bluuebunny/crossref_metadata_2025_split huggingface dataset:
A geotechnical evaluation of the Cumba Pit Slope Failure, Dominican Republic
Authors: Bar N , McQuillan A , Ma T , Wai D , Hammah R , Corkum B , Yacoub T , Cobián JC , Mojica B 
Published: January 2023

Abstract
The combined availability of topographical, geological, structural, hydrogeological and monitoring data is rapidly increasing. Technology and software advances allow the real time incorporation of this data across various software platforms. This paper describes the back-analysis of a 70 m high, pit slope failure of an open pit gold mine in the Dominican Republic, using data from aerial photogrammetry, ground-based synthetic aperture radar and 3D limit equilibrium and finite element modelling. This back-analysis process is considered leading practice with the latest technology. The (northern) side of the Cumba pit slumped along a non-daylighting plane that was identified after the failure event. Remedial investigations included review of geological data, major structures, rock mass constitutive models and groundwater conditions. Topographical and structural data acquired from aerial photogrammetry, pre- and post-failure event, was input into 3D models to replicate observed ground movement. 3D models of pit progression were compared with displacements recorded by ground-based synthetic aperture radar to calibrate model inputs and increase reliability of forward predictions. Such a technical review was completed in less than one week, and the review process implemented for the Cumba pit slope failure now forms the baseline approach for all future geotechnical analysis at the operating mine.
Mechanical and physical characterization mapping of evaporitic rocks from Abu Dhabi city and its surroundings
Authors: Arman Hasan , Paramban Safwan , Saima Mahmoud Abu , Abdelghany Osman , Aldahan Ala 
Published: January 2023

Abstract
Safe and sustainable engineering structure designs always require carefully and detailed mechanical and physical characterization of rocks. Abu Dhabi city, which is the capital of the United Arab Emirates (UAE), have been fast developing and industrializing region in the country and it is located on evaporitic rocks. Construction companies in this city often face some technical problems associated with evaporite bedrocks. Mechanical and physical characterization of rocks in either in-situ or laboratory is relatively expensive, takes significant time, efforts and adequate rock specimens must be tested to achieve reliable and representative values. In this study, extensive field and laboratory studies were carried out and 152 evaporitic rock blocks, which represent the study area, were collected from 27 locations. Large number test samples were prepared, tested and the mechanical and physical characterization maps, which are prepared by interpretation of the obtained data sets from 27 locations, for each considered parameters like Unconfined Compressive Strength (USC), Indirect Tensile Strength (ITS), P Wave Velocity (Vp), Porosity (n), Water Content (wc) etc. Availability of such characterization maps for evaporitic rocks in the Abu Dhabi city vicinity will be practical, useful, economical and certainly provides vital information for the construction businesses, engineers, and decision makers.
Geotechnical assessment of rock masses in metallic mineral deposits, a view on the “hidden” issues in open-pit design
Authors: Peshevski I , Jovanovski M , Angelova E , Jovanovska T 
Published: January 2023

Abstract
Defining rock mass geotechnical properties is a critical step in the process of open-pit slope design. Geotechnical engineers assess the frequently highly altered rocks of metallic mineral deposits by applying standardized geotechnical classifications primarily developed for underground mining operations or design of civil structures such as tunnels and cut slopes. In some cases, the projects do not consider additional aspects of the rock masses, such as: zoning according to rock mass alteration schemes, prediction of blasting disturbance and weathering depth, rock strength loss over time, swelling effects, etc. Unfortunately, in some mineral deposits, many of these aspects appear to overlap, leading to difficulties in the process of open-pit design. In the case of neglecting such complex issues, there can be serious consequences in regard to future safe mine operation or even failure of slope/s. The paper presents findings from Macedonian legislation and literature overview on these aspects, regulations from other countries where available, as well as personal experiences of the authors. Some suggestions on the scope of geotechnical investigation works are briefly presented. It is considered that a more serious approach is needed in order to achieve a better understanding of the “long term” geotechnical behaviour of rock masses in such high risk environments.
Evaluation of the Performance of the ISRM Suggested Methods for Measuring Density and Porosity when Applied to Low-Porosity Rocks
Authors: Kiuru R , Nieman P , Rinne M 
Published: January 2023

