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Q-slope is one of the most recent empirical geomechanical classification systems and the least studied in South America. This study aims to expand the knowledge base regarding the Q-slope geomechanical method and demonstrate its applicability and reliability in rock slopes of Andean countries, such as Ecuador. To this end, thirty rocky slopes have been characterized considering (1) the physical visual approach—geographic location, climate, lithology, alteration, and stability (to obtain values of Jr, Ja, Jwice, and SRFa)—and (2) geomechanical stations and kinematic analysis (for the determination of the type of failure, Jn, O-factor, and SRFc for Q-slope). Field data were collected in contrasting environments (coastal, mountain, and forest), and different failure modes were considered (planar, wedge, block, and flexural topplings) to better understand the method. The results and main contributions of this research are (i) verifying the applicability of the Jwice parameters in different climatic settings and (ii) validating the Q-slope method by applying a confusion matrix to evaluate its reliability for slope stability assessment. The overall accuracy obtained is 80%, placing the Q-slope geomechanical method in the highest evaluation quartile and thus classifying it as very good for slope characterization.

[EN] Sediment budgets and morphological channel adjustments are closely related to changes in stream power. In ephemeral channels, whose geomorphic response depends on the magnitude and frequency of hydrological events isolated in time, such relationships are often difficult to establish. This study sought to quantitatively relate morphological adjustments to stream power along different reference channel reaches for the period 2018¿2020 in the Azohía Rambla, a Mediterranean gravel-bed ephemeral stream in southeastern Spain. Very high resolution digital terrain models (VHR DTM) (at 1 to 2.5 cm pixel size), combined with ortophotographs and 3D point clouds, generated via SfM photogrammetry and terrestrial laser scanning (TLS) for pre- and post-event stages, together with ground-based surveys were used to estimate the spatial variability of morphological sediment budgets and to assess channel bed mobility and changes in net sediment flux during the study period in two spatial scenarios: reference channel reaches (RCRs) and pilot bed survey areas (PBSAs). The hydraulic variables (flow velocity, Froude number, shear stress, mean stream power and energy gradient, among other) were estimated using a 1D hydrodynamic model calibrated with field information. The high resolution maps allowed a spatially-explicit analysis of stream power and transport efficiency in accordance with the areas of erosion and deposition in each RCR. The incision and bed armoring processes showed different trends according to the stream power (¿), cumulative excess energy (¿c), and relative bed stability (RBS). The greatest morphological adjustments at the event scale coincided with ¿ values above 300W m¿2, ¿c higher than 3 MJ, and RBS below 0.5. The relationships between the mean stream power gradient at peak flood discharges and the changes in bed elevation verified the bed aggradation (an average surface raising of 0.17 to 0.22 m for ¿¿/¿s of ¿6.2 to ¿14.5Wm¿2 m¿1) during the major flood and bed scour (average surface lowering of 0.16 to 0.19 m for ¿¿/¿s of 5.8 to 10.6 W m¿2 m¿1) in the moderated events at the bankfull and sub-bankfull stages. Furthermore, this study contributes new relevant data to the scarce existing literature on the relationships between stream power and morphosedimentary adjustments in a fluvial system highly sensitive and resilient to climate change, as is the case of ephemeral gravel-bed channels., This work has been financed by ERDF/Spanish Ministry of Science, Innovation and Universities-State Research Agency (AEI) /Project CGL2017-84625-C2-1-R (CCAMICEM) ; State Program for Research, Development and Innovation oriented to the Challenges of Society, and by the University of Alicante (Project GRE18-15) . We also would like to extend our thanks to AEMET and the Segura River Hydrographic Confederation Center (SHC) , Government of Spain, for their collaboration.

