bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application potentials and limits of rock reinforcement with polymer-based adhesives
Authors: Wagner S , Boley C , Pratter P 
Published: September 2021

Abstract
Gravitational mass movements, such as rockfalls or landslides, represent geo-risks that require geotechnical safety measures in order to avert monetary damage and to protect human life. For the targeted stabilization and consolidation of rock masses, the gluing of rock which is known from mining and tunnel construction, is ideal. Here, an adhesive is grouted into the rock fissures which, when cured, hold the rock together by means of adhesive and cohesive forces. The selection of the right adhesive is of great importance, as it has a decisive influence on the mechanical properties of the rock and thus determines the success of the securing measure. Various adhesives such as resins and acrylate gel were examined in an extensive experimental laboratory program which was expanded to include numerical simulations with FLAC3D. The subject of the laboratory tests are jointed sandstone samples. The test program of the rock mechanical standard tests was supplemented by special tests, such as adhesive tensile strength tests to determine the adhesion between adhesive and sandstone. In order to assess the effectiveness of the adhesive bond, glued and intact sandstone samples were compared. Based on the experimental and numerical investigations, the application possibilities and limits of different polymer-based adhesives are shown and an application recommendation is given.
Pilot study of the use of augmented reality (AR) in rock mechanics
Authors: Edelbro C , Ylitalo R , Furtney J 
Published: September 2021

Abstract
Augmented Reality (AR) is a relatively new and exciting technology that provides a real-world view with additional computer-generated enhancements. This paper presents the results from a pilot study on how AR can be used in rock mechanics and introduces cases linked to the use of AR in fields relevant for rock mechanics. To capture the need from the industry, a workshop was arranged and complemented with open-ended qualitative interviews. Nearly 60 people responded and identified several items as being important information to enhance the real-world view: underground excavations, geological information, geomechanical model, rock support and reinforcement, results from analysis, and measurements. Almost all respondents wanted to use AR for visualization of weak zones and structures. Using AR as a communication tool and for navigation and safety aspects was also highlighted. However, the vision is to visualize real-time analysis results in the field underground and to be able to do real-time adjustments of the design. Future tunnel inspections were suggested to be more strategic. The most difficult issue to solve at the moment is localization and positioning for underground excavations. The identified low-hanging fruit for near-future studies is, therefore, visualization for rock slopes.
Justification of seismic triggering of large prehistoric rockslides in Zagros (Iran) and Greater Caucasus (Russia)
Authors: Fomenko I K , Nikiforov S P , Shoaei Z , Strom A L , Tarabukin V V , Zerkal O V 
Published: September 2021

Abstract
Justification of seismic triggering of large prehistoric rockslides that originated on the slopes of anticlinal ridges armoured by thick carbonate units has been performed by examples of the gigantic Seimareh rockslide in Zagros (Iran) and two structurally similar, though much smaller rockslides in Dagestan (Greater Caucasus, Russia). Such structural and geomorphic conditions allow precise reconstruction of the pre-slide topography of the studied sites that increases reliability of their back analysis significantly. Linear dimensions of landslides are much larger than thickness of the siding block that makes the simplified 2D numerical modelling of these slopes quite realistic. The pseudostatic analysis performed at the first step confirmed that the study slopes could not fail without strong earthquakes. However, further dynamic analysis performed by use of the Newmark method allowed estimating characteristics of strong motions that could result in formation of rockslides that had converted in long runout rock avalanches. Possible uncertainties and open problems are discussed as well.
Comparative assessment of slope stability in weathered schists using Q-slope and LEM
Authors: Janevski B , Jovanovski M 
Published: September 2021

Abstract
The slope stability in weathered schists formations has always been of great importance for studies in rock mechanics. The majority of the methods used in the geotechnical practise for estimating the slope stability are based on the traditional limit equilibrium methods, analysing the possibilities of circular and non-circular failures. On the other side, very few empirical methods exist for assessment of the slope stability. Q-slope is a relatively new methodology for the assessment of slope stability in terrains built from rock masses. This method was developed over the last decade by Barton and Bar (2015, 2017), with modification of the original Q-system and it is based on the results of more than 500 case studies all over the world in reinforcement-free slopes. This paper presents results of the slope stability assessment with the limit equilibrium and Q-slope method at four characteristic cut sections with unusual general heights (ranging from 30 m to 92 m), along the route of the A2 motorway, section Kicevo-Ohrid in the Republic of N. Macedonia, which is under construction. The subject cuts presented in this paper were excavated in the period 2014 – 2018 without the application of special measures for protection. The research area is built mainly from phyllite, sericite schists, quartz-sericite schists and graphitic schists, which are folded, tectonically disturbed and affected by the process of degradation. According to the results of the analyses, it can be emphasised that both limit equilibrium method and Q-slope are applicable at terrains built from weathered and tectonically disturbed schists because the stability conditions on site were confirmed with these two methodologically different approaches. As a general conclusion, we can summarize that the best way to assess the slope stability condition is when we combine different tools and methodologies, especially when we face highly variable rock mass conditions.
A method to define the priority for maintenance and repair works of Italian motorway tunnels
Authors: Barla M , Barbero M , Baralis M , Insana A , Milan L , Rosso E , Selleri A , Marchiondelli A , Mele P , Tripoli L , Zilli L 
Published: September 2021