Abstract
Recent studies conducted in the context of geological disposal of spent nuclear fuel in low-porosity crystalline bedrock have found density and porosity values obtained following the ISRM Suggested Method (ISRM 1977) to occasionally be sporadic. To investigate this behaviour, 137 core specimens of 5 different rock types (granite, granitic pegmatoid, veined gneiss, mica gneiss and sandstone) were submerged in water under NTP conditions and measured repeatedly until the observed saturated mass was constant within the accuracy of the measurement system. These specimens were then fully dried and subsequently saturated again, this time following the Suggested Method (1 hour in water at <800 Pa vacuum) and measured again for density and porosity. Density and porosity values observed following the ISRM Suggested Method were found to be systematically lower than values observed using immersion saturation. Specimens saturated following the ISRM Suggested Method reached on average 40 – 60 % of the level of saturation reached with the immersion method. This resulted in significant differences in observed density and porosity values when compared to values observed after immersion saturation. Performance of the saturation method proposed in the ISRM Suggested Method should thus be studied in more detail and possibly re-evaluated.
Fluid flow of various configurations in a rock-proppant-system
Authors: Witte L C , Backers T 
Published: January 2023

Abstract
A high rock mass permeability is essential for developing an enhanced geothermal system and commonly achieved through the fracture conductivity. Hydraulic stimulation of fractures in combination with the use of proppants can significantly increase and maintain rock mass permeability. To investigate and quantify the effect of proppants, which are so far not commonly used to enhance deep geothermal reservoirs, on the rock mass hydraulic conductivity we performed various sets of laboratory experiments. We performed long-term creep deformation tests on a stack of rock samples with simultaneous a) fluid flow and b) acidification and fluid flow, in both cases with and without a proppant-filled fracture between the stacked rock samples. A central borehole served as fluid inlet into the lower sample of the stack. Two more boreholes in the lower sample allowed fluid flow. Sample stacks were placed in a Hoek cell at elevated confining pressures to prevent fluid flow along the sidewalls of the cylindrical sample setup. We compared the axial deformation and injection pressures between the experimental setups. The laboratory tests are part of the ZoKrateS Project, which aims at showing the feasibility of enhancing fractured carbonate rock mass by proppant placement for geothermal applications.
Hybrid InSARTrac for monitoring interglacial movement patterns
Authors: Zambanini C , Kieffer D S 
Published: January 2023

Abstract
InSARTrac is a hybrid 3D monitoring method, for which controlled field measurements have indicated significant potential for geotechnical applications. Various approaches can be taken to derive 3D displacements from InSAR measurements, such as combining multiple InSAR ascending and descending satellite passes or combining multi-geometrical radar datasets from ground and satellite based radars. InSARTrac is a cost-effective solution requiring only one terrestrial InSAR device and a camera used for feature tracking. This study summarizes the results of glacial displacement measurements that were conducted to test the InSARTrac methodology. The InSARTrac 3D displacement vectors show details concerning glacial retreat dynamics related to a combination of ice flow and volume loss. By extrapolating prior results obtained from controlled field measurements, the resultant displacement vector orientations have an estimated angular error of approximately 5 degrees. With a fixed camera mount and longer monitoring times this error can be further reduced. Current studies are focused on deploying InSARTrac to investigate its potential for landslide and geostructure monitoring.
An approach to estimate influence region of field investigation sampling points, investigation zone in civil infrastructure projects and brief review of existing field investigation process
Authors: Singh Naval 
Published: January 2023

Abstract
Geotechnical investigation is a cyclic process. The interdependency between different steps involved in whole process, i.e., from planning, performing investigation, transporting samples and analysis of data obtained from field or lab, present opportunities for improvements and further discussion.
For estimating number of investigation sampling points required for a particular site and selection of investigation methods, today we mostly relay on information from previously conducted site investigations, local experience from that area or site. In geotechnical investigation getting field samples which represents actual ground conditions for the whole site is well known challenge and has been highlighted in many research papers.
In this paper we are presenting concept of influence region of geotechnical investigation points and an approach for estimation of the same. We believe the influence region concept; its estimation approach will provide a mathematical model and will help in deciding number of sampling points at the geotechnical investigation sites. In author’s opinion the presented concept will further improve the quality of geotechnical ground investigation process and will provide help in getting representative, quality field samples for laboratory analysis.
The presented concept and estimation approach in this paper is based on author’s field experience and exposure gained from working in Swedish infrastructure projects. We think the influence region concept will further improve the existing geotechnical ground investigation process and will open opportunities for its validation through focused scientific research.
A brief overview of the existing ground investigation processes has been covered in the paper, along with examples from geotechnical site investigations from Trafikverket (The Swedish Transport Administration) projects in Sweden.
Tensile strength of anisotropic rocks from enhanced Brazilian laboratory testing and data analysis protocols
Authors: Packulak T R M , Day J J , Diederichs M S 
Published: January 2023

