bluuebunny/crossref_metadata_2025_split huggingface dataset:
Utilizing Coseismic Strain in the Modelling of Tunnel Loading in Deep Burst-Prone Mines
Authors: Malovichko D. A. , Rigby A. , Kaiser P. K. 
Published: August 2024

ABSTRACT:
Seismic monitoring data acquired at mines can be used to infer the characteristics of coseismic strain, including amount, orientation of principal directions and type (deviatoric, volumetric explosive or implosive). This strain corresponds to plastic strain increment if seismic events represent episodes of sudden deformation in confined environment. If sources of seismic events involve the convergence of excavations, then coseismic strain depends on the amount of the convergence. These peculiarities of coseismic strain are taken into account in the proposed method for its direct incorporation into a numerical stress model. The method is verified using analytical cases of confined inelastic deformation as well as brittle failure around a tunnel. The method can be used to assess the redistribution of stresses and change in the loading of tunnels in seismically active mines. A synthetic mining example is presented to illustrate the impact on tunnel stress.

1 INTRODUCTION
Seismic systems installed at mines record seismic waves radiated by episodes of sudden (i.e., durations on the order of fractions of a second) deformation within the rockmass. The analysis of these recorded waves make it possible to assess the time, location, amount and intensity of deformation, as well as its geometrical characteristics (e.g., direction of principal strains, proportion of volumetric and deviatoric shape change). This information is highly valuable for understanding the overall rockmass deformation induced by mining and the associated redistribution of stresses. It is quite logical that the characteristics of rockmass deformation inferred from seismic data are often utilized when performing numerical stress modelling. There are fundamentally two ways to do this.
Firstly, seismic data can help to improve the input parameters of the stress models. This is often done through qualitative or quantitative comparing of various aspects of seismic data (e.g., location of sources) with the corresponding modelling parameters (e.g., areas of high deviatoric stress) – see, for example, the works of Lachenicht (2001);
Beck and Brady (2002); Beck et al. (2006); Spottiswoode et al. (2008); O'Connor et al. (2010); Arndt et al. (2013); Kalenchuk (2022); Malovichko and Rigby (2024). The improved (calibrated) stress model is expected to deliver more realistic distribution of stresses for the current mining step and should provide better prediction of the stress redistribution for the future planned mining steps.
A Microscale Analysis of Millimeter-Wave Induced Vitrified Basalt for Use in Enhanced Geothermal Energy Systems
Authors: Meltzer E. R. , Stefaniuk D. , Einstein H. H. 
Published: August 2024

ABSTRACT:
Extraction of the energy available from geothermal heating in the Earth could provide substantial contributions to energy needs long-term. However, there are major technical limitations with the current geothermal drilling process. A new technology in the field of EGS that uses a millimeter (mm) wave gyrotron, which allows for quicker, more efficient drilling could be a potential way to overcome these limitations. The mm-wave drilling process, a technique developed by Dr. Paul Woskov of the MIT Plasma Lab, has two significant advantages as compared to traditional drilling: 1. The well hole advance is through melting of the rock, which is faster than mechanical drilling. 2. The molten rock then solidifies, creating a vitrified wall support without the need for extra casings. This drilling and casing process can potentially save money, time, and material. The study presented in this paper is aimed at understanding the strength and microscale mechanical and chemical properties of the vitrified material to see what is happening to the rock, specifically Basalt, pre- and post-melting by using a series of experimental and analytical tools.

1. INTRODUCTION
With global energy consumption on a continual upward slope, there is a growing need for a clean and renewable energy solution. At present, in the United States, geothermal energy constitutes merely 2% of the total renewable energy usage. However, both in the U.S. and globally, the utilization of geothermal energy has been steadily increasing. Tapping into the Earth's heat potential holds the promise of significantly reducing CO2 emissions and making substantial contributions to meet the escalating energy demand worldwide. Nevertheless, significant limitations currently impede the feasibility of this approach in the United States, creating the necessity of alternative methods. Thanks to researchers at the MIT plasma lab, a novel approach was introduced: the utilization of a millimeter – wave (MMW) gyrotron. This technology potentially allows one to drill wells by employing MMW heating, leading to the melting and vaporization of basement rock at extremely high temperatures. The rapid heating and subsequent cooling of the rock result in the formation of a glass-like substance, making it possible for this vitrified material to serve as a wellbore casing for geothermal injection and production wells.
Experimental Study of Underground Heat Storage via Hydraulic Fractures
Authors: Möri A. , Naftalski J. , Liardon T. , Talebkeikhah M. , Lecampion B. , Lu G. , Burghardt J. 
Published: August 2024