Abstract
The construction of motorways in Italy dates back to 1921 and still lasts today. Along them there is a large number of tunnels, many of which have been in service for more than 50 years and have experienced various levels of decay due to aging. An extensive assessment and inspection plan is taking place finalized to highlight situations where maintenance and repair works are needed to guarantee the continuation of service in safe conditions and functionality. Due to the number of tunnels, the need arises to classify them and define priorities for intervention on the basis of a first assessment and of a robust and scientific-based tool to orientate the investments. This paper describes the methodology that was developed by the Authors for this purpose, assessing the attention level of every tunnel. The method relies on a quantitative approach that allows quantifying the risk based on five risk factors composed of a number of relevant parameters. Their relative interaction, which guided the scores assigned to each parameter, was assessed by applying the Rock Engineering System [2]. A number of examples of existing tunnels are shown to illustrate the application of the method and to draw conclusions about its validity and reliability.
The role of block shape and slenderness in the preliminary estimation of rockfall propagation
Authors: Torsello G , Vallero G , Castelli M 
Published: September 2021

Abstract
Among the wide range of variables that influence the falling process of blocks during a rockfall event, the shape of the block often plays a crucial role. Spherical-like blocks typically reach longer runout distances while elongated and plate volumes stop earlier. Nevertheless, with reference to runout modelling and hazard analyses, the shape of the block was disregarded for very long time until the last two decades when more rigorous rockfall models were developed. Nowadays fully 3D rigid body models and particle-based ones can take into account different and complex aspects related to block geometry and size (e.g. shape, change of shape, slenderness, fragmentation, etc.) when in site-specific applications are addressed. On the other hand, when the rockfall analysis is extended over large areas, simplified runout models can be used for preliminary, quick analyses, aimed at highlighting the most critical zones of the area. In this case, the variables that influence the rockfall process should be included in the analysis in equivalent terms. Among these simplified models, the Cone Method allows to reduce the runout phase to an equivalent sliding motion of the block along an inclined plane. The inclination of this plane with respect to the horizontal plane (i.e. the energy angle Øp
) can be related to both block and slope properties of the real rockfall case. The authors of this paper developed a methodology for the estimation of the energy angle as a function of the condition of the site under analysis (characteristics of the blocks and the slope), to be used for preliminary forecasting analyses at medium-small scales. To this aim, a series of parametric analyses have been carried out to quantify the role of each variable on the energy angle. In this paper, the role of block shape and slenderness (i.e. the ratio between the height and the width of the rock block) is analysed via several propagation analyses carried out on simplified synthetic slopes by using the fully 3D RAMMS::ROCKFALL model. The results were finally statistically treated in terms of energy angles in order to take into account the variability of rockfall trajectories and provide a contribution for the estimation of the parameters within preliminary analyses based on the Cone Method.
Assessment on the 2014 Jure Landslide in Nepal – a disaster of extreme tragedy
Authors: Panthi K. K. 
Published: September 2021

Abstract
The landslides kill many people every year in Nepal and in the Himalayan region, which devastates society in the local area. A famous living memory of an example of landslide induced devastation was the landslide at Tinau river that took place in early September 1981 damming the river completely, which breached after few days causing huge flood downstream. The flood swept away concrete tower of the Tinau Hydropower Project, two suspension bridges, one concrete bridge at Butwal, part of Butwal city was completely damaged and many hundred people lost their life. Similarly, on the night of 2nd August 2014 (02:30 AM), a huge landslide, famously known as “Jure Slide”, took place along Sunkoshi River valley on Araniko Highway that connects Kathmandu with Tibet. The landslide killed 156 people who were on sleep in their houses, savaged 120 houses, partially damaged 37 more, dammed Sunkoshi river creating an artificial dam of approximately 50 m high and an approximately 3 km long reservoir was formed. A huge flood occurred after partial breach of the dam damaging barrage structures of the Sunkoshi Hydropower Project located about one kilometre downstream from the slide area. It took over two months to drain artificially created reservoir. The main aim of this manuscript is to describe and evaluate Jure landslide. Critical aspects on the causes of landslide will be highlighted giving emphasis on topography, geology, rock mass, monsoon, and earthquake.
Determination of the Biot coefficient of limestones from Perm Krai, Russia
Authors: Kukhtinskiy A E , Shustov D V , Efimov A A , Kashnikov Yu A , Ashikhmin S G 
Published: September 2021

