bluuebunny/crossref_metadata_2025_split huggingface dataset:
Engineering Geological Hazards Along Doroud-KhorramAbad Railway Rock NATM Tunnels
Authors: Azali Sadegh Tarigh , Samadi Hanan , Hassanpour Jafar , Rostami Jamal , Hamidishad Mohammad Hossein 
Published: August 2024

Abstract
The characterization of geological hazards holds significant importance in the context of underground spaces, specifically in tunnelling projects. This importance stems from its crucial role in determining the tunnel route, excavation techniques, and adopted risk management technologies. Tunnelling projects frequently encounter various engineering geological hazards, including issues related to ground conditions, groundwater levels, and in-situ stress regimes. Challenges such as encountering fault and crushed zones, mixed face formations, geological and structural instabilities such as wedge-failures and plan-failures, squeezing phenomena, karst formations, water inrush in the tunnel, hard and abrasive rock, landslides, and convergence are considered as primary causes of geotechnical risks in hard rock tunnelling. The primary objective of this study is to identify potential engineering geological hazards along the Doroud-KhorramAbad railway tunnels in Iran. The project spans 121 km, with 30 km comprising tunnels (13 tunnels) that have been excavated using the new Austrian tunnelling method (NATM). Detailed descriptions are provided regarding geotechnical considerations specific to tunneling. Based on the results of laboratory and field investigations, it has been determined that encountering crushed zone, structural instabilities and collapse as well as water inrush and rock fall, are the most significant hazards in this project.

Introduction
Railway tunnels used for underground transportation purposes have been widely constructed in recent years. Despite facing challenging geological conditions during construction, there remains a pressing need to effectively manage construction risks in complex and variable geological environments (Ren et al. 2016, Iegupov et al. 2018). Both highways and railways are recognized as efficient modes of transportation that play a crucial role in supporting the economic advancement of Iran. Consequently, the construction of tunnels has experienced a surge, positioning Iran as a country with the highest number of mountain tunnels.
Experimental Study on Interaction Behavior Between Caves and Fractures in Fractured-Vuggy Carbonate Rock
Authors: Zheng Zhenquan , Hou Bing , Zhao Zhiqiang 
Published: August 2024

ABSTRACT:
Deep fractured-vuggy carbonate rock oil reservoir storage spaces are complex, and natural reservoir structures develop randomly. The natural fractures and caves are the primary oil-containing zones within carbonate rock reservoirs. Conventional acid fracturing methods often encounter challenges in effectively communicating with these natural caves. Therefore, in order to reveal the interaction dynamics between acid fracturing and these caves, clarify the dominant factors affecting communication between natural caves and acid fractures, and improve the effect of acid fracturing, this study involves the preparation of 70mm×70mm×5mm thin rock plate samples from carbonate rock outcrops. Subsequently, indoor true triaxial acid fracturing experiments are conducted. For a model specimen of fractured-vuggy carbonate rock, the results show that: (1) Under the condition of the same in-situ stress field and fracturing construction conditions, the acid fluid will erode the nearby holes and disturb the large-scale holes at close range after the acid fracturing fractures connect the small-scale holes; (2) Under the conditions of the same hole structure and fracturing construction conditions, the expansion process of acid fracture is mainly influenced by the stress difference factor; (3) In high stress difference conditions, the expansion path of acid fractures in fractured-vuggy carbonate reservoirs becomes more complex, and it is highly likely to activate nearby natural fractures in the vicinity of the hole group, leading to the formation of a short and dense fractured-vuggy network structure.