ABSTRACT:
We present a laboratory setup to test the energy budget of underground heat storage in an otherwise impermeable rock through engineered fractures, a so-called Fracture Thermal Energy Storage (FTES) system. A hydraulic fracture is first created in a cubic specimen of Zimbabwe Gabbro. In the experiment, de-ionized water is circulated under high pressure through an injection steel tubing automatically heated to a target temperature. The fluid adjusts to the tubing temperature during its flow before entering a production well drilled into the 250 mm edge length block. The warm fluid then circulates through the previously created hydraulic fracture at mid-height of the block toward a production well drilled at the block periphery. The production well is equipped with a dedicated completion to allow fluid outflow. External fracture appearances are sealed using an epoxy resin. We demonstrated through the results of a preliminary heating experiment that we can transfer nearly all of the heat from the circulating fluid to the block. An efficient charging of the thermal battery is achieved. This first experiment is currently under further improvement and will ultimately help to better understand the engineering of mid- to large-scale field implementation of FTES systems.

1 INTRODUCTION
Storing excess heat produced during summer or as a byproduct of industrial treatments is of widespread interest in the context of the energy transition. Typically, the peaks in energy production are not aligned with peak consumption. This mismatch is notably observed for inter-seasonal differences in demand and production. Underground thermal energy storage (UTES) systems could provide an efficient mechanism to overcome these limitations. Several types of UTES systems are being used as of today. The most used systems, not including any phase change of the temperature carrier, as of today are Aquifer Thermal Energy Storages (ATES) (Bloemendal et al., 2015). Other systems include the use of a series of boreholes (Borehole Thermal Energy Storage - BTES) or underground caverns (Cavern Thermal Energy Storage - CTES). All of these systems have regulatory, economic, and geological advantages and disadvantages.
“SINTEF-TriPOD” in Underground Design – A Demonstration for Two Projects in Norway
Authors: Trinh N. , Grøv E. 
Published: August 2024

ABSTRACT:
Many rock engineering projects today may face rock mechanics challenges such as (a) particularly complicated profile or excavation plan, (b) located near to existing infrastructure and thus pose a high risk to such structures, and (c) complicated geological conditions. In such situations, there may be no similar existing experience to lean on. Empirical methods have limitations and uncertainties in such cases. Therefore, SINTEF has developed a rock engineering tool to deal with the challenges. The tool is a combination of Investigation, Numerical modelling, and Monitoring. We use the term "SINTEF-TriPOD" for the methodology, and through projects it has proved to be a reliable tool. This paper presents the application of the SINTEF-TriPOD for two important infrastructure projects in Oslo, Norway, which are Follo Line metro project (4 billion USD) and a fresh water supply project (approximately 1.2 billion USD).