This paper applies remote sensing techniques and 3D point cloud (3DPC) analysis to the study of historical quarries and the relationship between old quarry landscapes and the natural fracture systems of rock massifs. Ancient quarry landscapes present particular characteristics and different features from those of modern quarries. Consequently, specific considerations are needed when historical extractive places are studied. The proposed method is based on terrestrial 3D laser scanners and the structure from motion technique with remotely piloted aircraft systems. Additional specific fieldwork is required to identify and characterise quarry faces from old, blurry outcrops. A case study of the 18th century “Rambla Honda” quarries in La Romana (Alicante, SE Spain) is presented. The comparison between the fieldwork and 3DPC analysis enables the numbers and orientations of both (1) the discontinuity sets within the rock mass facilitating extraction and (2) the planes resulting from block extraction (traditional quarry faces) to be determined. The comparative analysis reveals how the stonecutters managed the extraction. The results show that structural and stratigraphic discontinuities act as planes of weakness for block extraction and determine the optimum orientation of the quarry face for minimising efforts and rock waste. The final quarry landscape is formed from the superposition of natural and artificial surfaces, but currently they appear eroded and partially covered by silting and plants. The proposed methodology contributes to distinguishing both natural and artificial discontinuities and to achieving a comprehensive knowledge of these cultural places. This research was funded by the Spanish Ministry of Economy and Competitiveness (MINECO) and EU FEDER under Project TEC2017-85244-C2-1-P, the University of Alicante (Vigrob-157 and GRE18-15), and the Spanish Ministry of Science and Innovation (Grants PID2020-116896RB-C21 and PID2020-116896RB-C22 funded by MCIN/AEI/10.13039/501100011033).

Granite boulders are characteristic geomorphological structures formed in granitic terrains. Due to their formation process associated with typical spheroidal weathering phenomena, they tend to show more or less ellipsoidal shapes prone to instability, and they often lie on small contact surfaces. Analyzing the stability of these boulders is not a straightforward task. First, these boulders may topple or slide. Additionally, their typically irregular geometry and uneven contact with the surface where they lie makes the analysis more complex. The authors have identified some critical issues that are relevant to characterize these boulders from a rock mechanics point of view, with the aim of estimating the stability of boulders. In particular, an accurate description of the geometry of the boulder is necessary to perform accurate toppling calculations. Additionally, the contact area and the features of the contact plane need to be known in detail. The study is intended to serve as a guideline to address the stability of these granite boulders in a rigorous way, since standard rock mechanics approaches (planar failure, toppling stability, standard rock joint strength criteria, etc.) may not be directly applicable to these particular cases. The first author acknowledges the Spanish Ministry of Science, Innovation and Universities for financial support of a related project awarded under Contract Reference No. RTI2018-093563-B-I00, partially financed by means of ERDF funds from the EU. The first author also gratefully thanks the Commission for Cultural, Educational, Scientific Exchange between the USA and Spain of the Fulbright Program for financing a Scholar Visit to Colorado School of Mines, where part of this study was completed. The fourth author acknowledges funding of part of his research in association boulder geometry acquisition from EU FEDER under Project TEC2017-85244-C2-1-P and by the University of Alicante (vigrob-157 and GRE18-05).

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.

After a recent forest fire, a weathered granite rock slope located in the northwest of Spain may become increasingly susceptible to rockfalls. This study presents a multi-approach assessment of rockfall hazard, with some features deserving particular attention. First, the geomorphological context represented by a weathered rock mass with multiple dispersed blocks presenting various potential instability mechanisms. Secondly, the presence of a hillfort behind the slope and a small village at its toe, limiting the available solutions for rockfall protection. Finally, the combination of different remote sensing techniques (unmanned aircraft system topography and light detection and ranging) with a semi-automatic geostructural analysis has been successfully applied to obtain both a 3D point cloud of the wide area under study in addition to an estimation of mean block volume for rockfall simulations. Additionally, the design and implementation of a protective measure (rock dynamic barrier) have been addressed.

Technological progress in remote sensing has enabled digital representation of terrain through new techniques (e.g. digital photogrammetry) and instruments (e.g. 3D laser scanners). However, the use of old aerial images remains important in geosciences to reconstruct past landforms and detect long-term topographic changes. Administrations have recently expressed growing interest in sharing photogrammetric datasets on public repositories, providing opportunities to exploit these resources and detect natural and anthropogenic topographic changes. The SfM-MVS photogrammetric technique was applied to scanned historical black and white aerial photos of the Serra de Fontcalent (Alicante, Spain), as well as to recent high-quality digital aerial photos. Ground control points (GCPs) extracted from a LiDAR-derived three-dimensional point cloud were used to georeference the results with non-linear deformations. Two point clouds obtained with SfM-MVS were compared with the LiDAR-derived reference point cloud. Based on the result, the quality of the models was analysed through the comparison of the stages on stable areas, i.e., lands where no variations were detected, and active areas, with quarries, new infrastructures, fillings, excavations or new buildings. This study also indicates that errors are higher for old aerial photos (up to 5 m on average) than recent digital photos (up to 0.5 m). The application of SfM-MVS to open access data generated 3D models that enhance the geomorphological analysis, compared to stereophotogrammetry, and effectively detected activities in quarries and building of landfills. This work was partially funded by the University of Alicante, Spain, under Projects vigrob-157 GRE14-04, and GRE15-19; the University of Florence Earth Science Department, Italy; the Spanish Ministry of Economy and Competitiveness (MINECO), Spain, and EU FEDER, under Projects TIN2014-55413-C2-2-P and TEC2017-85244-C2-1-P and the Spanish Ministry of Education, Culture and Sport, Spain, under project PSX17/00439.