1. INTRODUCTION
Acid fracturing is one of the most commonly used methods for reservoir modification in carbonate reservoirs[1,2], and the complex distribution of hole clusters and highly developed natural fractures are the most representative geological qualities of carbonate reservoirs[3-5], which not only affect the expansion path of acid fracture, but also lead to changes in the geostress near the body of the holes[6-9], so that the connectivity effect of the hole clusters often determines the oil and gas recovery rate[10-13]. In this paper, we adopt a visualized experimental method for real-time observation of acid fracture initiation and extension[14-15].
SOSAT: Geohazard Risk Assessment in Carbon Sequestration Operations
Authors: Haagenson R. , Burghardt J. , Wang W. , Saxena S. , Appriou D. 
Published: August 2024

ABSTRACT:
Like all operations in which fluids are injected into the subsurface, geologic carbon storage (GCS) presents inherit risks that must be assessed and mitigated to successfully deploy such technology in the field. For example, alterations to pore pressure and the stress state due to fluid injection may trigger certain geohazards, such as potential fault activation and induced seismicity or unintentional hydraulic fracturing. Here we present capabilities for assessing these potential risks using the State of Stress Analysis Tool (SOSAT): a Python library and web-based application capable of probabilistically estimating the subsurface state of stress informed by various field observations. Using posterior distributions of principal stress components, SOSAT can assess the risk of fault activation within the injection formation for either a critically oriented fault or a fault with a user-prescribed orientation. Additionally, SOSAT can estimate the probability of unintentional hydraulic fracturing of the intact reservoir rock. Here, we demonstrate these SOSAT capabilities using a hypothetical GCS site. This type of risk assessment can assist with the effective deployment of GCS technology in the field by informing safe design and management practices.

1. INTRODUCTION
One potential approach to lowering carbon emissions is to capture produced carbon at the source and inject it into a safe, subsurface storage site for permanent sequestration (Alivisatos & Buchanan, 2010; Fahs et al., 2023; IPCC, 2005). This process, called geologic carbon sequestration (GCS), has been a prevalent topic of recent research, from reservoir simulation studies (Tang et al., 2022; Lyu & Voskov, 2023) to field testing (Pawar et al., 2006). Numerous GCS projects are currently operational, with many more in the planning stages (Greenberg, 2021). Successful deployment of GCS, though, relies on the appropriate assessment of the associated geomechanical risk.
As with any subsurface operation, GCS contains certain risks that must be carefully considered and mitigated to safely deploy the technology in the field. For example, geohazards – such a fault activation and induced seismicity or unintentional hydraulic fracturing potentially leading to upward fluid migration – might arise during GCS operations if not carefully designed and managed. A systematic method for assessing geomechanical risk, therefore, would provide critical insights into the sensitivity of a given injection site to GCS operations and what mitigation strategies might be employed to ensure project safety. When planned and managed with care and appropriate risk mitigation strategies, GCS can be effectively deployed in the field, ensuring both operational safety and a reduction in carbon emissions.
A Discussion of Traditional Rock Slope Stability Analysis Methods with a Technical Evaluation of a Former Quarry Site in Jessup, Pennsylvania
Authors: Fleischer N. A. , Thomas R. D. 
Published: August 2024

ABSTRACT:
Rock slope stability is generally controlled by the orientations of the discontinuities present in a rock mass. Depending upon the orientations of these features and the orientation of the slope in question, slope failures may be possible. In this analysis, common analytical methods are discussed and presented for a site in Pennsylvania. An analysis first begins with discontinuity mapping. In this study, quarry walls were mapped, and observations of active slope failures were made. The data collected were plotted on stereonets for cluster and kinematic analyses, which identified several potential failures. Field and laboratory data were used to calculate the Factor of Safety for each predicted failure mode for each slope. Several slopes had elevated failure risks and mitigation recommendations were provided to the client. Rock slope stability analysis is a crucial step when considering development in proximity to rock slopes. It is necessary to understand the continuity of the rock mass and failure risks, and to mitigate those risks which can have devastating impacts on human lives and infrastructure. This technical paper aims to present a basic example of a complete analysis in the hope of providing a guide for fundamental rock slope stability analysis methods.

1. INTRODUCTION
Rock slope stability at a site is generally controlled by the orientations and conditions of the discontinuities (bedding planes, fractures, faults, and joints) that are present in the rock mass. These roughly planar features often form the edges of the individual blocks of rock that constitute the overall rock mass. Depending upon the orientations of these features and the orientation and dip of the slope in question, planar, wedge, and/or toppling failures may be indicated. Other factors such as the presence of groundwater, vegetation, ice, surcharge loads, seismicity, along with the geomechanical properties of the rock can also greatly affect the stability of rock slopes.