1. INTRODUCTION
Many rock engineering projects today may face rock mechanics challenges such as (a) particularly complicated profile or excavation plan, (b) located near to and thus cause a high risk to existing structures, and (c) complicated geological conditions. In such situations, there may be no similar existing experience to lean on. Empirical methods have limitations and uncertainties in such cases. Therefore, SINTEF has developed a reliable rock engineering tool to deal with the challenges. The tool is a combination of Investigation, Numerical modelling, and Monitoring:
• Investigation: The investigation can be rock stress measurements before and during construction (hydraulic fracturing from rock surface, 2D and 3D over-coring), different geological surveys, drill holes, and geological engineering mappings to evaluate the rock mass quality. Obtained information is used for the second component of the "SINTEF-TriPOD" – numerical model.
• Numerical model: Establish a comprehensive numerical model, normally 3D numerical model is preferred as such model can handle complicated geometry and construction plans and methods. Simulations are to be carried out in certain order with clear objectives for each simulation steps. This is done to follow the planning and construction closely, helping the project team in making correct decisions.
• Monitoring: To improve the numerical model even further, stress and displacement are monitored continuously, and comparing them to the values from the numerical model. The model is calibrated, verified, and improved with the observations made in the surveillance program. This gives project team a reliable tool to help for decision making during implementation of the project.
Progressive Excavation Disturbance Zone Evolution During and Post Mine-By Tunneling (PRECODE) – Insight into a New Underground Research Laboratory for Crystalline Rocks in the BedrettoLab
Authors: Hamdi P. , Achtziger P. , Dickmann J. , Kruszewski M. , Rinaldi A. P. , Villiger L. , Shakas A. , Perras M. , Bahrani N. , Jiang D. , Amann F. , Wiemer S. 
Published: August 2024

ABSTRACT:
Development of brittle damage around tunnels is quite common in massive rocks under highly-stressed conditions. Understanding the shape and extent of the Excavation Damage Zone (EDZ) is important, particularly for deep geological repositories (DGRs) for nuclear waste. Within the EDZ, permeability is often increased, and in the context of nuclear waste disposal, this increased permeability may create preferred pathways for the migration of radionuclides. Therefore, a comprehensive assessment of brittle fracture formation in space and time requires multidisciplinary monitoring systems. A new Underground Research Laboratory (URL) in Southern Switzerland in the old Bedretto Gallery is under construction for the purpose of studying the evolution of the Excavation Damage Zone (EDZ) in crystalline rocks. The new experimental tunnel will form a new branch from the existing Bedretto tunnel which will be densely instrumented prior to the excavation with various sensors. The main objectives of the PRECODE experiment are to understand: (1) short-term rock mass behavior and EDZ formation during tunneling; (2) long-term fracture propagation within the EDZ associated with environmental conditions (fluctuations in humidity and temperature); (3) permeability evolution around an open excavation and (4) the impact of tunneling on potential dislocations of nearby fault zones. In-situ data and a series of comprehensive laboratory tests form a hydro-seismo-mechanically coupled reference data set for numerical simulations with the aim to further improve predictive models. This paper outlines an overview of the project objectives, details of the planned monitoring systems, and some preliminary results obtained from a baseline study.

1. INTRODUCTION
Development of brittle fracturing around tunnels in massive and highly stressed rocks is quite common. In crystalline rocks (i.e. granite), the brittle fracturing is depicted through spalling and in a severe case rock bursting (Diederichs, 2007). The fracture initiation and propagation often start during the tunneling process and develop over time. These progressive failures may lead to an interconnected fracture network typically associated with the radiation of micro-seismic signals. Within the excavation damage zone (EDZ), the permeability is often enhanced and – in the framework of nuclear waste disposal – may provide preferential pathways for radionuclide migration.
Characterization of Direction-Dependent Properties of Sierra White Granite: Initial Results
Authors: Kafle L. , Mok U. , Einstein H. H. , Villamor-Lora R. , Germaine J. 
Published: August 2024

ABSTRACT:
Most granites have preferred directions ("rift", "grain", and "hardway") that affect the ease with which the rock can be split. In this study, we present a series of uniaxial and triaxial tests on the directional-dependent properties of Sierra White Granite, a rock that has been chosen as a laboratory analog for the FORGE site granitoid. We performed triaxial tests on 1.5" by 3.5" cylindrical cores involving a test program including isotropic compression, cyclic loading, and triaxial compression in three preferred directions under low to high confining pressure. In these tests, we measured stress, displacement, axial and circumferential strain, and P-wave velocity. We found no significant degree of direction dependency in the deformation (stiffness) and strength parameters. On the other hand, the P-wave velocity results show the largest velocity along (equation) (direction perpendicular to plane C) then (equation) and (equation). More tests are needed to accurately quantify the direction-dependent behavior of the given test material.

