in case they get broken. However, due to their careless fabrication process, it seems reasonable to think that they are unprecise. In contrast, front-end mirrors are more expensive and delicate, and consequently, deflecting angles are more precise. In this research, we designed a laboratory test to analyze the arising noise when standard and high-quality mirrors are used during the TLS scanning process. The results show that the noise introduced when scanning through a standard mirror is higher than that produced when using a high-quality mirror. However, both cases show that this introduced error is lower than the instrumental error. As a result, this study concludes that it is reasonable to use standard mirrors when scanning in similar conditions to this laboratory test.This work was partially funded by the University of Alicante (vigrob-157 Project, GRE14-04 Project and GRE15-19 Project), the Spanish Ministry of Economy and Competitiveness (MINECO) and EU FEDER, under Project TIN2014-55413-C2-2-P

Relationship between Monitored Natural Slaking Behaviour, Field Degradation Behaviour and Slake Durability Test of Marly Flysch Rocks: Preliminary Results

According to various studies, the degradation of marly lithologies that constitute heterogeneous rock masses such as flysch, can trigger and condition many slope instabilities. However, not all marly lithologies degrade in the same way, exhibiting considerable differences in the rates and ways of degradation. Therefore, it is very important to know the degradation behaviour of different lithotypes against environmental conditions, characterizing their weathering patterns and quantifying their rates of deterioration. This issue has been widely studied trough different approaches: a) through laboratory tests, mainly based on the slake durability test (SDT); b) through the study of monitored natural slaking behaviour; and c) by means of the characterization of in situ observed patterns and natural degradation rates. The main aim of this work is to link these different approaches used to perform this characterization. For this purpose, an experimental test, in which various samples have been exposed under monitored natural climatic conditions for 12 months and have been characterized through the study of the fragment size distribution curves of the degraded particles, has been developed. Additionally, these samples have been also classified based on the Potential Degradation Index (PDI) determined through laboratory tests. Finally, the in situ weathering behaviour profiles have been also logged. Preliminary results of this research suggest the existence of a clear relation between the different classes of degradation stated by the Potential Degradation Index (PDI), the behaviour of the fragments retained in the drum along the SDT cycles, the slaking behaviour under natural climatic conditions and the weathering behaviour patterns and rates observed at weathered profiles in the field.This work was funded by the University of Alicante under the project GRE14–04

Failure mechanisms and stability analyses of granitic boulders focusing a case study in Galicia (Spain)

Granitic boulders are widespread geomorphological elements, particularly found in humid granitic areas. Although they seldom represent a hazard for people or infrastructures, sometimes their location in steep or natural slopes may jeopardise their stability and potentially affect people or infrastructures. In addition, their complex geometry makes the instability mechanisms difficult to identify, so it is even more difficult to compute factors of safety regarding their stability. In this paper, the authors analyse potential failure mechanisms of granite boulders based on analytical mechanic calculations and physical tilt tests, permitting understanding the phenomena under scrutiny. Then, they study the stability of one of these boulders: the Pena do Equilibrio or equilibrium rock. To do that they resort to standard geotechnical characterization and advanced geometrical characterization derived from UAV photogrammetric and 3D Laser Scanning of the boulder. The presented results exemplify how the application of these recently available topographic technologies, in combination with rock mechanics approaches, enable a rigorous analysis of the stability of granite boulders