[EN] Stream power represents the rate of energy expenditure along a stream reach and can be calculated using topographic data acquired via structure-from-motion (SfM) photogrammetry and terrestrial laser scanning (TLS). This study sought to quantitatively relate morphological adjustments in the Azohia Rambla, a gravel-bed ephemeral stream in southeastern Spain, to stream power (omega), critical power (omega(c)), and energy gradients ( partial differential omega/ partial differential s), along different reference channel reaches of 200 to 300 m in length. High-resolution digital terrain models (HRDTMs), combined with ortophotographs and point clouds from 2018, 2019, and 2020, and ground-based surveys, were used to estimate the spatial variability of morphological sediment budgets and to assess channel bed mobility during the study period at different spatial scales: reference channel reaches (RCRs), pilot bed survey areas (PBSAs), and representative geomorphic units (RGUs). The optimized complementary role of the SfM technique and terrestrial laser scanning allowed the generation of accurate and reliable HRDTMs, upon which a 1-D hydrodynamic model was calibrated and sediment budgets calculated. The resulting high-resolution maps allowed a spatially explicit analysis of stream power and transport efficiency in relation to volumes of erosion and deposition in the RCR and PBSA. In addition, net incision or downcutting and vertical sedimentary accretion were monitored for each flood event in relation to bedforms and hydraulic variables. Sediment sources and sinks and bed armoring processes showed different trends according to the critical energy and stream power gradient, which were verified from field observations. During flows exceeding bankfull discharges (between 18 and 24 m(3) s(-1) according to channel reach), significant variations in partial differential omega/ partial differential s values and omega/omega(c) ratios (e.g., -15 < partial differential omega/ partial differential s < 15 Wm(-3); omega/omega(c) > 2 for a peak discharge of 31 m(3) s(-1)) were associated with a large amount of bedload mobilized upstream and vertical accretion along the middle reach (average rise height of 0.20 to 0.35 m for the same event). By contrast, more moderate peak flows (, This research was funded by ERDF/Spanish Ministry of Science, Innovation and Universities-State Research Agency/Project CGL2017-84625-C2-1-R (CCAMICEM); State Program for Research, Development and Innovation Focused on the Challenges of Society, 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 and GRE18-05).

Earth fissures are pervasive cracks that develop on valley floors as a consequence of land subsidence associated with extensive groundwater withdrawal. To capture geometrical, geological and geotechnical information of ground fissures is of paramount importance for their characterization. Recent advances in remote sensing techniques and the accessibility to remotely piloted aircraft systems (RPAS) as well as the evolution of onboard digital cameras enable the capture of digital photos and videos. Using digital photos along with the Structure from Motion (SfM) technique and following certain strategies, we can reconstruct a 3-D model of the earth fissures under study. This technique requires digital photos, but when a digital video is available, we can convert it into a set of frames and equally apply the procedure. Besides, the extraction of frames from a video assures a key condition for the SfM technique: the overlap between photos. The resulting 3-D model should be scaled and oriented using a rigid transformation matrix or even better including ground control points (GCP) into the captured photos or frames. The latter enables the geo-referencing of the point cloud and the correction of linear and non-linear deformations. In this work, the proposed methodology is illustrated through the application of SfM technique to a high-resolution video downloaded from YouTube (i.e. https://youtu.be/9xdAnftBKvY, last access: 20 February 2020). The video shows a mile-long earth fissure that appeared sometime between March 2014 and December 2014 near the Tator Hills (Arizona, USA) over Quaternary sediments. The Arizona Geological Survey captured these videos using an RPAS. The frames of the video were downloaded and extracted using a simple Matlab code. Then, we sub-sampled the frames and processed them using the software Agisoft Metashape Professional. Finally, we got metric data from Google Earth and generated a 3-D model. The quality of the 3-D model strongly depends on the quality of the photos and the GCP. However, this study shows the potential of this technique, instrumentation and data available on Internet for the development of 3-D point clouds and 3-D models for the detailed analysis of earth fissures. This research has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO) and the European Funds for Regional Development (FEDER) (grant no. TEC2017-85244-C2-1-P), the UNESCO (grant no. ICGP641 project), the Universidad de Alicante (grant no. GRE17-11), the Universidad de Alicante (grant no. GRE18-15), and the Universidad de Alicante (grant no. vigrob-157).