2. BASIC FIELD METHODS
To understand the fabric of the rock mass and determine the orientations of the discontinuities present throughout, a geologist or geotechnical engineer should visit the site of the proposed or existing rock slope to complete a thorough reconnaissance of the slope(s) in question. The reconnaissance should involve a systematic evaluation of rock slope conditions including detailed rock discontinuity mapping, observation, examinations of the presence of groundwater and photo-documentation of key rock slope features.
Deep Learning for S-Wave Arrival Time Picking in Acoustic Emission Source Location Analysis
Authors: Xiong Q. , Johnson E. K. , Wu C. S. , Hampton J. C. 
Published: August 2024

ABSTRACT:
Traditional laboratory acoustic emission (AE) source location analysis predominantly relies on P-wave arrival times, limiting the number of locatable sources due to the requirement of four signals for solving four unknowns. This paper explores the feasibility of incorporating S-wave arrival times, which are often otherwise discarded, into source location analysis to reduce the fundamental requirement from four to two signals. We employ a U-Net deep learning model to pick S-wave arrival times on AE signals, trained using theoretical calculations based on P-wave and S-wave velocities. Despite only achieving an accuracy of 29.6% on the testing dataset, the model shows promising improvement towards the desired shape after only 100 epochs of training. Potential approaches for improvement, such as integrating error distributions into the analysis and employing a training→prediction→and manual picking cycle, are discussed. These findings suggest pathways for future work to enhance AE source location analysis through deep learning techniques, potentially unlocking new insights into rock fracture processes in laboratory settings.

1. INTRODUCTION
Traditional laboratory acoustic emission (AE) source location analysis uses primarily P-wave arrival times for solving source locations [1-7] with a limited number of studies using S-wave arrival times. In the mathematical inverse process, the P-wave arrival times of AE signals and the coordinates of the sensor array are inputs to an optimization function. This optimization function is based on the time delay of wave propagation from source to sensor (Fig. 1(a)) and has four unknowns, i.e., three spatial coordinates and one source onset time. The source locations produced by the mathematical inverse process are also refined based on the physical principle [8] or mathematical (i.e., error or residual) features [9-11]. Upon this conventionally practiced procedure, at least four signals must be involved to solve the four unknowns [12]. Because energy releases of rock fractures are scale-invariant [13, 14], i.e., its frequency-magnitude distribution obeys the power law, sources with low magnitude that only trigger a few signal recordings are exponentially more prominent than those of greater magnitude. This leads to the number of locatable sources being one to three orders of magnitude lower than the total signals [15] with only a small percentage being used for source location [12, 16]. A majority of recorded signals will be discarded from the catalog and will not be considered in the subsequent advanced AE data analyses [17-21].
A Novel Evaluation Method of Double Sweet Spots in Shale Oil Reservoirs: A Case Study
Authors: Ji Pengcheng , Zhu Haiyan , Zhang Zhaopeng , He Xiao , She Chaoyi , Zheng Majia , Song Junbei , Wang Dajiang , Li Yuanzhao 
Published: August 2024

ABSTRACT:
This paper mainly studied the effects of eight parameters including Young's modulus, formation brittleness, internal friction angle, fracture energy, fracture toughness, porosity, permeability, and clay content on the double sweet spots of shale oil reservoirs. We calculated the double sweet spot indexes comprehensively. Further, the double sweet spot index profiles were imported into the Petrel software to obtain the correlation diagram of the double sweet spot index versus the well depth for a single-well and the three-dimensional model of the double sweet spots in the target block. Double sweet spot evaluation was conducted on shale oil reservoirs in Jiyang Depression. The results show that the double sweet spot layers of FY1-X well are located at the depth of 4034∼4160m and 4556∼4686m. The double sweet spot layers of well FY1-Y are located at 4883∼5043m, 5121∼5280m, and 5394∼5717m depth. The double sweet spot index of this block is between 0 and 1.41. In the middle of the block, the double sweet spot index is almost 0, while in the southwest and northeast of the block, the double sweet spot index is greater than 1, which is considered as a double sweet spot area.