1. INTRODUCTION
The direction dependence (anisotropy) of granite is often reported in the literature, both in relation to practical engineering and scientific aspects. With respect to practical engineering, the best known are the orthogonally oriented so-called "quarry planes" rift, grain, and hardway, indicating the ease of splitting or cleavage in this sequence (i.e., rift the easiest, and hardway the hardest). In quarrying, this direction dependence is often used to split the rock by a hammer blow in the rift direction.
From the geotechnical viewpoint, one wants to know what causes the direction dependence, if it affects other small- and larger-scale properties, and what these effects are. Moreover, understanding the material reaction to external influences such as stress, temperature, electrical currents, and chemical agents, is also important to better design geotechnical structures. Most researchers agree that the mechanical properties along the rift orientation depend on the orientation of microcracks and fluid intrusions – which in turn are affected by the direction dependence of quartz (see e.g. Douglass & Voight, 1969; Osborne, 1935). The reasons behind the other two directional dependencies are less clear, but most likely involve the effects of foliation, large-scale stress, and/or temperature changes (Osborne, 1935). It should be noted, however, that some granite samples used in laboratory experiments do not show preferred directions (Chen et al., 1999).
The Two-Phase Flow of Oil-Gas Multiple Rounds Injection-Production in the Reconstructed of Gas Storage with Oil-Ring Condensate Gas Reservoir
Authors: Liu Qi , Yao Yuedong , Wang Lian 
Published: August 2024

ABSTRACT:
There will be multiple rounds of oil and gas mutual displacement during the operation of the condensate gas reservoir with oil-ring. Up to now, the experimental research on the characteristics of two-phase flow in the industry mainly focuses on gas-water or oil-water mutual displacement. While, the construction and operation of gas storage reservoirs in condensate reservoirs with oil-rings will appear the phenomenon of two-phase flow of oil and gas, the indoor physical simulation method has been used to carry out the two-phase flow characteristics experiments of the actual reservoirs relative to the relatively high, medium, and low penetration cores of each of the eight times of the two-phase seepage characteristics of the mutual displacement of oil and gas. Studies the flow of oil-gas in two phases during the operation of gas storage, analyzes the influence of multiple rounds of oil-gas mutual displacement on the storage capacity of gas storage, grasps the changes of oil-gas flow under different permeability conditions, and optimizes the optimal reservoir suitable for the construction of gas storage.

1. INTRODUCTION
As an important means of developing clean energy, underground gas storage has the characteristics of large capacity and low cost(Yuan et al, 2020). Generally speaking, there are two purposes for the construction of underground gas storage: one is to meet the gas demand and seasonal peak shaving needs of nearby urban residents, and the other is to serve as a strategic resource reserve. The construction and operation of gas storage has been relatively mature abroad, but it is still in the development stage in China(Ding, et al, 2020). For the construction of gas storage, foreign theories cannot be copied, and the construction of gas storages must be carried out based on my country's national conditions and local conditions (Zhang 2018, Yin 2013). During the operation of gas storage, it has the characteristics of alternating strong injection and extraction of gas, high-speed seepage of single well, large flow huff and puff fluid, etc. In order to ensure the normal operation of gas storage after built, it is necessary to study the relative permeability of gas storage fluid.
At present, a large number of scholars have carried out indoor physical model experiments on the two-phase flow rules of gas-water mutual flooding in different types of gas storage, and there are few studies on the relative permeability of oil-gas mutual flooding in gas storage.
Unveiling the Invisible: Mapping Basement Faults Using Microseismic Clouds
Authors: Wang Chaoyi , Sherman Christopher S. , Kroll Kayla W. , Glubokovskikh Stanislav , Alumbaugh David , Morris Joseph P. 
Published: August 2024