Minimizing energy expenditure is one of the main purposes of the managers of pressurized irrigation systems. From the energy consumption standpoint, they can reduce energy consumption by supplying a constant flow into the system (a scheme different from urban water pressurized networks in which water demands depend on users). Managers can keep energy demands (opening and closing valves) while meeting pressure restrictions. We developed a computer application in MATLAB containing a genetic algorithm to find the best moment to open and to close valves to minimize an objective function which measures the differences between the objective and the real injected flows. We tested this program in the pressurized irrigation network of the San Vicente Campus, University of Alicante (Southeast Spain) and we calculated the water and energy balance (from the later and present irrigation network) and the carbon credits not emitted to the atmosphere. This research was conducted within the projects GRE‐16‐08 and GRE17‐12 coordinated by the University of Alicante. Antonio Jodar‐Abellan acknowledges financial support received from the Spanish FPU scholarship for the training of university teachers. In the same way, this work was funded partially by the Cátedra del Agua of the University of Alicante and the Diputación Provincial de Alicante (https://catedradelaguaua.org/).

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.

Data collection for kinematic and structural analyses in hills or rock slopes still maintains, nowadays, an important manual component. The set of lithological, structural and characteristic observations of the rock mass, directed to engineering design, is referred to as geomechanics observation point or geomechanical station. The properties and orientation of discontinuities and rock matrix of a geomechanics observation point are obtained in situ, by normalized templates. Subsequent laboratory/office work determines the resistant properties of the discontinuities, evaluates the geomechanical quality of the rock mass (e.g. using the RMR, Q, or GSI indices) and carries out a census of discontinuities, grouping into main sets. Field data are combined with laboratory results, in situ and geophysical tests, with the objective of elaborating a "geomechanical model" of the rock mass. Field characterization plays an important role in preliminary studies and, in many cases, is the only information available in the first stages of investigation and project development. Traditionally, rock mass field data collection has been carried out by physically accessing the slope. However, remote acquisition techniques have provided a new perspective. The main two remote data collection techniques are Interferometric Synthetic Aperture Radar –InSAR-and Light Detection and Ranging -LiDAR, InSAR enables high precision measurements of terrain surface movements, and is usually applied to monitor and detect landslides. LiDAR provides a 3D point cloud of the terrain surface. The comparison of point clouds acquired in different time frames also enables the monitoring and detection of landslides. Additionally, the use of 3D point clouds offers the possibility of working with geometrical surface information. Complementarily, digital photography has experienced significant advances with the development of photogrammetry techniques. The Structure from Motion (SfM) technique must be highlighted, as it enables surface reconstruction from 3D point clouds of digital photographs. SfM is considered a high-resolution, low-cost automated photogrammetry method, and it is based on the same principles of stereoscopic photogrammetry (the 3D structure can be built from image superposition). SfM originated from the artificial vision area and from the development of automated algorithms for digital image correlation (DIC). SfM is different from conventional photogrammetry, as the scene geometry, camera positions and orientation are solved automatically without the need of establishing, a priori, a control point network with known 3D coordinates. Collinearity equations are solved from the high number of conjugated points (common image points) identified during the automatic correlation phase of a set of superimposed images acquired in an unstructured way. The equipment utilized in the application of this technique entails lower economic costs than with LiDAR instrumentation, and results are reasonably acceptable. The limitation of SfM is mainly the dependence on the quality of the lens and the processing time, the procedure for capturing images and resource consumption by the machine. Generally, the higher the number, quality and resolution of the images, the higher the quality of the generated model. This, however, entails in a higher consumption of resources and higher computational time 3D point cloud treatment enables semi-automatic identification and extraction of information from plane discontinuity sets. Such information is very important for the development of kinematic analyses of block-controlled instabilities. The SfM technique9 has been attracting attention and becoming popular, as indicated by the increasing number of publications. These techniques permit the characterization of important geomechanical parameters such as orientation, roughness and persistence and spacing of discontinuities. Of all geomechanical parameters that can be extracted from 3D point clouds, analysis of plane discontinuities has probably been the most approached subject to this date. All proposed methods analyze the surface of the slope from 3D point clouds or from reconstruction via triangular elements (TIN, Triangular Irregular Network). In each surface point or element, the normal vector is estimated and a pole is determined; as a result, there is a population of poles available to analyze predominant surface orientations. The overarching objective of this work is to compare the results obtained in the collection of discontinuity orientations using a low-cost remote technique (i.e. SfM) and manual collection (compass). To this end, orientations are gathered with a compass for all accessible discontinuities of a slope, and from all discontinuities that are well represented in the 3D point cloud obtained with SfM. Plane extraction and 3D model orientations are carried out in two different ways: (1) by adjusting the planes to the point sets that belong to the same discontinuity, with Cloud Compare software27; and (2) semi-automatically, with Discontinuity Set Extractor software, DSE. The focus herein is only on the collection of discontinuity orientations, not on rock mass properties., Instituto Geológico y Minero de España, España, Departamento de Ingeniería Civil, Universidad de Alicante, España