Abstract
The tensile strength of rock and rock-like materials is a critical material property in rock engineering design and the prediction of rockmass behaviour to mitigate any potential failure that may affect personnel safety or damage property. This study presents new instrumentation guidelines to the Brazilian Tensile Strength (splitting tensile strength) test to enhance the data processing techniques to determine true tensile strength. For this study a total of eighteen (18) specimens of two lithologies (Pointe Du Bois tonalite gneiss and Key Anacon metabasalt) were instrumented, tested, and reviewed to determine the true tensile strength of the material. This paper also identifies three potential failure modes and presents a failure envelope based on the identified potential failure modes.
An example of digital field training for a diversity-friendly (and pandemic-proof) field education in geoengineering disciplines
Authors: Godlewska J C , Ogan M S , Duda M , Backers T 
Published: January 2023

Abstract
Geological field training and site inspections are important components of the education in geological and civil engineering and associated disciplines. However, field training is not inclusive, does not consider students’ family situations, for example associated with care work, places high demands on students’ financial resilience, and therefore does not address family educational backgrounds. Also, it is not pandemic proof. Through the implementation of digital field training, students can get access to important aspects of field work in a barrier-reduced and location-independent way. Knowledge associated with geological field training therefore becomes more accessible and inclusive. Moreover, outcrops or specific rock structures that are difficult or unsafe to access in the field can be explored digitally. In this project, parts of a geological mapping course physically held in southern Germany and taught at the Faculty of Geosciences at Ruhr-Universität Bochum were turned into a digital field course. A virtual 360° tour with 3D models of outcrops and rock samples was complemented by photo, video and audio material with information on the geological setting. The digital field training was integrated via Moodle as a full lecture with H5P elements. Additionally, individual components were combined in a game engine, so that students can immerse themselves into the project settings via virtual reality experiences or on-screen. The learning outcome includes the creation of a geological map in the study area in QGIS that is complemented by a field report. The choice of equipment, procedure and results are presented. While acknowledging that a digital experience cannot fully replace the learning experience of physical field trips, it can be a valuable complement to physical field work, provide access to inaccessible geological regions, support interdisciplinary teaching projects, and provide an alternative to marginalised students who would otherwise not be able to complete a geoengineering curriculum.
Measuring the hydraulic transmissivity of a rock joint under varying normal load
Authors: Jacobsson L , Godio M 
Published: January 2023

Abstract
The water flow rate through a rectangular granite specimen with a tight unopened natural induced joint of dimensions 200×200 mm was measured in two perpendicular directions. The measurements were conducted at five different levels of stress corresponding to loading from 0 to 8 MPa and unloading back to 0 MPa. The flow was measured at different hydraulic gradients in the range of 10 to 25. The results showed a joint transmissivity between 0.002–0.03 mm2/s and a hydraulic aperture of 8–32 μm. It was shown that the measurements performed in the second orientation displayed smaller transmissivity and hydraulic aperture as compared to those in the first orientation, showing a residual compaction after the first load cycle. The Reynolds number was less than one in all the measurements yielding laminar flow conditions. Deviations from the linear regime relationship were observed for the lowest flow rates (Re < 0.1). A transitory regime was observed when varying the hydraulic gradient. This regime was observed to be longer at the lowest flow rates.
Experimental assessment of dynamic loading response of grouted non-persistent jointed rock
Authors: Kumar Sachin , Tiwari Gaurav , Das Arghya 
Published: January 2023

Abstract
Grouting is a well-established engineering practice for stabilizing the jointed and/or fractured rock mass. This process may lead to the enhancement of the mechanical properties of fractured rocks. In the majority of the studies, the efficiency of grouting is determined under static loading conditions. Nonetheless, the grouted rock may be subjected to different dynamic loading from blasts or earthquakes. The present study explored the dynamic loading response, in terms of strength and fracture propagation, of a rock mass having a diagonal non-persistent joint (45° to the loading direction) subjected to impact loading to determine the efficiency of grout material. The focus of the study is to present a comparative assessment of different grout materials under dynamic loading. Split Hopkinson Pressure Bar (SHPB) was used to conduct the compressive impact tests on the synthetic rock mass with varying infill conditions (unfilled, cement-filled and epoxy-filled). The progressive fractures within the specimens were monitored by Photron fastcam analysis (PFA, a high-speed image analysis) and digital image correlation (DIC). The experiments highlighted that the strength of rock mass has an increasing trend with the dynamic strain rate. Epoxy resin provided a better strength enhancement than cement paste as the grout material. Due to the higher strength of epoxy resin than cement paste, the epoxy-grouted jointed rock demonstrates a similar response as the intact rock. In the case of both unfilled and cement-filled specimens, the nature of the primary crack was the coplanar shear crack. In contrast, with the injection of epoxy grout, the nature of the initial crack became the tensile or far-field tensile crack, which is often noticed in intact rocks.
Explicit numerical models for the prediction of plastic and weakening rockmass behaviour around a circular tunnel in isotropic and anisotropic stress conditions
Authors: Fischer C P , Diederichs M S 
Published: January 2023