Abstract
The study presents results of Biot coefficient determination for limestones from Perm krai, Russia. To the date there is no standard method to determine the poroelastic parameters. That’s why different researchers use different approaches to perform these tests. In this research an attempt was made to compare how some aspects of Biot coefficient determination influence its values. The tests were performed on a triaxial test system PIK-UIDK/PL where deformations are measured by LVDT sensors. The Biot coefficient was calculated using two different equations. The results from three types of tests were used for these calculations. These tests are: 1) test when both confining and pore pressures are changed for the same values (similar to what is called unjacketed test), 2) drained test (confined pressure is changed while pore pressure is maintained at a constant value, 3) pore pressure change (while confining pressure is maintained at a constant value). The variation of the calculated Biot coefficient values in relation to the amplitude of pressure variation in each test was analyzed. The tests for each sample were performed with small pressure steps in the beginning and then the tests were repeated with increased maximum amplitude and larger pressure steps. The results show significant nonlinearity in the deformation of samples with larger pressure amplitude. This results in significantly higher Biot coefficient values when the full load cycle is used for calculation. The obtained Biot coefficient values were then correlated with the P-wave velocity determined for these samples in the reservoir conditions on the test system in the beginning of each test.
Consideration of the mechanical damage behavior of rock salt during calculation of infiltration-cracks in the edge zone of gas storage caverns
Authors: Yildirim S 
Published: September 2021

Abstract
Underground storage in salt caverns is a preferred method for the intermediate storage of natural gas to cover seasonal fluctuation in consumption and commercial gas storage. The prove of the stability and tightness of the storage required for safe operation is continuously adapted to the current state of the art. For many years, an intensive scientific investigation has been carried out within the frame-work of repository research with continuous optimization of the rock mechanical modelling of the material behavior of rock salt. From the elaboration of the research results on the pressure-driven infiltration processes into the primarily non-permeable salt rock, it emerges that during gas storage operation, in addition to the areal infiltration, the formation of macroscopic infiltration-cracks in the cavern surrounding salt rock is to be expected as well. This thesis deals with the computational simulation of macroscopic infiltration-cracks within the scope of theoretical modelling of salt cavern behavior during gas storage, taking into account additional mechanical damage processes in the rock salt. On the basis of variational calculus, the infiltration fracture propagation will be evaluated, considering different model approaches in material behavior of the cavern surrounding rock salt mass. As a result of the present work, it should be noted that with regard to the propagation of infiltration-cracks in gas caverns, constitutive model approaches for the description of the mechanical damage and healing behavior of rock salt can be neglected for a conservative assessment.
Multiple radial fractures connecting horizontal boreholes – a lab study on the feasibility of the multifrac concept for geothermal heat extraction from deep reservoirs with low permeability
Authors: Stoeckhert F , Solibida C , Witte L , Alber M 
Published: September 2021

Abstract
We conducted a number of experiments on cubic rock specimens with low matrix permeability to create and investigate multifrac systems for geothermal heat production on laboratory scale. Special focus was set on phenomena impeding the parallel propagation of multiple fractures like stress shadow and redistribution effects, rock heterogeneity and discontinuities. We subjected the specimens to a true-triaxial stress state using servo-controlled hydraulic pistons for external loading. High viscosity fluids were injected into parallel boreholes at controlled volume rates with metering pumps. Pressure transducers were connected to all boreholes to register injection pressure and pressure responses in neighbouring boreholes. We also recorded acoustic emissions during the experiment for spatial and temporal monitoring of fracture growth processes and the interaction between propagating fractures. After the creation of the hydraulic fractures, the hydraulic connection between the boreholes was tested by fluid circulation. As inferred from acoustic monitoring, radial fractures were propagated stable and technically controllable. Hydraulic connection between the boreholes was established and verified by hydraulic circulation.
Additional insights to EC7 from the application of reliability-based design methods: the case of debris flow protection structures
Authors: Vagnon F , Ferrero AM , Alejano L 
Published: September 2021