A matlab‐based educational software (UAleaks) has been developed to consider the effect of water losses when solving the hydraulic problem in water pressurized networks. The results obtained are the new leaky network model and the water and energy audits calculation. This software can be used by students and practitioners. This study was supported by the research project “‘Desarrollo de herramientas específicas que permitan la gestión eficiente y sostenible del agua y de la energía en redes de agua a presión, GESAEN”' through the 2016 call of the Vicerrectorado de Investigación, Desarrollo e Innovación de la Universidad de Alicante GRE‐16‐08, and the Spanish Ministry of Economy and Competitiveness (MINECO) and EU FEDER, under Projects TIN2014‐55413‐C2‐2‐P and TEC2017‐85244‐C2‐1‐P.

Naked eye rock recognition is an essential activity for professionals and students of geosciences, architecture and engineering. Through a hand holding rock specimen, it is usually required not only to identify the type of rock but recognize their texture and understand its expected properties mechanical and petrophysical properties. Although a wide choice of books, websites and apps are available in the literature and on the Internet, their contents are two-dimensional (2D) and static. Nowadays, the application of remote sensing techniques such as Light Detection and Ranging (LiDAR) or Structure from Motion (SfM) enable the generation of three-dimensional (3D) interactive models, which are here presented as a novel perspective of learning and practising rocks recognition. Despite limitations of the technique, 3D digital models of rocks permit their virtual visualization and manipulation to reveal parts of the specimens that are hidden in the 2D photograph, as well as details of the rock specimen’s texture such as grain and minerals size, distribution and organization along with the possibility of identifying petrological features, foliation, mineral orientations and others. This provides a novel perspective of learning and practising rocks identification. Herein, a benchmark of digital rocks collected all around the world and generated using SfM technique is presented. The rocks are organised using a straightforward classification system based on the texture jointly with a detailed description to aid the specimen recognition. A behavioural geomechanical classification is then applied. Moreover, a linked datasheet shows the engineering classification, the weathering degree, the guide physical and mechanical properties (general, and specific when available), the engineering uses and others. The information is organised on an open-access website hosted by the University of Alicante (https://web.ua.es/digitalrocks). This initiative also aims to encourage students and professionals to generate their own models and to provide the description to enlarge the repository. This work was partially funded by the University of Alicante (vigrob-157 Project, GRE14-4, GRE15-19 and GRE17-011 Projects), the Spanish Ministry of Economy and Competitiveness (MINECO) and EU FEDER under Projects TIN2014-55413-C2-2-P and TEC2017-85244-C2-1-P. Authors thank Ignacio Pérez-Rey/ Leandro Alejano for the description some used samples.

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.