Abstract
The Geological Strength Index, GSI, is an assessment system for rockmass structure conditions (blockiness and discontinuity condition) based on the visual examination of exposed rockmass surfaces. The Generalized Hoek-Brown failure criterion is widely used with GSI to estimate the strength and stiffness of jointed rockmasses in traditional continuum numerical modelling. Modern numerical analysis tools allow networks of discrete structure to be represented with assigned properties based on site investigation data. In this paper, models with defined explicit structure are shown to yield similar results to implicit GSI-based models and provide more detailed information on the spatial variability of tunnel response when reasonable rockmass input parameters are estimated and calibrated. Once plastic explicit models are calibrated to give similar response to plastic implicit GSI-based models, explicit models using weakening joint and intact rock elements are used to determine appropriate post-yield strength and dilation parameters for use in implicit GSI-based modelling.
Evaluation of surface roughness of rock-like joints using close range photogrammetry method
Authors: Momeni A , Torkan M , Azhari A , Uotinen L , Baghbanan A 
Published: January 2023

Abstract
The surface roughness of the joints affects their hydraulic and mechanical behavior. There are various methods for assessing the surface roughness of discontinuities. With the development of photography technology and the release of powerful software, a photogrammetric analyzer has been introduced as a non-contact surface evaluation method. In this research, a three-dimensional model of the fracture surface was constructed using the close-range photogrammetric procedure and the joint roughness coefficient (JRC) is derived from the surface profiles. Also, the surface profiles were surveyed using the Profilometers (Barton Comb) and the JRC values were obtained using the Z2 method. Calculations were performed in two sampling steps of 0.42 and 1.27 mm. Ultimately, the results of the two methods were compared. A Sony Cybershot HX1 digital camera was used to capture the images. To process the images and build the 3D model, they were loaded in the “Agisoft metashape” software. A point cloud data was obtained with very high accuracy with a distance of 0.13 mm between points in the 3D model. The results show that the JRC values obtained from the photogrammetry method, for the upper surface of the joint, recorded 8% and 11% difference from the joint surface for sampling intervals of 1.27 and 0.42 mm, respectively. While for the bottom surface of the joint, these differences were 6.1% and 10% for sampling intervals of 1.27 and 0.42 mm, respectively.
A New Explanation of loading Rate Effect on Rock Compressive Strength
Authors: Zhu Jun , Deng Jianhui 
Published: January 2023

Abstract
Apart from several qualitative descriptions, such as the delay crack propagation and the difference in energy absorption, the involved mechanism of loading rate effect (rate-dependence) on unconfined compressive strength (UCS) of rock is not clear. According to the statistical analysis of the dominant frequency of acoustic emission (AE) waveforms, this work proposed a new explanation of rate-dependence on rock UCS from a micro failure perspective. The uniaxial compression tests, coupling with AE signals monitoring, of five types of hard rocks under different loading rates were conducted. The rate-dependence on compressive strength of various rocks was investigated comprehensively. By using batch processing and Fast Fourier Transform methods, the dominant frequencies of AE waveforms associated with rock failures were extracted and analyzed to explain the rate-dependence of rock UCS. The results show that, as the loading rates increase, the UCS of most of the rocks increase, while the AE waveforms with low dominant frequency released during the entire loading process significantly decrease. Moreover, the percentage of AE waveforms with low dominant frequency has a negative correlation with the rock UCS. The micro-tensile failures can be characterized by AE waveforms with low dominant frequency and its reduction can be responsible for the increase in the UCS with increasing loading rates. The proposed explanation provides a new and reasonable perspective on the rate-dependence of rock UCS based on its intrinsic property.
Why an indirect estimate of the unjacketed pore modulus may not work
Authors: Tarokh A , Labuz J F 
Published: January 2023

Abstract
The unjacketed pore modulus is a measure of changes in pore volume due to the variation in pore pressure for constant Terzaghi effective pressure. In the oil and gas industry, this parameter is commonly used in linking the undrained bulk modulus of a porous saturated rock to the drained bulk modulus and the properties of the fluid and solid components through Gassmann’s equation. For an ideal porous rock, the unjacketed pore modulus should be identical to the solid bulk modulus of the major mineral constituent. While direct measurements confirm this prediction, previous indirect estimates suggest that this parameter may have values close to the bulk modulus of the fluid rather than the bulk modulus of the grains. These indirect results demonstrate that the estimate of the undrained bulk modulus, due to substitution of different fluids in the rock, can change considerably if the unjacketed pore modulus is equal to the bulk modulus of the fluid. In this paper, we first briefly provide the results of the direct approach and then present laboratory measurements of Skempton’s pore pressure coefficient for a quartz arenite sandstone and use these data to indirectly estimate the unjacketed pore modulus. We show that the difficulties associated with the measurement of the Skempton coefficient clearly contribute to the underestimation from the indirect approach.