1. INTRODUCION
Shale oil refers to thermogenic petroleum resources occurring in shale formation mainly in free state, supplemented by adsorbed state and dissolved state. It includes the oil in the pores and fractures of shale, as well as the oil resources in the adjacent layers and interlayers of tight carbonate rocks or clastic rocks in shale formations. (Zhang et al., 2012) The technical recoverable resources of continental shale oil in China are 4.352 billion tons, ranking third in the world. Shale oil resources have become the focus and hot spot in current petroleum exploration and development research. Shale oil sweet spot refers to the relatively rich area of shale oil that can be extracted under current technical conditions. The evaluation of shale oil double sweet spots is of great help to the exploitation of shale oil resources. The efficient development of paleogene shale oil in Jiyang Depression of Bohai Bay is a major strategic measure to ensure national energy security. However, the high reservoir heterogeneity of shale oil in Jiyang Depression and complex distribution of favorable properties results in low recovery efficiency and reservoir productivity without design optimization of fracturing and construction parameters. Therefore, a dual-sweet spot evaluation model suitable for shale oil reservoir is established to provide strong support for efficient development of shale oil and optimization of fracturing construction parameters.
Numerical Modeling to Investigate the Influence of Jointing on Production Blast Fragmentation
Authors: Dare-Bryan P. C. 
Published: August 2024

ABSTRACT:
Blasthole pattern selection is often decided without any evaluation of the structure of the rock mass to be blasted. This is in part due to production constraints that can determine the position of a given blast in the pit, thereby making it difficult to correctly accommodate the rock structure in the pattern orientation. An improved understanding of the influence of blasthole pattern in relation to the jointing in the bench could aid blast design selection to achieve the required fragmentation. Numerical modelling using a hybrid finite/discrete element program coupled with a non-ideal detonation model was conducted to evaluate different orientations of a single joint set, and the influence of the blasthole spacing-to-burden (SB) ratio within different configurations of two joint sets. A comparison of the particle size distribution curves for the range of blast deigns and rock masses modelled highlighted the general trends that: wide jointing produces finer fragmentation than tighter jointing; wider SB ratios produce finer fragmentation in square jointing; and an equilateral SB ratio produces finer fragmentation in angled jointing.

1. INTRODUCTION
The aim of this study was to use numerical modelling to undertake an analysis of the influence of rock structure on fragmentation. While rock structure includes, folding, faulting, bedding planes and joint sets, for this study only jointing is investigated. However, even within jointing there can be a significant variation in how they present in the rock mass, for example in the top image of Figure 1, there are consistently spaced joint sets, while in the bottom image there are abrupt changes in the joint spacing and resulting in-situ block sizes.
Previous studies into the influence of rock structure and discontinuities have tended to be conducted in the laboratory. The detailed work by Fornery et al., (1983) investigated the influence of discontinuities on the transmission of blast induce stress waves, highlighting the resulting complex wave patterns. A considerable amount of work has been undertaken by researchers in India, constructing laboratory scaled benches from slabs of limestone bonded together with plaster of paris. Bhandari (1983) conducted a series of single blasthole tests with vertical and sub-vertical joint sets orientated parallel and perpendicular to the free face (Figure 2) and found that jointing perpendicular to the face produced excessive backbreak, while parallel jointing caused poor toe breakage.
Automation of Underground Void and Support Deformation Monitoring – Effective Decision-Making Data and Tools Without the Penalty in Time and Effort
Authors: Franke J. , Gonzalez C. 
Published: August 2024