La licuación es un proceso por el que una masa de suelo saturado, generalmente granular y de baja compacidad, disminuye drásticamente su resistencia por un aumento de su presión de poro, habitualmente asociado a cargas monotónicas o cíclicas, tales como las inducidas por los eventos sísmicos. Este efecto es recogido tanto por diversas normativas españolas como por el Anejo Nacional Español del Eurocódigo. En este trabajo se realiza un estudio comparativo sobre las diferencias y similitudes en la metodología de comprobación del potencial de licuación empleado en las diferentes normativas. Asimismo, con objeto de cuantificar las diferencias observadas, se ha determinado el factor de seguridad frente a la licuación para tres casos reales de suelos de la provincia de Alicante. En función de los resultados obtenidos se puede concluir que existen diferencias, en algunos casos significativas, en el factor de seguridad obtenido. Liquefaction is an effect for which a saturated soil suffers a severe loss of shear strength due to an increase of pore-water pressure. This effect, which generally affects loose granular soils, is usually produced by cyclic loading such as that the induced by earthquakes. In Spain, three different national standards plus Eurocode can currently be applied in the assessment of potential liquefaction of a soil site. In this research, a comparative study of the similarities and differences between these standards has been performed. Moreover, to improve understanding of the differences between standards, the factor of safety against liquefaction has been obtained for three real cases in the province of Alicante. According to the obtained results, it can be concluded that the safety factor can present significant differences depending on the code used. El trabajo ha sido parcialmente financiado por los proyectos del Ministerio de Economía y Competitividad de España y los Fondos Feder TIN2014-55413-C2-2-P y el proyecto UA GRE140-4.

Finding new ways to quantify discontinuity persistence values in rock masses in an automatic or semi-automatic manner is a considerable challenge, as an alternative to the use of traditional methods based on measuring patches or traces with tapes. Remote sensing techniques potentially provide new ways of analysing visible data from the rock mass. This work presents a methodology for the automatic mapping of discontinuity persistence on rock masses, using 3D point clouds. The method proposed herein starts by clustering points that belong to patches of a given discontinuity. Coplanar clusters are then merged into a single group of points. Persistence is measured in the directions of the dip and strike for each coplanar set of points, resulting in the extraction of the length of the maximum chord and the area of the convex hull. The proposed approach is implemented in a graphic interface with open source software. Three case studies are utilized to illustrate the methodology: (1) small-scale laboratory setup consisting of a regular distribution of cubes with similar dimensions, (2) more complex geometry consisting of a real rock mass surface in an excavated cavern and (3) slope with persistent sub-vertical discontinuities. Results presented good agreement with field measurements, validating the methodology. Complexities and difficulties related to the method (e.g., natural discontinuity waviness) are reported and discussed. An assessment on the applicability of the method to the 3D point cloud is also presented. Utilization of remote sensing data for a more objective characterization of the persistence of planar discontinuities affecting rock masses is highlighted herein. 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, Industry and Competitiveness (MINECO), the State Agency of Research (AEI) and the European Funds for Regional Development (FEDER) (projects TEC2017-85244-C2-1-P and TIN2014-55413-C2-2-P) and the Spanish Ministry of Education, Culture and Sport (project PRX17/00439). A. Abellán would like to acknowledge the support received from the H2020 Program of the European Commission under the Marie Skłodowska-Curie Individual Fellowship [MSCA-IF-2015-705215].

In recent years, there was an increasing number of studies focusing on rockfalls due to their impacts on social and sustainable development. This work carries out a three-dimensional (3D) simulation of rockfalls at a cultural heritage site nearby the village of Cortes de Pallás (Valencian Community, East Spain). The simulation is based on data collected previously, during an emergency declaration due to the occurrence of a considerable rockfall (7980 m3) on the southern bank of the Cortes de Pallás reservoir, on 6 April 2015. The hydroelectric power plant was damaged, and the main access road to the village of Cortes de Pallás was blocked for eight months. The predominant discontinuities of the rock mass were analyzed by means of the application of structure from motion (SfM) photogrammetry techniques to the set of images taken by remotely piloted aircraft systems (RPAS). The average size of the block was determined as 3.2 m in diameter and 17.6 m3 in volume. Additionally, a digital elevation model (DEM) was generated from an aerial laser scanning (ALS)-derived point cloud using a 1 1 grid. These data were implemented in RocPro3D software, obtaining the distances traveled by the blocks detached from different source areas at a cultural heritage site located near the rockfall event, which presents the same geological context. The simulation presented herein shows aggravating circumstances that endanger the cultural heritage area, with higher rockfall hazards than previous official studies (1991) displayed., Instituto Geológico y Minero de España, España, Departamento de Ingeniería Civil, Universidad de Alicante, España, Unidad de Granada, Instituto Geológico y Minero de España, España