ABSTRACT:
The Illinois Basin Decatur Project (IBDP) has piloted the process of large-scale injection of CO2 into a deep saline reservoir. During the project, microseismic clouds were observed from locations that were not identified in any previous geological database. Based on the injection depth, it is surmised that the pressure plume reached previously unidentified basement faults, altered their stress conditions, and triggered microseismic events. Understanding the presence and behavior of basement faults is critical for monitoring and managing induced seismic risks. However, basement faults with near-vertical dips can be challenging to detect using conventional seismic imaging methods due to poor incident angles. In this study, sponsored by the U.S. Department of Energy's SMART initiative, we developed a machine learning workflow using Long Short Term Memory (LSTM) recurrent neural network (RNN) architecture that maps basement faults using microseismic clouds. The LSTM-RNN is trained on synthetic microseismic catalogs produced by physics-based geomechanics models that simulate fluid injection into a reservoir above a faulted basement. Microseismic catalogs are passed to the LSTM-RNN to predict the location of the basement faults and shear stress state. The network aims to take real-time microseismic data and progressively produce an updated fault map. Our approach shows the potential of ML-based methods for mapping previously invisible basement faults, providing information to enable rapid decision-making during CO2 injection to prevent and mitigate induced seismic risks. However, there is still much room for improvement in the accuracy of the machine learning model, which we are actively working on.
LLNL Release Number: LLNL-CONF-860823

1 INTRODUCTION
Carbon sequestration is a process that involves capturing CO2 emissions from various sources such as industrial plants and power generation facilities, and storing the captured CO2 in subsurface reservoirs to help mitigate the buildup of greenhouse gases in the atmosphere (Halmann and Steinberg (1998); Pires et al. (2011); Herzog et al. (2000)). As nations and industries strive to reduce their carbon footprints and limit global warming, large-scale carbon sequestration has emerged as a significant, potential contributor toward meeting ambitious net-zero targets (Budinis et al. (2018); Meys et al. (2021)).
Development of a Photogrammetric Rockfall Database and Analysis of Trends at a Rock Slope Along I-70W, West of Idaho Springs, CO
Authors: Hollander J. A. , Walton G. , Kromer R. 
Published: August 2024

ABSTRACT:
Rockfall along roads can cause significant hazards to human health and infrastructure or interrupt transportation. A section of rock slope on Interstate 70 west, west of Idaho Springs, has been monitored at a daily frequency since March 2018 using a 5-camera photogrammetric system that collects high-definition photos to establish the rockfall MCF trends. An established semi-automated workflow was utilized to produce raw 3D point clouds and locate areas of potential rockfall using change detection. The high frequency of monitoring at this site allows for precise determination of timing and volume of rockfalls and creation of a high temporal resolution database. This database can then be leveraged to analyze trends in rockfall volume and frequency on an annual or seasonal basis. We provide an overview of the workflow applied for database development as well as preliminary results regarding interpretations of variations in rockfall activity.

1. INTRODUCTION
According to the US Census Bureau (2023) the US population has expanded from 151 million in 1950 to 331 million in 2020. This growth in population has led to an increased demand for previously undeveloped land, including in relatively hazardous mountainous regions (Thornton et al., 2022). Mountainous regions are prone to rockfall and other geohazards that can have serious repercussions on human infrastructure and health (Abellán et al., 2010; Copons and Vilaplana, 2008; Dussauge et al., 2002). The Colorado Department of Transportation (CDOT) is particularly interested in understanding rockfall trends along critical transportation routes in the mountains.
Rockfall can be described as a type of mass wasting event where an individual rock or multiple rock fragments detach from a slope and travel downhill (Cruden and Varnes, 1996; Varnes, 1978). Rockfall generally occurs when blocks detach along existing discontinuities or by sliding and toppling (Hungr et al., 2014). Rockfall can be further subdivided into two categories: primary and secondary. Primary falls occur when a block detaches from the host bedrock, and secondary falls occur when previously detached blocks are moved further downslope (Luckman, 2013).
A commonly investigated aspect of rockfall is the mechanism of its triggering and any seasonal trends a site might exhibit. Numerous studies have shown rockfall frequency to follow seasonal trends, likely controlled by weather conditions (Delonca et al., 2014; Matsuoka and Sakai, 1999). The importance of certain conditioning and triggering mechanisms that might be more prevalent in certain seasons can greatly influence these relationships (Krautblatter and Dikau, 2007).