Abstract
Debris flows are dangerous natural processes that cause extensive damages to infrastructures and urbanized areas and can lead to loss of human lives. Their unpredictability, their extremely high motion and their magnitude are the main causes of these harms. Mitigation measures are fundamental for reducing the associated risk and protecting infrastructures in mountainous areas. Their design is still an open issue: there are many formulations to evaluating impact pressure. Moreover, the uncertainties in the determination of flow characteristics (velocity and thickness) are significantly high and difficult to quantify. In the European Union, the design of any type of structures involved in rock mechanics field must comply with EN-1997 Geotechnical Design (CEN 2004) (EC7). For debris flow countermeasures, EC7 requirements are very difficult to apply in practice since partial safety factors are not provided for these phenomena. However, the basic philosophy of reliability-based design (RBD), as defined in EN1990 (CEN 2002) may be a suitable and complementary approach to provide geotechnical structures with a uniform probability of failure. Reliability Based Design (RBD) can provide additional insights to EC7 design and can be applied when partial factors have still to be proposed (by EC7) to cover uncertainties of less common parameters, as in case of debris flow countermeasures. This paper presents an analysis of the advantages and limitations on the applicability of RBD approach to debris flow countermeasures, by using the first-order reliability method (FORM). In particular, data availability, the possibilities for analysing data in a statistical framework and the choice of performance function are the main limitation of the method, which force to make assumptions regarding statistical distribution of the considered parameters. A sensitivity analyses, comparing different equations, commonly used for debris flow impact pressure estimation, were performed for quantifying the effect of the selected performance function on the RBD results.
Sliding stability analyses of a rock slope using deterministic, semi-probabilistic and probabilistic methods
Authors: Pereira R , Lamas L , Muralha J 
Published: September 2021

Abstract
Stability analyses of geotechnical structures in rock are traditionally performed using deterministic methods. In Europe, Eurocode7, introduced in the beginning of the 21st century, adopts limit state design and semi-probabilistic methods, using partial factors for the design of geotechnical structures. Meanwhile, reliability-based design, using probabilistic methods, is becoming more common in practical cases. The paper considers an intentionally simple case study—the analysis of a slope in a rock mass with one discontinuity, considered in a discrete way, forming a rock block to be stabilised by anchors—to compare the results obtained with the different methods. The objective is to calculate the force applied by the anchors so that the ultimate limit states of sliding of the rock block is verified. Deterministic-based design optimization considering both the traditional global safety factor approach and the partial factor approach following the Eurocode 7 are first applied. A reliability-based design optimization procedure—which takes geometrical and mechanical properties of the discontinuities as random variables—is then used, and the results are compared to the former ones. A discussion is presented concerning the consistency of the obtained results.
Performance evaluation and monitoring of the tunnel excavation with a Mobile Tunnel Borer
Authors: Di Giulio A , Sebastiani D , Cinelli M , Ginanneschi R , Zanetto G , Antonelli A , Leone C 
Published: September 2021

Abstract
The use of Tunnel Boring Machines (TBM) for tunnel excavation is widespread around the world for its capabilities and great advantages against the traditional tunnel excavation method, but sometimes this technology can be difficult to manage, requiring huge spaces for the assembly on the job site and involving complex installations at the tail of the machine.
Aiming at creating a versatile and compact tunnel borer, TunnelPro and Master Drilling designed the MTB (Mobile Tunnel Borer) that is built on crawlers, easy and fast to assembly with no need of special equipment. This prototype MTB is currently excavating a Platinum mine in South Africa, being tested in very hard rocks.
The study here presented, carried out by GEEG srl, startup of Sapienza University of Rome, compares the actual values of thrust, torque, penetration and cutter wear recorded during the trial excavation monitoring with those estimated with models commonly used in TBM performance prediction. The aims of this study, still ongoing, are a better comprehension of the MTB operation in terms of efficiency, work of the excavation tools, load distribution, and the evaluation of the adequacy of the most known methods when applied to this prototype machine.
Rock slope stability analysis adopting Eurocode 7, a limit state design approach for an open pit
Authors: Mathe L , Ferentinou M 
Published: September 2021

Abstract
In this paper we compare the partial factors approach of Eurocode 7 with a traditional deterministic limit equilibrium analysis approach and probabilistic approach. The example case is a simplistic model profile of an open pit mine cut slope configuration. The controlling parameters in a structurally dictated failure mechanism were introduced as random variables in the model, to account for the different types of uncertainties arising in rock engineering data. The limit equilibrium method was used in this study to conduct rock slope stability analysis, while the impact of naturally uncertain and variable parameters, among others water pressure and earthquake activities were considered. Different scenarios from the best to the worst-case were analysed and later compared. The sensitivity analysis revealed the importance of the joint failure plane, joint roughness coefficient and joint friction angle and how the actions (groundwater pressure and earthquake action) affect the slope’s stability. These results emphasize some advantages of the approach, and the potential further embracement from the rock engineering fraternity.