Landslides are very complex processes controlled by multiple factors. The knowledge and characterization of these factors is essential for a comprehensive understanding of the mechanisms and kinematics of the instabilities and for an efficient design of corrective measures. The aim of this work is to combine traditional geological and geotechnical techniques with geophysical, remote sensing and forensic techniques for obtaining a whole picture of an active lateral spreading affecting the Finestrat municipality in Alicante, SE Spain. Geomorphological, geotechnical and geophysical techniques (i.e. ground penetrating radar and refraction seismic) have provided essential information about the geometry, structure and petro-physical properties of the slope. A Terrestrial Laser Scanner was used for recognizing the most important sets of discontinuities affecting the rock mass and to evaluate the activity of the landslide slope. Complementarily, a forensic analysis of the building damage completed the available datasets, yielding very useful kinematic information of the landslide. Finally, a sensitivity analysis of the stability of the rock slope has been performed considering both block toppling and block sliding models. Therefore, the multisource analysis performed in this work has allowed the identification and characterization of a complex lateral spreading, highlighting its effectiveness for a comprehensive understanding of this type of landslide. This work has been supported by the University of Alicante under the project GRE14-04, Generalitat Valenciana under the project GV/2011/044, by the Ministry of Education, Culture and Sport trough the project PRX14/00100, by the Spanish Ministry of Economy and Competitiveness and EU FEDER funds under project TIN2014-55413-C2-2-P, by Swiss National Science Foundation (project numbers 138015 and 144040) and by the European Commission project MOMIT (Ref. no 777630). The second author would like to acknowledge the support received from the H2020 Program of the European Commission under the Marie Skłodowska-Curie Individual Fellowships (MSCA-IF-2015-705215).

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.

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.

Discontinuities play a key role in the mechanical, hydraulic and deformational behaviour of rock masses, frequently having a considerable influence on the stability of rock slopes. They can be characterized by several geometric parameters as the orientation, persistence, spacing, etc. Although orientation has been traditionally measured through well-known techniques as a compass, more recent remote sensing techniques such as 3D laser scanning allow deriving both strike and dip direction of discontinuities. The novel SfM (Structure from Motion) technique, which is much less expensive than 3D laser scanning, is becoming mainstream within the research community. This paper examines the generation of 3D point clouds of a rock slope obtained from both, 3D laser scanning and SfM techniques, and their application to the extraction of the orientations of the main discontinuity sets. To this aim, a selected sector from a cretaceous sedimentary rock cut slope placed in Alicante (Spain) is analyzed using both photogrammetric and terrestrial laser scanner (TLS) point clouds. Using ground control points extracted from printed targets scanned by means of TLS provided very accurate coordinates. As a result of this, the obtained adjustment error was minor than 3 mm. The comparison of the resulting point clouds shows a good correlation when the surface is orthogonal to the line of sight. On the contrary, the SfM dataset showed inaccuracies on sub-horizontal and oblique surfaces. Finally, a geometrical analysis was performed by means of DSE software. Three discontinuity sets were extracted from both point clouds. However, one more was extracted from the TLS dataset, but not from the SfM dataset.

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).

The integration of data from different sources can be very helpful in understanding the mechanism, the geometry, the kinematic, and the area affected by complex instabilities, especially when the available geotechnical information is limited. In this work, the suitability of different techniques for the study of a deep-seated landslide affecting a bridge in Alcoy (Spain) is evaluated. This infrastructure presents such severe damage that has rendered the bridge unusable, which prevents normal access to an important industrial area. Differential SAR Interferometry (DInSAR) and terrestrial Light Detection and Ranging (LiDAR) remote sensing techniques have been combined with ground displacement monitoring techniques, such as inclinometers and conventional geological and geotechnical investigation, electrical-seismic tomography, damage, and topographic surveys, to determine the boundaries, mechanism, and kinematics of the landslide. The successful case study that is illustrated in this work highlights the potential and the need for integrating multi-source data for the optimal management of complex landslides and the effective design of remedial measurements. This work has been supported by the University of Alicante under the projects GRE17-11, and 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.