ABSTRACT:
Despite the potential of Light Detection and Ranging (LiDAR) technology for tracking underground mining voids, its adoption has been slow because associated conventional data processing is excessively time consuming, and requires training, upskilling, and devotion by geotechnical engineers. This often becomes a bottleneck to bringing this otherwise highly advantageous method into use.
Our paper introduces a new solution of fully automated LiDAR point cloud data processing dedicated to void deformation tracking that not only enables geotechnical engineers to avoid having to learn unrelated skills, but also provides immediate output of sophisticated reporting deliverables not available elsewhere. This opens up the opportunity to monitor many more excavation volumes at a higher frequency and gain much better insights than is possible with conventional manual processing tools and methodology.
Critically, automatically generated 3D files for localized deformation assessment as well as automatically generated summary reports presenting key deformation tracking analysis outcomes to decision makers facilitate the detection and understanding of
• In situ support system capacity and capacity degradation
• Ground support behavior for dynamic conditions and squeezing ground
• Cost efficiency of ground support

1. INTRODUCTION
The introduction of LiDAR technology allows a quantitative assessment across the entire excavation volume and its rock surface by collecting a full three-dimensional (3D) image of the entirety of an excavation such as an underground drive, decline, stope or more generally a tunnel as also a core feature for civil engineering. Comparisons between epochs of complete 3D data coverage allows for change detection over time that doesn't feature otherwise typical omissions.
Such omissions are a fundamental flaw of single-point measurement systems including bolt-mounted laser sensors, extensometers, or wall-mounted prisms surveyed using total stations. Point-wise systems are functional mature technologies and accurate if used correctly, but they will never provide a representative measure of underground drive or tunnel deformation. This is because depending on how many single-point sensors are in use, which will never match the density of a LiDAR point cloud, they inevitably miss at least the worst, if not all deformations actually occurring in-situ. Fig. 1 illustrates this issue.
Mechanical Stability Analysis of Fracture-Cavity Carbonate Gas Storage
Authors: Tang Huiying , Zheng Xin , Wang Xiaoping , Zhao Zihan , Chen Yuye , Zhao Yulong , Zhang Liehui 
Published: August 2024

ABSTRACT:
The Chinese Laoweng Chang gas storage is developed from a typical depleted fractured-cavity carbonate gas reservoir. Due to the fast injection and production rates in gas storage period, the reservoir rocks, the caprock, the faults and the base may all suffer the ricks of failure. In this paper, the importance of cavities on stress distribution and failure in reservoir rock is emphasized. First, the influence of cavities on stress and failure risks is analyzed with numerical models. The analytical solutions for stress distribution around cavity is derived to be used for reservoir scale problems. The practical geological and geomechanical models of Laoweng Chang gas storage are used to analyze the mechanical risks of different regions. The stress evolution of each grid during production and injection processes is calculated with finite element method by one-way fluid-solid coupling. The calculated stresses of each grid in reservoir rock are considered as boundary conditions to obtain the stress distribution around cavities. Mohr-Coulomb criterion and tensile failure criterion are then used to judge the shearing and tensile failures. The results indicate that the low permeable caprock and base are less susceptible to failure. The existence of cavities increases the risks of both tensile and shearing failure in the reservoir rock. However, the failure of fault is the still dominate the mechanical stability of the gas storage. This work provides an effective method for considering the influence of cavities on reservoir rock failure in practical analysis.

1. INTRODUCTION
The underground gas storage, as a type of "artificial gas reservoir," serves as an effective means to ensure gas supply security and balance natural gas supply and demand. These storage facilities operate through multi-cycle high-speed injection and production processes, featuring injection and production rates that surpass those of natural gas reservoirs by 20-30 times, thereby exacerbating the risks associated with gas leakage and water intrusion. The occurrence of a leakage accident could result in irreversible economic losses. Therefore, studying the changes in in-situ stress during the operation of gas storage and conducting mechanical integrity assessments are particularly important (Jia et al., 2020; Verdon et al., 2013; Li et al., 2023). The Laoweng Chang gas storage in southwest China is a typical fracture-cavity carbonate gas storage. The stress distributions are significantly influenced by cavities and other medium spaces (natural fractures and rock matrix), posing greater challenges in characterization compared to conventional porous gas storage (Zhang et al., 2019).