This work describes a new procedure aimed to semi-automatically identify clusters of active persistent scatterers and preliminarily associate them with different potential types of deformational processes over wide areas. This procedure consists of three main modules: (i) ADAfinder, aimed at the detection of Active Deformation Areas (ADA) using Persistent Scatterer Interferometry (PSI) data; (ii) LOS2HV, focused on the decomposition of Line Of Sight (LOS) displacements from ascending and descending PSI datasets into vertical and east-west components; iii) ADAclassifier, that semi-automatically categorizes each ADA into potential deformational processes using the outputs derived from (i) and (ii), as well as ancillary external information. The proposed procedure enables infrastructures management authorities to identify, classify, monitor and categorize the most critical deformations measured by PSI techniques in order to provide the capacity for implementing prevention and mitigation actions over wide areas against geological threats. Zeri, Campiglia Marittima–Suvereto and Abbadia San Salvatore (Tuscany, central Italy) are used as case studies for illustrating the developed methodology. Three PSI datasets derived from the Sentinel-1 constellation have been used, jointly with the geological map of Italy (scale 1:50,000), the updated Italian landslide and land subsidence maps (scale 1:25,000), a 25 m grid Digital Elevation Model, and a cadastral vector map (scale 1:5000). The application to these cases of the proposed workflow demonstrates its capability to quickly process wide areas in very short times and a high compatibility with Geographical Information System (GIS) environments for data visualization and representation. The derived products are of key interest for infrastructures and land management as well as decision-making at a regional scale. This research was funded by the Shift2Rail Joint Undertaking under the European Union’s Horizon 2020 research and innovation program, with grant agreement No 777630, project MOMIT, “Multiscale Observation and Monitoring of railway Infrastructure Threats” and the Spanish Ministry of Economy, Industry and Competitiveness (MINECO), the State Agency of Research (AEI), and the European Funds for Regional Development (FEDER) under project TEC2017-85244-C2-1-P.

The natural stone industry generates large amounts of industrial waste every year. Limestone powder produced by the activity of this industry is dumped into landfills, generating an environmental impact that could be reduced by using this waste as a binder in building materials. In the present work, the use of this by-product as an addition for soil improvement of clayey soils has been studied. The tested natural soil is a soft clay from southeastern Spain, which has been mixed by adding 5, 10, 15, 20, and 25% of dry limestone dust by total dry weight of the soil. The natural soil and the additive have been characterized, in addition to the common geotechnical tests, by means of X-Ray diffraction and X-Ray Fluorescence. The improvement of the geotechnical properties of the mixed soil has been evaluated by means of the change in the Atterberg limits, free swell index, unconfined compressive strength, and one-dimensional consolidation test. The change in the microstructure of the mixed soil has been studied by scanning electron microscopy. In general, the results obtained show an increase in the strength of the soil and a reduction of its deformability when limestone powder is added. This research was funded by the University of Alicante under the projects GRE17-11.

Presentación de Riquelme et al del Workshop M3EF3, celebrado el 16 y 17 de noviembre de 2017 en la Universidad de Alicante. New 3D data acquisition techniques allow to obtain geometrical information of exposed rock masses. This information can be used to characterize some geo-mechanical parameters of rock slopes, allowing users to remotely obtain information. Recently, many researchers have been working on the extraction of geo-mechanical parameters of rock masses using 3D point clouds, such as the number of discontinuity sets and their orientations, the normal spacing and the persistence. In this contribution we use two novel open source programs: (1) Discontinuity Set Extractor (DSE) aids to analyse 3D point clouds detecting the number of discontinuity sets, classifying each point with its discontinuity set and plane equation and calculating their normal spacing; and (2) SMRTool calculates the geo-mechanical quality of a rock slope by means of the Slope Mass Rating (SMR) index. In order to illustrate the use of the two software programs, we analyse the geo-mechanical quality a slope placed in the National route N-332 in El Campello (Alicante, Spain), in the named Flysch sequence of Alicante, using 3D point clouds. The 3D point cloud was analysed using the previously mentioned open-access tools. Their use allowed to extract the discontinuity sets, normal spacing and persistence using a software which code can be inspected and improved without cost. Moreover, it allows to reproduce the full analysis process using the same method parameters. This work was partially funded by the University of Alicante (vigrob-157 Project and GRE14–04 Project), the Generalitat Valenciana (Projects GV/2011/044 and ACOMP/2014/136), the Spanish Ministry of Economy and Competitiveness (MINECO) and EU FEDER under Project TEC2011-28201-C02-02 and TIN2014-55413-C2-2-P. The 3D laser scanner used in this work for the 3D point cloud acquisition was acquired under the framework of the Programa Objetivo FEDER 2007-2013 Generalitat Valenciana - Unión Europea - Universidad de Alicante.

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. This work was partially funded by the University of Alicante (vigrob-157 Project and GRE1404 Project), the Generalitat Valenciana (Projects GV/2011/044 and ACOMP/2014/136), the Spanish Ministry of Economy and Competitiveness (MINECO) and EU FEDER under Projects TEC2011-28201-C02-02 and TIN2014-55413-C2-2-P.

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.